US2120217A - Ore flotation - Google Patents

Description

Patented June 7, 1938 UNITED STATES- PATENT OFFICE No Drawing. Application December 18, 1937, Serial No. 180,639

45C'laims.

My invention relates to the separation of mineral constituents of ores by flotation and related processes such as agglomeration.

The froth flotation of sulphide ores has reached a fairly high stage of development and is successfully practiced today with the use of various agents, particularly the xanthates. The concentration of the mineral values in the non-sulphide ores is still a major problem so far as flotation is concerned although, in the past few years, some new flotation agents have been developed which are somewhat efiective in this field.

My invention involves the utilization of new flotation agents which are highly eifectlve in the froth flotation of both sulphide and non-sulphide ores and permit the production of relatively pure concentrates with a high percentage of recovery of desired mineral values.

My invention is also concerned with modifying .the surface characteristics of the ore to permit the separation of constituents thereof by the wellknown agglomeration or granulation method, of which the Cattermole and Murex processes are illustrative, wherein the ore particles are selectively oiled and wherein the separation is effected by tabling as, for example, on a Wilfley table.

One object of my invention is, accordingly, the provision of a new class of reagents which are highly effective in flotation and agglomeration processes.

Another object is the provision of improved flotation frothing and foaming agents which will, in general, perform and function in either acid or alkaline media.

A further object is the provision of a flotation process which may be employed in the flotation of non-sulphide ores.

Still another object of my invention is the provision of novel procedures for effectively separating mineral values from gangue materials associated therewith in ores and the like by froth flotation and agglomeration procedures.

Still another object of my invention relates to effectively separating soluble salts from each other by either froth flotation or agglomeration methods.

Other objects and features of the invention will become apparent as the description proceeds.

In froth flotation one constituent of an ore is selectively modified by the reagents added. These reagents may modify the mineral surface by chemical action or adsorption or both or may modify the interfacial relations with the liquid. In most cases, it is the function of flotation reagents to so modify interfacial relationships that the mineral particles to be floated are water repellent. Another function of flotation reagents is to produce a froth in which the selectively modified mineral will be included.

In agglomeration or granulation methods of separation, which methods I include within the scope of the term flotation", the selectively modified mineral-liquid interface is wetted with an oleaginous substance to produce or increase water repellency and" the water repellent oil particles are then separated by mechanical means such as a conventional ore dressing table. In this type of separation, the frothing element necessary in froth flotation procedures need not be present. I have found, however, that it is sometimes advantageous to separate selectively oiled particles by froth flotation and this may be readily done in most cases by the addition of a frothing agent if the particles are not too large. It will be seen, therefore, that the initial steps in agglomeration and flotation processes .are fundamentally the same, namely, the production of a selectively modified interfacial relationship between the minerals and the liquid surrounding them, the only difl'erence being in the particular method employed for effecting the actual-separation of the mineral particles whose surfaces have been modified. a

In my Patent No. 1,917,250, I have disclosed a class of chemical substances which I have found can be used with satisfaction in theflotation of ores and minerals. The chemical substances disclosed in said patent have been described as being possessed of certain groupings which impart to the resulting molecule emulsifying, frothing, penetrating, and, in general, surface modifying properties whereby they may be used for various purposes. In said patent, I have shownsaid chemical substances to have particular utility as emulsifying agents and as addition agents in the manufacture of margarine, to which latter product they impart the property of substantial decrease in its spattering behavior when it is heated in an open pan. I refer those skilled in the art not only to my aforementioned patent but also to related Patents Nos. 1,917,251; 1,917,252; 1,917,255; 1,917,256; 1,917,257; 1,917,258; 1,917,259f and 1,917,260, for a more complete discussion of the characteristics of these substances and representative processes for preparing them.

In general, the classes of substances which I have discovered can be effectively employed as flotation agents in accordance with my present invention are characterized by the presence of both lipophile and hydrophile groups in the same molecule in a state of "balance". The important characteristics which distinguish the compounds which I employ herein are intimately related to the role which the substances play in the present invention. They are all either freely soluble in aqueous media or dispersible therein. Many of them are also rather freely dispersible in oleaginous media due to the dual character of the molecule, namely, the presence therein of both lipophile and hydrophile groups.

It will be understood that I employ the term hydrophile group" to include groups which possess affinity for water and aqueous media. As examples of such groups may be mentioned the following: hydroxy, sulphate, sulphonic, phosphate,-pyrophosphate, tetraphosphate, lower molecular weight sulpho-carboxylic acids such as sulpho-acetates, sulpho-propionates, etc., and quaternary ammonium or other hydrophilic nitrogenous or non-nitrogenous groups.

Contrasting'ly, the lipophile group is a group having a definite affinity for oils and fats and comprises, for example, either an alkyl, aralkyl, aryl, ether or ester group. The lipophile group possesses predominantly hydrocarbon characteristics and, in general, is derived from fats, oils, waxes, mineral oils, other hydrocarbons and the like.

The lipophile group with its marked amnity for oils and fats generally causes the molecule of which it is a part to orientate itself so that the lipophile group is in relatively closer proximity to the oil medium or phase as contrasted with the aqueous medium in oleaginous-aqueous emulsions.

For my present purposes, namely, for ore separation treatments, the chemical substances which I employ must possess sumcient lipophile mass and quality in order properly to ofiset and "balance the hydrophile group. Anexcess of either lipophile characteristics or hydrophile characteristics is undesirable because the substance then tends to become either predominantly lipophilic or predominantly hydrophilic and in neither case will the most satisfactory results attend the use thereof in ore separation processes. The so-called balance of' the two groups, namely, the lipophile and the hydrophile groups, in the molecule may be determined empirically by means of a margarine frying test as described in my prior Patent No. 1,917,250. However, in most cases, those skilled in the art will be able to select substances coming within the class suitable for my present purposes from merely an inspection of the molecule of the compound itself.

In general, the lipophile or non-polar group of my compounds should contain at least eight carbon atoms, although, in some specific cases, compounds having as low as four carbon atoms in the lipophile group are of utility for special purposes, this being dependent, in part, upon the specific character of the lipophile group present in the molecule, as well as upon the location of the two groups in the molecule. As a general rule, the hydrophile and lipophile groups should preferably be at the ends or extremities of the molecule as, for example, in the case of palmityl sodium sulphate wherein the palmityl group or, in other words, the lipophile group, is present at one end of the molecule and the sulphate or bydrophile group is present at the other end of the molecule.

Among the compounds the use of which for ore separation purposes falls within the scope of my invention are organic chemical substances having balanced lipophile and hydrophile groups, the lipophile group containing at least eight carbon atoms and the hydrophile group comprising a radical selected from the class consisting of oxygenated sulphur and oxygenated phosphorus inorganic acid radicals. One sub-class thereof which I have found to be particularly useful for the separation of mineral values from associated gangue material is the higher molecular weight alkyl sulphates and sulphonates such as heptyl sulphate, octyl sulphate, nonyl sulphate, decyl sulphate, dodecyl or lauryl sulphate, myristyl sul phate, cetyl sulphate, oleyl sulphate, ricinoleyl sulphate, linoleyl sulphate, palmitoleyl sulphate, stearyl sulphate, ceryl sulphate, myricyl sulphate, mellssyl sulphate, branched chain higher alcohol sulphates including the sulphates of branched chain octyl, decyl, dodecyl, tetradecyl, hexadecyl and octadecyl aliphatic alcohols as, for example, 2-ethyl hexanol-l, 2-n butyl octanol-l, 3-ethylhexanol-l, and the like, preferably employed in the form of their alkali metal salts, by which I include not only the sodium and potassium salts but also the ammonium salts. In general, the sulphates of the normal straight-chain saturated and unsaturated primary aliphatic alcohols having between 8 and 18 carbon atoms are most satisfactory. The alcohols from which these sulphates are prepared may be produced in any suitable manner as, for example, by the reduction of the corresponding fatty esters in accordance with the Bouveault-Blanc method or, alternatively, by the reduction or catalytic reduction with hydrogen of natural or hydrogenated animal or vegetable fats and oils in accordance with well known practices. Again, the alcohols may be derived from synthetic processes such as by the oxidation of hydrocarbons or may be prepared by saponification of waxes and the like. Alternatively, they may be prepared by reduction of aldehydes or'by the Grignard reaction. Still other methods known in the literature may be employed if thought desirable or expedient. It is likewise apparent that mixtures of the foregoing or other alcohols may be sulphated or sulphonated and employed as flotation or ore-treating agents in accordance with the teachings of my invention as, for example, the mixture of alcohols resulting from the hydrogenation of coconut oil or the free fatty acids of coconut oil. Lauryl alcohol comprises about 60% of the total alcohol mixture, the remaining alcohols running from C6 to C18. (See German Patents D 56471 IV/ of August 30, 1928, and D 56488 IV/l20 of September 4, 1928, for reduction with hydrogen of oils and fats and free fatty acids to produce alcohols.) Again, mixtures of alcohols such as are present in the so-called sperm-oil alcohols, as well as those present in wool fat, may also be sulphated or sulphonated and employed in ore-treating operations in accordance with my invention. Indeed, these higher molecular weight alcohols are generally, if, indeed, not almost invariably, offered on the market in the form of mixtures of different alcohols. If desired for any specific purpose, special fractions which predominate in a certain particular higher molecular weight alcohol may be utilized or, if so desired, the sulphates or sulphonates may be prepared from a single, substantially pure alcohol.

As I have indicated, I may utilize the sulphonates of the higher molecular weight alcohols as distinguished from the sulphates thereof. In

other words, I may employ such compounds as octyl sulphonic acid, decyl sulphonic acid, lauryl sulphonic acid, cetyl sulphonic acid, and, in general, the sulphonic acid derivatives corresponding to the above-mentioned sulphates, preferably in the form of their alkali metal or ammonium salts.

The sulphates and sulphonates described above may be represented by the general formula wherein R is a radical containing a hydrocarbon chain of at least eight carbon atoms, X is a sulphuric or sulphonic group present on the extremity of the radical represented by R, and Y is the radical of a salt-forming compound. In a more specific aspect of my invention, B. may represent the residue of a normal primary alcohol containing at least eight carbon atoms.

In a still more specific aspect of this phase of my invention, the sulphates may be represented by the general formula wherein R represents the residue of a normal primary alcohol containing from 8 to 18 carbon atoms, and Y represents the residue of a salt-forming compound such as sodium.

Another sub-class of compounds useful for flotation purposes are those compounds which correspond to the higher alkyl sulphates and sulphonates described above but wherein the hydrophile group comprises oxygenated phosphorus instead of oxygenated sulphur. Among these compounds may be mentioned lauryl phosphate, palmityl phosphate, sodium palmityl phosphate, stearyl phosphate, oleyl phosphate, calcium palmityl phosphate, monocholesteryl dihydrogen orthophosphate, dicholesteryl hydrogen orthophosphate, ceryl dihydrogen orthophosphate, melissyl phosphate, melissyl calcium phosphate, dipalmityl sodium orthophosphate, and the like. As in the case of the sulphates and sulphonates described previously, it is generally preferred to employ the oxygenated phosphorus derivatives in the form of their alkali or. ammonium salts.

A further sub-class of compounds, useful for ore separation processes, are compounds having balanced lipophile and hydrophile groups and comprising derivatives of polyhydroxy substances through which are linked lipophile and hydrophile radicals. In general, these compounds are relatively high molecular weight aliphatic or fatty ethers and esters of polyhydroxy substances wherein a hydrophile group, such as an oxygenated inorganic acid radical, is attached to the polyhydroxy nucleus. More specifically, these compounds may take the form of higher fatty acid esters of aliphatic polyhydric alcohols wherein the hydrogen of at least one of the remaining hydroxy groups of the polyhydric alcohol is replaced by a sulphate, a lower molecular weight sulpho-carboxylic acid or a phosphate radical. Among such compounds may be mentioned, by way of illustration, monostearin sodium sulphoacetate, mono-oleic acid ester of diethylene glycol sulphoacetate, monostearic acid ester of diethylene glycol sodium sulpho-acetate, dodecyl diethylene glycol ether sulphate (monoethanolamine salt), stearyl diethylene glycol dihydrogen orthophosphate, lauryl diethylene glycol ammonium sulphate, monolauryl sulphoacetate, sulphates of ethers of diethylene glycol sulphate (neutralized with sodium, potassium,

ammonium or the like) mixed coconut oil fatty acid mono-esters or mono-oleic acid ester of glycerol mono-sulphate (neutralized as indicated), sodium salt of the sulphate of diethylene glycol monobutyl ether, ammonium salt of oleyl and stearyl diethylene glycol, sodium salt of mono-ncaprylil diethylene glycol sulphate, monoethanolamine salt of the sulphate of diethylene glycol monobutyl ether, mono-olein disulphate, sulphate of the mono-oleic acid ester of diglycerol, sulphates of mono-fatty acid esters of glycerol such as monostearin mono-sulphate, and the like. For an even more complete disclosureof compounds of this type, reference may be had to my Patents No. 2,023,387, issued December 3, 1935 and No. 2,026,785, issued January 7, 1936, and to my copending application, Serial No. 627,096, filed July 30, 1932.

Other compounds having utility for my purposes, and possessing balanced lipophile and hydrophile groups, are the lower molecular weight lauryl sulphoacetate, lauryl sulpho-propionate,

myristyl sulphoacetate, cetyl sulphoacetate, choles teryl sulphoacetate, oleyl sulphoacetate, stearyl sulphoacetate, ricinoieyl sulphoacetate, linoleyl sulphoacetate, p-ethyl-hexyl sulphoacetate, and the like, preferably in the form of their alkali metal, ammonium, or organic amine, such as ethanolamine, salts.

A further subclass of compounds having utility in ore separating treatments, and having balanced lipophile and hydrophile groups, are certain derivatives of polyhydroxy substances or polyhydroxycarboxylic acids including, for example, such compounds as monostearic acid ester of dextro'se, mono-stearic acid ester of sucrose, mannitol mono-palmitate, stearyl tartaric acid, mucic acid mono-palmitate, stearyl malic acid, digitonincholesteride, and the like. For a further disclosure of such compounds, reference may be had to my Patent No. 1,917,257, above mentioned, and to my Patent No. 2,025,984, issued December 3, 1935.

Still another group of reagents which I have I found effective for my present purposes, and falling within the class of organic chemical substances having balanced lipophile and hydrophile groups with a lipophile group having at least eight carbon atoms, are organic nitrogenous substances. These compounds include organic nitrogen-containing haloides having a hydrocarbon group of at least eight and preferably at least twelve carbon atoms and, more specifically, aliphatic derivatives of anion-containing heterocyclic compounds such as aliphatic hydrocarbon derivatives of pyridinium halides such as pyridinium chloride or bromide. Among the specific compounds falling within this class may be mentioned, by way of illustration, cholesteryl ester of betaine hydrochloride, (carbocholesteroxy) methyl trimethylammonium chloride, cholesteryl ester of betaine hydrobromide, palmityl ester of betaine hydrochloride or hydrobromide, (carbopalmitoxy) methyl pyridinium bromide, melissyl ester of betaine hydrobromide, (carbocholesteroxy) methyl pyridinium bromide, (carbocholesteroxy) methyl dimethylphenyl ammonium .bromide, (carbocholesteroxy) methyl quinaldinium bromide, cholesteryl dimethylwithin this sub-class may be found in my Patent No. 2,023,075, issued December 3, 1935.

For the preparation of the higher aliphatic or higher fatty acid esters described hereinabove, such as monostearin sulphate, monolauric acid ester of diethylene glycol, and the like, the term "higher being employed to mean at least eight carbon atoms, the following acids may be employed as well as mixtures thereof: saturated and'unsaturated aliphatic and fatty acids including capryiic, capric, stearic acid, hydroxystearic acid, oleic acid, lauric acid, myristic acid, coconut oil mixed fatty acids, linoleic acid, ricino- .ieic acid, palmitic acid, melissic acid; and mixed higher fatty acids derived from animal and vegetable oils and fats, whether hydrogenated or not, such as cottonseed oil, corn oil, soya bean oil, sesame oil, fish oils, lard, oleo oil, and others, such as the fatty acids derived from waxes like beeswax and carnauba wax.

I have mentioned hereinabove that the sulphates, sulphonates and other oxygenated suiphur and phosphorus derivatives are preferably employed in the form of their alkali metal or ammonium salts. In certain instances, other cations may be present in place of sodium, potassium or ammonium, as, for example, calcium, magnesium, aluminum, zinc, and organic cationicfunctioning or neutralizing compounds such as the aliphatic and aromatic amines including, for example, tertiary amines, pyridine, quinaldine, alkylolamines such as mono-, diand triethanolamine and mixtures thereof, quaternary ammonium bases such as tetra-methyl and tetraethyl ammonium hydroxide, and the like.

While flotation reagents may be classified in general into frothers and collectors, this classification is not particularly useful in describing my invention since, under different conditions, these reagents may fall into one or both classiflcations. In general, reagents of the classes described hereinabove possess frothing properties in at least some degree and, in many cases, certain of these compounds may be used as frothers with the exertion of a minimum of influence on the flotation circuit other than to provide the necessary volume of froth. In other cases, the compounds function simultaneously as frothers and collectors. As an illustration, compounds of the type of lauric acid ester of diethylene glycol ammonium sulphate are highly selective collectors and may be used in conjunction with other agents without interfering with the selective properties thereof. On the other hand, lauric acid ester of diethylene glycol ammonium sulphate and similar compounds function both as frothers and collectors for the separation of such minerals as calcite and apatite from less readily floatable minerals. Again, the higher molecular weight alkyl sulphates are excellent frothing agents and, in many instances, also function as collecting agents.

As previously described, the reagents which I employ herein selectively modify the interface relationship of certain minerals so that they may be oiled and separated by either froth flotation methods or agglomeration and tabling. In some cases of agglomeration procedures, the oiling is not necessary. Where oiling is employed, it may be done simultaneously with the addition of the selectiveinterface modifying agents or the oiling may be carried on subsequently in a separate step.

Since the reagents which I employ herein possess good emulsifying and dispersing power, they may be advantageously used to prepare emulsions of petroleum oils, kerosene, vegetable and animal oils, normally solid or liquid higher fatty acids, and to prepare dispersions of other lipophilic solids such as metallic soaps and xanthates. These emulsions or suspensions are useful as collecting agents and the like in the flotation and agglomeration of minerals. I'hese emulsions may be prepared by any of the several methods known in the art. For example, the flotation agents of my invention may be admixed with a small amount of water in a mortar and then oil may be gradually added while continuously stirring or mixing until emulsiflcation is initiated. The oil may then be added more quickly until the formation of the emulsion is completed. It will be understood, of course, that the stability of the emulsion will be affected by various factors including the relative proportions of the flotation agent, water, and oil or the like, the specific type of agent and oil or the like, the pH, and the exact method of preparation. In general, the

oil-in-water type of emulsions produces superior results.

I shall now describe the manner in which the novel flotation agents may be used in the actual separation of mineral values from ores containing the same by froth flotation as well as by agglomeration methods.

Example I In the concentration of tungsten ore containing scheelite, calcite and quartz, the ore was ground to 100 mesh, the grinding being carried out preferably to keep the amount of lines as low as possible. The ore was then acidified to the extent of about 1.0 lb. of sulphuric acid per ton of pulp. 0.25 lb. of oleic acid per ton of ore and 0.25 lb. of lauric acid ester of diethylene glycol ammonium sulphate per ton of ore were added and the pulp subjected to froth flotation. The froth which contained only calcite was first removed. The acidity was then reduced to about 0.4 lb. per ton of pulp by the addition of caustic soda and the flotation was then continued. The concentrate and tailing obtained in this flotation is shown by the following table:

Weight; A per can ssa Product of on? Domain Recovery inal ore W0;

Concentrate 3. 6 65. 2 03. 6 a ng 74.9 0.04 1.2 Original 01's.... 2. 50

Example II In the treatment of a complex lead-zinc-iron sulphide ore from Utah, having the composition-lead 8.8%, zinc 9.7%, iron 28.2%, and the remainder silica and silicates, the ore was ground to pass a 60 mesh screen and was made into a pulp containing 20% solids. The pulp was then conditioned with 2.0 lbs. of sodium carbonate per ton and then subjected to froth flotation using as a reagent an aqueous emulsion containing 1.0% of lauric acid ester of diethylene glycol ammonium sulphate and 2% of corn oil. An amount of this reagent was initially added to give 0.2 lb. of the lauric acid ester of diethylene glycol ammonium sulphate per ton of ore. The

mineralized froth which formed immediately was removed as concentrate No. 1. Additional emulsion to double the original amount was then added and lifter several minutes further mineralized froth formed, this being removed as concentrate No. 2. .When no more mineral appeared in the froth, 0.2 lb. of copper sulphate per ton of ore was added and another concentrate removed which was designated as No. 3. The mineral remaining in the machine was removed as tailings. The analysis of the concentrates and tailings is shown in the following table:

l ko'rrr FLOTATIONUTAH COMPLEX Oar: Head analysis lead 8.8%--zinc 9.7%-iron 28.2%-

' Recovery Analysis percent mt Pb Zn Fe Pb Zn Fe lstconcentrate 76.2 1.0 0.5 2nd concentrate..- 1.8 00.5 L9 89 3rdconcentnte. .2 .8 60.2 80 railing .03 .08 1.0

It will thus be seen that the lead, zinc, iron and insolubles have been thoroughly separated. The lauric acid ester of diethylene glycol ammonium sulphate employed in this example may be replaced by other compounds of the types disclosed amounts as the lauric acid ester of diethylene glycol ammonium sulphate. The corn oil employed in the example may be replaced, with substantially the same results, by cottonseed oil, olive oil, palm oil and the like. Sardine oil, menhaden oil and lard oil may also be used although these are not quite so satisfactoryas the aforementioned oils. Petroleum oils of various grades give a somewhat lower selectivity than corn oil or cottonseed oil but may be preferred in certain instances because of their lower cost.

Example III In another example, involving the separation of :ilmenite from a gangue material composed of phosphate, quartz and garnet, the ore analyzed 1.8% T10: as ilmenite. The ore was ground to pass a 60 mesh screen and conditioned with 0.2 lb. sulphuric acid and 0.1 lb. of ferric ammonium sulphate per ton. The pulp, containing 20% solids, was then subjeced to froth flotation using an emulsion of 2.0% crude oil in water I containing 1% of mixed coconut oil fatty acid mono esters of glycerol sulphate neutralized with triethanolamine, an amount of the emulsion equivalent to 0.5% of oil per tonof ore being employed. The concentrate contained 37% of TiO:, representing a recovery of 94.5%.

Example IV As still another example, malachite was floated.

from a New Mexico copper ore using an aqueous emulsion containing 1% sardine oil and 1% normal decyl sodium sulphate. The ore contained 1.0% copper and produced an uncleaned concentrateanalyzing 38.2% copper.

The use of emulsions.

as described above, was effective in a slightly acid circuit on chromite ores, rutile ores, hematitc ores, and magnetite ores. In alkaline circuit, with the addition of copper sulphate, silica, limestone, barite, fluorspar. and magnesite were floated. In some cases particularly when the minerals were adapted to be freed at relatively coarse sizes, the froth flotation was effectively replaced by agglomeration or granulation and tabling. In this latter instance,

the first step of the process, namely, selective oiling, was carried out exactly as in the case of the use of emulsions for froth flotation as described I hereinabcve.

Example V An ore of rutile and apatite, containing 3.6% T10: as rutile, was ground to pass through a 20 mesh screen and conditioned in a thick pulp with an aqueous emulsion containing corn oil and mixed coconut oil mono-fatty acid esters of di-' ethylene glycol ammonium sulphate. Using 0.4 lb. of the sulphated reagent per ton and 3 lbs. of corn oil per ton, the ore was conditioned by thoroughly mixing. Water was then added to produce a pulp suitable for tabling. The results are shown in the following table:

Wt. per- T10; per- Pmd'm cent cent Table concentrates '4. l 88. 0 Table tails 95.9 4.9

As a general rule, it is preferable to add the surface modifying agent first in the very thin pulp followed by the addition of the oil and then the subsequent dilution of the pulp to the proper density for separation on the table. As illustrative of such practice, the treatment of an iron ore may be considered.

Ezample w An ore from the Lake Superior district, containing 30.2% iron, the gangue being silica, was ground to pass through a 14 mesh screen and mixed with a small amount of water, 2.0 lbs. of sulphuric acid and 1.0 lb. of the mixed coconut oil fatty acid mono esters of diethylene glycol ammonium sulphate per ton of ore. Crude mineral oil in the amount of 6 lbs. per ton was then addedand the entire mass mixed. The results, after dilution and tabling, were as follows:

Wt. pal- Fe per- Pmdm cent cent Table concentrates 51. 2 63. 2 Table tails 49. 8 8. 2

The process described in Example VI in connection with the concentration of iron ore may be used on chromite. magnetite, apatite, limestone, dolomite, magnesite and bauxite, without special care in the selection of the reagentfor the oil. In other cases, however, the selection of the flotation agent is quite critical as, for example, in the separation of sylvite and halite as they occur in Carlsbad, New Mexico. In this latter case, where agglomeration procedures are employed. the flotation agent must be soluble enough to promote oiling but mustselectively aflect the lnterfacial relationship between either the sodium chloride and the potassium chloride and the brine. Since potassium salts are, in general, moreinsoluble than sodium salts, it is my hypothesis that the flotation agent acts in this case by precipitation of a film of potassium salt. but enough of the flotation agent remains in solution to serve as an oil carrier. An agent which has produced unusually good results for the separation of halite and sylvite is mixed coconut oil fatty acid mono esters of diethylene glycol neutralized with ammonia sodium hydroxide, ethanolamines, such as triethanolamine and the like. Other neutralizing agents may be-used but the employment of such agents as indicated above has produced very satisfactory results. The process may be carried out according to several procedures to produce a mixture of brine, mineral oil and the neutralized mixed coconut oil fatty acid mono esters of diethylene glycol sulphate, the oil being selectively adsorbed by the sylvite but not coating the halite, the result being that the sylvite is formed into glomerules of such composition and size that ordinary tabling is sufficient to separate them. The concentrate will consist,'in general, of from 85% to 95% potassium chloride, the tailings containing only about 5% or less of potassium chloride. The concentrate may be either dried or otherwise treated to produce a product acceptable for agricultural pu p s Example VII As an example of the separation of halite and sylvite, an emulsion was formed of 25 lbs. of crude mineral oil, one lb. of neutralized mixed coconut oil fatty acid mono esters of diethylene glycol sulphate and enough brine made from the ore to produce a total of 100 lbs. of emulsion. This emulsion was then added to the ore, which was in the form of a relatively thin pulp of 12 to 16 mesh ore,the proportions being such that about 1% to 4 lbs. of the sulphate reagent and 10 to 15 lbs. of oil were present in about one ton of ore. The ore containing the: emulsion was agitated slowly for approximately five minutes until the sylvite agglomerated into particles of sumcient character and size to permit easy separation. The glomerules were easily observed so that it could readily be determined whether or not the product had advanced to a suitable condition for separation on the separating table. Although tabling proved very satisfactory for the separation, any other suitable method of separation commonly used in the ore dressing industries can be substituted therefor.

Example VIII In accordance with another method of separating the sylvite and halite, the crude oil was added to a very thick pulp and the sulphate reagent, previously dispersed in a small amount of water, was introduced into the pulp. By this method, the amount of the sulphate reagent was reduced to 1.6 lbs. per ton of ore. The results of a test made in this way are shown in the followingtablei I Total Wt. Percent Product K01 percent K01 mm Table concentrates 45. 2 y 85 l 95. 2 Table tails 54.8 4 0 4.8 Composite 100 40 6 100 Example IX In accordance with still another modification.

of mixed-coconut oil fatty acid mono-esters of diethylene glycol sulphate, thorough stirring being employed to produce a substantially uniform mixture. 15 lbs. of crude oil were then stirred into the mass and uniformly dispe e therein. Approximately 2000 lbs. of the brine were then incorporated and the total constituting about 2 tons was tabled. A high-grade concentrate of sylvite, averaging about 90% E01, was obtained with only about 5% KC] in the tailings. The. tails may be in part recirculated to increase the proportionate yield of KCl. The concentrate may be dried in any suitable manner as for example, in air, and may then be crushed to give an acceptable agricultural potassium chloride product.

The amount of flotation agent and all employed are not particularly critical so far as separation is concerned, but, in the interest of economy, it is apparent that no more of the reagent should be used than is sufllcient to produce satisfactory separation. It is desirable that not more than enough oil to wet the sylvite particles should be employed because the oil has a tendency to separate out on the table or other equipment used for separation and this requires periodic cleaning which can be avoided if the amount of oil is prop- 1 erly gauged.

While many oleaginous constituents may be employed, the best results appear to be obtained if a crude mineral oil, for example, is used. Gulf Coastcrude oils, for example, produce particularly good results. Ithas also been found that ii the crude oil is preliminarily treated to remove some of the voltile constituents, the amount of oil employed in the separation treatment can be decreased and, in general, somewhat better results are obtained. a

Other flotation agents with which satisfactory results have been obtained in the agglomeration to froth in saturated salt solutions makes them very valuable reagents for water-soluble salt separations by froth flotation methods and they may be used successfully, for example, in the separation of boric acid from potassium sulphate, ammonium chloride from sodium nitrate, sylvite from halite, the concentration of potassium sulphate and the separation thereof from its associated halite in the mineral langbeinite, the separation of salts of barium, lead, zirconium, and ferric iron from salts of potassium, zinc, calcium, magnesium and the like, and for other water-soluble salt separations.

In carrying out the separation of soluble salts from each other by froth flotation procedures, it is unnecessary to resort to oiling as described hereinabove. For effecting the separation, for

example, of sylvite from halite by froth flotation without oiling, according to my hypothesis an agent should be used for precipitating an insoluble potassium salt with a long chain lipophile group outward so as to make the particles water repellent. For this purpose, the alkali metal or ammonium salts of the fatty alcohol sulphates and sulphonates having from 6 to 14 carbon atoms are of utility. of unusual utility is normal octyl sodium sulphate.

Example X Total Weight KC] Product percent percent KCL'I Cleaner concentrates 42. 8 95. 6 94. 2

'Middlings 6. 8 25. 2 3. 2 Rougher concentrates- 50. 8 85. 8 98. 8 Tailings 49. 2 l. 4 l. 7 Composite 100 42. 9 lot) Since, according to my hypothesis, this flotation action would appear to depend upon the formation of an insoluble potassium salt, the method would be applicable to the separation of any mineral containing a soluble potassium salt. Thus, for example, cement dust containing 10% K20 was concentrated by froth flotation by adding 2 lbs. of sulphuric acid per ton and 1.2 lbs. of normal octyl sodium sulphate per ton. The concentrate analyzed 48.7% K20.

I have .also found that the flotation of at least many non-sulphide minerals can be inhibited by proper acid concentration. The following table, for example, shows the concentrations at which some of the common minerals are depressed when using a mixture of lauric acid ester of diethylene glycol ammonium sulphate and oleic acid as a froth flotation reagent:

H180 per ton p p Mineral Pou nda Rhodochrosite Calcite.

Scheelite; A pat ite. Hematite It will be understood that, while the flotation agents of my invention are very valuable in the flotation of non-sulphide minerals, and in this respect represent a distinct advance in the art,

being, of course, recognized that the treatment of different types of ores and minerals may require certain minor modifications and changes. However, in the light of my disclosures herein, it will be evident to those skilled in the art how to carry out my teachings and produce satisfactory separations.

As previously indicated, the concentration of the flotation agents employed is subject to considerable variation, this being dependent upon the potency of the particular agent selected, the nature of the specific ore treated, the degree or character of the separation desired, and upon other factors which are apparent to those versed in the art. In general, concentrations of about .01% up to several per cent of the agent, based upon the aqueous content of the ore mass being floated, will serve the purpose, the average case generally requiring from about .05% to 37%.

It will be appreciated that I may employ mixtures of the flotation agents described hereinabove in order to obtain novel eflects. For example, while dodecyl sodium sulphate is not quite so selective as lauric acid ester of diethylene glycol ammonium sulphate with respect to certain types of ores, mixtures of dodecyl sodium sulphate and lauric acid ester of diethylene glycol ammonium sulphate, with or without oleic acid or other similar collectors, can be used to produce a wide variety of froth textures which can be taken advantage of for the treatment of particular ores.

The novel flotation processes which I have described herein are applicable to the treatment of ores generally. Among the ores which have been treated with very good results in accordance with my invention are tungsten ores, lead-zinc-lron ores, oxidized ores such as lead carbonate, activated blende, kyanite ore, chromite ore. phosphate ores, bauxite, graphite ores, magnetite ores, the separation of silica from various types of ores,

. mica, zirkite ores, rutile ores, cassiterite ores, iron ores, kaolin, coal, and the like.

It will, of course, be understood, particularly in the light of the examples set forth hereinabove,

that the novel froth flotation and agglomeration reagents of the present invention may be employed in conjunction with one or more already known agents such as collecting agents, frothing agents, depressing agents, emulsifying agents, dispersing agents, activating agents, deactivating agents, inhibitors, and, in general, organic and inorganic conditioning agents, and the like. These agents include, among'others, mineral and vegetable oils, fuel oil, kerosene, mercaptans, xanthates, organic sulphides, hydrosulphides, carbamates, thiocarbamates, thioureas, di-thiophosphates, azo and diazo compounds, amines such as monoethanolamine, diethanolamines, triethanolamines and pyridine, alkali metal and heavy metal soaps, higher fatty acids such as oleic acid and palmitic acid, sulphonated oils and sulphonated higher fatty acids such as Turkey red oil and sulphonated oleic acid, gelatin, glue, starch, copper sulphate and other salts of copper, mercury and lead, alkali metal sulphides such, as sodium sulphide, alkalies such as sodium hydroxide, potassium hydroxide and sodium carbonate, alkali metal silicates such as sodium silicate and other agents which are commonly employed in flotation and agglomeration processes. It will also be understood, as described above, that the flotation circuit may be acid or alkaline depending on the particular ore being separated, the nature of the reagents used and the character of the separations desired. By controlling the pH of the cirruary 13, 1935.

in many cases, be very satisfactorily accom-- plished.

It will be understood that the description of my invention, although, detailed, is to be taken not in a limitative sense but only in a descriptive sense, the scope of my invention being pointed out in the appended claims.

The present application is a continuation-inpart of my prior applications, Serial No. 879,716, filed July l0, 1933 and Serial No. 55,393. flled Feb- What I claim as new and desire to Letteralfatent of the United States is:

1. In a process for concentrating non-sulfide protect by minerals by froth flotation, the step of adding to an ore pulp a proportion of an organic chemical substance having balanced lipophile and hydrophile groups, the lipophile group containing at least eight carbon atoms and the hydrophile group comprising a radical selected from the class consisting of oxygenated sulphur and oxygenated phosphorus inorganic-acid radicals, and subjecting the pulp to froth flotation.

2. In a process for concentrating non-sulfide minerals by froth flotation, the step of adding to.

an ore pulp a proportion of afatty acid and a proportion of an organic chemical substance hav ,ing balanced lipophile and hydrophile groups,

said lipophile group containing at least eight carbon atoms and the hydrophile group comprising a radical selected from the class consisting of oxygenated sulphur and oxygenated phosphorus inorganic acid radicals, and subjecting the pulp to froth flotation. I

3. In .a process for concentrating non-sulfide minerals by froth flotation, the step of adding to an ore pulp an acid in relatively high concentration and a proportion of an organic chemical substance having balanced lipophile and hydrophile groups, the lipophile groupcontaining at. least eight carbon atoms and the hydrophile group comprising a radical selected from the class consisting of oxygenated sulphur and oiwgenated phosphorus inorganic acid radicals, and subjecting the pulp to froth flotation.

4. In a. process for concentrating non-sulfide minerals by froth flotation, the step of adding to ore pulp an acid, and an organic chemical substance having balanced lipophile and hydrophile groups and having the property of foaming in an acid medium, said lipophile group containing at least eight carbon atoms and the hydrophile group comprising a radical selected from the class consisting of oxygenated sulphur and oxygenated phosphorus inorganic acid radicals.

5. In a froth flotation process for concentrating non-sulfide minerals, the step of treating a mass of pulp with an acid to produce a concenand oxygenated phosphorus inorganic acid radi-- cals.

6. In a process for concentrating non-sulfide minerals by flotation, the steps of acidifying pulp to the equivalent of at least 0.1 lb. of sulfuric acid per ton, adding oleic acid and an organic chemical substance having balanced lipophile and hydrophile groups, the lipophile group having at least eight carbon atoms and the hydrophile anomagroup comprising a radical selected from the class consisting of oxygenated sulphur and oxygenated phosphorus inorganic acid radicals, and subject- I ing the ore pulp to froth flotation.

I 7. In a process for concentrating non-sulfide minerals b'y flotation, the steps of acidifying pulp to the equivalent of at least 0.1 lb. of sulfuric acid p r ton, adding oleic acid and an organic chemical substance having balanced lipophile and hydrophile groups, having at least eight carbon atoms in the lipophile group and the hydrophile group comprising a radical selected from the class consisting of oxygenated sulphur and oxygenated phosphorus inorganic acid radicals, and subjecting theore pulp to froth flotation.

8. In a process for concentrating non-sulfide minerals by flotation, the steps of acidifying pulp to the equivalent of at least 0.1 lb. of sulfuric acid per ton, adding oleic acid and a sulfuric acidester of a higher molecular weight aliphatic alcohol, and subjecting the ore pulp to froth flotation, said ester having balanced lipophile and hydrophile groups.

9. In a froth flotation process for concentrating non-sulfide minerals, the step of treating a mass of pulp with an acid to produce a concentration equivalent to at least 0.1 lb. of sulfuric acid per ton of pulp, and adding to the pulp a proportion of free fatty acid and an organic substance having lipophile and hydrophile groups 'in a state of balance in the molecule, the lipophile group having at least eight carbon atoms and the hydrophile group comprising a radical selected from the classconsisting of oxygenated sulphur and oxygenated phosphorus inorganic acid radicals 10. In a froth flotation process for concentrating non-sulfide minerals, the step of treating a mass of pulp with an acid to produce a concentration equivalent to at least 0.1 lb. of sulfuric acid per ton of pulp, and adding to the pulp a proportion of oleic acid and an organic substance having lipophile and hydrophile groups in a state of balance in the molecule, the lipophile group having at least eight carbon atoms and the hydrophile group comprising a radical selected from the class consisting of oxygenated sulphur and oxygenated phosphorus inorganic acid radicals.

11. A method of concentrating non-sulfide minerals by froth flotation, which comprises treating a mass of pulp with an inorganic acid to produce a relatively strong concentration of acid, adding to the pulp an organic substance having lipophile and hydrophile groups in a state of balance in the molecule, the lipophile group containing at least eight carbon atoms and the hydrophile group comprising a member selected from the class consisting of oxygenated sulphur and o ygenated phosphorus inorganic acid radicals, and a relatively small amount of oleic acid, and subjecting the pulp to froth flotation.

' 12. A method of concentrating non-sulfide minerals by froth flotation, which comprises forming a pulp of an ore, incorporating with the pulp a proportion of a frother inthe form of a relatively high molecular weight fatty acid ester of a polyhydroxy substance wherein one of the hydrow groups of the polyhydroxy substance is replaced by an oxygenated inorganic acid radical,

together with a relatively small amount of a fatty 4 forming a pulp of an ore,.incorporating with the pulp'a proportion of a frother in the form of a relatively high molecularweight fatty acid ester of a polyhydroxy substance wherein one of the hydroxy groups of the polyhydroxy substance is replaced by a sulphonic acid radical. together with a relatively small amount of a fatty acid as a collector, and subjecting the pulp to froth 15. A method of' concentrating non-sulfide minerals by froth flotation, which comprises forming a pulp of an ore, incorporating with the pulp a proportion of monostearine-sulphoacetate and a relatively small proportion of a fatty acid as a collector, and subjecting the pulp to froth flotation.

16. In a process for concentrating non-sulfide materials by froth flotation, the step of adding .to an ore pulp a proportion of a chemical substance in the form of a relatively high molecular weight carboxylic acid ester of a polyhydroxy substance wherein at least one hydroxy group of the polyhydroxy substance is esterifled with an oxygenated inorganic acid radical.

1'7. In a process for concentrating non-sulfide materials by froth flotation, the step of adding to an ore pulp a proportion of a chemical substance in the form of a relatively high molecular weight carboxylic acid ester of a polyhydroxy alcohol wherein at least one hydroxy group of the polyhydroxy alcohol is esterifled with an oxygenated inorganic acid radical.

18. In a process for concentrating minerals, the step of adding to an ore pulp a proportion of a relatively high molecular weight carboxylic acid ester of a polyhydric alcohol wherein one hydroxy group of the polyhydric alcohol is esterifled with a sulphuric acid radical.

19. In a process for concentrating minerals, the step of adding to an ore pulp a proportion of a relatively high molecular weight carboxylic acid ester of a polyhydric alcohol wherein one hydroxy group of the polyhydric alcohol is esterifled with a sulphuric acid radical, said sulphuric acid radical being neutralized by an alkaline reacting substance.'

20. In a process for concentrating minerals, the step of adding to an ore pulp a proportion of a relatively high molecular weight fatty acid ester of glycol wherein one hydroxy group of the glycol is esterified with sulphuric acid.

21. In a process for concentrating minerals, the step of adding to an orepulp a proportion of a relatively high molecular weight fatty acid ester of glycol wherein one hydroxy group of the glycol is esterifled with a sulpho-fatty acid of relatively low molecular weight.

22. In the froth flotation of ores the step which comprises utilizing as a flotation agent a compound having the following general formula:

R-XY wherein R is a radical containing a hydrocarbon chain of at least 8 carbon atoms,'X is a sulfuric acid or sulfonic acid group present on the extremity of the radical represented by R, and Y is the radical of a salt-forming compound.

23. In the froth flotation of non-sulfide ores the step which comprises utilizing as a flotation non-sulfide ores in the presence agent a compound having the-following general formula:

R.-X-Y f whereinR represents the residue of a normal primary alcohol containing at least- 8 carbon atoms, X represents a sulfuric acid or sulfonic acidgroup, and Y represents the radical of a salt-forming compound.

' 24. A froth flotation process which comprises agitating and aerating an aqueous suspension of of a compound having the following general formula:

R-OSOaNa wherein R represents the residue of a normal primary alcohol having from 8 to 18 carbon atoms.

25. A froth flotation process which comprises frothing a suspension of ore in the presence of a fatty acid collecting agent and a compound having the following general formula:

. R'XY wherein R represents a radical containing a hydrocarbon group of at least 8 carbon atoms, X

represents a sulfuric acid or sulfonic acid group, and Y represents the residue of a salt-forming compound.

26. A froth flotation process which comprises agitating and aerating an aqueous suspension of non-sulfide ores in the presenceof a fatty acid collecting agent and a' compound having the following general formula:

nine carbon atoms.

28. In the process of concentrating ores by flotation, the step comprising adding to the aqueous flotation medium sodium dodecyl sulphate, and subjecting the ore to a flotation separation treatment.

29. In' the process ofconcentrating ores by flotation, the step comprising adding to the aqueous flotation medium a salt of a sulphuric acid ester of an aliphatic alcohol having'more than nine carbon atoms, and also adding a known flotation agent, and subjecting the ore to a flotation separation treatment.

30. A froth flotation processwhich comprises agitating and aerating an aqueous suspension of non-sulfide ores in the presence of a collecting agent and a water-soluble compound having the following general formula:

wherein R. represents the residue of a normal primary alcohol containing at least 8 carbon atoms, X represents a sulfuric acid or sulfonic acid group and Y represents the residue of a salt-forming compound.

31. A froth'flotation process which comprises agitating and aerating an aqueous suspension of non-sulfide ores in the'presence of a collecting agent and a water-soluble compound having the following general formula:

. R-x---Y wherein R represents the residue of a normal primary alcohol containing from 8 to 18 carbon atoms, X represents a sulfuric acid or sulfonic.

acid group and Y represents the residue of a salt-forming compound.

32. A froth flotation process which comprises agitating and aerating an aqueous suspension of non-sulfide ores in the presence of a collecting agent and a water-soluble compound having the following general formula:

R-OSOa-Y 34. A froth flotation process which comprises agitating and aerating an aqueous suspension of non-sulfide ores in the presence of a collecting agent and a water-soluble compound having the following general. formula:

R-OSOaNa wherein R represents the residue of a normal primary alcohol containing from 12 to 18 carbon atoms.

35. The process defined in claim 34 wherein the collecting agent is oleic acid.

36. A process of separating ores by froth flotation which includes subjecting a pulp of the ore to froth flotation in the presence of an organic nitrogenous substance having lipophile and hydrophile groups in a state of balance in the molecule, the lipophile group having at least eight carbon atoms.

3'7. A process of separating ores by froth flotation which includes subjecting a pulp of the ore to froth flotation in the presence of an organic nitrogenous substance having lipophile and hydrophile groups in a state of balance in the molecule, the lipophile group containing a hydrocarbon radical having at least twelve carbon atoms.

38. A process of separating ores by froth flotation which includes subjecting a pulp of the ore to froth flotation in the presence of an organic nitrogenous substance having lipophile and hydrophile groups in a state of balance in the molecule, the lipophile-group containing a straight chain aliphatic radical having at least twelve carbon atoms 39. A process of separating ores by froth flotation which includes subjecting a pulp of the ore to froth flotation in thepresence of a reagent including an organic nitrogen containing halide having a hydrocarbon group containing at least twelve carbon atoms.

40. A process of separating ore by froth flotation which includes subjecting a pulp of the ore to froth flotation in the presence of a reagent including an aliphatic hydrocarbon derivative of pyridinium bromide.

41. A process of separating ores by froth flotation which includes subjecting a pulp of the ore to froth flotation in the presence of a reagent comprising an aliphatic hydrocarbon derivative of a pyridinium halide.

42. The process of claim 41 wherein the aliphatic hydrocarbon group of the reagent contains at least twelve carbon atoms.

43. A process of separating ores by froth flotation which includes subjecting a pulp of the ore to froth flotation in the presence of a reagent comprising an aliphatic derivative of a halide of a heterocyclic compound.

44. The process of claim 43 wherein the allphatic hydrocarbon group of the reagent contains at least twelve carbon atoms.

45. In the process of concentrating ores by flotation, the step comprising adding to the flotation medium a sulphuric acid ester of a straight chain aliphatic alcohol containing at least eight carbon atoms.

BENJAMIN R. HARRIS.