Method for synchronously removing impurities in efficient lithium extraction process of clay type lithium ore

Abstract

The invention discloses a method for synchronously removing impurities in an efficient lithium extraction process of clay type lithium ores, and belongs to the technical field of comprehensive utilization of clay type lithium ores. Comprising the following steps: mechanically activating clay type lithium ore to obtain an activated material; a ferric sulfate solution is added into the activated material for ion exchange leaching, sulfuric acid is added in the leaching process to adjust the pH value of the system, impurity elements such as potassium and iron in a leaching solution are synchronously removed according to the jarosite principle, and a lithium-rich solution and filter residues containing jarosite are obtained; and performing concentration / lithium precipitation on the lithium-rich solution to obtain a high-purity lithium carbonate product. According to the method, synchronous removal of impurity elements is realized on the premise of efficiently leaching valuable metal lithium. The method has the advantages of being simple in process, easy and convenient to operate, environmentally friendly and the like, and meanwhile has good industrialization prospects.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive utilization of clay-type lithium ore resources, and in particular to a method for synchronously removing impurities during the efficient lithium extraction process of clay-type lithium ore. Background Art

[0003] Lithium resources in nature are mainly divided into three types: salt lake brine type, pegmatite type and clay type. At present, the mining of lithium resources mainly relies on brine deposits and pegmatite deposits. However, with the continuous increase in the demand for lithium resources, the effective development and utilization of clay-type lithium resources is of great significance. In recent years, large-scale clay-type lithium deposits have been discovered in southwest my country. The deposits have the characteristics of wide distribution area, stable output layer, large thickness and low mining cost, which have good research significance.

[0004] Patent CN 117684019A discloses a method for extracting lithium from clay lithium ore using a mixture of sulfuric acid and ferric chloride, wherein fine-grained clay lithium ore is roasted to obtain a roasted material, which is then leached using a mixture of sulfuric acid and ferric chloride. After leaching, the filtrate is collected by solid-liquid separation. This method can achieve a higher lithium leaching rate, but has the disadvantages of more impurity ions being dissolved and difficult to separate, which is not conducive to industrial application.

[0005] Patent CN 110358934A discloses a method for extracting lithium from carbonate clay-type lithium ore by ion exchange. After the clay mineral is activated by high-temperature roasting, an ion exchange leaching reaction is carried out with an iron salt solution. After the leaching is completed, the solid and liquid are separated to obtain a lithium-containing solution. This method has the characteristics of high leaching efficiency, but there are problems such as high energy consumption during the roasting process, and impurities such as aluminum and iron in the leachate will affect the purity of the lithium carbonate product.

[0006] Patent CN117802320A discloses a method for extracting lithium from clay-type lithium ore. The clay mineral is roasted and then leached with sulfuric acid. After the leaching, Na2SO4 is added to the acid leaching solution to control the pH of the system to form yellow sodium iron alum and sodium alum stone precipitation. The yellow sodium iron alum and sodium alum stone generated at the same time can generate Na2SO4 after hydrolysis, and the Na2SO4 solution can be recycled after evaporation and crystallization. This method has the advantages of good precipitation and separation performance and the recycling of auxiliary agents, but it also has the disadvantages of complex process and high energy consumption.

[0007] In summary, the existing methods for extracting lithium from clay-type lithium ores have problems such as long process flow, high process energy consumption, high impurity dissolution and difficulty in separation. Therefore, there is an urgent need for a method for simultaneous impurity removal during the efficient lithium extraction process of clay-type lithium ores, which can simultaneously achieve the precipitation of impurity elements such as iron and potassium into slag while ensuring efficient lithium leaching. Summary of the invention

[0008] To solve the above problems, the present invention provides a method for synchronous impurity removal in the process of efficient lithium extraction from clay-type lithium ore, so as to achieve efficient leaching of valuable metallic lithium and synchronous removal of impurity ions in clay-type lithium ore, and provide a new way for efficient utilization of clay-type lithium resources.

[0009] The present invention is achieved through the following technical solutions: A method for synchronously removing impurities during the efficient lithium extraction process of clay-type lithium ore, comprising the following steps:

[0010] (1) Mechanical activation: Mechanically activate the clay-type lithium ore to obtain an activated material;

[0011] (2) ion exchange leaching: adding ferric sulfate solution to the activated material obtained in step (1) to carry out ion exchange leaching, controlling the pH value of the system during the leaching process, and separating the solid and liquid after the leaching to obtain a lithium-rich solution and a filter residue containing jarosite;

[0012] (3) Concentration and lithium precipitation: The lithium-rich solution obtained in step (2) is concentrated and lithium is precipitated to obtain lithium carbonate.

[0013] The mechanical activation in step (1) is performed by ball milling at a rotation speed of 450 to 850 r / min for 2 to 6 hours, with a ball-to-material mass ratio of 2:1 to 6:1 g / g.

[0014] The ion exchange leaching in step (2) is carried out by adding a ferric sulfate solution to the activated material at a liquid-to-solid ratio of 2:1 to 8:1 mL / g, wherein the ferric sulfate in the ferric sulfate solution is 5% to 25% of the mass of the activated material, and then ion exchange leaching is carried out at a temperature of 50 to 90° C. for 1 to 4 hours.

[0015] The pH value of the control system in step (2) is adjusted to 1.0 to 3.0 by using sulfuric acid with a mass concentration of 5 to 30%.

[0016] The lithium precipitation in step (3) is carried out by using sodium carbonate, the amount of sodium carbonate added is 0.8 to 2.3 times the theoretical amount of lithium precipitation, the lithium precipitation temperature is 65 to 95° C., and the lithium precipitation time is 1.5 to 3.5 hours.

[0017] The beneficial effects of the above technical solution of the present invention are as follows:

[0018] The present invention provides a method for simultaneous impurity removal during the efficient lithium extraction process of clay-type lithium ore, which innovatively adds sulfuric acid to the ion exchange leaching process to adjust the pH value of the system, creating favorable conditions for the formation of potassium ferroaluminate, thereby simultaneously removing impurity elements such as potassium and iron in the leachate. In general, the present invention has the characteristics of short process flow, simple operation, high impurity ion removal rate, etc., and can achieve efficient extraction of valuable metal lithium and simultaneous removal of impurity ions in clay-type lithium ore. The present invention provides a new process idea for the development and utilization of clay-type lithium ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a process flow chart of the simultaneous removal of impurities in the process of efficient lithium extraction from clay-type lithium ore. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown, the method comprises the following steps:

[0022] (1) Mechanical activation: Mechanically activate the clay-type lithium ore to obtain an activated material;

[0023] (2) ion exchange leaching: adding ferric sulfate solution to the activated material obtained in step (1) to carry out ion exchange leaching, strictly controlling the pH value of the system during the leaching process, and separating the solid and liquid after the leaching to obtain a lithium-rich solution and a filter residue containing jarosite;

[0024] (3) Concentration and lithium precipitation: The lithium-rich solution obtained in step (2) is concentrated and lithium is precipitated to obtain a high-purity lithium carbonate product.

[0025] In order to more clearly demonstrate the technical solution and technical effects provided by the present invention, a method for simultaneous impurity removal in a clay-type lithium ore efficient lithium extraction process provided by the present invention is described in detail with reference to a specific embodiment below.

[0026] Example 1

[0027] (1) Mechanical activation: 80 g of clay-type lithium ore was mechanically activated by ball milling at a rotation speed of 850 r / min for 2 h, with a ball-to-material mass ratio of 3:1 g / g to obtain an activated material;

[0028] (2) ion exchange leaching: adding ferric sulfate solution to the activated material obtained in step (1) at a liquid-to-solid ratio of 5:1 mL / g, wherein the ferric sulfate content in the ferric sulfate solution is 5% of the mass of the activated material, and then ion exchange leaching is carried out at a temperature of 90° C. for 2 h. During the leaching process, sulfuric acid with a mass concentration of 10% is used to adjust the pH value of the system to 1.5 to keep the pH value of the system constant. After the leaching is completed, solid-liquid separation is performed to obtain a lithium-rich solution and a filter residue containing jarosite;

[0029] (3) Concentration and lithium precipitation: The lithium-rich solution obtained in step (2) is concentrated and lithium is precipitated using sodium carbonate. The amount of sodium carbonate added is 1.5 times the theoretical amount of lithium precipitation. The lithium precipitation temperature is 80° C. and the lithium precipitation time is 2.0 h to obtain high-purity lithium carbonate.

[0030] Through the above steps, the efficient extraction of valuable metallic lithium and the simultaneous removal of impurity ions in clay-type lithium ore can be achieved.

[0031] Example 2

[0032] (1) Mechanical activation: The clay-type lithium ore is mechanically activated by ball milling at a rotation speed of 600 r / min for 4 h, with a ball-to-material mass ratio of 2:1 g / g to obtain an activated material;

[0033] (2) ion exchange leaching: adding ferric sulfate solution to the activated material obtained in step (1) at a liquid-to-solid ratio of 4:1 mL / g, wherein the ferric sulfate content in the ferric sulfate solution is 10% of the mass of the activated material, and then ion exchange leaching is carried out at a temperature of 70° C. for 3 h. During the leaching process, sulfuric acid with a mass concentration of 5% is used to adjust the pH value of the system to 2.0 to keep the pH value of the system constant. After the leaching is completed, solid-liquid separation is performed to obtain a lithium-rich solution and a filter residue containing jarosite;

[0034] (3) Concentration and lithium precipitation: The lithium-rich solution obtained in step (2) is concentrated and lithium is precipitated using sodium carbonate. The amount of sodium carbonate added is 1.2 times the theoretical amount of lithium precipitation. The lithium precipitation temperature is 65° C. and the lithium precipitation time is 3 hours to obtain high-purity lithium carbonate.

[0035] Through the above steps, the efficient extraction of valuable metallic lithium and the simultaneous removal of impurity ions in clay-type lithium ore can be achieved.

[0036] Example 3

[0037] (1) Mechanical activation: The clay-type lithium ore is mechanically activated by ball milling at a rotation speed of 450 r / min for 6 h, with a ball-to-material mass ratio of 4:1 g / g to obtain an activated material;

[0038] (2) ion exchange leaching: adding ferric sulfate solution to the activated material obtained in step (1) at a liquid-to-solid ratio of 8:1 mL / g, wherein the ferric sulfate content in the ferric sulfate solution is 15% of the mass of the activated material, and then ion exchange leaching is carried out at a temperature of 60° C. for 2.5 h. During the leaching process, sulfuric acid with a mass concentration of 30% is used to adjust the pH value of the system to 2.5 to keep the pH value of the system constant. After the leaching is completed, solid-liquid separation is performed to obtain a lithium-rich solution and a filter residue containing jarosite;

[0039] (3) Concentration and lithium precipitation: The lithium-rich solution obtained in step (2) is concentrated and lithium is precipitated using sodium carbonate. The amount of sodium carbonate added is 0.8 times the theoretical amount of lithium precipitation. The lithium precipitation temperature is 75° C. and the lithium precipitation time is 2.5 h to obtain high-purity lithium carbonate.

[0040] Through the above steps, the efficient extraction of valuable metallic lithium and the simultaneous removal of impurity ions in clay-type lithium ore can be achieved.

[0041] Example 4

[0042] (1) Mechanical activation: The clay-type lithium ore was mechanically activated by ball milling at a rotation speed of 750 r / min for 3 h, with a ball-to-material mass ratio of 6:1 g / g to obtain an activated material;

[0043] (2) ion exchange leaching: adding ferric sulfate solution to the activated material obtained in step (1) at a liquid-to-solid ratio of 2:1 mL / g, wherein the ferric sulfate content in the ferric sulfate solution is 25% of the mass of the activated material, and then ion exchange leaching is carried out at a temperature of 50° C. for 1 h. During the leaching process, sulfuric acid with a mass concentration of 20% is used to adjust the pH value of the system to 3.0 to keep the pH value of the system constant. After the leaching is completed, solid-liquid separation is performed to obtain a lithium-rich solution and a filter residue containing jarosite;

[0044] (3) Concentration and lithium precipitation: The lithium-rich solution obtained in step (2) is concentrated and lithium is precipitated using sodium carbonate. The amount of sodium carbonate added is 2.3 times the theoretical amount of lithium precipitation. The lithium precipitation temperature is 90° C. and the lithium precipitation time is 3.5 h to obtain high-purity lithium carbonate.

[0045] Through the above steps, the efficient extraction of valuable metallic lithium and the simultaneous removal of impurity ions in clay-type lithium ore can be achieved.

[0046] Example 5

[0047] (1) Mechanical activation: The clay-type lithium ore is mechanically activated by ball milling at a rotation speed of 500 r / min for 5 h, with a ball-to-material mass ratio of 5:1 g / g to obtain an activated material;

[0048] (2) ion exchange leaching: adding ferric sulfate solution to the activated material obtained in step (1) at a liquid-to-solid ratio of 7:1 mL / g, wherein the ferric sulfate content in the ferric sulfate solution is 30% of the mass of the activated material, and then ion exchange leaching is carried out at a temperature of 80° C. for 4 h. During the leaching process, sulfuric acid with a mass concentration of 15% is used to adjust the pH value of the system to 1.0 to keep the pH value of the system constant. After the leaching is completed, solid-liquid separation is performed to obtain a lithium-rich solution and a filter residue containing jarosite;

[0049] (3) Concentration and lithium precipitation: The lithium-rich solution obtained in step (2) is concentrated and lithium is precipitated using sodium carbonate. The amount of sodium carbonate added is 2.0 times the theoretical amount of lithium precipitation. The lithium precipitation temperature is 95° C. and the lithium precipitation time is 1.5 h to obtain high-purity lithium carbonate.

[0050] Through the above steps, the efficient extraction of valuable metallic lithium and the simultaneous removal of impurity ions in clay-type lithium ore can be achieved.

[0051] Examples 1-5 are some embodiments of the present invention. The leaching rates of lithium, aluminum, iron and potassium in each example are shown in Table 1. The results show that the leaching rate of lithium is above 89%, the leaching rate of aluminum is less than 3%, the leaching rate of iron is less than 2%, and the leaching rate of potassium is less than 0.5%. It can be seen that the present invention achieves efficient leaching of valuable metal lithium in clay-type lithium ore and effective separation of it from impurity ions of aluminum, iron and potassium.

[0052] Table 1 Leaching rates of lithium, aluminum, iron and potassium in the examples

[0053] Example 1 Example 2 Example 3 Example 4 Example 5 Li leaching rate / % 94 92 95 96 89 Al leaching rate / % 0.2 1.3 2.3 2.5 2.8 Fe leaching rate / % 0.8 1.7 1.5 1.2 0.5 K leaching rate / % 0.4 0.1 0.07 0.15 0.05

[0054] Comparative Example 1

[0055] The difference between Comparative Example 1 and Example 1 is that the clay-type lithium ore is not mechanically activated, but ion exchange leaching is performed after roasting and activation. The results show that the aluminum leaching rate increases to 6.5%.

[0056] Comparative Example 2

[0057] The difference between Comparative Example 2 and Example 1 is that the amount of iron sulfate added is only 2.5% of the mass of the activated material, and the results show that the lithium leaching rate drops to 74%.

[0058] Comparative Example 3

[0059] The difference between Comparative Example 3 and Example 1 is that sulfuric acid is added to adjust the leaching pH to 3.5. The results show that the lithium leaching rate is reduced to 85%, and the leaching rates of iron and potassium are increased to 15% and 23%, respectively.

[0060] It can be seen from the comparative examples that factors such as the amount of ferric sulfate added, leaching pH, and leaching temperature directly affect the leaching effect of lithium and the generation of jarosite during the leaching process. When the operating conditions are not within the scope of the technical solution of the present invention, the effect is not ideal.

[0061] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for synchronously removing impurities during the efficient lithium extraction process of clay-type lithium ore, characterized in that The steps include: (1) Mechanical activation: Mechanically activate the clay-type lithium ore to obtain an activated material; (2) ion exchange leaching: adding ferric sulfate solution to the activated material obtained in step (1) to carry out ion exchange leaching, controlling the pH value of the system during the leaching process, and separating the solid and liquid after the leaching to obtain a lithium-rich solution and a filter residue containing jarosite; (3) Concentration and lithium precipitation: The lithium-rich solution obtained in step (2) is concentrated and lithium is precipitated to obtain lithium carbonate.

2. The method for synchronously removing impurities during efficient lithium extraction from clay-type lithium ore according to claim 1, characterized in that: The mechanical activation in step (1) is performed by ball milling at a rotation speed of 450 to 850 r / min for 2 to 6 hours, with a ball-to-material mass ratio of 2:1 to 6:1 g / g.

3. The method for synchronously removing impurities during efficient lithium extraction from clay-type lithium ore according to claim 1, characterized in that: The ion exchange leaching in step (2) is carried out by adding a ferric sulfate solution to the activated material at a liquid-to-solid ratio of 2:1 to 8:1 mL / g, wherein the ferric sulfate in the ferric sulfate solution is 5% to 25% of the mass of the activated material, and then ion exchange leaching is carried out at a temperature of 50 to 90° C. for 1 to 4 hours.

4. The method for synchronous impurity removal during efficient lithium extraction from clay-type lithium ore according to claim 1, characterized in that: The pH value of the control system in step (2) is adjusted to 1.0 to 3.0 by using sulfuric acid with a mass concentration of 5 to 30%.

5. The method for synchronous impurity removal during efficient lithium extraction from clay-type lithium ore according to claim 1, characterized in that: The lithium precipitation in step (3) is carried out by using sodium carbonate, the amount of sodium carbonate added is 0.8 to 2.3 times the theoretical amount of lithium precipitation, the lithium precipitation temperature is 65 to 95° C., and the lithium precipitation time is 1.5 to 3.5 hours.

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