A production process of heavy soda ash

Abstract

The present invention discloses a production process of heavy soda ash, comprising the following steps: (1) dissolving light ash in soft water to a saturated state at room temperature, homogenizing under high pressure, adding a precipitation aid, stirring, and centrifuging; (2) evaporating the saturated light ash aqueous solution, centrifuging, and then adding a saturated sodium carbonate alcohol aqueous solution and centrifuging; (3) mixing the refined light ash with the saturated sodium carbonate alcohol aqueous solution, and then placing it in a hydration machine for hydration reaction, and then homogenizing under high pressure and centrifuging; (4) adding a saturated sodium carbonate alcohol aqueous solution to monohydrate to filter press, wash, and place it in a heavy ash calcining furnace for dehydration to obtain heavy soda ash. The production process of the present invention can reduce the salt content and other impurities of heavy soda ash and improve the uniformity of the particle size distribution of heavy soda ash.

Description

Technical Field

[0001] The invention relates to a production process of dense soda ash, and belongs to the technical field of dense soda ash. Background Art

[0002] Heavy soda ash is one of the important basic chemical raw materials, widely used in glass, metallurgy, synthetic detergent and other industries, especially float glass, optical glass, color picture tube glass shell and other special industries. The existing methods of processing heavy soda ash from light soda ash mostly adopt solid phase hydration method and liquid phase hydration method. These two methods are relatively mature in technology. Both methods need to go through light ash calcination process and heavy ash calcination process to produce heavy soda ash. However, both methods have certain defects: solid phase hydration method, due to its process limitations, the particle size of heavy soda ash is uneven, the salt content and other impurities of the alkali are difficult to control, and it is difficult to achieve low salt of heavy ash finished products; liquid phase hydration method, the particle size distribution of sodium carbonate monohydrate that appears in the crystal is difficult to adjust, and it is easy to condense and agglomerate, which affects the particle size of heavy soda ash. In the glass industry, the high salt content of heavy soda ash greatly affects the service life and maintenance of the kiln; the uneven particle size distribution of heavy soda ash will reduce the quality of glass products and increase the difficulty and cost of production. Summary of the invention

[0003] In order to solve at least one problem existing in the above-mentioned prior art, the present invention provides a production process of heavy soda ash, which can reduce the salt content and other impurities in the heavy soda ash and improve the uniformity of the particle size distribution of the heavy soda ash.

[0004] In order to achieve the above object, the present invention adopts the following technical scheme: a production process of heavy soda ash, comprising the following steps:

[0005] (1) At room temperature, dissolve the light ash in soft water to a saturated state, homogenize it under high pressure for the first time, then add a sedimentation aid, stir to produce flocculants, and remove insoluble suspended matter by centrifugation to obtain a saturated light ash aqueous solution;

[0006] (2) evaporating the saturated light ash aqueous solution to remove water until the water content is 20-25%, centrifuging to remove the liquid, adding a saturated sodium carbonate alcohol aqueous solution, centrifuging to remove the solution, and obtaining refined light ash;

[0007] (3) Mixing the refined light ash with a saturated sodium carbonate alcohol aqueous solution, wherein the content of the saturated sodium carbonate alcohol aqueous solution is 34.5-38.2% of the light ash, and then placing it in a hydration machine for hydration reaction. After the hydration is completed, a second high-pressure homogenization is performed, and then the liquid is removed by centrifugation to obtain monohydrate alkali;

[0008] (4) Add saturated sodium carbonate alcohol aqueous solution to sodium carbonate monohydrate for filter pressing. After the filter cake is washed with saturated sodium carbonate aqueous solution, it is placed in a heavy ash calcining furnace for dehydration to obtain heavy soda ash.

[0009] Preferably, the pressure of the first high-pressure homogenization in step (1) is 80-100 MPa, and the homogenization time is 40-60 s.

[0010] Preferably, the sedimentation aid in step (1) is polyacrylamide, and its addition amount is 0.05-0.065% of the weight of the light ash, preferably 0.06%.

[0011] Preferably, in step (3), the saturated sodium carbonate alcohol aqueous solution is 35.3-36.8% of the light ash.

[0012] Preferably, the alkali outlet temperature of the hydration reaction in step (3) is 85-95°C, preferably 90-95°C.

[0013] Preferably, the pressure of the second high-pressure homogenization in step (3) is gradually increased from 10 MPa to 35 MPa.

[0014] Preferably, the rate of gradual pressure increase is 1-2 MPa / s.

[0015] Preferably, in the saturated sodium carbonate alcohol aqueous solution in step (2) and step (4), the alcohol aqueous solution is a mixture of water and ethanol or glycerol in a volume ratio of 4:1.

[0016] Preferably, the amount of saturated sodium carbonate alcohol aqueous solution added in step (2) is 35-45% of the weight of the light ash.

[0017] Preferably, the amount of saturated sodium carbonate alcohol aqueous solution added in step (4) is 35-45% of the weight of the light ash.

[0018] Preferably, the pressure of the filter press in step (4) is controlled at 2-3 MPa.

[0019] Preferably, in step (4), indirect heating and dehydration are performed in a heavy ash calcining furnace using 1.25-1.35 MPa steam.

[0020] The beneficial effects of the present invention are as follows: (1) The present invention adds a process of deep treatment of light ash, which reduces the salt and other solid impurities in the light ash on the one hand, and improves the dispersibility of the light ash on the other hand; (2) The refined light ash of the present invention is subjected to a solid-phase hydration reaction with a sodium carbonate alcohol aqueous solution, which can make the crystallization of monohydrate caustic soda more complete, increase the product particle size, further reduce the salt and other impurities, and improve the product crystal quality; (3) The present invention performs a homogenization treatment on the crystallization mixture after the solid-phase hydration reaction is completed, thereby improving the particle size and dispersibility of monohydrate caustic soda; (4) At the same time, the present invention performs filter pressing on the monohydrate caustic soda before dehydration in the heavy ash calcining furnace, which is beneficial to improving the bulk density of heavy soda ash. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the implementation of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents, instruments, and components used, they are all conventional products that can be purchased commercially.

[0022] The light ash used in the present invention has a total alkali content NaCO3 (on a dry basis) of 98.2% (w), a sodium chloride content (NaCl, on a dry basis) of 1% (w), an iron (Fe, on a dry basis) of 0.008% (w), and a water-insoluble matter of 0.13% (w).

[0023] Example 1

[0024] A production process of heavy soda ash, the specific process steps are as follows:

[0025] (1) At room temperature, 25 kg of light ash was dissolved in soft water to saturation, and high pressure homogenization was performed at a pressure of 80 MPa for 60 seconds. Then 12.5 g of polyacrylamide, a sedimentation aid, was added and stirred for 30 minutes to generate flocs. The insoluble suspended matter was removed by centrifugation at 18000 x g to obtain a saturated light ash aqueous solution.

[0026] (2) evaporating the saturated light ash aqueous solution to remove water, and when the water content is 20%, centrifuging to remove the liquid, adding 8.75 kg of saturated sodium carbonate alcohol aqueous solution, and centrifuging at 18000 x g to remove the solution to obtain refined light ash;

[0027] (3) Mix the refined light ash with 8.63 kg of saturated sodium carbonate alcohol aqueous solution, and then place it in a hydration machine for hydration reaction. Control the alkali output temperature at 85-90°C. After the hydration is completed, perform a second high-pressure homogenization at a rate of 1 MPa / s from 10 MPa to 35 MPa, and then centrifuge at 18,000 x g to remove the liquid to obtain alkali monohydrate;

[0028] (4) 8.75 kg of saturated sodium carbonate alcohol aqueous solution was first added to sodium carbonate monohydrate, and filter press was performed at 2 MPa. The filter cake was washed with 2 kg of saturated sodium carbonate aqueous solution, and then placed in a heavy ash calcining furnace for dehydration. The furnace was indirectly heated and dehydrated with 1.3 MPa steam to obtain heavy soda ash;

[0029] The saturated sodium carbonate alcohol aqueous solution of the present embodiment is prepared by mixing water and glycerol in a volume ratio of 4:1.

[0030] Example 2

[0031] A production process of heavy soda ash, the specific process steps are as follows:

[0032] (1) At room temperature, 25 kg of light ash was dissolved in soft water to saturation, and high pressure homogenization was performed at a pressure of 90 MPa for 50 seconds. Then 15 g of polyacrylamide, a sedimentation aid, was added and stirred for 30 minutes to generate flocs. The insoluble suspended matter was removed by centrifugation at 18000 x g to obtain a saturated light ash aqueous solution.

[0033] (2) evaporating the saturated light ash aqueous solution to remove water until the water content is 22.5%, centrifuging to remove the liquid, adding 10 kg of saturated sodium carbonate alcohol aqueous solution, centrifuging at 18000 x g to remove the solution, and obtaining refined light ash;

[0034] (3) Mix the refined light ash with 8.83 kg of saturated sodium carbonate alcohol aqueous solution, and then place it in a hydration machine for hydration reaction. Control the alkali output temperature at 90-95°C. After the hydration is completed, perform a second high-pressure homogenization from 10 MPa to 35 MPa at a rate of 1.5 MPa / s, and then centrifuge at 18,000 x g to remove the liquid to obtain alkali monohydrate;

[0035] (4) First, 10 kg of saturated sodium carbonate alcohol aqueous solution is added to the monohydrate, and the filter cake is filtered at 2.5 MPa. After the filter cake is washed with saturated sodium carbonate aqueous solution, it is placed in a heavy ash calcining furnace for dehydration. The furnace is indirectly heated and dehydrated with 1.3 MPa steam to obtain heavy soda ash.

[0036] The saturated sodium carbonate alcohol aqueous solution of the present embodiment is prepared by mixing water and ethanol in a volume ratio of 4:1.

[0037] Example 3

[0038] A production process of heavy soda ash, the specific process steps are as follows:

[0039] (1) At room temperature, 25 kg of light ash was dissolved in soft water to saturation, and high-pressure homogenization was performed at a pressure of 100 MPa for 40 seconds. Then, 16.25 kg of polyacrylamide as a sedimentation aid was added and stirred for 30 minutes to generate flocs. The insoluble suspended matter was removed by centrifugation at 18,000 x g to obtain a saturated light ash aqueous solution.

[0040] (2) evaporating the saturated light ash aqueous solution to remove water until the water content is 25%, centrifuging to remove the liquid, adding 11.25 kg of saturated sodium carbonate alcohol aqueous solution, centrifuging at 18000 x g to remove the solution, and obtaining refined light ash;

[0041] (3) Mix the refined light ash with 9 kg of saturated sodium carbonate alcohol aqueous solution, and then place it in a hydration machine for hydration reaction. Control the alkali output temperature at 85-90°C. After the hydration is completed, perform a second high-pressure homogenization from 10 MPa to 35 MPa at a rate of 2 MPa / s, and then centrifuge at 18,000 x g to remove the liquid to obtain alkali monohydrate;

[0042] (4) 11.25 kg of saturated sodium carbonate alcohol aqueous solution was first added to the monohydrate solution, and the filter cake was filtered at 3 MPa. After the filter cake was washed with saturated sodium carbonate aqueous solution, it was placed in a heavy ash calcining furnace for dehydration. The furnace was indirectly heated and dehydrated with 1.3 MPa steam to obtain heavy soda ash.

[0043] The saturated sodium carbonate alcohol aqueous solution of the present embodiment is prepared by mixing water and glycerol in a volume ratio of 4:1.

[0044] Example 4

[0045] A production process of heavy soda ash, the specific process steps are as follows:

[0046] (1) At room temperature, 25 kg of light ash was dissolved in soft water to saturation, and high pressure homogenization was performed at a pressure of 80 MPa for 50 seconds. Then 15 g of polyacrylamide, a sedimentation aid, was added and stirred for 30 minutes to generate flocs. The insoluble suspended matter was removed by centrifugation at 18000 x g to obtain a saturated light ash aqueous solution.

[0047] (2) evaporating the saturated light ash aqueous solution to remove water until the water content is 21%, centrifuging to remove the liquid, adding 10 kg of saturated sodium carbonate alcohol aqueous solution, centrifuging at 18000 x g to remove the solution, and obtaining refined light ash;

[0048] (3) Mix the refined light ash with 9.2 kg of saturated sodium carbonate alcohol aqueous solution, and then place it in a hydration machine for hydration reaction. Control the alkali output temperature at 90-95°C. After the hydration is completed, perform a second high-pressure homogenization at a rate of 1.5 MPa / s from 10 MPa to 35 MPa, and then centrifuge at 18,000 x g to remove the liquid to obtain alkali monohydrate;

[0049] (4) First, 10.5 kg of saturated sodium carbonate alcohol aqueous solution was added to the monohydrate, and the filter cake was filtered at 2.2 MPa. After the filter cake was washed with saturated sodium carbonate aqueous solution, it was placed in a heavy ash calcining furnace for dehydration. The furnace was indirectly heated and dehydrated with 1.3 MPa steam to obtain heavy soda ash.

[0050] The saturated sodium carbonate alcohol aqueous solution of the present embodiment is prepared by mixing water and glycerol in a volume ratio of 4:1.

[0051] Example 5

[0052] A production process of heavy soda ash, the specific process steps are as follows:

[0053] (1) At room temperature, 25 kg of light ash was dissolved in soft water to saturation, and high pressure homogenization was performed at a pressure of 80 MPa for 50 seconds. Then 15 g of polyacrylamide, a sedimentation aid, was added and stirred for 30 minutes to generate flocs. The insoluble suspended matter was removed by centrifugation at 18000 x g to obtain a saturated light ash aqueous solution.

[0054] (2) evaporating the saturated light ash aqueous solution to remove water until the water content is 21%, centrifuging to remove the liquid, adding 10 kg of saturated sodium carbonate alcohol aqueous solution, centrifuging at 18000 x g to remove the solution, and obtaining refined light ash;

[0055] (3) Mix the refined light ash with 9.5 kg of saturated sodium carbonate alcohol aqueous solution, and then place it in a hydration machine for hydration reaction. Control the alkali output temperature at 90-95°C. After the hydration is completed, perform a second high-pressure homogenization from 10 MPa to 35 MPa at a rate of 1.5 MPa / s, and then centrifuge at 18,000 x g to remove the liquid to obtain alkali monohydrate;

[0056] (4) First, 10.5 kg of saturated sodium carbonate alcohol aqueous solution was added to the monohydrate, and the filter cake was filtered at 2.2 MPa. After the filter cake was washed with saturated sodium carbonate aqueous solution, it was placed in a heavy ash calcining furnace for dehydration. The furnace was indirectly heated and dehydrated with 1.3 MPa steam to obtain heavy soda ash.

[0057] The saturated sodium carbonate alcohol aqueous solution of the present embodiment is prepared by mixing water and glycerol in a volume ratio of 4:1.

[0058] Comparative Example 1

[0059] A production process of heavy soda ash, the specific process steps are the same as those of Example 1, except that: step (1) does not involve high-pressure homogenization, and polyacrylamide is directly added under saturated conditions; the remaining steps are the same.

[0060] Comparative Example 2

[0061] A production process of dense soda ash, the specific process steps are the same as those of Example 1, except that: step (3) does not involve high-pressure homogenization, and the solution is directly removed by centrifugation after hydration is completed; the remaining steps are the same.

[0062] Comparative Example 3

[0063] A production process of heavy soda ash, wherein the specific process steps are the same as those of Example 1, except that: in step (4), the soda ash monohydrate is not subjected to filter press treatment, but is directly placed in a heavy ash calcining furnace for dehydration; the remaining steps are the same.

[0064] Comparative Example 4

[0065] A production process of heavy soda ash, the specific process steps are the same as those of Example 1, except that: in step (1), no precipitation aid is added, and after homogenization, the insoluble solid is removed; the remaining steps are the same.

[0066] Comparative Example 5

[0067] A production process of heavy soda ash, the specific process steps are the same as those of Example 1, except that: saturated sodium carbonate aqueous solution replaces saturated sodium carbonate alcohol aqueous solution; the remaining steps are the same.

[0068] Comparative Example 6

[0069] A production process of heavy soda ash, the specific process steps are the same as those in Example 1, except that: in step (3), the content of saturated sodium carbonate alcohol aqueous solution is 34% of the light ash; the remaining steps are the same.

[0070] Comparative Example 7

[0071] A production process of heavy soda ash, the specific process steps are the same as those of Example 1, except that: in step (3), the content of saturated sodium carbonate alcohol aqueous solution is 38.5% of the light ash; the remaining steps are the same.

[0072] The heavy soda ash prepared in the above Examples 1 to 5 and Comparative Examples 1 to 6 was measured according to GB / T 210-2022 Industrial Sodium Carbonate. The results are shown in Tables 1 and 2.

[0073] Table 1 Heavy soda ash prepared in Example 1 to Example 5

[0074]

[0075] Table 2 Heavy soda ash prepared in Comparative Examples 1 to 5

[0076]

[0077] From Table 1 above, it can be found that compared with Examples 1 to 5, in Comparative Example 1, the light ash is not subjected to high-pressure homogenization during the deep treatment, and the particle size of the light ash cannot be made smaller, and the dispersibility is poor. The subsequent treatment cannot fully treat the iron and water-insoluble matter, so that the iron and water-insoluble matter content of the heavy soda ash does not meet the standard, the particle size distribution is wide, and the salt content is relatively high; the monohydrate in Comparative Example 2 is not subjected to high-pressure homogenization, and the agglomerated monohydrate crystals cannot be refined. The particle size dispersibility of the heavy soda ash is poor, and the bulk density of the heavy soda ash is also reduced; the monohydrate in Comparative Example 3 is not subjected to filter press treatment. Since the high-pressure homogenization treatment breaks and refines the agglomerated monohydrate crystals, the crystal size of the monohydrate is The particle size is reduced and loose, thereby reducing the bulk density and particle size dispersion effect of heavy soda ash; in Comparative Example 4, no precipitation aid is used, the insoluble precipitate particles are small and cannot be filtered out, and the insoluble precipitate will adhere to the solid of the centrifuge during centrifugation, resulting in the iron and water-insoluble content of heavy soda ash failing to meet the standards; in Comparative Example 5, saturated sodium carbonate aqueous solution is used, and the crystals cannot be well dispersed during the crystallization of monohydrate, and the crystallization is not sufficient, so that the salt and impurities are wrapped, which relatively increases the salt, iron, and water-insoluble content of heavy soda ash; in Comparative Examples 6 and 7, the amount of saturated sodium carbonate aqueous solution used is large or small, which will affect the particle size and particle distribution of heavy soda ash.

[0078] In summary, the production process of heavy soda ash of the present invention can reduce the salt content and other impurities of heavy soda ash and improve the uniformity of the particle size distribution of heavy soda ash.

[0079] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit and essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0080] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A production process for heavy soda ash, characterized in that: The following steps are involved: (1) At room temperature, dissolve the light ash in soft water to a saturated state, homogenize under high pressure for the first time, then add a sedimentation aid, stir, and centrifuge to obtain a saturated light ash aqueous solution; (2) evaporating the saturated light ash aqueous solution to a water content of 20-25%, centrifuging, adding a saturated sodium carbonate alcohol aqueous solution, centrifuging, and obtaining refined light ash; (3) Mixing the refined light ash with a saturated sodium carbonate alcohol aqueous solution, wherein the content of the saturated sodium carbonate alcohol aqueous solution is 34.5-38.2% of the light ash, and then placing it in a hydration machine for hydration reaction. After the hydration is completed, it is subjected to a second high-pressure homogenization, and then centrifuged to obtain monohydrate alkali; (4) adding a saturated aqueous sodium carbonate alcohol solution to sodium carbonate monohydrate for filter pressing, washing the filter cake with a saturated aqueous sodium carbonate solution, and placing it in a heavy ash calcining furnace for dehydration to obtain heavy soda ash; The saturated sodium carbonate alcohol aqueous solution is a mixture of water and ethanol or glycerol in a volume ratio of 4:

1.

2. The production process of heavy soda ash according to claim 1, characterized in that: In step (1), the pressure of the first high-pressure homogenization is 80-100 MPa, and the homogenization time is 40-60 s.

3. The production process of heavy soda ash according to claim 1, characterized in that: In step (1), the sedimentation aid is polyacrylamide, and the amount added is 0.05-0.065% of the weight of the light ash.

4. The production process of heavy soda ash according to claim 1, characterized in that: In step (3), the saturated sodium carbonate alcohol aqueous solution is 35.3-36.8% of the light ash.

5. The production process of heavy soda ash according to claim 1, characterized in that: In step (3), the alkali outlet temperature of the hydration reaction is between 85 and 95°C.

6. The production process of heavy soda ash according to claim 1, characterized in that: In step (3), the pressure of the second high-pressure homogenization is gradually increased from 10 MPa to 35 MPa.

7. The production process of heavy soda ash according to claim 6, characterized in that: The rate of gradual pressure increase is 1~2Mpa / s.

8. The production process of heavy soda ash according to claim 1, characterized in that: In the saturated sodium carbonate alcohol aqueous solution in step (2) and step (4), the alcohol aqueous solution is a mixture of water and ethanol or glycerol in a volume ratio of 4:1, and the added amount of the saturated sodium carbonate alcohol aqueous solution is 35-45% of the weight of the light ash.

9. The production process of heavy soda ash according to claim 1, characterized in that: In step (4), the pressure of the filter press is controlled at 2-3 MPa.

10. The production process of heavy soda ash according to claim 1, characterized in that: In step (4), 1.25-1.35 MPa steam is used in the heavy ash calcining furnace for indirect heating and dehydration.

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