US1137835A - Briquet for use in zinc-furnaces. - Google Patents

Description

. weight of zinc ore crushed to the usual de- GEORGE s. nnooxs, or Daron, iLLmoIs, ASSIG'lNOB, TO THE NEW J'ERsnY zinc COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

- BRIQUET FOR usn IN ZINC-FURNACES.

NO Drawing.

To all whom it may concern:

Be .it known that I, GEORGE S. BROOKS, a citizen of the United States, residing at Depue, in the county of Bureau and State of Illinois, have invented a certain new and useful Briquet for Use in Zinc-Furnaces, of which the following is a description.

The briquet is composed of four parts by gree of fineness; one part of more finely powdered ore, or in lieu thereof, one part of commercial zinc oxid, which is in the form of powder; one and one half parts of coal of the usual grade of fineness; and a sufiicient quantity of common salt (sodium chlorid) dissolved in water to form a thick plastic mixture of the several ingredients, the amount of. salt solution which I have heretofore used being approximately onehalf of one per cent, in weight of the amount of ore in the mixture. v

The ingredients are thoroughly mixed 111 3, pug mill, anddelivered therefrom either 1n a loose mass or as a long continuous slug of a cross section approximating in shape that of the retort in which the briquets are to be used. If the material is delivered from the pug mill in a loose mass it is formed into briquets of the desired shape in a suitable press, while if delivered from the pug mill in the form of a continuous slug such slug is cut into briquets of the desired length. In my commercial practice of the invention at the present time I form the material into briquets (in the one way or the other) approximately 7% inches in diameter, which is slightly 'less than the internal diameter of the cylindrical retorts in which they are used, and about 7 inches in length, although their length may be varied as desired, and their diameter will always be made to approximate that of the retorts in which they are to be used. Where the briquets are cut from a continuous slug delivered from the pug mill I preferably place such briquets in a suitable place and subject them to pressure to true them up to form. Where the material is delivered from the plug mill in a loose mass and the briquets originally formed in a press, the same result is of course accomplished. Under my present practice I subject the briquets in either case to a pressure of approximately 90 pounds per square inch, but by increasing the pressure to which the briquet is subjected the Specification of Letters Patent.

Patented May 4, 1915..

Application filed November 28, 1913. Serial No. 803,432. r

time and temperature required for the subsequent drying of the briquet maybe correspondingly reduced.

After the briquets are formed in one or the other of the ways above described they are placed in a kiln and slowly dried at a moderate temperature, my present practice being to leave them in the kiln about 24: hours at a temperature of about 220 degrees Fahr. The result of this drying operation is that the salt is brought toward the surface of the briquet, and forms a hard crust or shell entirely inclosing it. This inclosing crust or shell, containing a large amount of salt, serves two purposes: In the first place, it forms a protecting shell or coating for the briquet, Which materially strengthens it and enables it to be handled under the ordinary conditions attending the commercial use of powder.

The finished briquets are charged into the retorts of the furnace with a suitable charging tool, that which I have employed being a semi-cylindrical trough or chute of sufiicient length to contain enough briquets to approximately jfill the length of the retort, so that one of these charging tools may be filled with a supply of briquets and then applied to the mouth of the retort, and the entire charge of briquets be pushed bodily into the retort. The briquets are preferably made of such length, relative to the length of the retorts in which they are to be used, thata given number of them will not quite fill the retort lengthwise, but leave room in the outer end of the retort for the introduction of a small quantity of coal. ,In my ractice at the present time, with 50-inch retorts I form the briquets approximately 7 inches in length and charge six of them into .each retort, but this relation of the length of the charge of briquets to thetotal length of the retort may be varied as desired or found briquets of relatively short lengths, and charging a considerable number of them into each retort, rather than having them of greater length and less number, is to accommodate them to any bending or warping of the retort, and the briquets are also made of sufiiciently less diameter than the internal diameterof the retorts for the same pur ose.

The practical advantages obtained rom tlieuse of my novel briquets are as follows: In the first place, a retort may be charged with from 15 to 20% more ore, in the compact form of the briquets than is possible where the ore and coal are introduced into the retort in the form of a loose mixture; and thecapacity of a furnace of given size for the reception of ore is therefore correspondingly iijgreased. In the second place, the quantity ofglglue powder produced is reduced approximately one-half by reason of the presence of the salt in the mixture and of the enforced passage of all of the fumes produced bydistillation through the shell or coating of high salt content surrounding and inclosing the ore within the briquet; and as this blue powder has a high zinc content and must be re-distilled to save such zinc content, the amount. of material thus requiring re-treatment is reduced one-half.

For instance, in a furnace having five hori- J zontal rows of retorts, the quantity of blue powder heretofore produced at each operation of the furnace has been such that the two upper rows of retorts have been required for its accommodation at the succeeding operation, so that at each operation of the furnace two-fifths of the retorts of the furnace have been required for the blue A powder, and only three-fifths of them have been available for fresh ore. By the use of my novel briquets, and the consequent reduction of the production of blue powder by one-half, one row of retorts suflices for the accommodation of the blue powder at each operation, and four rows may be charged with fresh ore. The capacity of such a furnace for the reception of fresh ore is thus increased 33%%. This increased capacity, plus the increased capacity of from 15 to 20% due to the compact forms in which the mixture is introduced into the retorts in the form of briquets as compared with the old practice of introducing it in the form of a'loose mixture, increases the capacity of such a furnace, for the reception of fresh orev at each charging, approximately 50%, with correspondingly advantageous results.

Instead of providing one part of finely powdered ore, or the same amount of commercial zinc oxid, in the charging mixture, fairly satisfactory results may be obtained by finely pulverizing part of the coalsay one-halfemployed in the mixture, the necessity or desideratum seeming to be that the mixture shall contain a suflicient amount my novel briquets are formed shall be composed in art of ore and coal of the usual degree of fineness I means that they shall be within thelimits, commonly employed in commercial practice, which for purposes of illustration may be said to range from a maximum of four millimeters to a minimum of one and one-half millimeters, referring to the sizes of the openings in the screens by which the materials are graded. Where I specify that the mixture shall include, as an additional element or factor, a portion of more finely powdered material, such as ore, coal or commercial zinc oxid, I mean that such additional material shall be reduced to a very considerably greater degree of fineness than the ore and coal of the usual degree of fineness. In practice'I employ additional material of such character reduced' to a degree of fineness which will permit it to pass through a screen having one-fourth millimeter openings, or a screen commonly known as a hundred mesh screen, but while thls degree of fineness is satisfactory a reduction of the material to a still greater degree of fineness would not only be unobjectionable but advantageous, since the more completely the interstices between the comparatively large particles of ore and coal are filled by the more finely pulverized material the better the results obtained.

I am aware that it has been known that the addition of a percentage of dry saltto the ore and coal forming the charging mixture would produce improved results, increasing the amount of spelter and reducing the amount of blue powder, and that it has beeii the practice in some instances to mix a percentage of dry salt with the ore and coal for thispurpose, but when salt is em- 11o ployed for such purpose in this manner it is not brought into such intimate association with the ore as where a salt solution is employed to form a plastic mixture of the ore and coal, and the latter formed into briquets under pressure, in addition to which no inclosing shell or filter of material having a high salt content is formed and a considerable part of the fumes driven from the ore in the process of distillation escape without having been brought into intimate contact with the salt, and the result has been that the addition of salt to the; charging mixture has not heretofore produced anything like the improved results attained by my invention.

I am of course aware that it is not broadly new to charge the ore-bearing mixture into retorts of a zinc-distillation furnace in the form of briquets, but I am not aware that it has heretofore been practised or proposed to 130 nae-asst form briquets of any such mixture as that of which my novel briquets are composed, or to produce bri uets having the essential chars acteristics o 'my novel briquets. I

Having thus fully described my invention, I claim:

1. A briquet forzinc furnaces, composed of zinc ore and coal surrounded by and inclosed within a protecting shell or coating containing a large percentage of common salt; substantially as described.

2. A briquet for zinc furnaces, composed of zinc ore and coal of the usual grades of fineness, and an additional quantity of more finely powdered material, suchas ore, coal or zinc oxid, all inclosed within a protecting shell or coating containing a large percentage of common salt; substantially as described.

3. A briquet for zinc furnaces, composed of approximately four parts of ore of. the usualgrade of fineness, one part of more timely powdered material such as ore, coal .or commercial zinc oxld and from one to one 4. The herein-described method of pro- 7 ducing briquets for zinc furnaces, consisting in forming a plast1c mixture com osed of ore and coal of the usual grades 0 fineness, an additional quantity of more finely &

powdered material, such as ore, coal or commercial zinc end, and a sufiicient quantity of salt solution to form a plastic mixture of the several ingredients, mixing said ingredients together to form such plastic mixture, forming a briquet of such mixture under pressure, and then slowly drying the'briquet to bring its salt content toward its surface and cause it to form a protecting shell or coating inclosing the bnquet, substantially as described.

5. The herein-described method of producing briquets for zinc furnaces, consisting in formin a plastic mixture com osed of ore and coa of the usual grades 0 fineness, an additional quantity of more finely mg and pressing such mixture into the form of a briquet'approximately-conforming in cross section to the interior of the retort in which the briquet is to b used, and then slowly drying the briquet tobring its salt 1 content to its surface and causing it to] form a protecting shell or coating inclosingthe briquet; substantially as described,

, enoaen s. anooxis.

Witnesses:

D. 0. Wear, R. H. Morrison.