A comprehensive utilization method of kaolin to remove iron-mica slag

Abstract

The invention relates to the technical field of environmental protection, and discloses a method for comprehensive utilization of kaolin iron-removing mica residue, comprising the following steps: (1) obtaining a mixture; (2) performing filter pressing treatment, evaporating and crystallizing to obtain sodium aluminate, countercurrent washing, and returning the second liquid obtained after filter pressing to prepare a slurry, and the remaining second solid is used for standby; (3) obtaining a mixture; (4) obtaining a soil conditioner; (5) countercurrent washing the obtained second filter residue, and returning it to mix with biogas residue for composting, and the remaining washing water is returned to prepare a slurry; (6) performing filter pressing after precipitating rare earths to precipitate lithium, rubidium, etc.; (7) recycling the washing water obtained above to perform permeation membrane filtration treatment when the potassium chloride in the washing water exceeds a certain concentration, and returning the washing water to prepare a slurry; the method of the invention can greatly improve the comprehensive utilization of kaolin iron-removing mica residue, thereby greatly improving the resource utilization rate and avoiding environmental pollution caused by a large amount of waste of iron-removing mica residue.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, in particular to a comprehensive utilization method of kaolin ore-removing mica slag. Background Art

[0002] Kaolin has excellent properties and can be widely used in papermaking, ceramics, refractory materials and other industries. However, kaolin produced in nature often presents different colors, such as red kaolin or brown kaolin. This is because kaolin produced in nature contains dyeing impurities, which affect the whiteness and performance of kaolin, which greatly reduces the commercial value and application performance of kaolin, and thus limits the expansion of kaolin application. The main impurities that cause kaolin dyeing in nature are tertiary iron oxides.

[0003] With the increase in the use of kaolin, kaolin companies need to carry out iron removal in order to ensure whiteness, which will produce a large amount of tailings solid waste (kaolin iron removal mica slag). The industry generally adopts methods such as extracting sodium silicate from kaolin tailings and preparing kaolin tailings lightweight through-pored ceramsite. The comprehensive utilization channels are narrow and the amount of solid waste reduction is small. Combined with the current trend of the kaolin industry, based on the principle of turning waste into treasure and material circulation, a method for large-scale reduction of solid waste and efficient comprehensive utilization of materials has been invented.

[0004] Based on this, we proposed a comprehensive utilization method of kaolin to remove iron-mica slag, hoping to solve the shortcomings of the existing technology. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies in the prior art, the present invention provides a comprehensive utilization method for kaolin minus iron-mica slag.

[0007] (II) Technical solution

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0009] A comprehensive utilization method of kaolinite slag with iron removal and mica residue, comprising the following steps:

[0010] (1) adding water to kaolinite iron-removing mica residue to prepare a slurry, adding solid sodium hydroxide, stirring at a speed of 500 r / min for 20 min, adjusting the pH of the system to 14, heating the temperature to 65-80° C., and continuing to stir for 2-3 hours to obtain a mixed material;

[0011] (2) The mixed material of step (1) is pumped to a plate-frame filter press by a plunger pump for filtration treatment, and then the obtained first liquid is evaporated and crystallized to obtain sodium aluminate. The obtained first solid is countercurrently washed and filtered to obtain a second liquid which is returned to step (1) for slurry preparation, and the remaining second solid is used for standby;

[0012] (3) mixing the second solid obtained in step (2) with hydrochloric acid, adjusting the pH to 3-4, and then adding 2-10% of the total mass of sodium chloride after the previous mixture, stirring evenly, and stacking for 2-12 hours to obtain a mixture;

[0013] (4) putting the mixture obtained in step (3) into a stirring barrel, adding water, stirring for 20-30 minutes, and then pumping it into a filter press with a plunger pump for filter pressing to obtain a first filtrate for standby use, using clean water to backwash the first filter residue until the pH reaches 6.5, and then adding it to the biogas residue at a mass ratio of 2-5:30 for composting, and then adding magnesium ammonium phosphate and stirring evenly to obtain a soil conditioner;

[0014] (5) The first filtrate of step (4) is put into a reaction barrel, and the pH value is adjusted to 4 with bicarbonate. After removing impurities such as iron and silicon, the filtrate is added to a filter press for solid-liquid separation to obtain a third liquid for standby use. The obtained second filter residue is backwashed in reverse flow and returned to step (4) for mixing with biogas residue for retting in a mass ratio of 1-2:40. The remaining washing water is returned to step (1) for slurry preparation;

[0015] (6) adding the first precipitant to the third liquid of step (5) to precipitate rare earths and then filtering, and adding the second precipitant to the obtained fourth liquid to precipitate lithium, rubidium, etc.;

[0016] (7) The wash water obtained above is recycled until the potassium chloride in the wash water exceeds a certain concentration, and then subjected to membrane filtration treatment, and then subjected to evaporation and crystallization treatment. The treated wash water is then returned to step (1) for slurry preparation.

[0017] As a further technical solution, in step (1), the kaolin iron-removing mica slag is slurried with water as follows:

[0018] Mix kaolin iron-removing mica slag and water in a mass ratio of 1:30-40.

[0019] As a further technical solution, the filtration pressure in step (2) is 0.6 MPa.

[0020] As a further technical solution: the evaporation crystallization temperature in step (2) is 90°C and the stirring speed is 40r / min.

[0021] As a further technical solution, the concentration of hydrochloric acid in step (3) is 5 mol / L;

[0022] The stacking temperature is 30-35°C.

[0023] As a further technical solution, the mass ratio of the mixture to water in step (4) is 1:25.

[0024] As a further technical solution: in step (4), the ammonium magnesium phosphate is ammonium magnesium phosphate hexahydrate;

[0025] Among them, the mixing mass ratio of sludge and ammonium magnesium phosphate is 50:1-2.

[0026] As a further technical solution: in step (5), the bicarbonate is ammonium bicarbonate or sodium bicarbonate.

[0027] As a further technical solution, in step (6), the first precipitant is: carbonate or oxalic acid;

[0028] The carbonate is ammonium bicarbonate or sodium bicarbonate;

[0029] The mass ratio of the third liquid to the first precipitant is 25:3-4;

[0030] The second precipitant is trisodium phosphate or potassium phosphate;

[0031] The mixing mass ratio of the fourth liquid to the second precipitant is 22:2-3.

[0032] As a further technical solution: in step (7), the potassium chloride exceeds a certain concentration of more than 3% by mass

[0033] Kaolin slag except iron contains aluminum, potassium and a small amount of lithium, rubidium and rare earth.

[0034] The filter press used is: automatic plate filter press;

[0035] The automatic platen filter press is driven by a motor and realizes automatic filtration through an automatic platen system;

[0036] Main parameters:

[0037] Model: XMZ-100 / 1000-U;

[0038] Filter plate size: 1000mm×1000mm;

[0039] Processing capacity: 20m 3 / h;

[0040] Filtration pressure: 0.6MPa.

[0041] The soil conditioner obtained in the present invention contains a variety of nutrients (such as nitrogen, phosphorus, potassium, trace elements) and organic substances such as organic matter, crude protein, amino acids, cellulose, hemicellulose, lignin, humic acid, etc., which can greatly improve the physical and chemical properties of the soil. At the same time, by treating the kaolin iron-removing mica residue of the present invention and introducing it into the biogas residue, the obtained soil conditioner is added to the soil, which can promote the production of stress-resistant substances, various hydrolases, auxins and certain antibiotics, beneficial bacteria, etc. in the soil, and these substances have the effects of promoting plant growth and development, improving soil, enhancing crop stress resistance, and thus improving crop yield and quality.

[0042] (III) Beneficial effects

[0043] Compared with the prior art, the present invention provides a comprehensive utilization method of kaolin to remove iron-containing mica residue, which has the following beneficial effects:

[0044] The method of the invention can greatly improve the comprehensive utilization of kaolin iron-removed mica slag, thereby greatly improving the resource utilization rate and avoiding environmental pollution caused by a large amount of waste of iron-removed mica slag.

[0045] The present invention can obtain a variety of by-products such as sodium aluminate, rare earth products, lithium, rubidium and the like through comprehensive utilization of iron-removing mica slag, and can also obtain a soil conditioner with excellent performance. The soil improved by the soil conditioner has a significant improvement on the growth index of plants, and the water retention performance of the soil is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a bar graph showing the effect of soil amendment on cucumber yield;

[0047] Figure 2 This is a diagram showing the influence of soil conditioners in different proportions on soil water retention performance. DETAILED DESCRIPTION

[0048] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0049] The following are specific embodiments:

[0050] Example 1

[0051] A comprehensive utilization method of kaolinite slag with iron removal and mica residue, comprising the following steps:

[0052] (1) After slurrying with water, solid sodium hydroxide was added to the kaolinite mica slag after iron removal, and the mixture was stirred at a speed of 500 r / min for 20 min, the pH value of the system was adjusted to 14, the temperature was heated to 65° C., and stirring was continued for 2 hours to obtain a mixed material; the slurrying of the kaolinite mica slag after iron removal was as follows:

[0053] Mix kaolin slag minus iron and mica with water in a mass ratio of 1:30.

[0054] (2) The mixed material of step (1) is pumped to a plate-frame filter press by a plunger pump for filtration, and then the obtained first liquid is evaporated and crystallized to obtain sodium aluminate. The obtained first solid is countercurrently washed and filtered, and the second liquid obtained is returned to step (1) for slurry adjustment, and the remaining second solid is used for standby; the filtration pressure is 0.6 MPa. The evaporation crystallization temperature is 90° C., and the stirring speed is 40 r / min.

[0055] (3) The second solid obtained in step (2) is stirred and mixed with hydrochloric acid to adjust the pH to 3, and then 2% of the total mass of sodium chloride after the previous mixture is added, and after stirring evenly, it is stacked for 2 hours to obtain a mixture; the concentration of hydrochloric acid is 5 mol / L;

[0056] The stacking temperature is 30°C.

[0057] (4) putting the mixture obtained in step (3) into a stirring barrel, adding water, stirring for 20 minutes, and then pumping it into a filter press with a plunger pump for filter pressing to obtain a first filtrate for standby use, using clean water to countercurrent wash the first filter residue until the pH reaches 6.5, and then adding it to the biogas residue in a mass ratio of 2:30 for composting, and then adding magnesium ammonium phosphate and stirring evenly to obtain a soil conditioner; the mass ratio of the mixture to water is 1:25; the magnesium ammonium phosphate is magnesium ammonium phosphate hexahydrate;

[0058] Among them, the mixing mass ratio of sludge and ammonium magnesium phosphate is 50:1.

[0059] (5) The first filtrate of step (4) is put into a reaction barrel, and the pH value is adjusted to 4 with ammonium bicarbonate or sodium bicarbonate. After removing impurities such as iron and silicon, the filtrate is added to a filter press for solid-liquid separation to obtain a third liquid for standby use. The obtained second filter residue is backwashed in reverse flow and returned to step (4) for mixing with biogas residue for retting at a mass ratio of 1:40. The remaining washing water is returned to step (1) for slurry preparation. The mass ratio of the third liquid to the first precipitant is 25:3.

[0060] (6) adding carbonate or oxalic acid to the third liquid of step (5) to precipitate rare earths and then filtering, and adding trisodium phosphate or potassium phosphate to the obtained fourth liquid to precipitate lithium, rubidium, etc.; the carbonate is ammonium bicarbonate or sodium bicarbonate;

[0061] The mixing mass ratio of the fourth liquid to the second precipitant is 22:2.

[0062] (7) The wash water obtained above is recycled until the potassium chloride in the wash water exceeds a certain concentration, and then subjected to membrane filtration treatment, and then subjected to evaporation and crystallization treatment, and the treated wash water is returned to step (1) for slurry preparation; the potassium chloride concentration exceeding the certain concentration is more than 3% by mass.

[0063] Example 2

[0064] A comprehensive utilization method of kaolinite slag with iron removal and mica residue, comprising the following steps:

[0065] (1) After slurrying with water, solid sodium hydroxide was added to the kaolinite iron removal mica slag, and the mixture was stirred at a speed of 500 r / min for 20 min, the pH value of the system was adjusted to 14, the temperature was heated to 68° C., and stirring was continued for 2.5 hours to obtain a mixed material; the slurrying of the kaolinite iron removal mica slag with water was as follows:

[0066] Mix kaolin slag minus iron and mica with water in a mass ratio of 1:32.

[0067] (2) The mixed material of step (1) is pumped to a plate-frame filter press by a plunger pump for filtration, and then the obtained first liquid is evaporated and crystallized to obtain sodium aluminate. The obtained first solid is countercurrently washed and filtered, and the second liquid obtained is returned to step (1) for slurry adjustment, and the remaining second solid is used for standby; the filtration pressure is 0.6 MPa. The evaporation crystallization temperature is 90° C., and the stirring speed is 40 r / min.

[0068] (3) The second solid obtained in step (2) is stirred and mixed with hydrochloric acid to adjust the pH to 3.5, and then 4% of the total mass of sodium chloride after the previous mixture is added, and the mixture is stirred evenly and stacked for 5 hours to obtain a mixture; the concentration of the hydrochloric acid is 5 mol / L;

[0069] The stacking temperature was 32°C.

[0070] (4) putting the mixture obtained in step (3) into a stirring barrel, adding water, stirring for 20-30 minutes, and then pumping it into a filter press with a plunger pump for filter pressing to obtain a first filtrate for standby use, using clean water to countercurrent wash the first filter residue until the pH reaches 6.5, and then adding it to the biogas residue in a mass ratio of 3:30 for composting, and then adding magnesium ammonium phosphate and stirring evenly to obtain a soil conditioner; the mass ratio of the mixture to water is 1:25; the magnesium ammonium phosphate is magnesium ammonium phosphate hexahydrate;

[0071] Among them, the mixing mass ratio of sludge and ammonium magnesium phosphate is 50:1.5.

[0072] (5) The first filtrate of step (4) is put into a reaction barrel, and the pH value is adjusted to 4 with ammonium bicarbonate or sodium bicarbonate. After removing impurities such as iron and silicon, the filtrate is added to a filter press for solid-liquid separation to obtain a third liquid for standby use. The obtained second filter residue is backwashed in reverse flow and returned to step (4) for mixing with biogas residue for retting at a mass ratio of 1.6:40. The remaining washing water is returned to step (1) for slurry preparation. The mass ratio of the third liquid to the first precipitant is 25:3.5.

[0073] (6) adding carbonate or oxalic acid to the third liquid of step (5) to precipitate rare earths and then filtering, and adding trisodium phosphate or potassium phosphate to the obtained fourth liquid to precipitate lithium, rubidium, etc.; the carbonate is ammonium bicarbonate or sodium bicarbonate;

[0074] The mixing mass ratio of the fourth liquid to the second precipitant is 22:2.8.

[0075] (7) The wash water obtained above is recycled until the potassium chloride in the wash water exceeds a certain concentration, and then subjected to membrane filtration treatment, and then subjected to evaporation and crystallization treatment, and the treated wash water is returned to step (1) for slurry preparation; the potassium chloride concentration exceeding the certain concentration is more than 3% by mass.

[0076] Example 3

[0077] A comprehensive utilization method of kaolinite slag with iron removal and mica residue, comprising the following steps:

[0078] (1) After slurrying with water, solid sodium hydroxide was added to the kaolinite mica slag after iron removal, and the mixture was stirred at a speed of 500 r / min for 20 min, the pH value of the system was adjusted to 14, the temperature was heated to 75° C., and stirring was continued for 2.5 hours to obtain a mixed material; the slurrying of the kaolinite mica slag after iron removal was as follows:

[0079] Mix kaolin slag minus iron and mica with water in a mass ratio of 1:38.

[0080] (2) The mixed material of step (1) is pumped to a plate-frame filter press by a plunger pump for filtration, and then the obtained first liquid is evaporated and crystallized to obtain sodium aluminate. The obtained first solid is countercurrently washed and filtered, and the second liquid obtained is returned to step (1) for slurry adjustment, and the remaining second solid is used for standby; the filtration pressure is 0.6 MPa. The evaporation crystallization temperature is 90° C., and the stirring speed is 40 r / min.

[0081] (3) The second solid obtained in step (2) is stirred and mixed with hydrochloric acid to adjust the pH to 3.8, and then 8% of the total mass of sodium chloride after the previous mixture is added, and the mixture is stirred evenly and stacked for 10 hours to obtain a mixture; the concentration of the hydrochloric acid is 5 mol / L;

[0082] The stacking temperature was 33°C.

[0083] (4) putting the mixture obtained in step (3) into a stirring barrel, adding water, stirring for 25 minutes, and then pumping it into a filter press with a plunger pump for filter pressing to obtain a first filtrate for standby use, using clean water to countercurrent wash the first filter residue until the pH reaches 6.5, and then adding it to the biogas residue in a mass ratio of 4:30 for composting, and then adding magnesium ammonium phosphate and stirring evenly to obtain a soil conditioner; the mass ratio of the mixture to water is 1:25; the magnesium ammonium phosphate is magnesium ammonium phosphate hexahydrate;

[0084] Among them, the mixing mass ratio of sludge and ammonium magnesium phosphate is 50:1.5.

[0085] (5) The first filtrate of step (4) is put into a reaction barrel, and the pH value is adjusted to 4 with ammonium bicarbonate or sodium bicarbonate. After removing impurities such as iron and silicon, the filtrate is added to a filter press for solid-liquid separation to obtain a third liquid for standby use. The obtained second filter residue is backwashed in reverse flow and returned to step (4) for mixing with biogas residue for retting at a mass ratio of 1.8:40. The remaining washing water is returned to step (1) for slurry preparation. The mass ratio of the third liquid to the first precipitant is 25:3.5.

[0086] (6) adding carbonate or oxalic acid to the third liquid of step (5) to precipitate rare earths and then filtering, and adding trisodium phosphate or potassium phosphate to the obtained fourth liquid to precipitate lithium, rubidium, etc.; the carbonate is ammonium bicarbonate or sodium bicarbonate;

[0087] The mixing mass ratio of the fourth liquid to the second precipitant is 22:2.8.

[0088] (7) The wash water obtained above is recycled until the potassium chloride in the wash water exceeds a certain concentration, and then subjected to membrane filtration treatment, and then subjected to evaporation and crystallization treatment, and the treated wash water is returned to step (1) for slurry preparation; the potassium chloride concentration exceeding the certain concentration is more than 3% by mass.

[0089] Example 4

[0090] A comprehensive utilization method of kaolinite slag with iron removal and mica residue, comprising the following steps:

[0091] (1) After slurrying with water, solid sodium hydroxide was added to the kaolinite iron removal mica slag, and the mixture was stirred at a speed of 500 r / min for 20 min, the pH value of the system was adjusted to 14, the temperature was heated to 80° C., and stirring was continued for 3 hours to obtain a mixed material; the slurrying of the kaolinite iron removal mica slag with water was as follows:

[0092] Mix kaolin slag minus iron and mica with water in a mass ratio of 1:40.

[0093] (2) The mixed material of step (1) is pumped to a plate-frame filter press by a plunger pump for filtration, and then the obtained first liquid is evaporated and crystallized to obtain sodium aluminate. The obtained first solid is countercurrently washed and filtered, and the second liquid obtained is returned to step (1) for slurry adjustment, and the remaining second solid is used for standby; the filtration pressure is 0.6 MPa. The evaporation crystallization temperature is 90° C., and the stirring speed is 40 r / min.

[0094] (3) The second solid obtained in step (2) is stirred and mixed with hydrochloric acid, and the pH is adjusted to 4, and then 10% of the total mass of sodium chloride after the previous mixture is added, and the mixture is stirred evenly and stacked for 12 hours to obtain a mixture; the concentration of the hydrochloric acid is 5 mol / L;

[0095] The stacking temperature is 35°C.

[0096] (4) putting the mixture obtained in step (3) into a stirring barrel, adding water, stirring for 20-30 minutes, and then pumping it into a filter press with a plunger pump for filter pressing to obtain a first filtrate for standby use, using clean water to countercurrent wash the first filter residue until the pH reaches 6.5, and then adding it to the biogas residue in a mass ratio of 5:30 for composting, and then adding magnesium ammonium phosphate and stirring evenly to obtain a soil conditioner; the mass ratio of the mixture to water is 1:25; the magnesium ammonium phosphate is magnesium ammonium phosphate hexahydrate;

[0097] Among them, the mixing mass ratio of sludge and ammonium magnesium phosphate is 50:2.

[0098] (5) The first filtrate of step (4) is put into a reaction barrel, and the pH is adjusted to 4 with ammonium bicarbonate or sodium bicarbonate. After removing impurities such as iron and silicon, it is added to a filter press for solid-liquid separation to obtain a third liquid for standby use. The obtained second filter residue is backwashed in reverse flow and returned to step (4) for mixing with biogas residue for retting, and the mixture is added in a mass ratio of 2:40. The remaining washing water is returned to step (1) for slurry preparation; the mass ratio of the third liquid to the first precipitant is 25:4;

[0099] (6) adding carbonate or oxalic acid to the third liquid of step (5) to precipitate rare earths and then filtering, and adding trisodium phosphate or potassium phosphate to the obtained fourth liquid to precipitate lithium, rubidium, etc.; the carbonate is ammonium bicarbonate or sodium bicarbonate;

[0100] The mixing mass ratio of the fourth liquid to the second precipitant is 22:3.

[0101] (7) The wash water obtained above is recycled until the potassium chloride in the wash water exceeds a certain concentration, and then subjected to membrane filtration treatment, and then subjected to evaporation and crystallization treatment, and the treated wash water is returned to step (1) for slurry preparation; the potassium chloride concentration exceeding the certain concentration is more than 3% by mass.

[0102] test:

[0103] The basic physical and chemical properties of the test soil are: pH 7.8, alkaline nitrogen 14.5 mg / kg, available phosphorus 19.2 mg / kg, available potassium 83.1 mg / kg, and organic matter 5.6 g / kg.

[0104] 50 cucumber seedlings with uniform growth and no pests and diseases were selected, and the soil conditioner in the embodiment was mixed with the soil at a mass ratio of 19:1, and the control group was not added. 10 kg of soil was added to each pot, and one cucumber seedling was planted respectively, and the growth index was measured after 30 days;

[0105] Table 1

[0106] Plant height(cm) Stem diameter (cm) Number of blades Example 1 107.63 7.54 12.82 Example 2 107.41 7.51 12.73 Example 3 107.25 7.49 12.68 Example 4 106.88 7.38 12.64 Control group 65.35 5.22 8.57

[0107] It can be seen from Table 1 that after the soil is improved by the soil conditioner obtained in the present invention, the growth index of cucumbers after planting is greatly improved.

[0108] Further experiments were conducted to compare the yield of cucumber per plant in each group;

[0109] Table 2

[0110] Yield per plant / kg Example 1 2.71 Example 2 2.76 Example 3 2.82 Example 4 2.73 Control group 1.65

[0111] It can be seen from Table 2 that the soil improved by the soil conditioner of the present invention can be greatly improved.

[0112] Taking Example 1 as the basic sample, the soil conditioner in Comparative Example 1 was mixed with soil at a mass ratio of 19:1, and then the water retention test was carried out:

[0113] Table 3

[0114] Water absorption g / g Example 1 4.38 Example 2 4.29 Example 3 4.36 Example 4 4.34 Control group 2.81

[0115] It can be seen from Table 3 that the water retention capacity of the soil can be greatly improved by introducing soil conditioners.

[0116] Figure 1 This is a bar graph showing the effect of soil amendment on cucumber yield;

[0117] Figure 2 This is a diagram showing the influence of soil conditioners in different proportions on soil water retention performance.

[0118] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A comprehensive utilization method of kaolin iron-removing mica slag, characterized in that: The following steps are involved: (1) After slurrying with water, solid sodium hydroxide was added to the kaolinite iron-removing mica residue, and the mixture was stirred at a speed of 500 r / min for 20 min, the pH value of the system was adjusted to 14, the temperature was heated to 65-80° C., and stirring was continued for 2-3 hours to obtain a mixed material; (2) The mixed material of step (1) is pumped to a plate-frame filter press by a plunger pump for filtration treatment, and then the obtained first liquid is evaporated and crystallized to obtain sodium aluminate. The obtained first solid is countercurrently washed and filtered, and the obtained second liquid is returned to step (1) for slurry preparation, and the remaining second solid is reserved; (3) The second solid obtained in step (2) is stirred and mixed with hydrochloric acid to adjust the pH to 3-4, and then 2-10% of the total mass of sodium chloride is added to the mixture, and the mixture is stirred evenly and stacked for 2-12 hours to obtain a mixture; (4) The mixture obtained in step (3) is put into a stirring barrel, and water is added, and stirred for 20-30 minutes, and then pumped into a filter press by a plunger pump for filter pressing treatment to obtain a first filtrate for standby use, and the first filter residue is backwashed with clean water until the pH reaches 6.5, and then added to the biogas residue in a mass ratio of 2-5:30 for composting, and then magnesium ammonium phosphate is added and stirred evenly to obtain a soil conditioner; (5) The first filtrate of step (4) is put into a reaction barrel, and the pH value is adjusted to 4 with bicarbonate. After removing iron and silicon impurities, it is added to a filter press for solid-liquid separation to obtain a third liquid for standby use. The obtained second filter residue is backwashed and returned to step (4) for mixing with biogas residue for retting at a mass ratio of 1-2:

40. The remaining washing water is returned to step (1) for slurry preparation; (6) adding the first precipitant to the third liquid of step (5) to precipitate rare earth and then filtering, and adding the second precipitant to the obtained fourth liquid to precipitate lithium or rubidium; (7) The obtained washing water is recycled until the potassium chloride in the washing water exceeds a certain concentration, and then subjected to membrane filtration treatment, and then subjected to evaporation and crystallization treatment. The treated washing water is then returned to step (1) for slurry preparation.

2. The comprehensive utilization method of kaolin iron-removing mica slag according to claim 1, characterized in that: Step (1) The kaolinite slag is slurried with water and iron removed mica residue to prepare the slurry: Mix kaolin iron-removing mica slag and water in a mass ratio of 1:30-40.

3. The comprehensive utilization method of kaolin iron-removing mica slag according to claim 1, characterized in that: The pressure of the filter press in step (2) is 0.6 MPa.

4. The comprehensive utilization method of kaolin iron-removing mica slag according to claim 1, characterized in that: The evaporation crystallization temperature in step (2) is 90° C. and the stirring speed is 40 r / min.

5. The comprehensive utilization method of kaolin iron-removing mica slag according to claim 1, characterized in that: The concentration of hydrochloric acid in step (3) is 5 mol / L; The stacking temperature is 30-35°C.

6. The comprehensive utilization method of kaolin iron-removing mica slag according to claim 1, characterized in that: The mass ratio of the mixture to water in step (4) is 1:

25.

7. The comprehensive utilization method of kaolin iron-removing mica slag according to claim 1, characterized in that: In step (4), the ammonium magnesium phosphate is ammonium magnesium phosphate hexahydrate; Among them, the mixing mass ratio of sludge and ammonium magnesium phosphate is 50:1-2.

8. The comprehensive utilization method of kaolin iron-removing mica slag according to claim 1, characterized in that: In step (5), the bicarbonate is ammonium bicarbonate or sodium bicarbonate.

9. The comprehensive utilization method of kaolin iron-removing mica slag according to claim 1, characterized in that: In step (6), the first precipitant is: carbonate or oxalic acid; The carbonate is ammonium bicarbonate or sodium bicarbonate; The mass ratio of the third liquid to the first precipitant is 25:3-4; The second precipitant is trisodium phosphate or potassium phosphate; The mixing mass ratio of the fourth liquid to the second precipitant is 22:2-3.

10. The comprehensive utilization method of kaolin iron-removing mica slag according to claim 1, characterized in that: In step (7), the potassium chloride exceeds a certain concentration of more than 3% by mass.

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