Dissolution process of potassium element in lithium smelting slag, dissolution product and application of dissolution product

Abstract

The invention relates to the technical field of lithium smelting slag resource utilization, and discloses a dissolution process of a potassium element in lithium smelting slag, a dissolution product and application of the dissolution product, and the dissolution process of the potassium element in the lithium smelting slag comprises the following steps: roasting the lithium smelting slag, then performing dissolution, and then performing solid-liquid separation to obtain a dissolution solution; concentrating the dissolution liquid to obtain a potassium-rich dissolution product; the lithium smelting slag is lepidolite lithium extraction smelting slag. According to the method, the lepidolite lithium extraction smelting slag is used as a main raw material to be roasted, dissolved out and concentrated to obtain a potassium-rich dissolved-out product, insoluble potassium in the lithium smelting slag can be converted into soluble potassium in the process, and resource utilization of the lithium smelting slag is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of resource utilization of lithium smelting slag, and in particular to a dissolution process of potassium element in lithium smelting slag, a dissolution product and application thereof. Background Art

[0002] The current large-scale mining of lithium mica has led to the continuous production of lithium smelting slag, which contains a large amount of potassium. However, there is currently no suitable process for effectively treating and disposing of lithium mica smelting slag to fully utilize the potassium. Therefore, it is urgent to provide a process for dissolving potassium from lithium smelting slag to fully utilize the potassium in lithium smelting slag. Summary of the invention

[0003] In view of this, the present invention provides a dissolution process of potassium element in lithium smelting slag, a dissolution product and application thereof, so as to fully utilize the potassium element in lithium smelting slag.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] In one aspect, the present invention provides a process for dissolving potassium in lithium smelting slag, comprising the following steps:

[0006] (1) roasting and dissolving lithium smelting slag, and then performing solid-liquid separation to obtain a dissolving solution;

[0007] (2) concentrating the dissolution solution to obtain a potassium-rich dissolution product;

[0008] The lithium smelting slag is lithium-extracting slag from lepidolite.

[0009] Preferably, the calcination temperature is 850-1150° C., and the calcination time is 0.25-3 h.

[0010] Preferably, an activator is also added during the calcination.

[0011] Preferably, the mass ratio of the activator to the lithium smelting slag is (0.5-1):1.

[0012] Preferably, the activator is a calcium-based chloride.

[0013] Preferably, the solvent used in the dissolution process is water, and the liquid-to-solid ratio is 5-10:1.

[0014] Preferably, the concentration temperature is 60-95°C.

[0015] On the other hand, the present invention also provides a dissolution product obtained by any of the dissolution processes described above.

[0016] Furthermore, the present invention also provides a dissolution product obtained by any of the dissolution processes described above or the use of the dissolution product in a soil conditioner.

[0017] The present invention provides a process for dissolving potassium in lithium smelting slag, a dissolving product and an application thereof. Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention uses lithium smelting slag extracted from lithium mica as a main raw material to obtain a potassium-rich dissolution product after roasting, dissolving and concentrating. This process can convert the insoluble potassium in the lithium smelting slag into soluble potassium, and the obtained dissolution product can be used as a soil conditioner due to its high potassium content. The present invention can fully utilize the potassium element in the lithium smelting slag and realize the resource utilization of the lithium smelting slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0020] Figure 1 This is the phase diagram of lithium-extracting slag from lepidolite;

[0021] Figure 2 This is an electron microscope scan of lithium-extracting slag from lepidolite;

[0022] Figure 3 This is the energy dispersive spectral analysis spectrum of lithium extraction from lithium mica smelting slag. DETAILED DESCRIPTION

[0023] The present invention will be described below by specific examples, and it will be appreciated by those skilled in the art that the following specific examples are only for illustrative purposes, and do not limit the scope of the present invention in any way. In addition, in the following examples, unless otherwise specified, the reagents and equipment used are all commercially available. If in the following examples, specific treatment conditions and treatment methods are not clearly described, then conditions and methods known in the art can be used to process.

[0024] In one aspect, the present invention provides a process for dissolving potassium in lithium smelting slag, comprising the following steps:

[0025] (1) The lithium smelting slag is roasted and then dissolved, and then solid-liquid separation is performed to obtain a dissolving solution.

[0026] In the present invention, the lithium smelting slag is lithium smelting slag from lepidolite, preferably lithium smelting slag from lepidolite obtained by sulfuric acid method, more preferably the particle size of the lithium smelting slag is 200 μm. Figure 1 As shown in the figure, the main phase of lithium smelting slag from lithium mica is blue quartz (Na 6 Ca 2 (AlSiO 4 )6(SO 4 ))、Nepheline(K 2 O·3Na 2 O·4Al 2 O 3 8SiO 2 )、Leucite(K(AlSi 2 O 6 )), fluorite (CaF 2 ), hematite (Fe 2 O 3 ), mica, quartz (SiO 2 ) and calcined gypsum (2CaSO 4 ·H 2 O). At the same time, scanning electron microscope analysis (SEM analysis) and energy dispersive spectroscopy analysis (EDS analysis) were performed on the lithium smelting slag from lithium mica, wherein: Figure 3 (a) corresponds to Figure 2 (a) EDS analysis diagram of the “+” area, Figure 3 (b) corresponds to Figure 2 (b) EDS analysis of the “+” area. Figure 2 and Figure 3 Analysis shows that the K element is mainly concentrated in Figure 2 (b) The “+” area is relatively smooth, and Al and Si are obviously enriched in this area, while the content of K, Al, Si and other elements in the “+” area of ​​2(a) is low. Therefore, the K element in the lithium extraction smelting slag of lithium mica is enriched in Figure 2 (b) In the “+” area, i.e. the insoluble phase, the enriched phase is mainly a composite compound containing K, Si and Al.

[0027] In some embodiments of the present invention, the roasting temperature is preferably 850-1150°C, for example, 850°C, 900°C, 950°C, 1000°C, 1150°C, etc.; the roasting time is preferably 0.25-3h, for example, 0.25h, 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, etc. The roasting process can convert the potassium that is difficult to dissolve in the lithium smelting slag mineral of lithium mica into potassium that is easily soluble or soluble in the mineral. Specifically, the potassium in the lithium mica is originally located in the nepheline K 2 O·3Na 2 O·4Al 2 O3 8SiO 2 , leucite K[AlSi 2 O 6 ] The potassium in these minerals is insoluble potassium. After the lithium mica is activated, the potassium in the crystal lattice is converted into potassium salt substances, converting the insoluble potassium in the lithium smelting slag into soluble or easily soluble potassium.

[0028] In some embodiments of the present invention, an activator is also added during the roasting, that is, the lithium smelting slag and the activator are mixed and then roasted, and a dissolving solution is obtained after dissolution and solid-liquid separation. Preferably, the mass ratio of the activator to the lithium smelting slag is (0.5-1):1, for example, it can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, etc. The activator is preferably a calcium-based chloride, such as calcium chloride. Roasting the lithium smelting slag with the calcium-based chloride can convert the insoluble potassium in the lithium smelting slag into soluble and easily soluble potassium, and convert the potassium-containing mineral into a soluble potassium-containing compound.

[0029] In some embodiments of the present invention, the solvent used in the dissolution process is water, and the liquid-to-solid ratio is 5-10:1, for example, it can be 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc. The dissolution temperature condition is room temperature, and the solid-liquid separation operation can be achieved by a solid-liquid separator, which is a routine operation in the experiment and is not specifically limited in the present invention.

[0030] (2) concentrating the eluate to obtain a potassium-rich eluate.

[0031] In this step, the concentration temperature is preferably 60-95°C, for example, 60°C, 75°C, 80°C, 85°C, 90°C, 95°C, etc. Since the main purpose of concentration is to reduce the storage volume and facilitate transportation, and the concentration process has no direct relationship with the precipitation process of other elements, the temperature of evaporation and concentration is not particularly limited and can be adjusted according to actual conditions. For example, when the concentration temperature is high, the soil conditioner finally prepared is solid and can be used after being diluted by an appropriate multiple during use. When the concentration temperature is low, the soil conditioner prepared is liquid and can be used directly or after being diluted by an appropriate multiple according to the situation.

[0032] In some embodiments of the present invention, crystallization is performed after concentration. The crystallization may be cooling crystallization. The crystallization operation is a conventional operation in experiments and is not particularly limited in the present invention.

[0033] After the dissolution is concentrated, the present invention obtains a liquid, solid or crystalline substance, which can be used as a soil conditioner to adjust the potassium content in the soil.

[0034] The technical scheme protected by the present invention is described in detail below through specific embodiments. The lithium mica smelting slag produced by using lithium mica as raw material and using the sulfate method to produce lithium carbonate is used. The elements in the lithium mica smelting slag include SiO 2 31.1%, Al 2 O 3 19.11%, Na 2 O 10.1%, SO 3 9.516%, CaO 7.579%, K 2 O7.127%, F 3.84%, Fe 2 O 3 2.682% and trace elements such as Mn, Zn, P, etc.

[0035] Example 1

[0036] This embodiment provides a process for dissolving potassium in lithium smelting slag, and the specific method is as follows:

[0037] (1) mixing an activator and lithium smelting slag (lithium smelting slag extracted from lithium mica with a particle size of 200 μm) in a mass ratio of 1:1, and then calcining the mixture at 850°C for 1 hour. The calcined mixed slag is dissolved in water at room temperature (liquid-to-solid ratio of 5:1), and a dissolving solution is obtained after solid-liquid separation;

[0038] (2) The eluate was concentrated at 70° C. for 2 h to obtain a potassium-rich eluate.

[0039] Examples 2-14 and Comparative Examples 1-2 are basically the same as Example 1, and the only difference is the selection of the activator in step (1), the mass ratio of the activator to the lithium smelting slag, the roasting temperature or the roasting time, see Table 1 for details. The present invention measures the dissolution rate of potassium in the lithium smelting slag treated by Examples 1-14 and Comparative Examples 1-2 according to "Determination of Phosphorus and Potassium Contents of Soil Conditioners" NYT 2273-2012, and the measurement results are shown in Table 1.

[0040] Table 1

[0041]

[0042]

[0043] It can be seen from Examples 1-3 that when lithium smelting slag is mixed with the activator CaCl 2 When the ratio of lithium smelting slag to activator CaCl is 1:1, with the increase of roasting temperature, the dissolution of potassium element first decreases and then increases. When the roasting temperature is 950℃, the dissolution rate reaches 78.9%. 2When the ratio of lithium smelting slag to activator CaCl is 1:2, the dissolution rate of potassium element after high temperature roasting is maintained above 40%. In combination with Examples 1-3, it is preferred that the lithium smelting slag and the activator CaCl 2 The ratio is 1:1.

[0044] As can be seen from Examples 6-9, no activator CaCl was added 2 The dissolution rate of potassium in lithium smelting slag increases with the increase of roasting temperature. When the roasting temperature is 1050℃, the dissolution rate reaches 47.6%. When the roasting temperature continues to increase, the dissolution rate shows a downward trend. 2 Under the conditions of , the optimal calcination temperature is 1050℃.

[0045] It can be seen from Examples 9-12 that whether the lithium smelting slag is roasted alone or the lithium smelting slag and the activator CaCl 2 The mixture is calcined. When the calcination time exceeds 2 hours, the dissolution rate of potassium element decreases with the increase of time. Therefore, it is preferred that the calcination time does not exceed 2 hours.

[0046] It can be seen from Example 13 and Comparative Example 1 that the activator CaCl 2 and CaCO 3 When lithium smelting slag is activated, the dissolution rates of potassium are 75.6% and 10% respectively, that is, the preferred activator in the present invention is CaCl 2 .

[0047] It can be seen from Example 13 and Comparative Example 2 that the activator CaCl 2 When lithium smelting slag is activated by NaOH and CaCl, the dissolution rates of potassium are 75.6% and 87.7% respectively. 2 When used as an activator, potassium has a high dissolution rate, takes less time, and has a lower temperature. However, since sodium hydroxide is a strong base, it is not suitable as a soil conditioner. Therefore, when the dissolution product is used as a soil conditioner, the preferred activator is CaCl 2 .

[0048] Comparative Examples 3-7

[0049] Comparative Examples 3-7 are substantially the same as Example 1, except that the lithium extraction smelting slag from lepidolite is replaced with lithium extraction smelting slag from spodumene.

[0050] The dissolution rate of potassium in the spodumene lithium extraction smelting slag after treatment in Comparative Examples 3-7 was measured in accordance with "Determination of Phosphorus and Potassium Contents of Soil Conditioners" NYT 2273-2012. The measurement results are shown in Table 2.

[0051] Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 K dissolution rate / % 40 43 39 37.5 41.6

[0052] It can be seen from the above table that although the dissolution process of the present invention can also dissolve the potassium element in spodumene lithium extraction smelting slag, the dissolution rate is only about 40%, and the dissolution effect is poor. Therefore, the dissolution process of the present invention is more suitable for the dissolution of potassium element in lepidolite lithium extraction smelting slag.

[0053] Test Example 1

[0054] In this test example, the potassium-rich leached products prepared in Examples 1-5 and Example 14 were tested for heavy metal content. The test method was based on "Determination of Phosphorus and Potassium Contents of Soil Conditioners" NYT 2273-2012. The test results are shown in Table 3.

[0055] Table 3

[0056]

[0057]

[0058] As can be seen from Table 3, the contents of nickel, chromium, mercury, arsenic and thallium in the activated lithium smelting slag are all ND and undetectable, and the contents of heavy metals such as lead and cadmium are also relatively low, and it contains a small amount of copper. It can be seen that the lithium smelting slag of the present invention will not cause the dissolution of heavy metals in the lithium smelting slag after being activated by an activator and roasted, and the dissolution products can act as soil conditioners.

[0059] Test Example 2

[0060] In this test example, the potassium-rich leaching products prepared in Examples 1-5 and Comparative Examples 3-7 were added in an amount of 525 kg / hectare and mixed with the soil in the field and then placed. After 7 days, a soil mixture sample was collected as a test group, and a soil sample without the addition of the potassium-rich leaching product was collected as a control group. The collected test group and control group samples were naturally air-dried at room temperature, and the debris in the soil was removed. The samples were crushed with a ceramic mortar, and after being fully mixed, they were successively sieved through 0.850 mm and 0.150 mm sieves, and the pH of the samples, as well as the alkaline nitrogen content, available phosphorus content, available potassium content and organic matter content in the soil mixture were tested. The test results are shown in Table 4.

[0061] Table 4

[0062]

[0063]

[0064] As shown in Table 4, after adding the potassium-rich leaching products of Examples 1-5 to the soil, the content of available potassium in the soil can be increased by 23.62%-30.11%, and the content of available phosphorus in the soil can be increased by 24.75%-75.99%, and the content of organic matter in the soil can be increased by 14.27%-28.28%.

[0065] However, after adding the potassium-rich dissolution products of Comparative Examples 3-7, the content of available potassium in the soil did not increase or even decreased, indicating that the dissolution process of the present application does not allow any potassium-rich dissolution product prepared with any lithium smelting slag as raw material to be used as a soil conditioner to increase the content of available potassium in the soil.

[0066] Test Example 3

[0067] Field A was divided into six equal areas, one of which was soil without adding potassium-rich leaching products, and the other five areas were mixed with the potassium-rich leaching products prepared in Examples 1-5 at an addition amount of 525 kg / hectare and placed in the soil for 7 days. Rice was planted in the six areas at the same time, and the six groups of rice were managed in the same way and harvested in July. The rice samples collected from each area were brought back to the laboratory and washed with tap water, and then washed with deionized water for 3 times. The clean fresh rice samples were divided into roots, stems and leaves, and rice grains, and were respectively sterilized at 105°C for 30 minutes and then dried at 60°C to constant weight to obtain the biomass (dry weight) of rice roots, stems and leaves, and rice grains.

[0068] The above test process was also carried out in Field B and Field C. The test results are shown in Table 5. The unit of biomass data in Table 5 is g / 3 plants.

[0069] Table 5

[0070]

[0071]

[0072] Note: The data in the table are mean ± standard deviation. Different letters in the same column indicate significant differences between different levels of treatment (p<0.05).

[0073] It can be seen from Table 5 that after the potassium-rich leaching products prepared in Examples 1-5 were mixed in the soil, the biomass of the roots, stems, leaves and rice grains of rice were all increased. Therefore, it can be explained that the potassium-rich leaching products prepared by using lithium extraction residues of lepidolite as raw materials in the present invention can be used as soil conditioners to increase the biomass of crops.

[0074] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A process for dissolving potassium from lithium smelting slag, characterized in that: The following steps are involved: (1) roasting and dissolving lithium smelting slag, and then performing solid-liquid separation to obtain a dissolving solution; (2) concentrating the dissolution solution to obtain a potassium-rich dissolution product; The lithium smelting slag is lithium-extracting slag from lepidolite.

2. The process for dissolving potassium from lithium smelting slag according to claim 1, characterized in that: The calcination temperature is 850-1150° C., and the calcination time is 0.25-3 hours.

3. The process for dissolving potassium from lithium smelting slag according to claim 1 or 2, characterized in that: An activator is also added during the calcination.

4. The process for dissolving potassium from lithium smelting slag according to claim 3, characterized in that: The mass ratio of the activator to the lithium smelting slag is (0.5-1):

1.

5. The process for dissolving potassium from lithium smelting slag according to claim 4, characterized in that: The activator is a calcium-based chloride.

6. The process for dissolving potassium from lithium smelting slag according to claim 1, characterized in that: The solvent used in the dissolution process is water, and the liquid-to-solid ratio is 5-10:

1.

7. The process for dissolving potassium from lithium smelting slag according to claim 1, characterized in that: The concentration temperature is 60-95°C.

8. A dissolution product obtained by the dissolution process according to any one of claims 1 to 7.

9. Use of a dissolution product obtained by the dissolution process according to any one of claims 1 to 7 or a dissolution product according to claim 8 in a soil conditioner.

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