CN101823738B - Method for producing light magnesium carbonate and coproducing fine calcium carbonate and water glass by chlor-alkali salt sludge - Google Patents

Abstract

The invention discloses a method for producing light magnesium carbonate and coproducing fine calcium carbonate and water glass by using chlorine salt mud.

Description

A method for producing light magnesium carbonate and co-producing fine calcium carbonate and water glass with chlor-alkali salt mud

technical field

The invention relates to a production method of magnesium carbonate and calcium carbonate, in particular to a method for producing light magnesium carbonate and co-producing fine calcium carbonate and water glass with chlor-alkali salt mud.

Background technique

Chlor-alkali salt mud comes from the pulpy discharge produced during the refining process of raw salt, and the precipitated discharge obtained after separating part of the sodium chloride from brine is sea salt mud. The main components of salt mud are magnesium oxide, calcium oxide, silicon dioxide, barium sulfate and a small amount of sodium chloride and mud. Therefore, it has potentially huge utilization value. However, at present, the salt mud of most manufacturers has not been effectively treated and utilized. It is only used for building dams and roadbed materials after dehydration, or is piled up in the factory all year round. Or directly discharged into nearby rivers, lakes and seas, causing serious environmental pollution.

Salt mud contains complex components, which brings certain difficulties to industrial utilization. However, because of its potential use value, people are constantly exploring ways to utilize salt mud waste and transform it into useful industrial products. The invention patent with the application number 200310122805.5 discloses a process for producing superfine barium sulfate and calcium carbonate by using chlor-alkali salt mud. Ultrafine barium sulfate is obtained through washing, drying, jet crushing and other processes; the filtered filtrate is added with ammonia water to adjust the pH to remove impurities such as iron and manganese, and the clear liquid after impurity removal is added with ammonium carbonate and surfactant, stirred and reacted to obtain ultrafine barium sulfate calcium carbonate. The invention has the advantages of waste utilization and reduced environmental pollution, and the superfine barium sulfate and calcium carbonate produced from the salt mud provide a new way for the comprehensive utilization of the salt mud. However, the process described in this invention only utilizes barium sulfate and calcium compounds contained in salt mud, but does not utilize and excavate magnesium compounds and silicon compounds. Therefore, it is not an ideal comprehensive utilization process of salt mud.

Therefore, in order to fully extract and utilize the effective components in salt mud and provide an economical and effective way for the comprehensive utilization of salt mud, it is necessary to carry out new exploration and research.

Contents of the invention

For this reason, the present invention provides a kind of method that produces light magnesium carbonate co-production fine calcium carbonate and water glass with chlor-alkali salt mud, this method effectively extracts and utilizes the compounds such as calcium, magnesium, silicon that contain in the salt mud, The potential value of salt mud is brought into full play, and an economical and effective way is provided for the comprehensive utilization of salt mud.

The technical scheme of the present invention is: a kind of method that produces light magnesium carbonate co-production fine calcium carbonate and water glass with chlor-alkali salt mud, comprises the steps:

A: Wash and filter the chlor-alkali salt mud with the washing filter (1) three times to remove soluble acid radical impurities; at this time, the salt mud contains compounds mainly composed of magnesium oxide, calcium oxide and silicon dioxide;

B: Put the salt mud obtained in step A into the first carbonizer (2), and put it into the first carbonizer (2) according to the mass ratio of magnesia contained in the salt mud to carbon dioxide pure substance 1: 1.8～2.2 Introduce carbon dioxide gas to carry out carbonization reaction; at this time, magnesium oxide reacts with carbon dioxide and water to produce magnesium bicarbonate or magnesium carbonate, both of which are soluble in water; calcium oxide reacts with carbon dioxide to produce calcium carbonate, which is basically insoluble in water, thus settling down;

C: filter the product obtained in step B through the first filter (4) to obtain the first filter cake and the first clear solution; calcium carbonate and silicon dioxide are the main components in the first filter cake; in the first clear solution Mainly magnesium bicarbonate or magnesium carbonate;

D: the first clarified solution obtained in step C is decomposed by heating in a settling tank (5), dried in a settling drier (6), and packaged in a wind separation packaging machine (7) to obtain a light magnesium carbonate product (17);

E: the first filter cake obtained in step C and ammonium chloride are put into the corrosion-resistant reactor (8) according to the mass ratio 1: 0.87～1.27 of the pure substance of calcium carbonate and ammonium chloride to react, generate calcium chloride and Ammonia and carbon dioxide gas are filtered through the second filter (9) to obtain the second filter cake and the second clarified filtrate; the second filter cake is based on silicon dioxide, and its mass content reaches 80%; the second clarified filtrate Mainly calcium chloride and ammonia water;

F: The second clarified filtrate that step E obtains is dropped into the second carbonizer (10), is that 1～5% surfactant is carried out surface treatment with mass concentration, and stirring rate is 120～220r/min, and to the second carbonizer Pass into carbon dioxide gas in the device (10), make the calcium chloride in the second clarification filtrate and carbon dioxide carry out carbonization according to the ratio of the mass of pure substance as 1: 0.19～0.59, product is filtered through the 3rd filter (12), obtains Clarified ammonium chloride filtrate and the third white filter cake; the third filter cake is calcium carbonate;

G: the white third filter cake of step E gained is washed by washing machine (13), dried by drier (14), pulverizer (15), obtains fine calcium carbonate product (18);

H: The second filter cake obtained in step E is put into the horizontal rotary drum reactor (16) according to the mass ratio of silicon dioxide and sodium hydroxide in a mass ratio of 1: 1.11 to 1.51, and then hydrolyzed reaction, the reaction generates a liquid sodium silicate aqueous solution, which is water glass (19).

In step B, use the first carbonization meter (3) to determine the end point of the carbonization reaction.

In step F, the end point of the carbonization reaction is determined with the second carbonization meter (11).

The carbon dioxide gas used in step B and step F is pure carbon dioxide gas or a mixed gas with a volume content of carbon dioxide greater than 20%.

The surfactant is selected from emulsion concentrate, Tween 80 and a mixture of the two.

The method of producing light magnesium carbonate co-production fine calcium carbonate and water glass with chlor-alkali salt mud of the present invention, its chemical reaction equation is:

MgO+2CO ₂ +H ₂ O＝Mg(HCO ₃ ) ₂

MgO+CO ₂ ＝MgCO ₃

Mg(HCO ₃ ) ₂ ＝MgCO ₃ +H ₂ O+CO ₂

CaCO ₃ +2NH ₄ Cl+H ₂ O＝CaCl ₂ +CO ₂ +2NH ₄ OH

CaCl ₂ +CO ₂ +2NH ₄ OH=CaCO ₃ +2NH ₄ Cl+H ₂ O

SiO ₂ +2NaOH=Na ₂ SiO ₃ +H ₂ O

The method for producing light magnesium carbonate and co-producing fine calcium carbonate and water glass with chlor-alkali salt mud of the present invention effectively extracts and utilizes compounds such as calcium, magnesium, and silicon contained in the salt mud, and fully utilizes the salt mud. Potential value, providing an economical and effective way for the comprehensive utilization of salt mud. The method is simple, easy to operate, and has high economic benefits.

Description of drawings

Fig. 1 has shown the method technological process of producing light magnesium carbonate co-production fine calcium carbonate and water glass with chlor-alkali salt mud of the present invention, wherein,

(1): Washing filter (2): The first carbonizer (3): The first carbonization table

(4): First filter (5): Settling tank (6): Settling dryer

(7): Wind separation and packaging machine (8): Corrosion-resistant reactor (9): Second filter

(10): Second carbonizer (11): Second carbonization meter (12): Third filter

(13): Washing machine (14): Dryer (15): Pulverizer

(16): Horizontal drum reactor (17): Magnesium carbonate product (18): Calcium carbonate product,

(19): water glass

Detailed ways

Below in conjunction with specific embodiment further describe and illustrate the method for producing light magnesium carbonate co-production microcalcium carbonate and water glass with chlor-alkali salt mud of the present invention, disclose how to utilize method described in the present invention to extract and utilize contained in salt mud Magnesium oxide, calcium oxide, silicon dioxide and other substances.

The chlor-alkali salt mud in the present invention comes from the salt mud obtained by making salt from sea salt. After testing, the mass content of magnesium oxide in the salt mud used in the following examples is 19.34%, the mass content of calcium oxide is 19%, and the mass content of silicon dioxide is 21.88%.

Embodiment one

A method for producing light magnesium carbonate and co-producing fine calcium carbonate and water glass with chlor-alkali salt mud, comprising the steps of washing and filtering 500kg of chlor-alkali salt mud with a washing filter (1) three times to remove soluble acid radical impurities. , the compound containing magnesium oxide, calcium oxide and silicon dioxide as the main components in the salt mud; then, the gained salt mud is put into the first carbonizer (2), and is passed into the first carbonizer (2) Pure carbon dioxide gas makes the magnesium oxide and carbon dioxide contained in the salt mud carbonized according to the mass ratio of pure substance 1:2.0; at this time, magnesium oxide reacts with carbon dioxide and water to produce magnesium bicarbonate or magnesium carbonate, both of which are soluble Calcium oxide reacts with carbon dioxide to produce calcium carbonate, which is basically insoluble in water and thus precipitates; the product obtained by the carbonization reaction is filtered through the first filter (4) to obtain the first filter cake and the first clarified solution. Calcium carbonate and silicon dioxide are the main components in the first filter cake, and magnesium bicarbonate or magnesium carbonate are the main components in the first clarified solution; ) drying, air separation and packaging machine (7) packaging, to obtain high-quality light magnesium carbonate product (17); the first filter cake and ammonium chloride are dropped into according to the mass ratio 1: 1.27 of the pure substance of calcium carbonate and ammonium chloride React in the corrosion-resistant reactor (8), generate calcium chloride and ammoniacal liquor and carbon dioxide gas, filter through the second filter (9), get the second filter cake and the second clarification filtrate; In the second filter cake, use carbon dioxide Silicon is main, and its mass content reaches 80%; Calcium chloride and ammoniacal liquor are main in the second clarification filtrate; The second clarification filtrate is dropped into the second carbonizer (10), is 1% tensio-active agent concentrated Emulsion treatment, stirring speed is 220r/min, and in the second carbonizer (10), the mixed gas that contains carbon dioxide gas volume is 25%, makes the calcium chloride in the second clarification filtrate and carbon dioxide according to the ratio of the mass of pure substance Carry out carbonization for 1: 0.19, carbonization reaction temperature is controlled to be 10～20 ℃ of products filter through the 3rd filter (12), obtain the 3rd filter cake of clarified ammonium chloride filtrate and white; The 3rd filter cake is calcium carbonate; The white third filter cake is washed by washing machine (13), dried by dryer (14), pulverizer (15), and obtains fine calcium carbonate product (18); the second filter cake is purified according to the purity of silicon dioxide and sodium hydroxide. The mass ratio of substance is 1: 1.11 and sodium hydroxide is dropped into horizontal drum reactor (16), carries out hydrolysis reaction, and the sodium silicate aqueous solution of reaction generation liquid is water glass (19).

Embodiment two

A method for producing light magnesium carbonate and co-producing fine calcium carbonate and water glass with chlor-alkali salt mud, comprising the steps of washing and filtering 500kg of chlor-alkali salt mud with a washing filter (1) three times to remove soluble acid radical impurities. , the compound containing magnesium oxide, calcium oxide and silicon dioxide as the main components in the salt mud; then, the gained salt mud is put into the first carbonizer (2), and is passed into the first carbonizer (2) The mixed gas containing carbon dioxide gas volume is 25%, so that the magnesia and carbon dioxide contained in the salt mud are carbonized according to the mass ratio of pure substance 1:1.8; at this time, magnesia reacts with carbon dioxide and water to produce magnesium bicarbonate or carbonic acid Magnesium, both of which are soluble in water; calcium oxide reacts with carbon dioxide to produce calcium carbonate, which is basically insoluble in water and thus precipitates; the product obtained from the carbonization reaction is filtered through the first filter (4) to obtain the first filter cake and the first clarified solution, calcium carbonate and silicon dioxide are the main components in the first filter cake, and magnesium bicarbonate or magnesium carbonate are the main components in the first clarified solution; the first clarified solution is heated through the settling tank (5) Decompose, settling drier (6) drying, winnowing packaging machine (7) packing, obtain light magnesium carbonate product (17); The first filter cake and ammonium chloride are according to the quality of the pure substance of calcium carbonate and ammonium chloride Ratio 1: 1.0 drops into the corrosion-resistant reactor (8) and reacts, generates calcium chloride and ammoniacal liquor and carbon dioxide gas, filters through the second filter (9), obtains the second filter cake and the second clarification filtrate; Based on silicon dioxide in the cake, its mass content reaches 80%; Calcium chloride and ammoniacal liquor are mainly based on the second clarified filtrate; The second clarified filtrate is dropped into the second carbonizer (10), with a mass concentration of 3 %surfactant treatment, stirring speed is 180r/min, and wherein containing mass concentration in the tensio-active agent is 2% concentrated emulsion and mass concentration is 2% Tween 80, and contains carbon dioxide gas in the second carbonizer (10) The volume is 40% mixed gas, so that calcium chloride and carbon dioxide in the second clarified filtrate are carbonized according to the mass ratio of pure substance as 1:0.30, the carbonization reaction temperature is controlled at 35 ~ 40 ℃, and the product passes through the third filter (12) filter to obtain the clarified ammonium chloride filtrate and the third white filter cake; the third filter cake is calcium carbonate; the third white filter cake is washed by washing machine (13), dried by drier (14), and pulverized Machine (15), obtain fine calcium carbonate product (18); The second filter cake is dropped into horizontal drum reactor (16) according to the mass ratio 1: 1.35 of the pure substance of silicon dioxide and sodium hydroxide together with sodium hydroxide ) Li, carry out hydrolysis reaction, the sodium silicate aqueous solution of reaction generation liquid, is water glass (19).

Embodiment three

A method for producing light magnesium carbonate and co-producing fine calcium carbonate and water glass with chlor-alkali salt mud, comprising the steps of washing and filtering 500kg of chlor-alkali salt mud with a washing filter (1) three times to remove soluble acid radical impurities. , containing magnesium oxide, calcium oxide and silicon dioxide as the main components of the compound in the salt mud; then, the gained salt mud is put into the first carbonizer (2), and contains carbon dioxide in the first carbonizer (2) The gas volume is 40% mixed gas, so that the magnesium oxide and carbon dioxide contained in the salt mud are carbonized according to the mass ratio of pure substance 1:2.2; at this time, magnesium oxide reacts with carbon dioxide and water to produce magnesium bicarbonate or magnesium carbonate, Both are soluble in water; calcium oxide reacts with carbon dioxide to produce calcium carbonate, which is basically insoluble in water and thus precipitates; the product obtained by the carbonization reaction is filtered through the first filter (4) to obtain the first filter cake and the second A clarified solution, calcium carbonate and silicon dioxide are the main components in the first filter cake, magnesium bicarbonate or magnesium carbonate is the main component in the first clarified solution; the first clarified solution is heated and decomposed by the settling tank (5), Settling drier (6) drying, air separation packaging machine (7) packing, obtain light magnesium carbonate product (17); The first filter cake and ammonium chloride are according to the mass ratio of the pure matter of calcium carbonate and ammonium chloride 1 : 0.87 drops into corrosion-resistant reactor (8) and reacts, generates calcium chloride and ammoniacal liquor and carbon dioxide gas, filters through the second filter (9), gets the second filter cake and the second clarification filtrate; In the second filter cake Based on silicon dioxide, its mass content reaches 80%; in the second clarified filtrate, mainly calcium chloride and ammoniacal liquor; the second clarified filtrate is dropped into the second carbonizer (10), with a mass concentration of 5% surface Activator Tween 80 is processed, and stirring speed is 120r/min, and in the second carbonizer (10), it is 35% mixed gas that the volume of gas containing carbon dioxide is passed into, the calcium chloride and carbon dioxide in the second clarification filtrate are according to The mass ratio of pure substance is 1: 0.59 carries out carbonization, and the carbonization reaction temperature is controlled to be 10～15 ℃ of products filter through the 3rd filter (12), obtain the 3rd filter cake of the clarified ammonium chloride filtrate and white; The filter cake is calcium carbonate; the third white filter cake is washed by washing machine (13), dried by drier (14), pulverizer (15), and obtains fine calcium carbonate product (18); The mass ratio of the pure substance of sodium hydroxide is 1: 1.51 and put into the horizontal drum reactor (16) together with sodium hydroxide, carry out hydrolysis reaction, the sodium silicate aqueous solution of reaction generation liquid, is water glass (19) .

The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Therefore, all equivalent changes or modifications made with the features and principles described in the claims of the present invention should be included in the present invention. within the scope of the claims.

Claims (4)

1. a method of producing Magnesium Carbonate Light 41-45 coproduction fine calcium carbonate and water glass with the chlor-alkali salt slurry is characterized in that, comprises the steps:

A: with the chlor-alkali salt slurry with washing filter (1) filter wash three times;

B: steps A gained salt slurry is put in first carbonizer (2), and in first carbonizer (2) in according to salt slurry contained Natural manganese dioxide and the mass ratio 1: 1.8～2.2 of carbonic acid gas pure substance feed dioxide gass, carry out carburizing reagent;

C: step B products therefrom is filtered through first strainer (4), obtain first filter cake and first settled solution;

Resulting first settled solution of D: step C obtains Magnesium Carbonate Light 41-45 product (17) through slurry tank (5) thermal degradation, dry, selection by winnowing wrapping machine (7) packing of sedimentation moisture eliminator (6);

E: first filter cake and ammonium chloride that step C obtains are put into reaction in the corrosion-resistant reactor (8) according to the mass ratio 1: 0.87～1.27 of the pure substance of lime carbonate and ammonium chloride; Generate calcium chloride and ammoniacal liquor and dioxide gas reaction product; Reaction product is filtered through second strainer (9), gets second filter cake and second clear filtrate;

F: second clear filtrate that step e obtains is knocked down second carbonizer (10); Using mass concentration is that 1～5% tensio-active agent carries out surface treatment; Stir speed (S.S.) is 120～220r/min, and in second carbonizer (10), feeds dioxide gas, and making calcium chloride and carbonic acid gas in second clear filtrate is 1: 0.19～0.59 to carry out carbonization according to the ratio of the quality of pure substance; Product filters through the 3rd strainer (12), gets the 3rd filter cake of clarifying ammonium chloride filtrating and white;

G: the 3rd filter cake of the white of step e gained is through washing machine (13) washing, moisture eliminator (14) drying, kibbler (15), obtains fine calcium carbonate product (18);

H: resulting second filter cake of step e is put into revolving horizontal drum reactor drum (16) lining with the mass ratio 1: 1.11～1.51 of the pure substance of sodium hydroxide with sodium hydroxide according to silicon-dioxide; Reaction is hydrolyzed; The sodium silicate aqueous solution of reaction solution body promptly is water glass (19).

2. method of producing Magnesium Carbonate Light 41-45 coproduction fine calcium carbonate and water glass with the chlor-alkali salt slurry as claimed in claim 1; It is characterized in that; Measure the carburizing reagent terminal point with the first carbonization table (3) among the step B, measure the carburizing reagent terminal point with the second carbonization table (11) in the step F.

3. method of producing Magnesium Carbonate Light 41-45 coproduction fine calcium carbonate and water glass with the chlor-alkali salt slurry as claimed in claim 1; It is characterized in that used dioxide gas is pure carbon dioxide gas or carbonic acid gas volume content greater than 20% mixed gas in step B and the step F.

4. method of producing Magnesium Carbonate Light 41-45 coproduction fine calcium carbonate and water glass with the chlor-alkali salt slurry as claimed in claim 1 is characterized in that said tensio-active agent is selected from emulsifiable concentrate, tween 80 and the mixture of the two.

Images