Roasting additive for low-chlorine efficient extraction of lithium and alkali metal, thallium removal and beryllium fixation from lithium-containing ore, extraction method and application

Abstract

The invention discloses a roasting additive for extracting lithium and alkali metals, removing thallium and fixing beryllium from lithium-containing ores with low chlorine and high efficiency, an extraction method and application, and belongs to the field of extraction and smelting of lithium and alkali metals. The invention discloses a lithium-containing ore roasting additive, and aims to solve the technical problems of low leaching extraction rate of alkali metals such as lithium, high thallium concentration in brine and excessive leaching toxicity of dangerous elements in tailings in the lithium extraction process of roasting lithium ore by using composite sulfate in the prior art in order to solve the technical problems of low leaching extraction rate of alkali metals such as lithium and the like, high thallium concentration in brine and excessive leaching toxicity of dangerous elements in tailings in the prior art. Or a chloride, sulfate and a calcium-containing alkaline compound, wherein the use amount of the chloride is 0.1-15% of the mass of the lithium-containing ore. The method is used for extracting lithium or alkaline metal, or reducing beryllium and thallium contents in lithium slag or lithium slag leachate, or increasing the extraction rate of extracting lithium or alkaline metal, or reducing generation and emission of acid gas. The method is applied to the field of lithium extraction.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of lithium extraction, and particularly relates to a roasting additive for low-chlorine efficient lithium extraction and alkali metal, thallium removal and beryllium fixation from lithium-containing ores as well as an extraction method and application. BACKGROUND

[0002] Lithium and its compounds play a key role in energy-saving and environmental protection, high-end equipment manufacturing, information and biology, and other emerging industries. Lithium hydroxide and lithium carbonate are two main products produced by the lithium extraction industry and are widely used in the preparation of lithium cobaltate, lithium manganate, ternary materials and lithium iron phosphate, etc. lithium ion battery cathode materials.

[0003] Lithium-containing minerals can be divided into lithium ores and lithium-containing brine, among which lithium ores include spodumene, lithium mica, lithium-containing porcelain clay, etc. At present, there are many methods for extracting lithium from lithium-containing ores, such as sulfuric acid leaching, chlorination roasting, sulfate roasting and limestone roasting. The chlorination roasting method has been eliminated by the market because the amount of chlorides used is generally greater than 50% of the mass of the lithium ore, and a large amount of chlorine and HCl is generated in the roasting process and evaporation process, which seriously corrodes the equipment and pollutes the environment. The sulfate roasting method has become the preferred process for lithium ore extraction enterprises due to its low cost, small equipment corrosion, and small amount of auxiliary salt addition. This process is also the most widely used lithium ore extraction process in industry.

[0004] However, it is worth noting that there are still some difficult problems to be solved in the sulfate roasting method. First, the composite sulfate roasting method often fails to achieve deep lithium extraction, and the extraction rate of other alkali metals such as rubidium, cesium, thallium, potassium and beryllium in lithium ore is very low, which limits the production capacity of the lithium extraction industry; directly affecting the value and benefit of low-grade lithium ore mining. Second, the sulfate roasting method produces high-concentration thallium ions and beryllium ions in the lithium extraction brine, which needs to be strictly treated to meet the discharge standard. In this process, a large amount of sludge containing thallium and beryllium with extremely high danger is also produced. Finally, the lithium residue left after the sulfate roasting method for lithium extraction contains relatively high concentrations of dangerous elements such as beryllium and thallium, and the leaching toxicity of beryllium and thallium in the lithium residue exceeds the standard, which restricts the treatment and disposal of bulk lithium residue. Therefore, it is necessary to develop a high-efficiency and clean lithium extraction technology from lithium ore, which can improve the extraction rate of alkali metals in lithium ore and reduce the environmental hazards caused by brine, waste residue and tail gas.

[0005] Liu, et al. published in "Inorganic salt industry" in 2018, "Lithium mica mixed salt method for lithium extraction and salt recovery and recycling" discloses: the traditional lithium mica mixed salt method for lithium extraction uses mainly sodium sulfate-calcium chloride (mass ratio 5:3), and the total mass of sodium sulfate-calcium chloride accounts for 80% of the mass of lithium mica, of which the mass of calcium chloride is about 30% of the mass of lithium mica. The experiment intends to replace part of the calcium chloride with sodium chloride, while reducing the total amount of sulfate and chloride salt, in order to achieve the purpose of reducing the cost of raw materials. The process of lithium mica mixed roasting with different proportions of sulfate-chloride salt and water leaching lithium is studied, and the possibility of using the precipitated salt in the preparation of lithium carbonate and lithium phosphate to the lithium mica roasting process is investigated. The experimental results show that when the proportioning ratio (mass ratio of lithium mica, sodium sulfate, calcium sulfate, calcium chloride, sodium chloride) is 1:0.2:0.2:0.1:0.2, the roasting temperature is 900℃, the roasting time is 1h, and the water immersion is 0.5h at room temperature, the leaching rate of lithium oxide is the highest (93.35%); the precipitated salt is mixed with lithium mica as an auxiliary material for roasting, and then water leaching, the leaching rate of lithium oxide is close to that of industrial grade sulfate-chloride salt. Although it gives more than 90% of the leaching rate of lithium oxide, the amount of chloride used in the technology is too much, which is almost equivalent to the amount of sulfate, and there is a problem of chlorine and HCl pollution and corrosion of equipment, and it does not point out the influence of the method on the extraction of alkali metals. Moreover, the technology is not clear about the influence of thallium and beryllium content in waste water and waste residue. SUMMARY

[0006] The purpose of the present application is to solve the technical problems of low leaching extraction rate of lithium and other alkali metals, high thallium concentration in brine, and tailings leaching toxicity exceeding the standard in the existing lithium ore extraction process, especially the composite sulfate roasting lithium ore extraction process, and to provide a low-chlorine efficient lithium extraction and alkali metal, thallium removal and beryllium fixation roasting additive for lithium-containing ores, extraction method and application.

[0007] The present application is a low-chlorine efficient lithium extraction and alkali metal, thallium removal roasting additive for lithium-containing ores, which contains chloride and sulfate in the lithium-containing ore roasting additive, and the amount of chloride is 0.1% to 15% of the mass of lithium-containing ore.

[0008] The chloride is one or more of a compound or mixture containing chloride ions, which can specifically be one or more of sodium chloride, potassium chloride, calcium chloride, aluminum chloride, iron chloride, magnesium chloride, zinc chloride, copper chloride, titanium chloride, chlorine, HCl, CCl4, and NH4Cl.

[0009] Further, the amount of chloride is 0.1% to 10% of the mass of lithium-containing ore.

[0010] Further, the amount of chloride is 0.1% to 6% of the mass of lithium-containing ore.

[0011] Further, the roasting temperature of the lithium-containing ore roasting additive is 500-1200 DEG C.

[0012] Further, the lithium-containing ore is one or more of lepidolite, spodumene, petalite, eucryptite, and clay-type lithium ore.

[0013] The application of the lithium-containing ore low-chlorine high-efficiency lithium and alkali metal roasting additive, the lithium-containing ore roasting additive is used for extracting lithium or alkali metal, or reducing the thallium content in lithium residue or lithium residue leaching solution, or increasing the extraction rate of lithium or alkali metal extraction, or reducing the generation and emission of acid gas.

[0014] The lithium-containing ore low-chlorine high-efficiency lithium and alkali metal roasting additive of the application contains chlorides and alkaline substances capable of absorbing or neutralizing HCl or Cl2, wherein the amount of chlorides is 0.1%-15% of the mass of lithium ore.

[0015] The chlorides are one or more of compounds or mixtures containing chloride ions, and specifically can be one or more of sodium chloride, potassium chloride, calcium chloride, aluminum chloride, iron chloride, magnesium chloride, zinc chloride, copper chloride, titanium chloride, chlorine, HCl, CCl4, and NH4Cl.

[0016] The lithium-containing ore low-chlorine high-efficiency lithium and alkali metal roasting additive of the application contains chlorides, sulfates, and calcium-containing alkaline substances, wherein the amount of chlorides is 0.1%-15% of the mass of lithium ore.

[0017] The chlorides are one or more of compounds or mixtures containing chloride ions, and specifically can be one or more of sodium chloride, potassium chloride, calcium chloride, aluminum chloride, iron chloride, magnesium chloride, zinc chloride, copper chloride, titanium chloride, chlorine, HCl, CCl4, and NH4Cl.

[0018] Further, the calcium-containing substances are one or more of calcium carbonate, calcium oxide, calcium hydroxide, slag, cement, calcium-containing alkaline minerals, and calcium-containing alkaline waste residue.

[0019] The technical principle of the application is as follows:

[0020] The present application provides a lithium ore roasting additive for low-chlorine and high-efficiency lithium extraction and alkali substance and thallium and beryllium removal. A small amount of chlorides is added to the lithium ore roasting additive, wherein the amount of chlorides is 0.1% to 15% of the mass of lithium ore, preferably, the mass of chlorides is 0.1% to 25% of the mass of sulfates. It is worth noting that when the amount of chlorides added in the present application is 0.5% to 6% of the mass of lithium ore, the lithium extraction rate of the lithium ore sulfates roasting method can be greatly improved, the thallium element volatilization can be improved, and the thallium content in lithium residue can be reduced. The present application also proposes that a small amount of calcium carbonate, calcium oxide, calcium hydroxide, slag, cement and other alkali substances or calcium-containing alkali substances are added to the lithium ore roasting system, which can further reduce the amount of chlorides in the lithium ore roasting additive and improve the lithium extraction rate at the same time. The present application also proposes that the low amount of chlorides enhances the destruction of Si-O and Al-O bonds in lithium ore by calcium-containing alkali compounds, and improves the volatilization of thallium element into the gas phase and enrichment. The present application also proposes that the combined use of chlorides and calcium-containing alkali substances not only improves the extraction rate of alkali metals such as potassium, rubidium and cesium, but also significantly improves the solidification effect of beryllium. The chlorides can be one or more of conventional chlorine-containing compounds such as sodium chloride, potassium chloride, calcium chloride, aluminum chloride, iron chloride, magnesium chloride, zinc chloride, copper chloride, titanium chloride, chlorine, HCl, CCl4 and NH4Cl, which all have beneficial effects. Preferably, the chlorine-containing compounds in the present application are one or more of calcium chloride, sodium chloride and potassium chloride. Conventional alkali substances and calcium-containing compounds can meet the requirements.

[0021] The present application has the following beneficial effects:

[0022] (1) The lithium ore roasting and clean lithium extraction method provided by the present application can improve the lithium extraction rate by 5% to 15% and the extraction rate of alkali metals such as potassium, rubidium and cesium by more than 40% compared with the existing chlorination roasting method, sulfates roasting method and limestone roasting method and other lithium extraction methods, by adding a small amount of chlorides to the roasting additive in the lithium extraction process.

[0023] (2) The lithium ore roasting and clean lithium extraction method provided by the present application can reduce the thallium content of wastewater and residue generated in the lithium extraction process, reduce the beryllium content in lithium residue, reduce environmental risks and reduce the amount of hazardous waste generated by lithium carbonate production enterprises. By adding a small amount of chlorides to the roasting process in the lithium mica lithium extraction process, the thallium concentration in the brine can be reduced by more than 95%, and the acid leaching concentration of thallium in lithium residue is less than 1 μg / L.

[0024] (3) The lithium ore roasting and clean lithium extraction method provided by the present application has low chlorides addition amount, low acid gas generation amount, low reagent production cost and low addition amount, which greatly saves the subsequent treatment cost of lithium extraction tailings, wastewater and waste gas, and improves the production value of lithium carbonate enterprises.

[0025] (4) The present application also proposes adding a small amount of alkaline substances or calcium-containing compounds, such as calcium carbonate, calcium oxide, calcium hydroxide, slag, and cement, in the lithium-containing ore roasting system, which not only reduces the corrosion of HCl or Cl2 on the equipment and air pollution, but also further reduces the amount of chloride salt in the lithium-containing ore roasting additive, while improving the lithium extraction rate, that is, using a lower amount of chloride salt to obtain a higher lithium extraction rate.

[0026] (5) The present application proposes that a small amount of chloride can significantly enhance the displacement of alkali metals by sulfates and achieve a higher lithium extraction rate.

[0027] (6) The present application proposes that a small amount of chloride can enhance the destruction of Si-O and Al-O bonds in lithium ore by a small amount of calcium-containing alkaline compounds, and promote the volatilization and enrichment of thallium elements in the gas phase.

[0028] (7) Existing research shows that the lithium extraction rate of most sulfate roasting methods is usually less than 90%, and when the total amount of chloride salt is less than 20% of the weight of lepidolite in the sulfate-chloride mixed roasting process, the lithium extraction rate is also often less than 90%, but when the chloride salt is higher than 20%, the equipment corrosion and air pollution are too serious, so the sulfate-chloride mixed salt roasting process for lithium extraction has not been able to be mass-produced. The present application finds that when the chloride salt reaches 2% in the sulfate-chloride mixed roasting process for lithium extraction, the lithium extraction rate can exceed 90%, and when the chloride salt reaches 3%, the lithium extraction rate can exceed 95%. Since the amount of chloride added at this time is low, the addition of a small amount of adsorbent can effectively inhibit the corrosion of gas on the equipment, achieving high lithium extraction rate, low production of acid gas, small equipment corrosion, and low leaching rate of beryllium and thallium in lithium residue.

[0029] (8) The present application also proposes the combined use of chloride and calcium-containing alkaline substances to improve the lithium extraction rate in the lithium-containing ore roasting process, while significantly improving the solidification effect of beryllium in lithium residue.

[0030] (9) The present application proposes a low-chlorine high-efficiency lithium extraction and thallium removal roasting additive and extraction method, which is more significant in improving the lithium extraction rate of low-grade lithium ore roasting, thereby improving the mining and smelting value of low-grade lithium-containing ore. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions and advantages of the embodiments of the present application more clear and explicit, the spirit of the present application will be described in detail below. Any person skilled in the art can modify and modify the technology taught by the present application content after understanding the embodiments of the present application content, without departing from the spirit and scope of the present application content.

[0032] The schematic embodiments of the present application and their descriptions are used to explain the present application, but not as a limitation on the present application.

[0033] The lithium mica concentrate after flotation provided by a lithium carbonate production enterprise is taken as the object, and the alkali metal extraction rate in the lithium ore powder, the content of hazardous elements in the brine, the content of acid gas in the flue gas, and the leaching toxicity of the lithium extraction tailings in the process of extracting lithium are investigated.

[0034] Example 1-1:

[0035] Lithium mica, calcium sulfate, sodium sulfate and calcium chloride are accurately weighed in a mass ratio of 10:3:2:1, and uniformly mixed. The mixed material is heated to 900℃ and continues to be kept for 120 minutes. After cooling to room temperature, the calcined product is taken out, mechanically crushed, and then leached at room temperature for 60 minutes with a solid-liquid ratio of 1.5:1. The mixed slurry is subjected to solid-liquid separation, and the contents of lithium, potassium, rubidium, cesium and other elements in the leaching solution and the residual alkali metal content in the residue are determined by ICP-OES to calculate the leaching rate; the content of thallium in the leaching solution is determined by ICP-MS; and the thallium leaching toxicity of the lithium extraction tailings is analyzed according to the Solid Waste Leaching Toxicity Leaching Method-Sulfuric Acid and Nitric Acid Method (HJ / T 299-2007).

[0036] Example 1-2:

[0037] The difference between this embodiment and Example 1-1 is that the ratio of lithium mica, calcium sulfate, sodium sulfate and calcium chloride is 10:3:2:0.5. The other steps and parameters are the same as those in Example 1-1.

[0038] Example 1-3:

[0039] The difference between this embodiment and Example 1-1 is that the ratio of lithium mica, calcium sulfate, sodium sulfate and calcium chloride is 10:3:2:0.3. The other steps and parameters are the same as those in Example 1-1.

[0040] Example 1-4:

[0041] The difference between this embodiment and Example 1-1 is that the ratio of lithium mica, calcium sulfate, sodium sulfate and calcium chloride is 10:3:2:0.1. The other steps and parameters are the same as those in Example 1-1.

[0042] Example 1-5:

[0043] The difference between this embodiment and Example 1-1 is that the ratio of lithium mica, calcium sulfate and calcium chloride is 10:5:0.5. The other steps and parameters are the same as those in Example 1-1.

[0044] Comparative Example 1-1:

[0045] The difference between this embodiment and Example 1-1 is that the ratio of lithium mica, calcium sulfate and sodium sulfate is 10:3:2. The other steps and parameters are the same as those in Example 1-1.

[0046] Comparative Example 1-2:

[0047] The difference between this example and Example 1-1 is that the ratio of lepidolite, calcium sulfate, and sodium sulfate is 10:5:3. The other steps and parameters are the same as those in Example 1-1.

[0048] Comparative Example 1-3:

[0049] The difference between this example and Example 1-1 is that the ratio of lepidolite and calcium chloride is 10:5. The other steps and parameters are the same as those in Example 1-1.

[0050] Comparative Example 1-4:

[0051] The difference between this example and Example 1-1 is that the ratio of lepidolite and calcium chloride is 10:10. The other steps and parameters are the same as those in Example 1-1.

[0052] Examples 1 and Comparative Examples 1 aim to explain the low-chlorine and high-efficiency lithium extraction and thallium removal technology described in the present application in the form of experimental data. As can be seen from the results, Comparative Example 1-1 only uses composite sulfate for calcination, and the extraction rates of lithium, rubidium, cesium, and potassium are 85.63%, 3.36%, 2.36%, and 82.63%, respectively. In Comparative Example 1-2, the amount of composite salt is increased to 80% of the concentrate, and the improvement effect of alkali metal extraction rate is very limited. In Comparative Examples 1-3 and 1-4, only calcium chloride is added for lithium extraction by calcination, and it is found that it is difficult to achieve high extraction rate of lithium by using chlorides alone. Even if the amount of calcium chloride added reaches 100%, the recovery rate of lithium is still not more than 90%. When a small amount of calcium chloride is added (Examples 1-1 to 1-4), the extraction rates of lithium, potassium, rubidium, and cesium are increased by 9-13%, 5-6%, 10-40%, and 20-40%, respectively, which proves that a small amount of chloride can significantly enhance the displacement effect of sulfate on alkali metals. At the same time, after the addition of calcium chloride, the content of thallium in the calcination product is greatly reduced, which greatly reduces the Tl risk in the brine and the residue, and the Tl concentration in the brine and the leaching toxicity of Tl in the lithium residue are both lower than the local thallium pollutant discharge standard. In Example 1-5, calcium sulfate is used as a secondary salt and a small amount of chloride is used as an additive, and the results show that the addition of chloride also has a significant effect on increasing the extraction rate of alkali metals and reducing thallium pollution.

[0053] Table 2

[0054]

[0055]

[0056] Example 2-1:

[0057] Lepidolite, calcium sulfate, sodium sulfate, calcium carbonate and calcium chloride were accurately weighed in a ratio of 10:3:2:0.5:0.3, and the dry materials were fully stirred for 2 minutes until uniformly mixed. The mixture was heated to 900°C and continued to be kept for 120 minutes. After cooling to room temperature, the calcined product was taken out and then immersed in water at a ratio of 1.5:1 for 60 minutes at room temperature. The mixed slurry was subjected to solid-liquid separation, and the contents of lithium, potassium, rubidium, cesium and other elements in the leaching solution and the residual alkali metal content in the residue were determined by ICP-OES to calculate the leaching rate; the content of thallium in the leaching solution was determined by ICP-MS; the leaching toxicity of beryllium and thallium in the tailings after lithium extraction was analyzed according to the “Solid Waste Leaching Toxicity Leaching Method-Sulfuric Acid and Nitric Acid Method” (HJ / T 299-2007); the contents of fluorine and chlorine in the clinker were tested by XRF, and the proportion of acid gas generated was calculated by difference method.

[0058] Example 2-2:

[0059] The difference between this example and Example 2-1 is that the ratio of lepidolite, calcium sulfate, sodium sulfate, calcium oxide and calcium chloride is 10:3:2:0.5:0.3. The other steps and parameters are the same as those in Example 2-1.

[0060] Example 2-3:

[0061] The difference between this example and Example 2-1 is that the ratio of lepidolite, calcium sulfate, sodium sulfate, calcium oxide and calcium chloride is 10:3:2:0.5:0.3. The other steps and parameters are the same as those in Example 2-1.

[0062] Example 2-4:

[0063] The difference between this example and Example 2-1 is that the ratio of lepidolite, calcium sulfate, sodium sulfate, calcium oxide and calcium chloride is 10:3:2:0.5:0.3. The other steps and parameters are the same as those in Example 2-1.

[0064] Comparative Example 2-1

[0065] The difference between this example and Example 2-1 is that the ratio of lepidolite, calcium sulfate, sodium sulfate, calcium oxide and calcium chloride is 10:3:2:0.5:0.3. The other steps and parameters are the same as those in Example 2-1.

[0066] Comparative Example 2-2

[0067] The difference between this example and Example 2-1 is that the ratio of lepidolite, calcium sulfate, sodium sulfate, calcium oxide and calcium chloride is 10:3:2:0.5:0.3. The other steps and parameters are the same as those in Example 2-1.

[0068] Comparative Example 2-3

[0069] The embodiment is different from example 2-1 in that the ratio of lithium mica, sodium sulfate and calcium chloride is 10:3:2. The other steps and parameters are the same as example 2-1.

[0070] Examples 2-1 to 2-4 and Comparative Example 2-1 are intended to explain the low-chlorine high-efficiency lithium extraction, thallium removal and acid gas reduction technology described in the present application in the form of experimental data.

[0071] Comparative Example 2-3 uses a composite salt of sodium sulfate and calcium chloride for calcination to extract lithium. The process also has a high lithium extraction rate, but this method has problems of large emission of acid gas and exceeding of the leaching toxicity of lithium residue. Because 20% of the chlorides are added in this method, more than 60 kg of acid gas will be produced per ton of concentrate during the calcination process, and the leaching toxicity of beryllium in the lithium residue far exceeds the national hazardous waste leaching toxicity identification standard of 20 μg / L, which does not meet the green demand in actual application.

[0072] Comparative Example 2-2 uses a composite sulfate method of sodium sulfate and calcium sulfate for calcination to extract lithium. This process is widely used in production, but as can be seen from the data in Table 3, this method produces a large amount of thallium element in the wastewater, and the leaching concentration of beryllium and thallium in the waste residue also exceeds the hazardous waste limit value.

[0073] In examples 2-1 to 2-4, the amount of chlorides added is only 15% of the amount of chlorides added in comparative example 2-3, and some common calcium-containing compounds are added, which reduces the amount of acid gas produced by more than 98%, and significantly suppresses the leaching toxicity of beryllium and thallium in the lithium residue. At the same time, compared with comparative example 2-1, it is found that the addition of calcium-containing alkaline compounds helps to further improve the recovery rate of alkali metals and reduce the amount of chlorides. When 0.5% of calcium-containing alkaline substances are added, the amount of chlorides required is significantly reduced by 40% under the same alkali metal recovery rate. The above shows that the addition of a small amount of chlorides and calcium-containing alkaline compounds to the calcination process can solve the problems of low lithium extraction rate, high environmental risk of waste species beryllium and thallium, and high acid gas emission in the chlorination calcination method.

[0074] Table 3

[0075]

[0076]

[0077] Example 3-1:

[0078] Lepidolite, calcium carbonate and calcium chloride were accurately weighed in a ratio of 10:8:0.5, and the dry materials were stirred for 2 minutes until evenly mixed. The mixture was heated to 950℃ and kept for 120 minutes. After cooling to room temperature, the calcined product was removed and then immersed in water at a ratio of 1.5:1 for 60 minutes at room temperature. The mixed slurry was subjected to solid-liquid separation, and the contents of lithium, potassium, rubidium, cesium and other elements in the leaching solution and the residual alkali metal content in the residue were determined by ICP-OES, and the leaching rate was calculated; the content of thallium in the leaching solution was determined by ICP-MS; the thallium leaching toxicity of the tailings after lithium extraction was analyzed according to the Solid Waste Leaching Toxicity Leaching Method-Sulfuric Acid and Nitric Acid Method (HJ / T 299-2007); the contents of fluorine and chlorine in the clinker were tested by XRF, and the proportion of acid gas generated was calculated by difference method.

[0079] Example 3-2

[0080] The difference between this example and Example 3-1 is that the ratio of lepidolite, blast furnace granulated slag and calcium chloride is 10:8:0.5. The other steps and parameters are the same as those in Example 3-1.

[0081] Example 3-3

[0082] The difference between this example and Example 3-1 is that the ratio of lepidolite, quicklime and calcium chloride is 10:8:0.5. The other steps and parameters are the same as those in Example 3-1.

[0083] Comparative Example 3-1

[0084] The difference between this example and Example 3-1 is that the ratio of lepidolite, calcium carbonate is 10:8. The other steps and parameters are the same as those in Example 3-1.

[0085] Comparative Example 3-2

[0086] The difference between this example and Example 3-1 is that the ratio of lepidolite, blast furnace granulated slag is 10:8. The other steps and parameters are the same as those in Example 3-1.

[0087] Comparative Example 3-3

[0088] The difference between this example and Example 3-1 is that the ratio of lepidolite, quicklime is 10:8. The other steps and parameters are the same as those in Example 3-1.

[0089] Example 3 illustrates the use of low amounts of chloride to enhance the destruction of Si-O and Al-O bonds in lithium ores by calcium-containing alkaline compounds, to improve the recovery of alkali elements and to promote the volatilization of thallium into the gas phase and its enrichment. As can be seen from Table 4, when 80% of calcium-containing alkaline compounds (calcium carbonate, blast furnace granulated slag and quicklime) are added alone for the extraction of lithium from lithium ores, the recovery of alkali metals is low, and there is a certain amount of thallium element in the remaining wastewater and waste residue, which has environmental risks; when a small amount of chloride (0.5%) is used as an auxiliary agent in the above process, the recovery of alkali metals is significantly improved, with the recovery of lithium, potassium, rubidium and cesium being increased by 30%, 30%, 40% and 20%, respectively, and under this condition, the thallium element in the lithium ore is mostly enriched in the gas phase, greatly reducing the environmental risks of lithium extraction wastewater and waste residue.

[0090] Table 4

[0091]

[0092]

[0093] Example 4-1:

[0094] Lepidolite, calcium sulfate, sodium sulfate and potassium chloride were accurately weighed in a mass ratio of 10:3:2:0.5 and mixed uniformly. The mixture was heated to 900°C and continued to be kept for 120 minutes. After cooling to room temperature, the calcined product was taken out, mechanically crushed, and then leached at room temperature for 60 minutes at a solid-to-water ratio of 1.5:1. The mixed slurry was subjected to solid-liquid separation, and the content of lithium, potassium, rubidium, cesium and other elements in the leaching solution and the content of residual alkali metals in the residue were determined using ICP-OES to calculate the leaching rate; the content of thallium in the leaching solution was determined using ICP-MS; and the leaching toxicity of thallium in the tailings after lithium extraction was analyzed in accordance with the "Solid Waste Leaching Toxicity Leaching Method - Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007).

[0095] Example 4-2:

[0096] The difference between this example and Example 4-1 is that sodium chloride is added. The other steps and parameters are the same as those of Example 4-1.

[0097] Example 4-3:

[0098] The difference between this example and Example 4-1 is that aluminum chloride is added. The other steps and parameters are the same as those of Example 4-1.

[0099] Example 4-4:

[0100] The difference between this example and Example 4-1 is that magnesium chloride is added. The other steps and parameters are the same as those of Example 4-1.

[0101] Example 4-5:

[0102] The difference between this example and Example 4-1 is that the chloride added is NH4C1. Other steps and parameters are the same as in Example 4-1.

[0103] Example 4 aims to illustrate the universality of chloride in this system. As can be seen from Table 5, the addition of sodium chloride, potassium chloride, aluminum chloride and magnesium chloride, four kinds of chlorides, also has the effect of improving the recovery rate of alkali metals and reducing the risk of thallium.

[0104] Table 5

[0105]

[0106]

Claims

1. A roasting additive for efficient lithium extraction with low chlorine and alkali metals, thallium removal from lithium-containing ores, characterized in that: The roasting additive for lithium-containing ores contains chlorides and sulfates, wherein the amount of chlorides is 0.1%-15% of the mass of the lithium-containing ores.

2. The roasting additive for low-chlorine and high-efficiency lithium extraction and alkali metal and thallium removal from lithium-containing ores according to claim 1, characterized in that: The amount of chlorides is 0.1%-10% of the mass of the lithium-containing ores.

3. The roasting additive for low-chlorine and high-efficiency lithium extraction and alkali metal, thallium removal of lithium-containing ores according to claim 1 or 2, characterized in that: The chlorides are one or more of compounds or mixtures containing chloride ions or chlorine elements.

4. The roasting additive for low-chlorine and high-efficiency lithium extraction and alkali metal and thallium removal of lithium-containing ores according to claim 1 or 2, characterized in that: The chlorides are one or more of sodium chloride, potassium chloride, calcium chloride, aluminum chloride, iron chloride, magnesium chloride, zinc chloride, copper chloride, titanium chloride, chlorine gas, HCl, CCl4, and NH4Cl.

5. The roasting additive for lithium-containing ores according to claim 1 or 2, characterized in that: The roasting temperature of the roasting additive for lithium-containing ores in the process of extracting lithium and alkali metals and removing thallium is 500-1200°C.

6. The roasting additive for lithium-containing ores according to claim 1, characterized in that: The lithium-containing ores are one or more of lepidolite, spodumene, petalite, eucolite, and clay-type lithium ores.

7. The use of a roasting additive for efficient lithium extraction with low chlorine and thallium removal from lithium-containing ores according to claim 1 or 2, characterized in that: The roasting additive for lithium-containing ores is used for extracting lithium or alkali metals, reducing the content of beryllium in lithium residues or lithium residue leaching liquor, improving the extraction rate of lithium or alkali metals, or reducing the generation and emission of acid gases.

8. A roasting additive for efficient lithium extraction with low chlorine and for alkali metals, thallium removal and beryllium fixation from lithium-containing ores, characterized by: The roasting additive for lithium-containing ores contains chlorides and alkaline substances that can absorb or neutralize HCl or Cl2, wherein the amount of chlorides is 0.1%-15% of the mass of the lithium-containing ores.

9. A roasting additive for efficient lithium extraction with low chlorine and alkali metals, thallium removal and beryllium fixation from lithium-containing ores, characterized by: The roasting additive for lithium-containing ores contains chlorides, sulfates, and calcium-containing alkaline substances, wherein the amount of chlorides is 0.1%-15% of the mass of the lithium-containing ores.

10. The roasting additive for efficient lithium extraction with low chlorine and for alkali metals, thallium removal and beryllium fixation from lithium-containing ores according to claim 9, characterized in that: The calcium-containing substances are one or more of calcium carbonate, calcium oxide, calcium hydroxide, slag, cement, calcium-containing alkaline minerals, and calcium-containing alkaline waste residues.

Images