Method for roasting-leaching clay type lithium ore by replacing roasting aid with biomass

Abstract

The invention provides a method for roasting-leaching clay type lithium ore by replacing a roasting aid with biomass, and belongs to the technical field of ore dressing processes. According to the method, the plant ash generated after biomass combustion is used for replacing part of alkali-containing salt or alkali in the clay type lithium ore so as to achieve the purpose of alkali roasting-water leaching, the sintering condition of a roasting auxiliary and the clay type ore can be effectively reduced through addition of the plant ash, and bulk consumption of solid waste of the plant ash is achieved. The invention provides a mixed roasting-water leaching method of plant ash generated after biomass combustion and clay type lithium ore, so that the consumption of a roasting auxiliary agent is greatly reduced (the consumption of an alkaline agent is reduced by 50-80%), the phenomenon that the roasting auxiliary agent and the clay type ore are easy to sinter at high temperature is improved, clean and effective utilization of biomass is realized, and the method is suitable for industrial production. The lithium obtained through the method is high in leaching rate and low in cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mineral processing and treatment, and particularly relates to a method for roasting and leaching clay-type lithium ore by using biomass instead of roasting aids. BACKGROUND

[0002] Lithium is mainly used in battery, grease and ceramic industries. With the rapid increase in the popularity of electric vehicles in China and the gradual development of the energy storage industry, the demand for lithium resources for power batteries and energy storage batteries continues to rise. At present, the lithium ore resources exploited and utilized in China mainly include pegmatite ore deposits and brine ore deposits. In recent years, clay-type lithium ore with rich reserves in the southwest of China has been explored and discovered. Effective development and utilization of such clay-type lithium ore will to some extent alleviate the situation of tight supply and demand of lithium resources in China.

[0003] At present, the main method for extracting and utilizing clay-type lithium ore is the roasting-leaching method, including roasting-sulfuric acid method, limestone (roasting aid)-water leaching method, soda roasting-leaching method, etc. Although the roasting-sulfuric acid method has a wide range of applications, it has the disadvantages of high acid consumption, high energy consumption, high process cost, and low value of by-products; the limestone (roasting aid)-water leaching method is more suitable for the industrialized water leaching process of the roasted product, but a large amount of basic roasting aid needs to be added during roasting, the roasting temperature is high, and the energy consumption is large; the soda roasting-leaching method produces a large amount of solid waste with low recycling value and difficult to handle while extracting lithium, and has poor environmental cleanliness. Therefore, the current extraction and utilization method for clay-type lithium ore still has many deficiencies that need to be improved.

[0004] Patent document CN111893318A provides a method for extracting lithium from lithium-containing clay, which mixes lithium-containing clay, calcium carbonate, sodium sulfate and potassium sulfate, and then roasts the mixture. The roasted product is obtained by water leaching method, and the lithium recovery rate is >90%. The lithium extraction process adopted by the invention is relatively simple, but there are problems such as high price of roasting aid, high energy consumption for balling, and high roasting energy consumption.

[0005] Patent document 118685635A provides a method for extracting lithium from clay-type lithium ore with the aid of an aid, which mixes potassium sulfate and clay-type lithium ore, presses the mixture into a tablet, roasts the tablet, and then leaches the tablet with water as a leaching agent. Finally, a lithium leaching rate of 92-96% can be obtained. This method has high lithium leaching rate and low subsequent impurity content, but has problems such as high roasting temperature, high equipment energy consumption, and complex process flow.

[0006] Patent document CN113753924B provides a method for extracting lithium carbonate and co-producing aluminum sodium silicate from lithium-rich clay by activated water leaching. The method mixes lithium ore, sodium carbonate and sodium sulfate, grinds and roasts, the roasting temperature is 600-1000℃, the roasting time is 20-60min, and water is used as leaching agent. The final process indicators are lithium leaching rate >95%, aluminum sodium silicate leaching rate >94%. The invention realizes effective leaching of lithium resources, and co-produces aluminum sodium silicate, and produces multiple products. However, the invention still has problems such as long and complex process flow, high roasting energy consumption, long leaching and solution aging time.

[0007] Biomass contains a large amount of volatile carbonaceous substances, which can produce different reducing gases such as CO, H2, CH4, C n H m At the same time, biomass can release a large amount of heat during roasting, which can increase the roasting temperature and accelerate the endothermic reaction process. Biomass is applied in the processing of various products, solid waste processing, soil improvement, etc. Patent document CN115127105A invents a low-carbon method of coal mixed with sludge and biomass particles to replace coal, which aims to utilize biomass and sludge simultaneously to ensure that odors are not directly discharged into the air during the treatment process. Patent document CN117327857A invents a method of using biomass charcoal for direct reduction in a rotary hearth furnace, which uses biomass charcoal to replace part of the carbon source and mixes with metallurgical sludge to reduce the probability of balling and improve the balling rate of metallized pellets. Patent document CN117683952A invents a blast furnace blowing biomass system and an ironmaking process for protecting coke, which mainly uses biomass charcoal to replace part of the coal for ironmaking in the blast furnace, thereby reducing the melting loss of coke, improving the strength of coke, and reducing the consumption of solid carbon (coke). The above patents all show that biomass can effectively replace coal, sludge, etc. to improve and affect the test.

[0008] Wood ash refers to the residue after burning of plants (herbs and woody plants), which belongs to insoluble substances, and wood ash is light and alkaline. Because the wood ash after biomass burning is often alkaline, and the raw materials are cheap and large in quantity, it is often a byproduct of combustion for power generation and other methods. However, how to utilize the waste products such as wood ash after biomass burning to realize the water leaching of lithium from clay-type lithium ore, the current research is very limited.

[0009] Therefore, if a method for utilizing wood ash after biomass burning for lithium extraction from clay-type lithium ore can be provided, it will add a new process method with high feasibility to the existing lithium extraction process. SUMMARY

[0010] The present application is to solve the above technical problems, thereby providing a method for roasting and leaching clay-type lithium ore by using biomass instead of roasting aid. The technical purpose of the present application is to solve the problems of complex process, high roasting temperature, high cost and low lithium leaching rate in the existing lithium extraction process for clay-type lithium ore, and to provide a lithium extraction method for clay-type lithium ore with simple process flow, low roasting temperature, low cost and high lithium leaching rate.

[0011] In order to achieve the above technical purpose, the technical solution adopted by the present application is as follows:

[0012] The present application first provides a method for roasting and leaching clay-type lithium ore by using biomass instead of roasting aid, comprising the following steps:

[0013] (1) crushing and grinding the clay-type lithium ore to obtain mineral powder;

[0014] (2) cutting and crushing the collected biomass to obtain biomass particles;

[0015] (3) burning the biomass particles obtained in step (2) at 100 DEG C for 20-30 min to obtain wood ash;

[0016] (4) collecting the wood ash after burning and the mineral powder obtained in step (1), and mixing with roasting aid according to the mass ratio (1.25-2.3):1:(0.5-0.2), and preparing pellets by pelletizing the above mixture;

[0017] (5) putting the pellets obtained in step (4) into a roasting device for preheating treatment, the preheating treatment temperature is 200-350 DEG C, and the treatment time is 30-90 min;

[0018] (6) sending the preheated pellets into a suspension roasting device, setting the roasting temperature to 700-900 DEG C, and the roasting time to 30-180 min;

[0019] (7) crushing the obtained material in step (6) and leaching in water, the leaching temperature is 50-95 DEG C, the leaching time is 30-120 min, then performing suction filtration to obtain lithium leaching solution and leaching residue.

[0020] The biomass ash produced after biomass combustion is used to replace part of the alkali-containing salt or alkali in the clay-type lithium ore in the present application to achieve the purpose of alkali roasting-water leaching. The addition of the biomass ash can effectively reduce the sintering of the roasting aid and the clay-type mineral, and realize the large-scale consumption of solid waste of the biomass ash. Therefore, the present application innovatively proposes a method of mixing and roasting-water leaching of the biomass ash produced after biomass combustion and the clay-type lithium ore, which not only greatly reduces the consumption of roasting aid (reduces the consumption of alkali agent by 50-80%), but also improves the phenomenon that the roasting aid and the clay-type mineral are easily sintered at high temperature, and realizes the clean and effective utilization of biomass.

[0021] The main elements of the biomass ash are K, Na, Ca and Mg, and the oxides CaO, K2O and MgO are the main alkali substances of the biomass ash, and the content ranges are 35-40%, 10-15% and 10-15% respectively. In addition, the biomass ash also contains a certain amount of SiO2, and the content is about 15-25%. After XRD detection, the main components of the minerals in the biomass ash are calcite (CaCO3), potassium carbonate (K2CO3), quartz and other salts.

[0022] In particular, the contents of calcium oxide, potassium carbonate and silicon dioxide in the biomass ash obtained after roasting of different biomass are quite different. For example, the content of CaO in the needle tree ash is relatively high, and the contents of K2CO3 and K2O in the sunflower stem ash are relatively high. In addition, the place of origin of the biomass also has a great influence on the components. The biomass of the present application can be woody, herbaceous and grassy biomass. As a preferred, the pine and cypress ash in a certain place in Sichuan is selected as the biomass ash.

[0023] Further, in step (1), the mineral powder with a particle size of-0.074 mm accounting for 50-90% is obtained after grinding.

[0024] Further, in step (2), the particle size of the biomass particles is greater than 0.1 cm, and the particle size of the biomass particles is greater than 0.1 cm.

[0025] Further, in step (2), the biomass is woody, herbaceous or grassy biomass.

[0026] Further, in step (4), the roasting aid is a mixture of CaSO4 and CaO, and the mass ratio of CaO:CaSO4 is (1-2):1.

[0027] Further, in step (4), the mixed powder is balling by a balling machine, and a small amount of balling binder is added, and the model of the balling machine is PQ(T)-500.

[0028] Further, in step (4), the balling radius is 0.05-0.10 cm.

[0029] Further, the mass ratio of the wood ash, mineral powder and calcination aid in step (4) is 2:1:0.5.

[0030] In particular, the clay-type lithium ore in the present application mainly includes lithium chlorite, which is a layered silicate clay-type mineral close to di-octahedral.

[0031] In particular, the CaO, K2CO3 and MgO in the method of the present application can also react with SiO2 to form silicate precipitates, which can destroy the crystal structure of the clay-type lithium ore, and the calcination aid CaSO4 can exchange with lithium in the crystal lattice of the clay-type lithium ore to form soluble lithium salt.

[0032] In particular, the main reactions involved in the present application are shown in the following formulas, wherein M is a metal element with a valence of 1-2:

[0033] CaO+SiO2=CaSiO3 (1)

[0034] MgO+SiO2=MgSiO3 (2)

[0035] K2CO3+SiO2=K2SiO3+CO2↑ (3)

[0036] CaO+Al2O3=Ca(AlO2)2 (4)

[0037] K2O+Al2O3=2KAlO2 (5)

[0038] M2SO4+Li + =Li2SO4+2M + (6)

[0039] MSO4+Li + =Li2SO4+M 2+ (7)

[0040] The substances formed by reactions (1)-(3) are all insoluble in water or slowly soluble in cold water; although reactions (4) and (5) are soluble in water, they can be subsequently purged of impurities by passing in CO2. Reactions (6) and (7) are exchange reactions between lithium and metal elements in the sulfate salt. The present application only focuses on the effective leaching of lithium. Therefore, after calcination of the above materials, a large amount of precipitates are produced, and lithium exists in the form of sulfate salt and is easily soluble in water.

[0041] In particular, the final lithium leaching rate obtained by the method of the present application is ≥90%, and the calculation formula of the lithium leaching rate in the present application is as follows:

[0042]

[0043] wherein α is the lithium leaching rate, %.渣 is the mass of the leaching residue, g; w 渣 is the mass fraction of lithium in the leaching residue, %; m 原 is the mass of the initial raw material, g; w 原 is the mass fraction of lithium in the raw material, %.

[0044] The beneficial effects of the present application are as follows:

[0045] The present application innovatively proposes a method of mixing and roasting-water leaching of biomass ash produced after biomass combustion and clay-type lithium ore, which not only greatly reduces the consumption of roasting aids (alkali agent consumption is reduced by 50-80%), improves the phenomenon that roasting aids and clay-type minerals are easily sintered at high temperature, but also realizes the clean and effective utilization of biomass. The present application can finally obtain a process index with a lithium leaching rate of 90% or more, while greatly saving the cost. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is a flowchart of a process for treating clay-type lithium ore by partially replacing roasting aids with biomass. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the present application more clear and explicit, the present application is specifically described below in combination with examples. It is necessary to point out that the following examples are only used to explain and illustrate the present application, and do not limit the present application. Some non-essential improvements and adjustments made by those skilled in the art based on the above disclosure still fall within the protection scope of the present application.

[0048] Example 1

[0049] A clay-type lithium ore in the southern part of Sichuan Province has the following main chemical components: Li2O 0.12%, SiO2 37.78%, Al2O3 31.35%, Fe2O3 4.27%, CaO 0.24%, MgO 0.27%, and K2O 0.33%. The steps of roasting treatment of clay-type lithium-poor ore by replacing part of the roasting aid with wood ash are as follows:

[0050] (1) After crushing and grinding the clay-type lithium ore, a mineral powder sample with a particle size of-0.074 mm accounting for 70.51% is obtained;

[0051] (2) After the collected biomass is cut and crushed, the biomass particles are sieved by particle size, and finally biomass particles with a particle size of-0.1 cm accounting for 99% are obtained;

[0052] (3) The biomass particles with qualified particle size are subjected to a combustion process at a combustion temperature of 100℃ for 30 min;

[0053] (4) Collect the grass ash after combustion and the mass ratio of clay type lithium ore and roasting aid (CaSO4: CaO = 1:1) is 2:1:0.5, and the three materials are mixed and balling in the above ratio;

[0054] (5) The prepared pellets are put into the roasting equipment for preheating treatment, the roasting equipment is set to 300℃, and the roasting time is 30 min, the hydroxyl in the clay type lithium ore is removed, and the volatile components in the grass ash are further removed;

[0055] (6) After preheating, the pellets are sent to the suspension roasting device, the roasting temperature is 900℃, and the roasting time is 120 min, the lithium in the structure of the clay type lithium ore is fully released, and exchanges with the metal ions in the sulfate;

[0056] (7) The roasted ore pellets are crushed and leached, the leaching agent is water, the leaching time is 60 min, and the leaching temperature is 90℃;

[0057] (8) The product is filtered, and finally the process index of lithium leaching rate of 91.15% is obtained.

[0058] Example 2

[0059] A clay type lithium ore in the south of Yunnan Province, the main chemical composition is Li2O 0.21%, SiO2 35.78%, Al2O3 34.35%, Fe2O3 2.16%, CaO 0.13%, MgO 0.34%, K2O 0.27%. The steps of replacing part of the roasting aid to roast the clay type lithium-poor ore with grass ash are as follows:

[0060] (1) After crushing and grinding the clay type lithium ore, a mineral powder sample with a particle size of-0.074 mm accounting for 63.84% is obtained;

[0061] (2) After the collected biomass is cut and crushed, the biomass particles are sieved by particle size, and finally biomass particles with a particle size of-0.1 cm accounting for 99% are obtained;

[0062] (3) The biomass particles with qualified particle size are burned at a temperature of 150℃ for 20 min;

[0063] (4) Collect the grass ash after combustion and the mass ratio of clay type lithium ore and roasting aid (CaSO4: CaO = 1:1.5) is 1.8:1:0.2, and the three materials are mixed and balling in the above ratio;

[0064] (5) The prepared pellets are put into the roasting equipment for preheating treatment, the roasting equipment is set to 250℃, and the roasting time is 30 min, the hydroxyl in the clay type lithium ore is removed, and the volatile components in the grass ash are further removed;

[0065] (6) After preheating is completed, send the pellets into the suspension roasting device, the roasting temperature is 850°C, and the roasting time is 120 min, so as to fully release lithium in the lithium mineral structure of the clay type and exchange with metal ions in the sulfate;

[0066] (7) After the roasted ore pellets are crushed, leaching is performed, the leaching agent is water, the leaching time is 90 min, and the leaching temperature is 90°C;

[0067] (8) The product is subjected to suction filtration, and finally the process index of a lithium leaching rate of 90.89% can be obtained.

[0068] Example 3

[0069] A clay type lithium mine in the southwest of Sichuan Province, the main component is li serpentine, the chemical composition content is Li2O 0.19%, SiO2 40.68%, Al2O3 35.45%, Fe2O3 2.21%, CaO 0.30%, MgO 0.24%, K2O 0.29%. The steps of replacing part of the roasting aid with wood ash to roast the clay type lithium-poor mine are as follows:

[0070] (1) After the clay type lithium mine is crushed and ground, a mineral powder sample with a particle size of-0.074 mm accounting for 89.51% is obtained;

[0071] (2) After the collected biomass is subjected to shearing and crushing processes, the biomass particles are subjected to particle size screening, and finally biomass particles with a particle size of-0.1 cm accounting for 99% are obtained;

[0072] (3) The biomass particles with qualified particle size are subjected to a combustion process at a combustion temperature of 150°C for 90 min;

[0073] (4) The wood ash collected after combustion is mixed with the clay type lithium mine and the roasting aid (CaSO4: CaO = 1:2) in a mass ratio of 1.25:1:0.3, and the three materials are mixed and formed into pellets according to the above ratio;

[0074] (5) The prepared pellets are placed into a roasting device for preheating treatment, the roasting device is set to 250°C, and the roasting time is 30 min, so as to remove the hydroxyl groups in the clay type lithium mine and further remove the volatile components in the wood ash;

[0075] (6) After preheating is completed, send the pellets into the suspension roasting device, the roasting temperature is 850°C, and the roasting time is 180 min, so as to fully release lithium in the lithium mineral structure of the clay type and exchange with metal ions in the sulfate;

[0076] (7) The roasted ore pellets are crushed and then leached with water for 60 min at 90°C;

[0077] (8) The product is filtered, and finally the process index of lithium leaching rate of 90.07% is obtained.

[0078] Example 4

[0079] A clay-type lithium ore in the west of Guizhou Province has main chemical components of Li2O 0.09%, SiO2 39.77%, Al2O3 37.88%, Fe2O3 5.07%, CaO 0.38%, MgO 0.41%, and K2O 0.50%. The steps of roasting the clay-type lithium-poor ore by replacing part of the roasting aid with wood ash are as follows:

[0080] (1) After crushing and grinding the clay-type lithium ore, the particle size of 82.22% is obtained.

[0081] (2) After the collected biomass is cut and crushed, the biomass particles are sieved by particle size, and finally the biomass particles with a particle size of 99% are obtained.

[0082] (3) The biomass particles with qualified particle size are combusted at a temperature of 100°C for 30 min.

[0083] (4) The wood ash after combustion is collected and mixed with the clay-type lithium ore and the roasting aid (CaSO4: CaO = 1:1.2) in a mass ratio of 2.3:1:0.5, and the three materials are mixed and pelletized in the above ratio.

[0084] (5) The prepared pellets are put into a roasting device for preheating treatment, the roasting device is set to 300°C, and the roasting time is 30 min, so as to remove the hydroxyl groups in the clay-type lithium ore and further remove the volatile components in the wood ash.

[0085] (6) After preheating, the pellets are sent to a suspension roasting device, the roasting temperature is 900°C, and the roasting time is 180 min, so as to fully release the lithium in the clay-type lithium ore structure and exchange with the metal ions in the sulfate.

[0086] (7) The roasted ore pellets are crushed and then leached with water for 60 min at 80°C;

[0087] (8) The product is filtered, and finally the process index of lithium leaching rate of 91.45% is obtained.

[0088] Comparative Example 1

[0089] Different from example 1, the mass ratio of wood ash, clay type lithium ore and calcination aid (CaSO4, CaO) in comparative example 1 is 1:1:0.5, and the pellets are prepared by mixing the above three materials. The final lithium leaching rate is 85.32%, which shows that the amount of wood ash is too small to make the lithium leaching rate decrease.

[0090] Comparative example 2

[0091] Different from example 2, the roasting temperature in step (6) of comparative example 2 is set to 1100℃, and the roasting time is 120 min. The lithium leaching rate is 81.36%, and sintering phenomenon occurs in the roasted ore, which gradually becomes serious with the increase of roasting temperature. The reason for the significant decrease of lithium leaching rate is that the high temperature makes the silicon dioxide melt and rewrap the lithium-containing structure, which makes the lithium in the subsequent leaching process unable to be completely released. Therefore, the roasting temperature of 700-900℃ in the present application is appropriate and reasonable. In addition, the addition of wood ash in biomass can effectively reduce the probability of sintering phenomenon occurring in the roasting reaction process.

[0092] Comparative example 3

[0093] Different from example 3, the roasting temperature in comparative example 3 is 600℃, and the roasting time is 180 min. The final lithium recovery rate is 85.32%, which shows that the decrease of roasting temperature is not conducive to improving the lithium recovery rate within the appropriate roasting time range.

[0094] Comparative example 4

[0095] Different from example 4, the leaching temperature in comparative example 4 is 40℃, and the leaching time is 150 min. The final lithium leaching rate is 80.20%, which shows that the leaching temperature is also one of the factors affecting the lithium leaching rate.

Claims

1. A method of roasting-leaching a clay-type lithium ore with biomass instead of roasting aid, characterized by, The method comprises the following steps: (1) crushing and grinding the clay-type lithium ore to obtain mineral powder; (2) cutting and crushing the collected biomass to obtain biomass particles; (3) burning the biomass particles obtained in step (2) at 100℃ for 20-30min to obtain wood ash; (4) collecting the wood ash after burning and the mineral powder obtained in step (1), and mixing with a roasting aid according to a mass ratio of (1.25-2.3):1:(0.2-0.5), and preparing pellets by pelletizing the above mixture; (5) putting the pellets obtained in step (4) into a roasting device for preheating treatment, and the preheating treatment temperature is 200-350℃, and the treatment time is 30-90min; (6) putting the pellets after preheating treatment into a suspension roasting device, and setting the roasting temperature to 700-900℃, and the roasting time is 30-180min; (7) crushing the obtained material in step (6) and leaching in water, the leaching temperature is 50-95℃, the leaching time is 30-120min, then performing suction filtration to obtain lithium leaching liquid and leaching residue.

2. The method of claim 1, wherein, In step (1), the mineral powder obtained after grinding has a particle size of-0.074mm, and the proportion is 50-90%.

3. The method of claim 1, wherein, In step (2), the particle size of the biomass particles is-0.1cm, and the proportion is more than 99%.

4. The method of claim 1, wherein, In step (2), the biomass is woody, herbaceous or grassy biomass.

5. The method of claim 1, wherein, In step (4), the roasting aid is a mixture of CaSO4 and CaO, and the mass ratio of CaO:CaSO4 is (1-2):

1.

6. The method of claim 1, wherein, In step (4), a binder is added during pelletizing.

7. The method of claim 1, wherein, In step (4), the pelletizing radius is 0.05cm-0.10cm.

8. The method of claim 1, wherein, In step (4), the mass ratio of wood ash, mineral powder and roasting aid is 2:1:0.

5.

9. The method according to any one of claims 1 to 8, characterized in that, The method obtains a lithium leaching rate of more than 90%.

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