Auxiliary salt and lepidolite roasting process
By using sulfate, calcium-containing substances and coal-based auxiliary salts in the lithium mica lithium extraction process, the roasting conditions are optimized, and the problem of large amount of auxiliary salts in the sulfate roasting method is solved, and the amount of auxiliary salts and tailings are reduced. Improved energy efficiency.
Patent Information
- Application Number
- CN202411226615.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-03
- Publication Date
- 2024-12-31
AI Technical Summary
The amount of auxiliary salt used in the existing lithium mica extraction process is large, resulting in high pressure for subsequent leaching and tailing treatment and high energy consumption.
Using auxiliary salts including sulfates, calcium-containing substances and coal, coal can improve heat utilization through redox reactions during the roasting process, and act as a combustion-enhancing material to reduce natural gas energy consumption. The roasting temperature and auxiliary salt ratio in the lithium mica roasting process are optimized. , reduce the amount of auxiliary salt and tailings production.
It effectively reduces the amount of auxiliary salt and tailings slag yield, reduces the pressure of leaching operations and tailings slag treatment, and reduces the natural gas consumption and energy consumption of the roasting process.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of lepidolite roasting, and in particular to an auxiliary salt and a lepidolite roasting process. Background Art
[0002] With the vigorous development of the new energy industry, lithium, as an important strategic resource in the new energy industry, is in increasing demand. The ways to extract lithium include extracting lithium from salt lakes, extracting lithium from lithium ores, and extracting lithium from lithium product recycling. Among them, lithium extraction from lithium mica is the main source of lithium products.
[0003] At present, lithium extraction from lithium mica mostly uses sulfate roasting to prepare industrial-grade or battery-grade lithium carbonate. The main process is that the lithium mica roasting temperature is 920-1050℃, the mass ratio of lithium mica: auxiliary salt is about 100:60, and lithium sulfate solution is obtained after water leaching, and then after impurity removal, purification, lithium precipitation, drying, and crushing, lithium carbonate is obtained. The sulfate roasting method can process lithium mica of different grades and has high adaptability, but the existing process uses a large amount of auxiliary salt, which puts a great pressure on the subsequent leaching and tailings treatment. Summary of the invention
[0004] 1. Technical issues to be resolved
[0005] In view of the deficiencies of the prior art, the present invention provides an auxiliary salt and a lepidolite roasting process, which solves the technical problem of a large amount of auxiliary salt used in the prior sulfate roasting process.
[0006] (II) Technical solution
[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:
[0008] In a first aspect, the present invention provides a secondary salt comprising the following components in parts by weight:
[0009] Sulfate 10-15 parts,
[0010] Contains 15-40 parts of calcium,
[0011] 5-7 parts coal.
[0012] The auxiliary salts include sulfate, calcium-containing substances and coal. During the roasting process, the coal undergoes an oxidation-reduction reaction on the surface of the lepidolite, which improves the utilization rate of the heat generated by the oxidation-reduction reaction, thereby reducing the amount of auxiliary salts. In addition, the coal acts as a combustion aid, thereby reducing the energy consumption of natural gas.
[0013] Preferably, the sulfate is selected from at least one of sodium sulfate and potassium sulfate, and the sulfate is of analytical grade.
[0014] Preferably, the calcium-containing substance is selected from at least one of calcium carbonate, calcium sulfate and calcium hydroxide, and the calcium-containing substance is analytically pure. Calcium carbonate, calcium sulfate and calcium hydroxide are selected to destroy the stable structure of lithium in lithium ore and convert it into lithium ions soluble in water.
[0015] Preferably, the coal is selected from soot.
[0016] Preferably, the coal composition includes: ash content 3.73%, volatile matter 20.27%, and carbon content 76.00%.
[0017] In a second aspect, the present invention provides a lepidolite roasting process, comprising the following steps:
[0018] (1) uniformly mixing the lepidolite concentrate with the auxiliary salt according to any one of claims 1 to 5 in a mass ratio of 100:(30-55) to obtain a raw material;
[0019] (2) roasting the raw material at 880°C-950°C for 90 min-120 min, and cooling naturally to obtain clinker.
[0020] (3) Soaking the clinker in water and filtering to obtain an extract.
[0021] Compared with the existing sulfate process, the above-mentioned lithium mica roasting process reduces the amount of auxiliary salts used. The mass ratio of lithium mica to auxiliary salts is reduced from 100:60 to 100:30 at most, the amount of auxiliary salts used is reduced by about 8.1 tons per ton of lithium carbonate, and the tailings output is reduced by about 7 tons per ton of lithium carbonate, which reduces the pressure of leaching operations and tailings treatment. The reduction in the amount of auxiliary salts also reduces the amount of natural gas used in the roasting process, and the amount of natural gas is reduced by at least about 618m 3 / ton of lithium carbonate. The above-mentioned lithium mica roasting process has a low roasting temperature, which can save production energy consumption to a large extent.
[0022] Preferably, in step (2), the roasting includes roasting the raw material alone or roasting the raw material mixed with water. The dry raw material has poor adhesion and cannot be compacted into shape. Adding a small amount of water can enhance the viscosity and facilitate the pressing and molding of the raw material.
[0023] Preferably, the raw material mixed with water and then roasted includes uniformly mixing the raw material and water, compacting the raw material, and operating a kiln car in the tunnel kiln to transport the material. In order to improve the space utilization rate in the kiln, the raw material needs to be pressed into bricks for stacking, and then entering the kiln for drying and then roasting.
[0024] Preferably, the mass of the water accounts for 4%-6% of the mass of the raw material. DETAILED DESCRIPTION
[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.
[0026] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation methods.
[0027] Example 1
[0028] 0.2%-0.35% lepidolite ore in Yichun City, Jiangxi Province is used to obtain 2.0% lepidolite concentrate according to a conventional method.
[0029] The mass ratio of lithium mica concentrate: sodium sulfate: calcium sulfate: calcium carbonate: coal is 100:10:35:5:5, and the auxiliary salt is sodium sulfate, calcium sulfate, calcium carbonate, coal. The mass ratio of lithium mica concentrate to auxiliary salt is 100:55 to obtain raw material A. Water accounting for 4% of its mass is added to raw material A, and mixed evenly to obtain raw material B. Raw material B is placed in a mold and compacted under a pressure of 20MPa to obtain raw material C. Raw material C is taken out and dried at a temperature of 120°C. After the water is evaporated, raw material D is obtained. Raw material D is then placed in a muffle furnace for high-temperature roasting at a heating rate of 8°C / min. It is roasted at a high temperature of 925°C for 120min and naturally cooled to obtain clinker.
[0030] The clinker was crushed and ground to obtain clinker powder with a fineness of 150 mesh. The powder was tested for total lithium oxide content and lithium oxide soluble in water, and the clinker conversion rate was found to be 87.68%.
[0031] Example 2
[0032] The mass ratio of lithium mica concentrate: sodium sulfate: calcium sulfate: coal is 100:15:35:5, and the auxiliary salt is sodium sulfate, calcium sulfate, coal, and the mass ratio of lithium mica concentrate to auxiliary salt is 100:55 to obtain raw material. Then the raw material is loaded into a crucible and placed in a muffle furnace for high-temperature roasting at a heating rate of 10°C / min. At a high temperature of 950°C, it is maintained for 120 minutes and naturally cooled to obtain clinker.
[0033] The clinker was crushed and ground to obtain clinker powder with a fineness of 150 mesh. The powder was tested for total lithium oxide content and lithium oxide soluble in water, and the clinker conversion rate was found to be 82.33%.
[0034] The clinker powder was mixed with water of the same mass in a ratio of 1:1, and stirred at 60°C for 90 minutes at a speed of 200 rpm. After stirring was complete, the mixture was filtered to obtain a leachate and leach residue.
[0035] The leachate and leached residue were collected and tested for lithium oxide content. The lithium oxide leaching rate in the clinker was 99.58%, the lithium ion concentration in the leachate was 12.58 g / L, and the lithium oxide content in the dried leached residue was 0.33%.
[0036] Example 3
[0037] The raw material is obtained by uniformly mixing lithium mica concentrate, sodium sulfate, calcium hydroxide and coal in a mass ratio of 100:15:25:5, with the auxiliary salts of sodium sulfate, calcium hydroxide and coal, and the mass ratio of mica concentrate to auxiliary salt is 100:45. The raw material is then put into a crucible and placed in a muffle furnace for high-temperature roasting at a heating rate of 10°C / min, at a high temperature of 950°C, maintained for 120 minutes, and naturally cooled to obtain clinker.
[0038] The clinker was crushed and ground to obtain clinker powder with a fineness of 150 mesh. The powder was tested for total lithium oxide content and lithium oxide soluble in water, and the clinker conversion rate was found to be 83.10%.
[0039] Example 4
[0040] The mass ratio of lithium mica concentrate: sodium sulfate: calcium hydroxide: coal is 100:15:20:5, the auxiliary salt is sodium sulfate, calcium hydroxide, coal, and the mass ratio of lithium mica concentrate to auxiliary salt is 100:40 to obtain raw material A. Then add 5% water by mass of raw material A and mix evenly to obtain raw material B. Put raw material B into a mold and compact it under a pressure of 20MPa to obtain raw material C. Take out raw material C, dry it at a temperature of 120℃, and obtain dry raw material D after evaporating the water. Then put raw material D into a tunnel kiln for high-temperature roasting, with a heating rate of 10℃ / min, and keep it at a high temperature of 880℃ for 90min, and wait for natural cooling to obtain clinker.
[0041] The clinker was crushed and ground to obtain clinker powder with a fineness of 150 mesh. The powder was tested for total lithium oxide content and lithium oxide soluble in water, and the clinker conversion rate was found to be 79.83%.
[0042] Example 5
[0043] The mass ratio of lithium mica concentrate: potassium sulfate: calcium hydroxide: coal is 100:15:20:5, and the auxiliary salt is potassium sulfate, calcium hydroxide, coal. The mass ratio of lithium mica concentrate to auxiliary salt is 100:40 to obtain raw material A. Then add 6% water by mass of raw material A and mix evenly to obtain raw material B. Put raw material B into a mold and compact it under a pressure of 20MPa to obtain raw material C. Take out raw material C, dry it at a temperature of 120℃, and obtain dry raw material D after evaporating the water. Then put raw material D into a tunnel kiln for high-temperature roasting, with a heating rate of 10℃ / min, and keep it at a high temperature of 891℃ for 90min, and wait for natural cooling to obtain clinker.
[0044] The clinker was crushed and ground to obtain clinker powder with a fineness of 150 mesh. The powder was tested for total lithium oxide content and lithium oxide soluble in water, and the clinker conversion rate was found to be 85.38%.
[0045] The clinker powder was mixed with water of the same mass in a ratio of 1:1, and stirred at a temperature of 60°C for 60 minutes at a stirring speed of 120 rpm. After stirring was complete, the mixture was filtered to obtain a leachate and leach residue.
[0046] The leachate and leached residue were collected and tested for lithium oxide content. The lithium oxide leaching rate in the clinker was 95.56%, the lithium ion concentration in the leachate was 13.70 g / L, and the lithium oxide content of the dried leached residue was 0.26%.
[0047] Example 6
[0048] The mass ratio of lithium mica concentrate: potassium sulfate: calcium hydroxide: coal is 100:15:15:7, the auxiliary salt is potassium sulfate, calcium hydroxide, coal, and the mass ratio of lithium mica concentrate to auxiliary salt is 100:37 to obtain raw material A. Then add 6% water by mass of raw material A and mix evenly to obtain raw material B. Put raw material B into a mold and compact it under a pressure of 20MPa to obtain raw material C. Take out raw material C, dry it at a temperature of 120℃, and obtain dry raw material D after evaporating the water. Then put raw material D into a tunnel kiln for high-temperature roasting, the heating rate is 10℃ / min, and it is kept at a high temperature of 891℃ for 90min, and it is naturally cooled to obtain clinker.
[0049] The clinker was crushed and ground to obtain clinker powder with a fineness of 150 mesh. The powder was tested for total lithium oxide content and lithium oxide soluble in water, and the clinker conversion rate was found to be 83.74%.
[0050] The clinker powder was mixed with water of the same mass in a ratio of 1:1, and stirred at a temperature of 60°C for 60 minutes at a stirring speed of 120 rpm. After stirring was complete, the mixture was filtered to obtain a leachate and leach residue.
[0051] The leachate and leached residue were collected and the lithium oxide content was tested respectively. The lithium oxide leaching rate in the clinker was 97.71%, the lithium ion concentration in the leachate was 14.49 g / L, and the lithium oxide content of the dried leached residue was 0.35%.
[0052] Comparative Example 1
[0053] The difference between this comparative example and Example 6 is that the auxiliary salt is only potassium sulfate, and the mass ratio of lithium mica to the auxiliary salt is 100:60. The rest is the same as Example 6. The powder is tested for the total lithium oxide content and the lithium oxide that can be dissolved in water, and the clinker conversion rate is 63.77%.
[0054] Compared with Comparative Example 1, Example 1 and Example 2 have significantly improved clinker conversion rate, but the mass ratio of lithium mica to auxiliary salt is reduced from 100:60 to 100:55, the auxiliary salt consumption is reduced by about 6.3 tons / ton of lithium carbonate, and the tailings production is reduced by about 9.9 tons / ton of lithium carbonate, which reduces the pressure of leaching operation and tailings treatment. The reduction of auxiliary salt also reduces the natural gas consumption in the roasting process, and the natural gas consumption is reduced by at least about 1071m 3 / ton of lithium carbonate.
[0055] Compared with Comparative Example 1, Example 3 shows a significantly improved clinker conversion rate, a mass ratio of lithium mica to auxiliary salts from 100:60 to 100:45, a reduced auxiliary salt dosage of about 10.6 tons / ton of lithium carbonate, and a reduced tailings output of about 14.8 tons / ton of lithium carbonate, which reduces the pressure of leaching operations and tailings treatment. The reduction in the amount of auxiliary salts also reduces the amount of natural gas used in the roasting process, which is reduced by at least about 1350 m 3 / ton of lithium carbonate.
[0056] Compared with Comparative Example 1, Example 4 and Example 5 have similar clinker conversion rates, the mass ratio of lithium mica to auxiliary salt is reduced from 100:60 to 100:40, the auxiliary salt consumption is reduced by about 12 tons / ton of lithium carbonate, and the tailings production is reduced by about 16.0 tons / ton of lithium carbonate, which reduces the pressure of leaching operations and tailings treatment. The reduction in the amount of auxiliary salt also reduces the amount of natural gas used in the roasting process, and the amount of natural gas is reduced by at least about 1455m 3 / ton of lithium carbonate.
[0057] Compared with Comparative Example 1, Example 6 has a similar clinker conversion rate, the mass ratio of lithium mica to auxiliary salt is reduced from 100:60 to 100:37, the auxiliary salt consumption is reduced by about 12.9 tons / ton of lithium carbonate, and the tailings production is reduced by about 16.8 tons / ton of lithium carbonate, which reduces the pressure of leaching operations and tailings treatment. The reduction in the amount of auxiliary salt also reduces the amount of natural gas used in the roasting process, and the amount of natural gas is reduced by at least about 1522m 3 / ton of lithium carbonate.
[0058] Comparative Example 2
[0059] The difference between this comparative example and Example 6 is that the auxiliary salt is only potassium sulfate. The rest is the same as Example 6. The powder is tested for the total lithium oxide content and the lithium oxide soluble in water, and the clinker conversion rate is 49.63%.
[0060] The clinker powder is mixed with an equal mass of water to obtain a leachate and a leach residue.
[0061] The leaching solution and leaching residue were collected, and the lithium oxide leaching rate in the clinker was 97.23%, the lithium ion concentration in the leaching solution was 8.55 g / L, and the lithium oxide content of the leaching residue after drying was 1.09%.
[0062] Comparing Comparative Example 2 with Example 6, it can be seen that, under the condition of the same auxiliary salt dosage, the clinker conversion rate of Example 6 is higher, that is, the lithium mica roasting method of the present application can reduce the auxiliary salt dosage.
[0063] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.
[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A secondary salt, characterized in that The composition comprises the following components in parts by weight: Sulfate 10-15 parts, Contains 15-40 parts of calcium, 5-7 parts coal.
2. The auxiliary salt according to claim 1, characterized in that The sulfate is selected from at least one of sodium sulfate and potassium sulfate.
3. The auxiliary salt according to claim 1, characterized in that The calcium-containing substance is selected from at least one of calcium carbonate, calcium sulfate and calcium hydroxide.
4. The auxiliary salt according to claim 1, characterized in that The coal is selected from smoke coal.
5. The auxiliary salt according to claim 1, characterized in that The coal composition includes: ash content 3.73%, volatile matter 20.27%, and carbon content 76.00%.
6. A lepidolite roasting process, characterized in that: The steps include: (1) uniformly mixing the lepidolite concentrate with the auxiliary salt according to any one of claims 1 to 5 in a mass ratio of 100:(30-55) to obtain a raw material; (2) roasting the raw material at 880° C.-950° C. for 90 min-120 min, and cooling naturally to obtain clinker; (3) Soaking the clinker in water and filtering to obtain a leachate.
7. The process according to claim 6, characterized in that In step (2), the roasting includes roasting the raw material alone or roasting the raw material mixed with water.
8. The process according to claim 7, characterized in that The method of mixing the raw material with water and then roasting includes uniformly mixing the raw material with water, compacting and drying the raw material, and then roasting the raw material with water.
9. The process according to claim 8, characterized in that The mass of the water accounts for 4%-6% of the mass of the raw material.