Method for efficiently recovering potassium from lithium smelting slag

Abstract

The invention relates to the technical field of lithium extraction smelting slag recovery, and particularly provides a method for efficiently recovering potassium from lithium smelting slag. The method has the beneficial effects that the overall consumption of potassium in the sulfate method is effectively reduced, and the cost is greatly reduced; the reaction conditions are mild.

Description

Technical Field

[0001] The invention relates to the technical field of lithium smelting slag recovery, and in particular to a method for efficiently recovering potassium from lithium smelting slag. Background Art

[0002] Lithium, as an important rare element that promotes the development of modernization construction and related industries such as science and technology, is one of the most promising new energy sources and strategic resources. It is widely used in many fields such as high-energy lithium batteries, rubber industry, aerospace, ceramics, lasers, medicine, welding, explosives, cement, smelting and new energy.

[0003] In the prior art, the methods for extracting lithium from ores mainly include sulfuric acid method, sulfate method, limestone method, etc. Among them, in the process of extracting lithium by sulfate method, a large amount of potassium salt needs to be added to replace the lithium in the ore, so that the originally insoluble lithium becomes soluble.

[0004] This results in a large amount of potassium in the smelting slag of the sulfate process, which results in a large amount of potassium becoming solid waste along with the smelting slag. Since a large amount of potassium is used in the sulfate process and the price of potassium is high, the cost of the sulfate process is high.

[0005] Being able to recycle potassium in smelting slag, significantly reduce the consumption of potassium in the sulfate process, and significantly reduce costs are the urgent pursuits of those skilled in the art.

[0006] In the prior art, there is no method for recovering the potassium element in the above-mentioned smelting slag.

[0007] In the field of potash fertilizer extraction, there are related reports claiming that the hydrothermal treatment of potassium feldspar at 280°C can achieve a potassium leaching rate of 96.4-99.3%. (Wu Yusheng, Yu Meng, Li Laishi, Wu Xiushi. Optimization of potassium extraction process from potassium feldspar based on response surface methodology. Journal of Shenyang University of Technology. 2023, 45(1): 36-42).

[0008] However, since the structure of smelting slag is different from that of potassium feldspar, technicians in the field of lithium extraction have no motivation to directly apply the above method to potassium extraction from smelting slag. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a method for extracting lithium from ore by pyrometallurgical method, which solves the problems existing in the prior art.

[0010] One of the purposes of the present invention is to verify whether the hydrothermal method can be used to extract potassium from smelting slag;

[0011] A second object of the present invention is to determine the optimal parameters.

[0012] The present invention discloses a method for efficiently recovering potassium from lithium smelting slag, comprising the following steps:

[0013] S1, mixing smelting slag, a calcium source, and water and stirring them evenly, wherein the calcium source is selected from at least one of calcium oxide, hydroxide, or salt; and the smelting slag is leached slag produced after lithium is extracted from the smelting slag by sulfate method;

[0014] S2, heating the mixture prepared in step S1 for reaction;

[0015] S3, adding water to the product obtained in step S2 to leach out, and filtering; the obtained filter residue is calcium residue, and the obtained filtrate is used for crystallization;

[0016] S4. Crystallize the filtrate obtained in step S3 to obtain potassium sulfate.

[0017] Preferably, in step S1, the calcium source is calcium oxide and / or calcium hydroxide.

[0018] Preferably, in step S1, m is expressed in terms of mass fraction. 钙源 :m 冶炼矿渣 The ratio is 1 to 1.5:1, wherein the mass of the calcium source is converted into the mass of calcium oxide.

[0019] Preferably, in step S1, the liquid-to-solid ratio is 7.5 to 10:1 by mass fraction.

[0020] Preferably, in step S2, the reaction temperature is 220-260° C. More preferably, in step S2, the reaction temperature is 240° C.

[0021] Preferably, in step S2, the reaction time is 4 to 6 hours.

[0022] Preferably, in step S3, the leaching time is 30 minutes.

[0023] Preferably, the method for efficiently recovering potassium from lithium smelting slag comprises the following steps:

[0024] S1, mixing and stirring smelting slag leaching residue, calcium oxide and / or calcium hydroxide, and water; the smelting slag is leached by sulfate method to produce lithium leaching residue; in terms of mass fraction, m 钙源 :m 冶炼矿渣 The ratio of liquid to solid is 1.5:1, where the mass of the calcium source is converted into the mass of calcium oxide; in terms of mass fraction, the liquid-to-solid ratio is 10:1;

[0025] S2, heating the mixture prepared in step S1 for reaction; the reaction temperature is 240°C, and the reaction time is 6 hours;

[0026] S3, adding water to the product obtained in step S2 for leaching for 30 min, and filtering; the obtained filter residue is calcium residue, and the obtained filtrate is used for crystallization;

[0027] S4. Crystallize the filtrate obtained in step S3 to obtain potassium sulfate.

[0028] Preferably, the method for efficiently recovering potassium from lithium smelting slag comprises the following steps:

[0029] S1, mixing smelting slag leaching residue, calcium oxide and water and stirring them evenly; the smelting slag is leached by sulfate method to produce lithium leaching residue; in terms of mass fraction, m 钙源 :m 冶炼矿渣 The ratio of liquid to solid is 1.2:1, where the mass of the calcium source is converted into the mass of calcium oxide; in terms of mass fraction, the liquid-to-solid ratio is 7.5:1;

[0030] S2, heating the mixture prepared in step S1 for reaction; the reaction temperature is 240°C, and the reaction time is 6 hours;

[0031] S3, adding water to the product obtained in step S2 for leaching for 30 min, and filtering; the obtained filter residue is calcium residue, and the obtained filtrate is used for crystallization;

[0032] S4. Crystallize the filtrate obtained in step S3 to obtain potassium sulfate.

[0033] The beneficial effects of the present invention are:

[0034] 1. Provides a method for efficiently recovering potassium from lithium smelting slag;

[0035] 2. Effectively reduce the overall consumption of potassium in the sulfate process and significantly reduce costs;

[0036] 3. Mild reaction conditions and low energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Flow chart of the present invention. DETAILED DESCRIPTION

[0038] The specific implementation modes of the present invention are further described below in conjunction with examples. The following examples are only used to more clearly illustrate the technical embodiments of the present invention and are not intended to limit the protection scope of the present invention.

[0039] Example 1

[0040] The present invention discloses a method for efficiently recovering potassium from lithium smelting slag, comprising the following steps:

[0041] S1, mixing smelting slag leaching residue, calcium oxide and water and stirring them evenly; the smelting slag is leached by sulfate method to produce lithium leaching residue; in terms of mass fraction, m 钙源 :m 冶炼矿渣 The ratio of liquid to solid is 1.5:1, wherein the mass of the calcium source is converted into the mass of calcium oxide; in terms of mass fraction, the liquid-to-solid ratio is 7.5:1;

[0042] S2, heating the mixture prepared in step S1 for reaction; the reaction temperature is 240°C, and the reaction time is 6 hours;

[0043] S3, adding water to the product obtained in step S2 for leaching for 30 min, and filtering; the obtained filter residue is calcium residue, and the obtained filtrate is used for crystallization;

[0044] S4, evaporating and crystallizing the filtrate obtained in step S3 to obtain potassium sulfate. The potassium recovery rate is 88.27%.

[0045] Embodiments 2 to 14

[0046] The difference between Examples 2 to 14 and Example 1 is that the condition parameters are different. The parameters of each example are shown in Table 1 below:

[0047] Table 1 Parameters of the embodiment

[0048]

[0049] In order to further illustrate the beneficial effects of the technical solution of the present invention, the following comparative examples are set:

[0050] Comparative Examples 1 to 6

[0051] The difference between Comparative Examples 1 to 4 and Example 1 is only in the parameters; the difference between Comparative Examples 5 to 7 and Example 1 is that the roasting method is adopted; the specific parameters are shown in Table 2 below:

[0052] Table 2 Comparative parameter table

[0053]

[0054]

[0055] Note: When the "liquid-to-solid ratio" in the above table is " / ", it means no water is added, and the temperature of step S2 in the "calcination method" is adjusted to the temperature in the table.

[0056] In order to further verify the beneficial effects of the present invention, the above-mentioned embodiments and comparative examples were leached according to the method described in step S3 of embodiment 1, and the data are shown in the following Table 3:

[0057] Table 3 Leaching results data table

[0058]

[0059]

[0060] Analysis of the above results:

[0061] 1. By comparing the embodiment with comparative examples 5 to 7, it can be seen that the leaching effect of the hydrothermal method is much higher than that of the roasting method.

[0062] 2. By comparing Example 1 with Comparative Examples 1 to 2, it can be seen that the selection of the liquid-to-solid ratio affects the final leaching result.

[0063] 3. By comparing Example 2 with Comparative Example 3, it can be seen that the amount of calcium source added affects the final leaching result.

[0064] 4. By comparing the embodiment with comparative example 4, it can be seen that the selection of temperature affects the final leaching result.

[0065] 5. By comparing Examples 2 to 6, Example 10 and Example 12 with other examples, it can be seen that the coordination between the amount of calcium source added and the liquid-to-solid ratio can produce unexpected effects.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for efficiently recovering potassium from lithium smelting slag, characterized in that: The steps include: S1, mixing smelting slag, a calcium source, and water and stirring them evenly, wherein the calcium source is selected from at least one of calcium oxide, hydroxide, or salt; and the smelting slag is leached slag produced after lithium is extracted from the smelting slag by sulfate method; S2, heating the mixture prepared in step S1 for reaction; S3, adding water to the product obtained in step S2 to leach out, and filtering; the obtained filter residue is calcium residue, and the obtained filtrate is used for crystallization; S4. Crystallize the filtrate obtained in step S3 to obtain potassium sulfate.

2. The method for efficiently recovering potassium from lithium smelting slag according to claim 1, characterized in that: In step S1, the calcium source is calcium oxide and / or calcium hydroxide.

3. The method for efficiently recovering potassium from lithium smelting slag according to claim 1, characterized in that: In step S1, m is expressed in terms of mass fraction. 钙源 :m 冶炼矿渣 The ratio is 1 to 1.5:1, wherein the mass of the calcium source is converted into the mass of calcium oxide.

4. The method for efficiently recovering potassium from lithium smelting slag according to claim 1, characterized in that: In step S1, the liquid-to-solid ratio is 7.5 to 10:1 by mass fraction.

5. The method for efficiently recovering potassium from lithium smelting slag according to claim 1, characterized in that: In step S2, the reaction temperature is 200-260°C.

6. The method for efficiently recovering potassium from lithium smelting slag according to claim 1, characterized in that: In step S2, the reaction temperature is 240°C.

7. The method for efficiently recovering potassium from lithium smelting slag according to claim 1, characterized in that: In step S2, the reaction time is 4 to 6 hours.

8. The method for efficiently recovering potassium from lithium smelting slag according to claim 1, characterized in that: In step S3, the leaching time is 30 min.

9. The method for efficiently recovering potassium from lithium smelting slag according to claim 1, characterized in that: The steps include: S1, mixing and stirring smelting slag leaching residue, calcium oxide and / or calcium hydroxide, and water; the smelting slag is leached by sulfate method to produce lithium leaching residue; in terms of mass fraction, m 钙源 :m 冶炼矿渣 The ratio of liquid to solid is 1.5:1, where the mass of the calcium source is converted into the mass of calcium oxide; in terms of mass fraction, the liquid-to-solid ratio is 10:1; S2, heating the mixture prepared in step S1 for reaction; the reaction temperature is 240°C, and the reaction time is 6 hours; S3, adding water to the product obtained in step S2 for leaching for 30 min, and filtering; the obtained filter residue is calcium residue, and the obtained filtrate is used for crystallization; S4. Crystallize the filtrate obtained in step S3 to obtain potassium sulfate.

10. The method for efficiently recovering potassium from lithium smelting slag according to claim 1, characterized in that: The steps include: S1, mixing smelting slag leaching residue, calcium oxide and water and stirring them evenly; the smelting slag is leached by sulfate method to produce lithium leaching residue; in terms of mass fraction, m 钙源 :m 冶炼矿渣 The ratio of liquid to solid is 1.2:1, where the mass of the calcium source is converted into the mass of calcium oxide; in terms of mass fraction, the liquid-to-solid ratio is 7.5:1; S2, heating the mixture prepared in step S1 for reaction; the reaction temperature is 240°C, and the reaction time is 6 hours; S3, adding water to the product obtained in step S2 for leaching for 30 min, and filtering; the obtained filter residue is calcium residue, and the obtained filtrate is used for crystallization; S4. Crystallize the filtrate obtained in step S3 to obtain potassium sulfate.

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