阅读说明：本技术 一种利用稻壳灰制取复合硅酸钙的生产工艺 (Production process for preparing composite calcium silicate by using rice hull ash ) 是由 宣全 于 2020-03-06 设计创作，主要内容包括：本发明公开了一种利用稻壳灰制取复合硅酸钙的生产工艺,由稻壳灰制备的水玻璃和生石灰为原料,经过生石灰消化、制备低模数的硅酸钠溶液、硅酸钙合成反应、过滤、洗涤、脱碱并降低pH值和烘干、打散、包装,制取复活硅酸钙成品,采用本发明大幅度降低了原材料成本,有效的提高了原材料品质；采用本发明生产工艺既节能又减排,各工艺步骤中的废液都能循环或重复利用,整个工艺流程耗能较低。(The invention discloses a production process for preparing composite calcium silicate by using rice hull ash, which takes water glass and quicklime prepared from the rice hull ash as raw materials, prepares a low-modulus sodium silicate solution through quicklime digestion, calcium silicate synthesis reaction, filtration, washing, dealkalization, pH value reduction, drying, scattering and packaging to prepare a finished product of the revived calcium silicate; the production process of the invention is energy-saving and emission-reducing, the waste liquid in each process step can be recycled, and the energy consumption of the whole process flow is lower.)

1. A production process for preparing composite calcium silicate by using rice hull ash is characterized in that water glass prepared from the rice hull ash and quick lime are used as raw materials, and a revived calcium silicate finished product is prepared by slaking the quick lime, preparing a low-modulus sodium silicate solution, synthesizing, filtering, washing, dealkalizing, reducing the pH value, drying, scattering and packaging, wherein the specific production process comprises the following steps:

(1) slaking of burnt lime

Putting the standard quicklime into a lime slaker, adding 5-8 times of water, stirring, digesting for 30 minutes, putting the lime milk generated after digestion into a lime milk tank, and sampling to detect the effective CaO content;

(2) preparation of water glass

A. Collecting rice husk ash:

packing, transporting and collecting solid waste rice hull ash generated by burning rice hulls in a power generation and gas supply boiler to a raw material warehouse for later use;

B. and (3) generation of water glass:

uniformly mixing the collected rice hull ash with water and NaOH solution according to the mass ratio of 1: 3-4: 1, heating to 220 ℃ under stirring, pressurizing to 0.6-0.9Mpa, reacting for 2.5-3.5 hours, and sending to a sedimentation tank to separate water glass from carbon to obtain water glass mother liquor; conveying the mixture to a plate frame through a water pump, and filtering the mixture to obtain liquid water glass for later use;

(3) preparation of low modulus sodium silicate solution

Putting liquid water glass into a container, adding liquid alkali, namely sodium hydroxide, and reducing the modulus to 0.8-1.2 and SiO₂The concentration is reduced to 55-65 g/L, and sodium silicate solution with low modulus is prepared;

(4) calcium silicate Synthesis reaction

Pumping the low-modulus sodium silicate solution into a synthesis tank, heating to 75-85 ℃, slowly adding lime milk with the temperature of 50-60 ℃ into the synthesis tank according to the proportion of 1: 1, stirring, keeping the stirring speed at 25-35 r/min, keeping the reaction temperature at 70-80 ℃, and carrying out synthesis reaction for 50-80 min to prepare calcium silicate slurry;

(5) filtering and washing

Conveying the calcium silicate slurry to a plate-and-frame filter press by using a slurry pump for filter pressing, conveying filtrate to a circulating lye tank for storage, and performing three times of reverse washing on filter cakes after filter pressing, wherein the water consumption is 8-12 times of the mass of calcium silicate, and the water temperature is kept above 75 ℃ until the filter cakes are washed clean;

(6) dealkalization and pH reduction

Putting the clear calcium silicate filter cake into a synthesis tank, adding hot water and lime milk, wherein the addition amount of the hot water is 1.5-3 times of that of the calcium silicate dry base, the addition amount of the lime milk is 1-10% of that of the calcium silicate dry base, then heating to 90-110 ℃, stirring for reaction for 10-40 minutes at the stirring speed of 25-35 r/min to generate dealkalized calcium silicate slurry, adding carbon dioxide gas into the dealkalized calcium silicate slurry, the aeration speed of the carbon dioxide is 5-10 kg/min, aerating for 5-10 minutes, pumping the calcium silicate slurry added with the carbon dioxide gas into a plate-and-frame filter press for filter pressing, then washing for one time, the water consumption is 1.5-3 times of the mass of the calcium silicate dry base, then washing with 1% dilute sulfuric acid, and the washing acid consumption is 3-8 times of the mass of the calcium silicate dry base, the pH value is below 9;

(7) drying and scattering package

Conveying the calcium silicate filter cake to drying equipment by using a belt for drying at the drying temperature of 200 ℃ and 300 ℃, then scattering, wherein the bag used for packaging is a vacuum-pumping heat sealing bag, the moisture of the calcium silicate can be ensured to meet the requirement, and the packaging specification is 10-15 kg/bag.

2. The production process for preparing composite calcium silicate by using rice hull ash as claimed in claim 1, wherein the specific production process for preparing the finished product of the reactivated calcium silicate comprises the following steps:

(1) slaking of burnt lime

Putting the standard quicklime into a lime slaker, adding 6 times of water, stirring, digesting for 30 minutes, and putting the lime milk generated after digestion into a lime milk tank;

(2) preparation of water glass

A. Collecting rice husk ash:

packing, transporting and collecting solid waste rice hull ash generated by burning rice hulls in a power generation and gas supply boiler to a raw material warehouse for later use;

B. and (3) generation of water glass:

uniformly mixing the collected rice hull ash with water and NaOH solution according to the mass ratio of 1: 3-4: 1, heating to 220 ℃ under stirring, pressurizing to 0.6-0.9Mpa, reacting for 2.5-3.5 hours, and sending to a sedimentation tank to separate water glass from carbon to obtain water glass mother liquor; conveying the mixture to a plate frame through a water pump, and filtering the mixture to obtain liquid water glass for later use;

(3) preparation of low modulus sodium silicate solution

Putting liquid water glass into a container, adding liquid alkali, namely sodium hydroxide, and reducing the modulus to 0.8-1.2 and SiO₂The concentration is reduced to 55-65 g/L, and sodium silicate solution with low modulus is prepared;

(4) calcium silicate Synthesis reaction

Pumping a low-modulus sodium silicate solution into a synthesis tank, heating to 75 ℃, slowly adding lime milk with the temperature of 60 ℃ into the synthesis tank according to the proportion of 1: 1, stirring, keeping the stirring speed at 35 revolutions per minute, keeping the reaction temperature at 75 ℃, and carrying out synthesis reaction for 60 minutes to prepare calcium silicate slurry;

(5) filtering and washing

Conveying the calcium silicate slurry to a plate-and-frame filter press by using a slurry pump for filter pressing, conveying the filtrate to a circulating lye tank for storage, and washing a filter cake obtained after filter pressing in a three-time reverse manner, wherein the water consumption is 9 times of the mass of the calcium silicate, and the water temperature is kept above 75 ℃ until the filter cake is clear;

(6) dealkalization and pH reduction

Putting the clear calcium silicate filter cake into a synthesis tank, adding hot water and lime milk, wherein the addition amount of the hot water is 1.5-3 times of that of a calcium silicate dry base, the addition amount of the lime milk is 1-10% of that of the calcium silicate dry base, then heating to 100 ℃, stirring for reaction for 30 minutes, and the stirring speed is 35 r/min to generate dealkalized calcium silicate slurry, then adding carbon dioxide gas into the dealkalized calcium silicate slurry, wherein the aeration speed of the carbon dioxide is 7 kg/min, aerating for 7 minutes, pumping the calcium silicate slurry added with the carbon dioxide gas into a plate-and-frame filter press for filter pressing, then washing for one time, wherein the water consumption is 2 times of the mass of the calcium silicate dry base, finally washing with 1% of dilute sulfuric acid, the washing acid consumption is 5 times of the mass of the calcium silicate dry base, and the pH value is below 9;

(7) drying and scattering package

Conveying the calcium silicate filter cake into an oven by using a belt to be dried, wherein the drying temperature is 260 ℃, then scattering, and a bag used for packaging is a vacuumizing heat sealing bag, so that the moisture of the calcium silicate can meet the requirement, and the packaging specification is 10-15 kg/bag.

3. The production process for preparing composite calcium silicate by using rice hull ash as claimed in claim 1, wherein the specific production process for preparing the finished product of the reactivated calcium silicate comprises the following steps:

(1) slaking of burnt lime

Putting the standard quicklime into a lime slaker, adding 7 times of water, stirring, digesting for 30 minutes, putting the lime milk generated after digestion into a lime milk tank, and sampling to detect the effective CaO content;

(2) preparation of water glass

A. Collecting rice husk ash:

packing, transporting and collecting solid waste rice hull ash generated by burning rice hulls in a power generation and gas supply boiler to a raw material warehouse for later use;

B. and (3) generation of water glass:

uniformly mixing the collected rice hull ash with water and NaOH solution according to the mass ratio of 1: 3-4: 1, heating to 220 ℃ under stirring, pressurizing to 0.6-0.9Mpa, reacting for 2.5-3.5 hours, and sending to a sedimentation tank to separate water glass from carbon to obtain water glass mother liquor; conveying the mixture to a plate frame through a water pump, and filtering the mixture to obtain liquid water glass for later use;

(3) preparation of low modulus sodium silicate solution

Putting liquid water glass into a container, adding liquid alkali, namely sodium hydroxide, and reducing the modulus to 0.8-1.2 and SiO₂The concentration is reduced to 55-65 g/L, and sodium silicate solution with low modulus is prepared;

(4) calcium silicate Synthesis reaction

Pumping a low-modulus sodium silicate solution into a synthesis tank, heating to 80 ℃, slowly adding lime milk with the temperature of 55 ℃ into the synthesis tank according to the proportion of 1: 1, stirring, keeping the stirring speed at 30 revolutions per minute, keeping the reaction temperature at 77 ℃, and carrying out synthesis reaction for 70 minutes to prepare calcium silicate slurry;

(5) filtering and washing

Conveying the calcium silicate slurry to a plate-and-frame filter press by using a slurry pump for filter pressing, conveying filtrate to a circulating lye tank for storage, and washing a filter cake obtained after filter pressing in a three-time reverse manner, wherein the water consumption is 10 times of the mass of the calcium silicate, and the water temperature is kept above 75 ℃ until the filter cake is clear;

(6) dealkalization and pH reduction

Putting the clear calcium silicate filter cake into a synthesis tank, adding hot water and lime milk, wherein the addition amount of the hot water is 2.5 times of that of a calcium silicate dry base, the addition amount of the lime milk is 1-10% of that of the calcium silicate dry base, heating to 105 ℃, stirring for reaction for 10-40 minutes, and stirring at 30 r/min to generate dealkalized calcium silicate slurry, adding carbon dioxide gas into the dealkalized calcium silicate slurry, wherein the aeration rate of the carbon dioxide gas is 9 kg/min, and the aeration rate is 8 minutes, pumping the calcium silicate slurry after the carbon dioxide gas is added into a plate-and-frame filter press for filter pressing, and then washing for one time, wherein the water consumption is 2.5 times of that of the calcium silicate dry base, and finally washing with 1% of dilute sulfuric acid, the washing acid consumption is 6 times of that of the calcium silicate dry base, and the pH value is below 9;

(7) drying and scattering package

Conveying the calcium silicate filter cake into an oven by using a belt to be dried, wherein the drying temperature is 280 ℃, then scattering, and the bag used for packaging is a vacuumized heat sealing bag which can ensure that the moisture of the calcium silicate meets the requirement, and the packaging specification is 10-15 kg per bag.

4. The production process for preparing composite calcium silicate by using rice hull ash as claimed in claim 1, wherein the specific production process for preparing the finished product of the reactivated calcium silicate comprises the following steps:

(1) slaking of burnt lime

Putting the standard quicklime into a lime slaker, adding 8 times of water, stirring, digesting for 30 minutes, putting the lime milk generated after digestion into a lime milk tank, and sampling to detect the effective CaO content;

(2) preparation of water glass

A. Collecting rice husk ash:

packing, transporting and collecting solid waste rice hull ash generated by burning rice hulls in a power generation and gas supply boiler to a raw material warehouse for later use;

B. and (3) generation of water glass:

uniformly mixing the collected rice hull ash with water and NaOH solution according to the mass ratio of 1: 3-4: 1, heating to 220 ℃ under stirring, pressurizing to 0.6-0.9Mpa, reacting for 2.5-3.5 hours, and sending to a sedimentation tank to separate water glass from carbon to obtain water glass mother liquor; conveying the mixture to a plate frame through a water pump, and filtering the mixture to obtain liquid water glass for later use;

(3) preparing low-modulus sodium silicate solution

Putting liquid water glass into a container, adding liquid alkali, namely sodium hydroxide, and reducing the modulus to 0.8-1.2 and SiO₂The concentration is reduced to 55-65 g/L, and sodium silicate solution with low modulus is prepared;

(4) calcium silicate Synthesis reaction

Pumping a low-modulus sodium silicate solution into a synthesis tank, heating to 85 ℃, slowly adding lime milk with the temperature of 50 ℃ into the synthesis tank according to the proportion of 1: 1, stirring, keeping the stirring speed at 25 revolutions per minute, keeping the reaction temperature at 80 ℃, and carrying out synthesis reaction for 80 minutes to prepare calcium silicate slurry;

(5) filtering and washing

Conveying the calcium silicate slurry to a plate-and-frame filter press by using a slurry pump for filter pressing, conveying the filtrate to a circulating lye tank for storage, and washing a filter cake obtained after filter pressing in a three-time reverse manner, wherein the water consumption is 11 times of the mass of the calcium silicate, and the water temperature is kept above 75 ℃ until the filter cake is clear;

(6) dealkalization and pH reduction

Putting the clear calcium silicate filter cake into a synthesis tank, adding hot water and lime milk, wherein the addition amount of the hot water is 3 times of that of a calcium silicate dry base, the addition amount of the lime milk is 1-10% of that of the calcium silicate dry base, heating to 98 ℃, stirring for 40 minutes, and stirring at 25-35 r/min to generate dealkalized calcium silicate slurry, adding carbon dioxide gas into the dealkalized calcium silicate slurry, wherein the aeration rate of the carbon dioxide is 8 kg/min, aerating for 9 minutes, pumping the calcium silicate slurry added with the carbon dioxide gas into a plate-and-frame filter press for filter pressing, washing for one time, the water consumption is 3 times of that of the calcium silicate dry base, finally washing with 1% dilute sulfuric acid, the washing acid consumption is 7 times of that of the calcium silicate dry base, and the pH value is below 9;

(7) drying and scattering package

Conveying the calcium silicate filter cake into an oven by using a belt to be dried, wherein the drying temperature is 300 ℃, then scattering, and the bag used for packaging is a vacuumized heat sealing bag which can ensure that the moisture of the calcium silicate meets the requirement, and the packaging specification is 10-15 kg per bag.

5. The production process for preparing composite calcium silicate by using rice hull ash as claimed in claim 1, wherein the specific production process for preparing the finished product of the reactivated calcium silicate comprises the following steps: liquid water glassPlacing the glass in a container, adding liquid alkali, i.e. sodium hydroxide, to reduce the modulus to 1.00, SiO₂The concentration is reduced to 60 g/l and a low modulus sodium silicate solution is produced.

6. The production process for preparing composite calcium silicate by using rice hull ash as claimed in claim 1, wherein the specific production process for preparing the finished product of the reactivated calcium silicate comprises the following steps: pumping the low-modulus sodium silicate solution into a synthesis tank, heating to 75-85 ℃, slowly adding lime milk with the temperature of 50-60 ℃ into the synthesis tank according to the proportion of 1: 1, stirring, keeping the stirring speed at 25-35 r/min, keeping the reaction temperature at 70-80 ℃, and carrying out synthesis reaction for 50-80 min to prepare the calcium silicate slurry.

7. The process for preparing composite calcium silicate from rice hull ash according to claim 1, wherein the specific production process for preparing the finished product of the reactivated calcium silicate comprises the following steps: conveying the calcium silicate slurry to a plate-and-frame filter press by using a slurry pump for filter pressing, conveying filtrate to a circulating lye tank for storage, and performing three times of reverse washing on filter cakes after filter pressing, wherein the water consumption is 8-12 times of the mass of calcium silicate, and the water temperature is kept above 75 ℃ until the filter cakes are washed to be clear.

8. The production process for preparing composite calcium silicate by using rice hull ash as claimed in claim 1, wherein the specific production process for preparing the finished product of the reactivated calcium silicate comprises the following steps: putting the clear calcium silicate filter cake into a synthesis tank, adding hot water and lime milk, wherein the addition amount of the hot water is 1.5-3 times of that of the calcium silicate dry base, the addition amount of the lime milk is 1-10% of that of the calcium silicate dry base, then heating to 90-110 ℃, stirring for reaction for 10-40 minutes at the stirring speed of 25-35 r/min to generate dealkalized calcium silicate slurry, adding carbon dioxide gas into the dealkalized calcium silicate slurry, the aeration speed of the carbon dioxide is 5-10 kg/min, aerating for 5-10 minutes, pumping the calcium silicate slurry added with the carbon dioxide gas into a plate-and-frame filter press for filter pressing, then washing for one time, the water consumption is 1.5-3 times of the mass of the calcium silicate dry base, then washing with 1% dilute sulfuric acid, and the washing acid consumption is 3-8 times of the mass of the calcium silicate dry base, the pH value is below 9.

Technical Field

The invention relates to a production process for preparing composite calcium silicate by using rice hull ash; in particular to a process for preparing a silicon raw material by using rice hull ash so as to realize the production of composite calcium silicate.

Technical Field

The composite calcium silicate is a material with good heat-insulating and fire-resistant properties, and because the cost for producing the composite calcium silicate is high, particularly the high cost of a silicon source material, the development of the composite calcium silicate industry is slow, and the application of the composite calcium silicate is hindered; at present, rice hull ash and limestone are used as raw materials, limestone is calcined for 205 minutes at the high temperature of 900 ℃ in a laboratory, the calcined limestone is ground to fine powder with the fineness of less than 200 micrometers, the rice hull ash is calcined at the high temperature of more than 800 ℃, and then the calcined rice hull ash and the calcined limestone powder are used for preparing the composite calcium silicate by a flotation method.

Disclosure of Invention

The invention aims to provide a production process for preparing composite calcium silicate by using rice hull ash, which uses the rice hull ash as a silicon source material, greatly reduces the cost of raw materials, provides a process route for solving the rapid development of the composite calcium silicate industry under the existing conditions, and solves the problem of difficult preparation process of the composite calcium silicate for a long time.

In order to realize the purpose, the production process for preparing the composite calcium silicate by using the rice hull ash comprises the following steps of preparing a finished product of the composite calcium silicate by using water glass prepared from the rice hull ash and quick lime as raw materials through quick lime digestion, preparing a low-modulus sodium silicate solution, synthesizing, filtering, washing, dealkalizing, reducing the pH value, drying, scattering and packaging, wherein the specific production process comprises the following steps:

1. slaking of burnt lime

Putting the standard quicklime into a lime slaker, adding 5-8 times of water, stirring, digesting for 30 minutes, putting the lime milk generated after digestion into a lime milk tank, and sampling to detect the effective CaO content;

2. preparation of water glass

A. Collecting rice husk ash:

packing, transporting and collecting solid waste rice hull ash generated by burning rice hulls in a power generation and gas supply boiler to a raw material warehouse for later use;

B. and (3) generation of water glass:

uniformly mixing the collected rice hull ash with water and NaOH solution according to the mass ratio of 1: 3-4: 1, heating to 220 ℃ under stirring, pressurizing to 0.6-0.9Mpa, reacting for 2.5-3.5 hours, and sending to a sedimentation tank to separate water glass from carbon to obtain water glass mother liquor; conveying the mixture to a plate frame through a water pump, and filtering the mixture to obtain liquid water glass for later use;

3. preparation of low modulus sodium silicate solution

Putting liquid water glass into a container, adding liquid alkali, namely sodium hydroxide, and reducing the modulus to 0.8-1.2 and SiO₂The concentration is reduced to 55-65 g/L, and sodium silicate solution with low modulus is prepared;

4. calcium silicate Synthesis reaction

Pumping the low-modulus sodium silicate solution into a synthesis tank, heating to 75-85 ℃, slowly adding lime milk with the temperature of 50-60 ℃ into the synthesis tank according to the proportion of 1: 1, stirring, keeping the stirring speed at 25-35 r/min, keeping the reaction temperature at 70-80 ℃, and carrying out synthesis reaction for 50-80 min to prepare calcium silicate slurry;

5. filtering and washing

Conveying the calcium silicate slurry to a plate-and-frame filter press by using a slurry pump for filter pressing, conveying filtrate to a circulating lye tank for storage, and performing three times of reverse washing on filter cakes after filter pressing, wherein the water consumption is 8-12 times of the mass of calcium silicate, and the water temperature is kept above 75 ℃ until the filter cakes are washed clean;

6. dealkalization and pH reduction

Putting the clear calcium silicate filter cake into a synthesis tank, adding hot water and lime milk, wherein the addition amount of the hot water is 1.5-3 times of that of the calcium silicate dry base, the addition amount of the lime milk is 1-10% of that of the calcium silicate dry base, then heating to 90-110 ℃, stirring for reaction for 10-40 minutes at the stirring speed of 25-35 r/min to generate dealkalized calcium silicate slurry, adding carbon dioxide gas into the dealkalized calcium silicate slurry, the aeration speed of the carbon dioxide is 5-10 kg/min, aerating for 5-10 minutes, pumping the calcium silicate slurry added with the carbon dioxide gas into a plate-and-frame filter press for filter pressing, then washing for one time, the water consumption is 1.5-3 times of the mass of the calcium silicate dry base, then washing with 1% dilute sulfuric acid, and the washing acid consumption is 3-8 times of the mass of the calcium silicate dry base, the pH value is below 9;

7. drying and scattering package

Conveying the calcium silicate filter cake to drying equipment by using a belt for drying at the drying temperature of 200 ℃ and 300 ℃, then scattering, wherein the bag used for packaging is a vacuum-pumping heat sealing bag, the moisture of the calcium silicate can be ensured to meet the requirement, and the packaging specification is 10-15 kg/bag.

Compared with the prior art, the production process for preparing the composite calcium silicate by using the rice hull ash has the following excellent effects.

The invention adopts the rice hull ash to prepare the water glass, namely the sodium silicate as the silicon source material, greatly reduces the cost of the raw materials and effectively improves the quality of the raw materials; the process route and the used equipment conditions adopted by the invention solve the problem of difficult manufacturing process of the composite calcium silicate for a long time, greatly reduce the cost of the production process, and provide the process route for solving the rapid development of the composite calcium silicate industry under the existing conditions.

Detailed Description

The production process of the present invention for preparing composite calcium silicate from rice hull ash is described in further detail below.

The invention relates to a production process for preparing composite calcium silicate by using rice hull ash, which takes water glass and quicklime prepared from the rice hull ash as raw materials, prepares a low-modulus sodium silicate solution through quicklime digestion, synthesis, filtration washing, dealkalization, pH value reduction, drying, scattering and packaging, and prepares a revived calcium silicate finished product, and the specific production process comprises the following steps:

1. slaking of burnt lime

Putting the standard quicklime into a lime slaker, adding 5-8 times of water, stirring, digesting for 30 minutes, putting the lime milk generated after digestion into a lime milk tank, and sampling to detect the effective CaO content;

2. preparation of water glass

A. Collecting rice husk ash:

packing, transporting and collecting solid waste rice hull ash generated by burning rice hulls in a power generation and gas supply boiler to a raw material warehouse for later use;

B. and (3) generation of water glass:

uniformly mixing the collected rice hull ash with water and NaOH solution according to the mass ratio of 1: 3-4: 1, heating to 220 ℃ under stirring, pressurizing to 0.6-0.9Mpa, reacting for 2.5-3.5 hours, and sending to a sedimentation tank to separate water glass from carbon to obtain water glass mother liquor; conveying the mixture to a plate frame through a water pump, and filtering the mixture to obtain liquid water glass for later use;

3. preparation of low modulus sodium silicate solution

Putting liquid water glass into a container, adding liquid alkali, namely sodium hydroxide, and reducing the modulus to 0.8-1.2 and SiO₂The concentration is reduced to 55-65 g/L, and sodium silicate solution with low modulus is prepared;

4. calcium silicate Synthesis reaction

Pumping the low-modulus sodium silicate solution into a synthesis tank, heating to 75-85 ℃, slowly adding lime milk with the temperature of 50-60 ℃ into the synthesis tank according to the proportion of 1: 1, stirring, keeping the stirring speed at 25-35 r/min, keeping the reaction temperature at 70-80 ℃, and carrying out synthesis reaction for 50-80 min to prepare calcium silicate slurry;

5. filtering and washing

Conveying the calcium silicate slurry to a plate-and-frame filter press by using a slurry pump for filter pressing, conveying filtrate to a circulating lye tank for storage, and performing three times of reverse washing on filter cakes after filter pressing, wherein the water consumption is 8-12 times of the mass of calcium silicate, and the water temperature is kept above 75 ℃ until the filter cakes are washed clean;

6. dealkalization and pH reduction

Putting the clear calcium silicate filter cake into a synthesis tank, adding hot water and lime milk, wherein the addition amount of the hot water is 1.5-3 times of that of the calcium silicate dry base, the addition amount of the lime milk is 1-10% of that of the calcium silicate dry base, then heating to 90-110 ℃, stirring for reaction for 10-40 minutes at the stirring speed of 25-35 r/min to generate dealkalized calcium silicate slurry, adding carbon dioxide gas into the dealkalized calcium silicate slurry, the aeration speed of the carbon dioxide is 5-10 kg/min, aerating for 5-10 minutes, pumping the calcium silicate slurry added with the carbon dioxide gas into a plate-and-frame filter press for filter pressing, then washing for one time, the water consumption is 1.5-3 times of the mass of the calcium silicate dry base, then washing with 1% dilute sulfuric acid, and the washing acid consumption is 3-8 times of the mass of the calcium silicate dry base, the pH value is below 9;

7. drying and scattering package

Conveying the calcium silicate filter cake to drying equipment by using a belt for drying at the drying temperature of 200 ℃ and 300 ℃, then scattering, wherein the bag used for packaging is a vacuum-pumping heat sealing bag, the moisture of the calcium silicate can be ensured to meet the requirement, and the packaging specification is 10-15 kg/bag.