Method for preparing lithium carbonate from lithium-containing glass powder

Abstract

The invention discloses a method for preparing lithium carbonate from lithium-containing glass powder. The method comprises the following steps: carrying out first-stage acid mixing, first-stage low-temperature roasting, second-stage acid mixing and second-stage high-temperature roasting on glass powder, carrying out water leaching on the material subjected to second-stage roasting, and carrying out solid-liquid separation by utilizing a machine washing filter press to obtain a high-content lithium sulfate solution and qualified glass powder leaching residues (less than 0.20%), wherein the ratio of the leaching washing water of the glass powder to the dry slag is controlled within 1.2 to ensure that a high-content lithium sulfate solution (the lithium content is more than 18g / L) is obtained; and leached liquid is subjected to impurity removal, fluorine removal, calcium removal, boron removal, lithium precipitation, washing, drying, crushing and magnetism removal, and battery-grade lithium carbonate is prepared.

Description

Technical Field

[0001] The present invention belongs to the technical field of recycling of lithium-containing glass powder, and particularly relates to a method for preparing lithium carbonate from lithium-containing glass powder. Background Art

[0002] Lithium is widely used in batteries, ceramics, glass, lubricants, nuclear industry and optoelectronic industries. With the continuous development of electronic products such as computers, digital cameras, mobile phones, and mobile power tools, the battery industry has become the largest consumer field of lithium. In addition, lithium carbonate is one of the effective ways to reduce energy consumption and environmental protection in the ceramic industry, and the demand for lithium will also increase. At the same time, various new functions of lithium in glass are constantly being discovered, and the demand for lithium in the glass industry remains on the rise. Therefore, the glass and ceramic industries have become the second largest consumer fields of lithium, and the extraction of lithium from glass will also become a recycling field with great potential in the future.

[0003] Chinese Patent CN107089673A, a method for preparing lithium carbonate by two-stage conversion of lithium ore, mainly aims at spodumene. The material used in this application is recycled lithium-containing glass powder, and the chemical and physical properties of the two materials are completely different; secondly, the temperature range of the two-stage roasting is different. The roasting temperature in CN107089673A is higher, which means higher energy waste. This application allows part of the aluminum to be leached in the leaching stage, and the yield is increased by adding lithium phosphate to reduce the influence of aluminum on the adsorption of lithium. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for preparing lithium carbonate from lithium-containing glass powder. Using glass powder as the raw material, a method combining two-stage acid-mixing roasting and water leaching is adopted, and battery-grade lithium carbonate is obtained through impurity removal, calcium removal, boron removal, lithium precipitation, washing, drying, crushing, etc.; the method includes one-stage acid-mixing roasting and two-stage acid-mixing roasting.

[0006] Furthermore, the method adopts acid-mixing roasting first and then leaching, and the specific steps are as follows:

[0007] (1) After the coarse particles of the glass powder raw material are ball-milled and sorted, a mixing equipment is used to carry out acid-mixing activation on the glass powder and 98% concentrated sulfuric acid, and an externally heated kiln is used to roast the acid-mixed material;

[0008] (2) Add X parts of 98% concentrated sulfuric acid to the first-stage roasted material for the first acid-mixing, and use an externally heated kiln to carry out the first-stage roasting on the acid-mixed material; complete the first-stage conversion to ensure that the lithium conversion rate is above 75%;

[0009] (3) Add Y parts of 98% concentrated sulfuric acid to the first-stage roasted material for the second acid-mixing, and use an externally heated kiln to carry out the second-stage roasting on the acid-mixed material; complete the second-stage conversion to ensure that the lithium conversion rate is above 95%;

[0010] (4) The material after ball milling of the two-stage calcined pellets is sent to the leaching section. The bottom water is a mixed solution of mother liquor and washing water. Calcium carbonate is added to adjust the pH, and a filter press is used for filtration. The filter residue becomes qualified residue after being washed three times in a countercurrent manner by the filter press. The filtrate undergoes secondary cycle leaching to produce mother liquor with a high lithium content, and the liquid lithium content is above 18 g / L.

[0011] (5) The leaching mother liquor is subjected to impurity removal, defluorination, deboronization, and pre-precipitation to obtain a refined lithium sulfate solution, and then lithium precipitation, washing, drying, air flow pulverization, and demagnetization are carried out to obtain battery-grade lithium carbonate.

[0012] Further, in step (1), the lithium content of the glass powder raw material is 2.0% - 3.0%, the passing rate of the material after ball milling through a 200-mesh sieve is above 80%, the moisture content is within 3%, the addition amount of acid in the first-stage acid mixing is 1.0 - 2.5 times the lithium equivalent of the raw material, the calcination temperature is 300 - 350 °C, and the calcination time is 1.5 - 2.5 hours.

[0013] Further, in step (1), a mixer is used as the acid mixing equipment, and the acid mixing time should be maintained for more than 10 minutes to ensure uniform mixing of the materials. Heat is generated during the acid mixing process, and the acid mixing equipment is equipped with circulating cooling water to keep the temperature below 65 °C. Ensure uniform acid mixing without caking after acid mixing.

[0014] Further, in step (1), to ensure the progress of the acid mixing process, auxiliary materials need to be added during the acid mixing process to prevent the materials from becoming sticky, and the addition amount is 2.0% - 5.0% of the raw material quality.

[0015] Further, in step (2), the amount of acid in the second-stage acid mixing is 0.5 - 1.5 times the lithium equivalent of the raw material, the temperature is 320 - 420 °C, and the calcination time is 1.5 - 3.5 hours.

[0016] Further, in step (3), calcium carbonate, quicklime or calcium hydroxide is used for pH adjustment, and the pH value is adjusted to 4.5 - 5.0. The mass ratio of washing water to leaching dry residue is 1:1; the residual acid in the second-stage material in step (3) is controlled within 0.3%, the passing rate is controlled above 80% through a 200-mesh sieve, the total lithium content of the leaching residue is less than 0.20%, and the leaching yield is greater than 90%.

[0017] Further, in step (4), quicklime is used for impurity removal to adjust the pH, and the pH end point is controlled at 9.0 - 10.0; the defluorinating agent is a magnesium-based compound, and the liquid fluorine content after defluorination should be controlled below 20 ppm, and the pH at the defluorination end point is controlled at 12.5 - 13.0; LSC800 resin is used for deboronization, and the content after deboronization should be controlled within 10 ppm.

[0018] Further, in step (4), the lithium content of the refined lithium sulfate solution is greater than 18 g / l, and the sulfate radical content is less than 150 g / l.

[0019] Beneficial effects: The present invention extracts lithium from lithium-containing glass powder by means of two-stage acid mixing roasting, which improves the leaching yield of glass powder; a viscosity reducer is added to solve the problem of material sticking during direct acid mixing; cyclic leaching is used to obtain a lithium precipitation precursor solution with a high content; a magnesium-based defluorinating agent and LSC800 resin are used to remove boron to ensure the production of battery-grade lithium carbonate. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of a method for preparing battery-grade lithium carbonate by two-stage roasting leaching of lithium-containing glass powder. Detailed Embodiments

[0021] The following further elaborates on the specific technical solutions of the present invention in conjunction with the embodiments and the drawings. In the embodiments, each component is in parts by mass or mass ratio, and the concentrations involved are all mass concentrations. Example 1

[0022] Using a ton bag feeding station, 500 ± 3 kg of glass powder is added to a mixer, the stirring speed is set at 20 HZ, 144.3 kg of 98% concentrated sulfuric acid and 10 kg of auxiliary materials are added to reduce the viscosity, and the mixing and stirring time is 10 minutes. The acid-mixed material is subjected to a first-stage low-temperature roasting in an externally heated kiln at a temperature of 320 - 340 °C for 2 hours. Another 108.2 kg of concentrated sulfuric acid is added to the first-stage roasted material, and it is stirred in the mixer for 10 minutes. Then, the acid-mixed material is roasted in a rotary kiln at a temperature of 400 - 420 °C for 2 hours. The second-stage roasted material is crushed and ground. 10 cubic meters of the mother liquor and recycled water mixture is added to the leaching kettle, and then 5000 kg of the ground second-stage roasted material is added, and the reaction lasts for 1 hour. Calcium carbonate is added to adjust the pH to 4.5 - 5.0. The slurry enters a filter press for solid-liquid separation. The filter residue is washed three times in a countercurrent manner to obtain a qualified residue. The mother liquor is added with quicklime to adjust the pH to 12.0 - 13.0 for impurity removal. After filtration, the impurity-removed liquid is defluorinated, deboronated, and pre-precipitated to obtain a refined lithium sulfate solution, and then lithium precipitation, washing, drying, air-flow pulverization, and demagnetization are carried out to obtain battery-grade lithium carbonate.

[0023] The passing rate of the used glass powder through a 200-mesh sieve is 85%, and the lithium content is 2.02%. The mixer has circulating cooling water, and the material temperature is maintained at 58 - 62 °C. The stirring time is 10 minutes. If the time is too long, the material will absorb water and the viscosity will increase.

[0024] The amount of concentrated sulfuric acid added in the first-stage acid mixing is 2.0 times the lithium equivalent of 500 kg of glass powder, and the amount of concentrated sulfuric acid added in the second-stage acid mixing is 1.5 times the lithium equivalent of 500 kg of glass powder.

[0025] The residual acid of the second-stage material is 0.22%, and the lithium content in the mother liquor is 18.50 g / l.

[0026] The filter residue is washed three times in countercurrent. The mass ratio of dry residue to washing water is 1:1. The total lithium content in the leaching residue is 0.11%, the water-soluble lithium content is 0.02%, and the leaching yield is 90%.

[0027] The aluminum ion content in the mother liquor is less than 0.5 g / l, and the amount of impurity removal slag is small. It can be returned to the leaching kettle to adjust the pH, reducing the usage amount of calcium carbonate.

[0028] Before using the magnesium-based defluorination agent, the pH of the impurity removal liquid should be adjusted to 9.5 - 10.0, and the reaction time should be controlled within 0.5 - 1.0 hours.

[0029] The data of the refined lithium sulfate solution after the impurity removal liquid is defluorinated and debored are shown in Table 1.

[0030]

[0031] During the lithium precipitation process, EDTA should be added to reduce the calcium ion content, and the addition amount is 200g / m 3 Then, the lithium carbonate is washed, dried, pulverized by air flow, and demagnetized to obtain battery-grade lithium carbonate. The quality of the obtained battery-grade lithium carbonate is shown in Table 2.

[0032] Example 2

[0033] Use a ton bag feeding station to add 500 ± 30 kg of glass powder into the mixer. The stirring speed is set at 20HZ. Add a certain amount of sulfuric acid and mechanically activate for 10 minutes. Then enter the rotary kiln for roasting. The temperature is set at 330 - 340°C and the time is 2 hours. The first-stage roasted material is mechanically activated with concentrated sulfuric acid for 10 minutes and then enters the rotary kiln for roasting. The temperature is set at 400 - 410°C and the time is 1.5 hours. The second-stage roasted material is ground and separated by a ball mill and then leached. The bottom water for leaching is the mother liquor and the recycled water in a ratio of 1:1. After leaching, calcium carbonate is added to adjust the pH to 4.5 - 5.0. After solid-liquid separation by a filter press, the filter residue is washed three times in countercurrent to obtain qualified residue. The filtrate needs to be purified, defluorinated, debored, and pre-precipitated to obtain a refined lithium sulfate solution, and then lithium precipitation, washing, drying, pulverizing by air flow, and demagnetizing are carried out to obtain battery-grade lithium carbonate.

[0034] The lithium content in the glass powder is 2.51%. The addition equivalent of concentrated sulfuric acid in the first-stage acid mixing is 1.8 times. The addition equivalent of concentrated sulfuric acid in the second-stage acid mixing is 1.5 times. A coarse crushing device is provided at the discharge port of the rotary kiln to break the materials agglomerated during the rotation of the furnace.

[0035] The residual acid in the second-stage roasted material is 0.18%, the total lithium content in the leaching residue is 0.13%, the water-soluble lithium content is 0.02%, and the leaching yield is 92.0%. The data of the refined lithium sulfate solution after the mother liquor from leaching is purified, defluorinated, and debored are shown in Table 3

[0036]

[0037] After that, lithium precipitation, washing, drying, air-flow comminution, and demagnetization are carried out to obtain battery-grade lithium carbonate. The quality of the obtained battery-grade lithium carbonate is shown in Table 4

[0038]

Claims

1. A method for preparing lithium carbonate from lithium-containing glass powder, characterized in that, Using glass powder as raw material, a high-content lithium sulfate liquid is obtained by combining two-stage acid mixing roasting and water leaching. The leaching mother liquor is sent for impurity removal, calcium removal, boron removal, lithium precipitation, washing, drying, and crushing to obtain battery-grade lithium carbonate.

2. The method for preparing lithium carbonate from lithium-containing glass powder according to claim 1, wherein The method adopts a two-stage acid mixing roasting and leaching method, and the specific steps are as follows: (1) Add X parts of 98% concentrated sulfuric acid to the glass powder raw material for the first acid mixing, and carry out the first-stage low-temperature roasting. After the first-stage roasting, add Y parts of 98% concentrated sulfuric acid to the material for the second acid mixing, and use an externally heated kiln to carry out the second-stage high-temperature roasting on the acid-mixed material; (2) After ball milling the second-stage roasted material, carry out water leaching, add calcium carbonate to adjust the pH to 4.5 - 5.0, and use a filter press for filtration; the filter residue is qualified leaching residue (lithium in the residue < 0.20%) after being washed three times in countercurrent by the filter press, and the filtrate is used for cyclic leaching to produce a high-content leaching mother liquor; (3) The high-content leaching mother liquor is subjected to impurity removal, fluorine removal, calcium removal, boron removal, lithium precipitation, washing, drying, pulverization, and demagnetization to obtain battery-grade lithium carbonate.

3. A method for preparing lithium carbonate from lithium-containing glass powder according to claim 2, characterized in that, In step (1), the lithium content of the glass powder raw material is 2.0% - 3.0%, the passing rate of the ball-milled material through a 200-mesh sieve is above 80%, the moisture content is within 3%, the addition amount of the first-stage acid mixing is 1.0 - 2.0 times the lithium molar equivalent of the raw material, the roasting temperature is 300 - 350 °C, and the roasting time is 1.5 - 2.5 hours.

4. A method for preparing lithium carbonate from lithium-containing glass powder according to claim 2, characterized in that, In step (1), the acid mixing equipment adopts a mixer, and the acid mixing time should be maintained for more than 10 minutes to ensure uniform mixing of the materials. Heat will be generated during the acid mixing process, and the acid mixing equipment is equipped with circulating cooling water to keep the temperature below 65 °C.

5. The method for preparing lithium carbonate from lithium-containing glass powder according to claim 2, characterized in that, In step (1), to ensure the progress of the acid mixing process, auxiliary materials need to be added during the acid mixing process to prevent the materials from becoming sticky, and the addition amount is 2.0% - 5.0% of the raw material quality.

6. A method for preparing lithium carbonate from lithium-containing glass powder according to claim 2, characterized in that, In step (2), the addition amount of the second-stage acid mixing is 0.5 - 1.5 times the lithium molar equivalent of the raw material, the temperature is 320 - 420 °C, and the roasting time is 1.5 - 3.5 hours.

7. A method for preparing lithium carbonate from lithium-containing glass powder according to claim 2, characterized in that, In step (3), calcium carbonate, quicklime or calcium hydroxide is used for pH adjustment, and the pH value is adjusted to 4.5 - 5.

0. The mass ratio of the washing water to the leaching dry residue is 1.2:1; in step (3), the residual acid of the second-stage material is controlled within 0.3%, the total lithium content of the leaching residue is less than 0.20%, and the leaching yield is greater than 90%.

8. A method for preparing lithium carbonate from lithium-containing glass powder according to claim 2, characterized in that, In step (4), quicklime is used for impurity removal to adjust the pH, and the pH end point is controlled at 10 - 11; the defluorinating agent is a magnesium-based compound, and the fluorine content in the liquid after defluorination should be controlled below 20 ppm, and the pH at the defluorination end point is controlled at 10.3 - 10.5; LSC800 resin is used for boron removal, and the boron content after removal should be controlled within 10 ppm.

9. A method for preparing lithium carbonate from lithium-containing glass powder according to claim 2, characterized in that, In step (4), the lithium content of the refined lithium sulfate solution is greater than 18 g / l, and the sulfate radical content is less than 150 g / l.

10. A method for preparing lithium carbonate from lithium-containing glass powder, characterized in that, The material contains lithium carbonate prepared by the method according to any one of claims 1 - 9.

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