Treatment method of lithium ore slag elution waste liquid

Abstract

The invention discloses a lithium ore slag elution waste liquid treatment method, and belongs to the technical field of wastewater treatment.The lithium ore slag elution waste liquid treatment method comprises the steps that elution waste liquid is sequentially subjected to cooling, filtering and heating, then dialysis treatment is conducted, dialyzate and penetrating fluid are obtained, nanofiltration treatment is conducted on the dialyzate, metal ion concentrated liquid and nanofiltration penetrating fluid are obtained, and the metal ion concentrated liquid and the nanofiltration penetrating fluid are concentrated; and carrying out adsorption treatment on the nanofiltration permeate to recover lithium ions. According to the method, the elution waste liquid is sequentially subjected to cooling, filtering and heating treatment firstly, so that the content of calcium sulfate in the elution waste liquid is reduced, and the situation that calcium sulfate is separated out on a membrane used in dialysis treatment in subsequent treatment and influences dialysis treatment is prevented; then the heated elution waste liquid is subjected to dialysis treatment, acid and metal ions in the elution waste liquid are separated, dialysis liquid containing the metal ions is subjected to nanofiltration treatment, high-valence metal ions are further concentrated, nanofiltration permeate liquid containing low-valence lithium ions is subjected to adsorption treatment, and the lithium ions in the nanofiltration permeate liquid are recycled.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, and particularly relates to a treatment method of lithium ore slag elution waste liquid. BACKGROUND

[0002] In order to realize large-scale consumption of lithium smelting slag, it is necessary to dissociate and replace the toxic components in the lithium smelting slag from the smelting slag. The acid leaching method is usually used, and therefore a large amount of elution acid waste liquid is generated. The acid waste liquid contains unreacted acid, a large amount of metal ions such as calcium, magnesium, silicon, iron, aluminum and lithium, and other easily precipitated compounds such as calcium sulfate. Therefore, the disposal is difficult and the cost is high. SUMMARY

[0003] Therefore, the present application provides a treatment method of lithium ore slag elution waste liquid, which comprises the following steps: The elution waste liquid is sequentially subjected to cooling, filtration and heating, and then subjected to dialysis treatment to obtain dialysate and permeate. The dialysate is subjected to nanofiltration treatment to obtain metal ion concentrate and nanofiltration permeate, and the nanofiltration permeate is subjected to adsorption treatment to recover lithium ions.

[0004] The present application reduces the content of calcium sulfate in the elution waste liquid by sequentially subjecting the elution waste liquid to cooling, filtration and heating treatment, prevents calcium sulfate from precipitating in solid form on the membrane used in the dialysis treatment in the subsequent treatment, and affects the dialysis treatment. Subsequently, the elution waste liquid after heating is subjected to dialysis treatment to separate the acid and metal ions therein, and the dialysate containing metal ions is subjected to nanofiltration treatment to further concentrate the high-valence metal ions, and the nanofiltration permeate containing low-valence lithium ions is subjected to adsorption treatment to recover the lithium ions therein.

[0005] In some embodiments, the elution waste liquid satisfies at least one of the following conditions: The elution waste liquid contains at least one of hydrochloric acid, sulfuric acid or nitric acid; The acid concentration of the elution waste liquid is 1-5 mol / L; The elution waste liquid contains at least one of calcium ions, magnesium ions, aluminum ions, iron ions, sodium ions, lithium ions, beryllium ions and thallium ions.

[0006] In some embodiments, the elution waste liquid is cooled to 10-15 DEG C; And / or, the elution waste liquid is heated to 35-40 DEG C.

[0007] In some embodiments, the filtration precision is not greater than 0.2 microns.

[0008] In some embodiments, during the dialysis treatment, the ratio of the input flow rate of the elution waste liquid to the output flow rate of the permeate is A, which satisfies 1.25 <= A <= 2.

[0009] In some embodiments, the acid concentration of the permeate is 1.2-6 mol / L. And / or, the acid concentration of the dialysate is 0.11-1.66 mol / L.

[0010] In some embodiments, when the dialysate is subjected to nanofiltration treatment, the permeation rate of lithium ions is 60%-99%.

[0011] In some embodiments, the nanofiltration permeate after adsorption treatment is added to the dialysate in the dialysis treatment.

[0012] In some embodiments, the permeate is subjected to acid-resistant nanofiltration treatment to obtain acid-resistant nanofiltration concentrate and acid, the acid-resistant nanofiltration concentrate is added to the elution waste liquid, and the acid is subjected to recovery treatment.

[0013] In some embodiments, the acid-resistant nanofiltration concentrate is added to the elution waste liquid, and the acid is subjected to recovery treatment.

[0014] The present application reduces the content of calcium sulfate in the elution waste liquid by sequentially subjecting the elution waste liquid to cooling, filtration and warming treatment, prevents calcium sulfate from precipitating in solid form on the membrane used in the dialysis treatment in subsequent treatment, which affects the dialysis treatment, then separates the acid and metal ions in the elution waste liquid after warming by dialysis treatment, and subjects the dialysate containing metal ions to nanofiltration treatment to further concentrate high-valence metal ions, subjects the nanofiltration permeate containing low-valence lithium ions to adsorption treatment to recover lithium ions therein, and recycles the nanofiltration permeate after adsorption treatment as dialysate for dialysis treatment; by subjecting the permeate to acid-resistant nanofiltration, a small amount of metal ions remaining in the permeate are separated to obtain pure acid, the acid containing a small amount of metal ions is put into the elution waste liquid for recycling treatment, and the obtained pure acid is recovered and recycled. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A flowchart of the elution waste liquid treatment of lithium ore slag provided by the present application is provided. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below with examples. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0017] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the implementation or example are included in at least one implementation or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same implementation or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more implementations or examples as appropriate.

[0018] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0019] Since there is a problem that the elution acid waste liquid after the elution of the lithium ore slag is difficult to handle in the prior art.

[0020] In order to solve the above technical problems, the present application provides a treatment method for lithium ore slag elution waste liquid, comprising: The elution waste liquid is sequentially subjected to cooling, filtration and heating, and then subjected to dialysis treatment to obtain dialysate and permeate, the dialysate is subjected to nanofiltration treatment to obtain metal ion concentrate and nanofiltration permeate, the nanofiltration permeate is subjected to adsorption treatment to recover lithium ions, and the nanofiltration permeate after adsorption treatment is added to the dialysate in the dialysis treatment; the permeate is subjected to acid-resistant nanofiltration treatment to obtain acid-resistant nanofiltration concentrate and acid liquid, the acid-resistant nanofiltration concentrate is added to the elution waste liquid for recycling treatment, and the acid liquid is subjected to recovery treatment.

[0021] Specifically, the dialysate is a pure water solution arranged on the permeation side of the separation membrane at the beginning of the dialysis treatment.

[0022] The application reduces the content of calcium sulfate in the elution waste liquid by sequentially performing cooling, filtering and heating on the elution waste liquid, prevents calcium sulfate from precipitating in solid form on the membrane used in the subsequent dialysis treatment, which affects the dialysis treatment, then separates the acid and metal ions in the elution waste liquid after heating by dialysis treatment, performs nanofiltration treatment on the dialysate containing metal ions to further concentrate the high-valence metal ions, performs adsorption treatment on the nanofiltration permeate containing low-valence lithium ions to recover lithium ions therein, and recycles the nanofiltration permeate after adsorption treatment as dialysate for the dialysis treatment; the residual small amount of metal ions in the permeate are separated by acid-resistant nanofiltration to obtain pure acid liquid, the acid liquid containing a small amount of metal ions is put into the permeate for the next acid-resistant nanofiltration separation, and the obtained pure acid liquid is recovered and recycled.

[0023] In some embodiments, the elution waste liquid satisfies at least one of the following conditions: The elution waste liquid contains at least one of hydrochloric acid, sulfuric acid or nitric acid; The acid concentration of the elution waste liquid is 1-5 mol / L; The elution waste liquid contains at least one of calcium ions, magnesium ions, aluminum ions, iron ions, sodium ions, lithium ions, beryllium ions and thallium ions.

[0024] In some embodiments, the elution waste liquid is cooled to 10-15℃; And / or, the elution waste liquid is heated to 35-40℃.

[0025] Based on the above embodiments, the application first cools the elution waste liquid to precipitate calcium sulfate in the waste liquid, and then removes the calcium sulfate by filtering, and then heats the waste liquid to further prevent the precipitation of calcium sulfate in the subsequent treatment.

[0026] In some embodiments, the filtering precision is not greater than 0.2 μm.

[0027] Based on the above embodiments, the solid impurities in the elution waste liquid are further eluted by controlling the filtering precision to prevent the damage of the solid particles with large particle size to the filter membrane in the subsequent dialysis treatment.

[0028] In some embodiments, during the dialysis treatment, the ratio of the input flow rate of the elution waste liquid to the output flow rate of the permeate is A, which satisfies 1.25≤A≤2.

[0029] Based on the above embodiments, the application controls the flow rate of the input end of the dialysis treatment to be greater than that of the output end, so as to ensure that there is more acid on the side of the elution waste liquid in the dialysis treatment, and avoid the precipitation of residual calcium sulfate in the waste liquid due to the reduction of solvent.

[0030] In some embodiments, the acid concentration of the permeate is 1.2-6 mol / L; and / or, the acid concentration of the dialysate is 0.11-1.66 mol / L.

[0031] Based on the above embodiment, the present application separates the acid radical ions in the elution waste liquid by dialysis treatment.

[0032] In some embodiments, when the dialysate is subjected to nanofiltration treatment, the permeation rate of lithium ions is 60%-99%.

[0033] Based on the above embodiment, by nanofiltration treatment, high-valence metal ions are intercepted, and low-valence lithium ions are permeated, so as to subsequently adsorb and recover lithium ions.

[0034] The present application will be further described according to the following examples and comparative examples.

[0035] Example 1 In this embodiment, the treatment process of the lithium ore slag elution waste liquid is as follows: 1. The elution waste liquid with an acid concentration of 2 mol / L is cooled to 10°C and then sent to a ceramic membrane microfiltration device for filtration, and the ceramic membrane pore size is 0.2 microns. The filtered elution waste liquid is warmed to 35°C and then sent to the dialysis side of the diffusion dialysis device, and pure water is first sent to the permeation side. The ratio of the input flow rate of the elution waste liquid after warming to the dialysate side to the water flow rate of the permeation side is 1.25.

[0036] 2. When the acidity of the dialysate on the dialysis side is 0.2 mol / L, the dialysate is subjected to nanofiltration treatment to obtain a metal ion concentrate and a nanofiltration permeate, the metal ion concentrate is recovered, and the nanofiltration permeate after removing lithium ions by the adsorption unit is replaced by pure water and sent to the permeation side of the diffusion dialysis.

[0037] 3. At the same time, when the water acidity of the diffusion dialysis permeation side is increased to 2.3 mol / L, it is sent to the acid-resistant nanofiltration concentration unit to obtain an acid liquid and an acid-resistant nanofiltration concentrate, and the acid liquid is recovered and used as purified acid for recycling. The acid-resistant nanofiltration concentrate is combined with the warmed elution waste liquid and then sent to the diffusion dialysis unit.

[0038] Examples 2-11 in the present application are basically the same as Example 1, and the specific differences are shown in Table 1. Comparative Example 1 does not cool and warm the elution waste liquid before dialysis treatment compared with Example 1.

[0039] The detection method is as follows: sampling and detecting the elution waste liquid after heating to obtain the metal ion concentration and acid concentration in the elution waste liquid before dialysis treatment, then sampling and detecting the metal ion concentrate and the acid liquid respectively, and comparing the detection results before and after treatment to obtain the metal ion recovery rate and the acid recovery rate. The lithium ion recovery rate is obtained by comparing the reduction amount of lithium ion in the nanofiltration permeate liquid before and after adsorption with the total amount of lithium ion in the elution waste liquid.

[0040] The test results of examples 1-13 and comparative example 1 are shown in Table 1.

[0041] Table 1.

[0042] According to the test results of examples 1-3 and comparative example 1, within the operation condition range provided in the present application, the metal ions and acid in the elution waste liquid of lithium slag can be efficiently recovered by using the method provided in the present application. According to examples 4-7 and example 2, too high cooling temperature or too low heating temperature will result in insufficient calcium sulfate precipitation, and calcium sulfate will precipitate on the membrane in the subsequent dialysis treatment, thereby reducing the separation effect of the membrane and reducing the yield. Too high heating temperature will cause part of the acid in the elution waste liquid to volatilize, resulting in a decrease in acid recovery rate. As can be seen from example 9, too large filtration precision will result in a large amount of solid waste in the elution waste liquid, thereby damaging the separation membrane and reducing the yield. As can be seen from the comparison of the test results of examples 10, 11 and example 2, when A is less than 1.25, the acid concentration on the permeation side is not enough, resulting in a low concentration of the final acid liquid, and under the same volume of acid liquid output, the acid recovery rate will decrease. When A is greater than 2, the acid concentration on the permeation side will be relatively high, resulting in a decrease in acid permeation rate during dialysis, thereby reducing the yield.

[0043] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for treating lithium ore slag washing waste liquid, characterized in that, include: The elution waste liquid is sequentially cooled, filtered, and heated, and then subjected to dialysis to obtain dialysis solution and permeate. The dialysis solution is then subjected to nanofiltration to obtain a metal ion concentrate and a nanofiltration permeate. The nanofiltration permeate is then subjected to adsorption treatment to recover lithium ions.

2. The method for treating lithium ore slag washing waste liquid according to claim 1, characterized in that, The elution waste liquid meets at least one of the following conditions: The elution waste liquid contains at least one of hydrochloric acid, sulfuric acid, or nitric acid; The acid concentration of the elution waste liquid is 1~5 mol / L; The elution waste liquid contains at least one of calcium ions, magnesium ions, aluminum ions, iron ions, sodium ions, lithium ions, beryllium ions, and thallium ions.

3. The method for treating lithium ore slag washing waste liquid according to claim 1, characterized in that, Cool the elution waste liquid to 10-15℃; And / or, heat the elution waste liquid to 35-40°C.

4. The method for treating lithium ore slag washing waste liquid according to claim 1, characterized in that, The filtration accuracy is no greater than 0.2μm.

5. The method for treating lithium ore slag washing waste liquid according to claim 1, characterized in that, During dialysis, the ratio of the input flow rate of the elution waste liquid to the output flow rate of the permeate is A, which satisfies 1.25≤A≤2.

6. The method for treating lithium ore slag washing waste liquid according to claim 1, characterized in that, The acid concentration of the permeate is 1.2-6 mol / L; And / or, the acid concentration of the dialysis solution is 0.11-1.66 mol / L.

7. The method for treating lithium ore slag washing waste liquid according to claim 1, characterized in that, When the dialysis solution is subjected to nanofiltration, the lithium ion permeability is 60%-99%.

8. The method for treating lithium ore slag washing waste liquid according to claim 1, characterized in that, The nanofiltration permeate after adsorption treatment is added to the dialysis solution in the dialysis treatment.

9. The method for treating lithium ore slag washing waste liquid according to claim 1, characterized in that, The permeate was subjected to acid-resistant nanofiltration to obtain an acid-resistant nanofiltration concentrate and an acid solution.

10. The method for treating lithium ore slag washing waste liquid according to claim 9, characterized in that, The acid-resistant nanofiltration concentrate is added to the elution waste liquid, and the acid is recycled.

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