Method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide

Abstract

Described is a method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide. This method includes a. adding an aluminum salt to the brine, adding an alkali solution, then subjecting to crystallization reaction and solid-liquid separation to obtain lithium-containing brine; b. evaporating and concentrating the lithium-containing brine, adding an aluminum salt, adding an alkali solution dropwise to perform a co-precipitation reaction and solid-liquid separation to obtain a lithium-containing layered material filter cake, wherein in steps a and b, the alkali solution is an alkali solution free of carbonate ion; c. dispersing the lithium-containing layered material filter cake in deionized water to form a suspension slurry, then adjusting the pH value of the suspension slurry so as to carry out a lithium deintercalation reaction; d. filtering to obtain aluminum hydroxide filter cake; e. washing the aluminum hydroxide filter cake with deionized water and drying.

Claims

1. A method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide, the method comprising: a. adding an aluminum salt to a salt lake brine to obtain a mixed salt solution A, adding an alkali solution to the mixed salt solution A for co-precipitation reaction, then subjecting to crystallization reaction and solid-liquid separation at the end of the crystallization reaction to obtain magnesium-aluminum hydrotalcite solid product and lithium-containing brine, wherein in step a, the alkali solution is an alkali solution free of carbonate ion; b. evaporating and concentrating the lithium-containing brine to obtain a lithium-rich brine, adding an aluminum salt to the lithium-rich brine to obtain a mixed salt solution B, adding an alkali solution dropwise to the mixed salt solution B to perform a co-precipitation reaction and solid-liquid separation after the end of the reaction to obtain a lithium-containing liquid and a lithium-containing layered material filter cake, wherein in step b, the alkali solution is an alkali solution free of carbonate ion and wherein in step b, the lithium-containing layered material has a chemical formula LiAlx(OH)3xCl mH2O, where x=1-10, and m=1-10; c. dispersing the lithium-containing layered material filter cake in deionized water to form a suspension slurry, then adjusting the pH value of the suspension slurry so as to carry out a lithium deintercalation reaction; d. filtering the slurry obtained after the lithium deintercalation reaction to obtain a lithium-containing solution and aluminum hydroxide filter cake; and e. washing the aluminum hydroxide filter cake with deionized water and drying to obtain aluminum hydroxide solid.

2. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein the brine in step a is sulfate type or chloride type salt lake brine, which is rich in Li+, Mg2+, K+, and Na+, and in which the concentration of Li+ is 1-3 g/L, the concentration of Mg2+ is 10-30 g/L, the concentration of K+ is 5-7 g/L, and the concentration of Na+ is 70-90 g/L, with respect to the total volume of the brine.

3. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step b, the lithium ion concentration in the lithium-rich brine is 0.1-0.5 g/L with respect to the total volume of the lithium-rich brine.

4. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step b, the molar concentration of lithium ion is 1-6 times that of aluminum ion in the mixed salt solution B.

5. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step b, the aluminum salt is aluminum nitrate and/or aluminum chloride.

6. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step b, the alkali solution has a molar concentration of 2-4 mol/L with respect to its total volume; and the alkali solution is added dropwise at a rate of 1-2 mL/min.

7. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step b, the alkali solution is aqueous sodium hydroxide solution and/or aqueous potassium hydroxide solution.

8. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step b, the co-precipitation reaction is carried out at a temperature of 40° C.-100° C. for a period of 6-24 hours, with the pH controlled at 7-8 during the reaction.

9. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step b, the lithium-containing layered material filter cake has a solid content of 60-95%.

10. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step b, the concentration of Li+ is 0.01-0.05 g/L, the concentration of K+ is 0.5-1 g/L, the concentration of Na+ is 40-60 g/L, the concentration of Cl− is 50-70 g/L, and the concentration of SO.sub.4.sup.2− is 1-5 g/L in the lithium-containing liquid, with respect to the total volume of the lithium-containing liquid.

11. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, further comprising an operation of evaporating and concentrating the lithium-containing liquid from step b to a lithium ion concentration of 0.1-0.5 g/L and then recycling it as the lithium-containing brine.

12. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step c, the suspension slurry has a solid content of 5-50 g/L with respect to the total volume of the suspension slurry.

13. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step c, the adjusting the pH value of the suspension slurry is to adjust the pH value of the suspension slurry to 5-8.

14. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step c, the pH value of the suspension slurry is adjusted to 5-8 by using hydrochloric acid or aqueous sodium hydroxide solution with a molar concentration of 2-4 mol/L.

15. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step c, the lithium deintercalation reaction is carried out at a temperature of 60° C.-100° C. for a period of 30 to 180 minutes.

16. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step c, the lithium deintercalation reaction is carried out at a stirring rate of 30-200 rpm.

17. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, further comprising an operation of evaporating and concentrating the lithium-containing solution from step d to a lithium ion concentration of 20-25 g/L and then using it as a lithium solution for preparing battery grade lithium carbonate.

18. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step e, the washing with deionized water is repeated 3 to 5 times.

19. The method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide according to claim 1, wherein in step e, the drying is carried out at 60° C.-80° C. for 3-12 hours.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is the XRD pattern of the lithium-containing layered material prepared in Example 1 of the present disclosure.

(2) FIG. 2 is the transmission electron micrograph of the lithium-containing layered material prepared in Example 1 of the present disclosure.

DETAILED DESCRIPTION

(3) In order to more clearly understanding the technical features, purposes and beneficial effects of the present disclosure, the implementation process and beneficial effects of the present disclosure will now be described below in details through specific examples and drawings, which is intended to help readers better understand the essence and features of the present disclosure, but not to limit the implementable scope of the present disclosure.

Example 1

(4) This Example provides a method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide, wherein the method includes the following steps:

(5) a. According to the method disclosed in Chinese Patent Application CN 105152193 A, weighing 26.0325 g of MgCl.sub.2.6H.sub.2O, 25.7993 g of MgSO.sub.4.7H.sub.2O, 18.7290 g of AlCl.sub.3.6H.sub.2O, 3.3873 g of KCl, 1.8768 g of LiCl, 8.068 g of NaCl, and dissolving the above substances in 250 mL of deionized water to obtain a mixed salt solution A;

(6) weighing 19.8593 g of NaOH, and dissolving it in 250 mL of deionized water to obtain an alkaline solution;

(7) pouring the mixed salt solution A and the alkaline solution into a colloid mill at the same time, and rotating at a speed of 3000 rpm for 3 minutes to form crystal nucleus of MgAl-LDH; transferring the solution of crystal nucleus to a reactor and dynamically crystallizing under stirring at 80° C. for 12 h for growing MgAl-LDH; filtering to obtain a filter cake of MgAl-LDH and drying the filter cake of MgAl-LDH at 70° C. for 12 hours to obtain a white solid MgAl-LDH product; collecting the filtrate to a container, wherein the filtrate is lithium-containing brine.

(8) b. Evaporating and concentrating the lithium-containing brine to a concentration of lithium ion of 0.4432 g/L to obtain a lithium-rich brine, adding 30.83 g of solid aluminum chloride to 1 L of the lithium-rich brine to obtain a mixed salt solution B, adding aqueous sodium hydroxide solution having a molar concentration of 4 mol/L dropwise to the mixed salt solution B at a rate of 1 mL/min until the pH value is 7, reacting at 80° C. for 12 hours, solid-liquid separating after the end of the reaction to obtain a lithium-containing liquid and a filter cake of LiAl-LDH; evaporating and concentrating the filtrate (lithium-containing liquid) to a concentration of lithium ion of 0.3 g/L and returning it to the lithium-containing brine for recycling;

(9) wherein the filter cake of LiAl-LDH is a lithium-containing layered material filter cake, and the lithium-containing layered material has a molecular formula LiAl.sub.2(OH).sub.6Cl.3H.sub.2O and a solid content of 85%. The XRD pattern and the transmission electron micrograph of the lithium-containing layered material are shown in FIG. 1 and FIG. 2, respectively.

(10) c. Dispersing 30 g of the filter cake with a solid content of 85% in 3 L of deionized water to prepare a suspension slurry (pH=7), adding the suspension slurry in a tank reactor, heating to 85° C. under stirring at 60 rpm, and maintaining the reaction at a constant temperature for 90 minutes to carry out lithium deintercalation reaction.

(11) d. Filtering the slurry after the lithium deintercalation reaction in step c to obtain a lithium-containing solution and aluminum hydroxide filter cake, evaporating and concentrating the lithium-containing solution to a concentration of lithium ion of 23 g/L, and using the resultant as the lithium-containing solution for preparing battery grade lithium carbonate. The concentration of lithium ion in the filtrate (lithium-containing solution) was 272 mg/L as detected by ICP.

(12) Next, it was calculated through the following equation 1) and equation 2) that the lithium deintercalation rate was 99.8%. It can be seen that in this Example, the lithium loss (which is equal to 1-R) was only 0.2%, which is small.
R=C.Math.V/(p.Math.m)  equation 1);

(13) In equation 1), R is lithium deintercalation rate, %;

(14) C is the concentration of lithium ion in the filtrate. In this Example, the concentration was 272 mg/L;

(15) V is the volume of the filtrate. In this Example, the volume of the filtrate was 2.582 L;

(16) m is the mass of lithium-containing layered material for reaction. In this Example, the mass was 30 g×85%=25.5 g;

(17) p is a mass percentage of lithium in the lithium-containing layered material. In this Example, the mass percentage of lithium was 2.76%, which was calculated by the following equation 2);
p=(c(Li.sup.+).sub.LDH.Math.V.sub.LDH)/m.sub.LDHs  equation 2);

(18) In equation 2), c(Li.sup.+).sub.LDH is the concentration of lithium ion in the lithium-containing layered material measured by ICP. In this Example, the concentration value was 13.8 mg/L; V.sub.LDH was 10 mL that is the volume of nitric acid solution used for ICP test; mums was 0.005 g that is the mass of the lithium-containing layered material for ICP test.

(19) e. Washing the filter cake obtained in step d with deionized water 5 times, and drying in an oven at 60° C. for 12 hours to obtain 18.5 g white solid aluminium hydroxide product.

(20) The ignition loss (igloss) and moisture (attached water) of this white solid aluminium hydroxide product was 34.48% and 6.92% respectively, as measured by conventional methods in the art. It can be seen that the Al(OH).sub.3 product prepared by Example 1 of the present disclosuremeets the requirement of the National Standard GB/T 4294-2010 for aluminum hydroxide, wherein the main indexes and data specified in the National Standard GB/T 4294-2010 are that the ignition loss (igloss) is 34.5±0.5%, and the moisture (attached water) is no more than 12%.

Example 2

(21) This Example provides a method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide, wherein the method includes the following steps:

(22) a. According to the method disclosed in Chinese Patent Application CN 105152193 A, weighing 26.0325 g of MgCl.sub.2.6H.sub.2O, 25.7993 g of MgSO.sub.4.7H.sub.2O, 18.7290 g of AlCl.sub.3.6H.sub.2O, 3.3873 g of KCl, 1.8768 g of LiCl, 8.068 g of NaCl, and dissolving the above substances in 250 mL of deionized water to obtain a mixed salt solution A;

(23) weighing 19.8593 g of NaOH, and dissolving it in 250 mL of deionized water to obtain an alkaline solution;

(24) pouring the mixed salt solution A and the alkaline solution into a colloid mill at the same time, and rotating at a speed of 3000 rpm for 3 minutes to form crystal nucleus of MgAl-LDH; transferring the solution of crystal nucleus to a reactor and dynamically crystallizing under stirring at 80° C. for 12 h for growing MgAl-LDH; filtering to obtain a filter cake of MgAl-LDH and drying the filter cake of MgAl-LDH at 70° C. for 12 hours to obtain a white solid MgAl-LDH product; collecting the filtrate to a container, wherein the filtrate is lithium-containing brine.

(25) b. Evaporating and concentrating the lithium-containing brine to a concentration of lithium ion of 0.4385 g/L to obtain a lithium-rich brine, adding 45.76 g of solid aluminum chloride to 1 L of the lithium-rich brine to obtain a mixed salt solution B, adding aqueous sodium hydroxide solution having the molar concentration of 4 mol/L dropwise to the mixed salt solution B at a rate of 1 mL/min until the pH value is 7, reacting at 80° C. for 12 hours, solid-liquid separating after the end of the reaction to obtain a lithium-containing liquid and a filter cake of LiAl-LDH; evaporating and concentrating the filtrate (lithium-containing liquid) to a concentration of lithium ion of 0.4 g/L and returning it to the lithium-containing brine for recycling.

(26) The filter cake of LiAl-LDH is a lithium-containing layered material filter cake, and the lithium-containing layered material has a molecular formula LiAl.sub.3(OH).sub.9Cl.5H.sub.2O and a solid content of 85%.

(27) c. Dispersing 30 g of the filter cake with a solid content of 85% in 3 L of deionized water, in which the pH value is adjusted to 6 by using 2 mol/L of hydrochloric acid, to prepare a suspension slurry, adding the suspension slurry in a tank reactor, heating to 65° C. under stirring at 80 rpm, and maintaining the reaction at a constant temperature for 90 minutes for lithium deintercalation reaction.

(28) d. Filtering the slurry after the lithium deintercalation reaction in step c to obtain a lithium-containing solution and aluminum hydroxide filter cake, evaporating and concentrating the lithium-containing solution to a concentration of lithium ion of 22 g/L, and using the resultant as the lithium-containing solution for preparing battery grade lithium carbonate. The concentration of lithium ion in the filtrate (lithium-containing solution) was 188 mg/L as detected by ICP.

(29) Next, it was calculated through the following equation 1) and equation 2) that the lithium deintercalation rate was 99%. It can be seen that in this Example, the lithium loss (which is equal to 1-R) was only 1%, which is small.
R=C.Math.V/(p.Math.m)  equation 1);

(30) In equation 1), R is lithium deintercalation rate, %;

(31) C is the concentration of lithium ion in the filtrate. In this Example, the concentration was 188 mg/L;

(32) V is the volume of the filtrate. In this Example, the volume of the filtrate was 2.552 L;

(33) m is the mass of lithium-containing layered material for reaction. In this Example, the mass was 30 g×85%=25.5 g;

(34) p is a mass percentage of lithium in the lithium-containing layered material. In this Example, the mass percentage of lithium was 1.9%, which was calculated by the following equation 2);
p=(c(Li.sup.+).sub.LDH.Math.V.sub.LDH)/m.sub.LDHs  equation 2);

(35) In equation 2), c(Li.sup.+).sub.LDH is the concentration of lithium ion in the lithium-containing layered material measured by ICP. In this Example, the concentration value was 9.5 mg/L; V.sub.LDH was 10 mL that is the volume of nitric acid solution used for ICP test; m.sub.LDHs was 0.005 g that is the mass of the lithium-containing layered material for ICP test.

(36) e. Washing the filter cake obtained in step d with deionized water 5 times, and drying in an oven at 70° C. for 10 hours to obtain 13.8 g white solid aluminium hydroxide product.

(37) The ignition loss (igloss) and moisture (attached water) of this white solid aluminium hydroxide product was 34.5% and 7.69% respectively, as measured by conventional methods in the art. It can be seen that the Al(OH).sub.3 product prepared by Example 2 of the present disclosure meets the requirement of the National Standard GB/T 4294-2010 for aluminum hydroxide, wherein the main indexes and data specified in the National Standard GB/T 4294-2010 are that the ignition loss (igloss) is 34.5±0.5%, and the moisture (attached water) is no more than 12%.

Example 3

(38) This Example provides a method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide, wherein the method includes the following steps:

(39) a. According to the method disclosed in Chinese Patent Application CN 105152193 A, weighing 26.0325 g of MgCl.sub.2.6H.sub.2O, 25.7993 g of MgSO.sub.4.7H.sub.2O, 18.7290 g of AlCl.sub.3.6H.sub.2O, 3.3873 g of KCl, 1.8768 g of LiCl, 8.068 g of NaCl, and dissolving the above substances in 250 mL of deionized water to obtain a mixed salt solution A;

(40) weighing 19.8593 g of NaOH, and dissolving it in 250 mL of deionized water to obtain an alkaline solution;

(41) pouring the mixed salt solution A and the alkaline solution into a colloid mill at the same time, and rotating at a speed of 3000 rpm for 3 minutes to form crystal nucleus of MgAl-LDH; transferring the solution of crystal nucleus to a reactor and dynamically crystallizing under stirring at 80° C. for 12 h for growing MgAl-LDH; filtering to obtain a filter cake of MgAl-LDH and drying the filter cake of MgAl-LDH at 70° C. for 12 hours to obtain a white solid MgAl-LDH product; collecting the filtrate to a container, wherein the filtrate is lithium-containing brine.

(42) b. Evaporating and concentrating the lithium-containing brine to a concentration of lithium ion of 0.4108 g/L to obtain a lithium-rich brine, adding 57.16 g of solid aluminum chloride to 1 L of the lithium-rich brine to obtain a mixed salt solution B, adding aqueous sodium hydroxide solution having a molar concentration of 4 mol/L dropwise to the mixed salt solution B at a rate of 1 mL/min until the pH value is 7, reacting at 80° C. for 12 hours, solid-liquid separating after the end of the reaction to obtain a lithium-containing liquid and filter cake of LiAl-LDH; evaporating and concentrating the filtrate (lithium-containing liquid) to a concentration of lithium ion of 0.2 g/L and returning it to the lithium-containing brine for recycling.

(43) The filter cake of LiAl-LDH is a lithium-containing layered material filter cake, and the lithium-containing layered material has a molecular formula LiAl.sub.4(OH).sub.12Cl.7H.sub.2O, and a solid content of 85%.

(44) c. Dispersing 30 g of the filter cake with a solid content of 85% in 3 L deionized water, in which the pH value is adjusted to 5.5 by using 2 mol/L of hydrochloric acid, to prepare a suspension slurry, adding the suspension slurry in a tank reactor, heating to 65° C. under stirring at 100 rpm, and maintaining the reaction at a constant temperature for 30 minutes to carry out lithium deintercalation reaction.

(45) d. Filtering the slurry after the lithium deintercalation reaction in step c to obtain a lithium-containing solution and aluminum hydroxide filter cake, evaporating and concentrating the lithium-containing solution to a concentration of lithium ion of 21 g/L, and using the resultant as the lithium-containing solution for preparing battery grade lithium carbonate. The concentration of lithium ion in the filtrate (lithium-containing solution) was 142 mg/L as detected by ICP.

(46) Next, it was calculated through the following equation 1) and equation 2) that the lithium deintercalation rate was 98.5%. It can be seen that in this Example, the lithium loss (which is equal to 1-R) was only 1.5%, which is small.
R=C.Math.V/(p.Math.m)  equation 1);

(47) In equation 1), R is lithium deintercalation rate, %;

(48) C is the concentration of lithium ion in the filtrate. In this Example, the concentration was 142 mg/L;

(49) V is the volume of the filtrate. In this Example, the volume of the filtrate was 2.546 L;

(50) m is the mass of lithium-containing layered material for reaction. In this Example, the mass was 30 g×85%=25.5 g;

(51) p is a mass percentage of lithium in the lithium-containing layered material. In this Example, the mass percentage of lithium was 1.44%, which was calculated by the following equation 2);
p=(c(Li.sup.+).sub.LDH.Math.V.sub.LDH)/m.sub.LDHs  equation 2);

(52) In equation 2), c(Li.sup.+).sub.LDH is the concentration of lithium ion in the lithium-containing layered material measured by ICP. In this Example, the concentration value was 7.2 mg/L; V.sub.LDH was 10 mL that is the volume of nitric acid solution used for ICP test; m.sub.LDHs was 0.005 g that is the mass of the lithium-containing layered material for ICP test.

(53) e. Washing the filter cake obtained in step d with deionized water 5 times, and drying in an oven at 80° C. for 8 hours to obtain 9.74 g white solid aluminium hydroxide product.

(54) The ignition loss (igloss) and moisture (attached water) of this white solid aluminium hydroxide product was 34.55% and 8.08% respectively, as measured by conventional methods in the art. It can be seen that the Al(OH).sub.3 product prepared by Example 3 of the present disclosuremeets the requirement of the National Standard GB/T 4294-2010 for aluminum hydroxide, wherein the main indexes and data specified in the National Standard GB/T 4294-2010 are that the ignition loss (igloss) is 34.5±0.5%, and the moisture (attached water) is no more than 12%.

Example 4

(55) This Example provides a method for extracting lithium from salt lake brine and simultaneously preparing aluminum hydroxide, wherein the method includes the following steps:

(56) a. According to the method disclosed in Chinese Patent Application CN 105152193 A, weighing 26.0325 g of MgCl.sub.2.6H.sub.2O, 25.7993 g of MgSO.sub.4.7H.sub.2O, 18.7290 g of AlCl.sub.3.6H.sub.2O, 3.3873 g of KCl, 1.8768 g of LiCl, 8.068 g of NaCl, and dissolving the above substances in 250 mL of deionized water to obtain a mixed salt solution A;

(57) weighing 19.8593 g of NaOH, and dissolving it in 250 mL of deionized water to obtain an alkaline solution;

(58) pouring the mixed salt solution A and the alkaline solution into a colloid mill at the same time, and rotating at a speed of 3000 rpm for 3 minutes to form crystal nucleus of MgAl-LDH; transferring the solution of crystal nucleus to a reactor and dynamically crystallizing under stirring at 80° C. for 12 h for growing MgAl-LDH; filtering to obtain a filter cake of MgAl-LDH and drying the filter cake of MgAl-LDH at 70° C. for 12 hours to obtain a white solid that is the product of MgAl-LDH; collecting the filtrate to a container, wherein the filtrate is lithium-containing brine.

(59) b. Evaporating and concentrating the lithium-containing brine to a concentration of lithium ion of 0.4573 g/L to obtain a lithium-rich brine, adding 79.53 g of solid aluminum chloride to 1 L of lithium-rich brine to obtain a mixed salt solution B, adding aqueous sodium hydroxide solution having a molar concentration of 4 mol/L dropwise to the mixed salt solution B at a rate of 1 mL/min until the pH value is 7, reacting at 80° C. for 12 hours, solid-liquid separating after the end of the reaction to obtain a lithium-containing liquid and filter cake of LiAl-LDH; evaporating and concentrating the filtrate (lithium-containing liquid) to a concentration of lithium ion of 0.4 g/L and returning it to the lithium-containing brine for recycling.

(60) The filter cake of LiAl-LDH is a lithium-containing layered material filter cake, and the lithium-containing layered material has a molecular formula LiAl.sub.5(OH).sub.15Cl.9H.sub.2O and a solid content of 85%.

(61) c. Dispersing 30 g of the filter cake with a solid content of 85% in 1 L of deionized water, in which the pH value is adjusted to 7.5 with 2 mol/L of sodium hydroxide, to prepare a suspension slurry, adding the suspension slurry in a tank reactor, heating to 85° C. under stirring at 120 rpm, and maintaining the reaction at a constant temperature for 90 minutes to carry out lithium deintercalation reaction.

(62) d. Filtering the slurry after the lithium deintercalation reaction in step c to obtain a lithium-containing solution and aluminum hydroxide filter cake, evaporating and concentrating the lithium-containing solution to a concentration of lithium ion of 25 g/L, and using the resultant as the lithium-containing solution for preparing battery grade lithium carbonate. The concentration of lithium ion in the filtrate (lithium-containing solution) was 346 mg/L as detected by ICP.

(63) Next, it was calculated through the following equation 1) and equation 2) that the lithium deintercalation rate was 98.8%. It can be seen that in this Example, the lithium loss (which is equal to 1-R) was only 1.2%, which is small.
R=C.Math.V/(p.Math.m)  equation 1);

(64) In equation 1), R is lithium deintercalation rate, %;

(65) C is the concentration of lithium ion in the filtrate. In this Example, the concentration was 346 mg/L;

(66) V is the volume of the filtrate. In this Example, the volume of the filtrate was 0.845 L;

(67) m is the mass of lithium-containing layered material for reaction. In this Example, the mass was 30 g×85%=25.5 g;

(68) p is a mass percentage of lithium in the lithium-containing layered material. In this Example, the mass percentage of lithium was 1.16%, which was calculated by the following equation 2);
p=(c(Li.sup.+).sub.LDH.Math.V.sub.LDH)/m.sub.LDHs  equation 2);

(69) In equation 2), c(Li.sup.+).sub.LDH is the concentration of lithium ion in the lithium-containing layered material measured by ICP. In this Example, the concentration value was 5.8 mg/L; V.sub.LDH was 10 mL that is the volume of nitric acid solution used for ICP test; mums was 0.005 g that is the mass of the lithium-containing layered material for ICP test.

(70) e. Washing the filter cake obtained in step d with deionized water 5 times, and drying in an oven at 80° C. for 6 hours to obtain 7.9 g white solid aluminium hydroxide product.

(71) The ignition loss (igloss) and moisture (attached water) of this white solid aluminium hydroxide product was 34.58% and 8.31% respectively, as measured by conventional methods in the art. It can be seen that the Al(OH).sub.3 product prepared by Example 4 of the present disclosure meets the requirement of the National Standard GB/T 4294-2010 for aluminum hydroxide, wherein the main indexes and data specified in the National Standard GB/T 4294-2010 are that the ignition loss (igloss) is 34.5±0.5%, and the moisture (attached water) is no more than 12%.