Serpentine treatment method

Abstract

The invention provides a treatment method of serpentine. The treatment method comprises the steps that S1, serpentine is sequentially subjected to acidification treatment and oxygen pressure leaching treatment, and iron-silicon slag and leaching filtrate are obtained; s2, the iron-silicon slag is subjected to pressurized alkaline leaching treatment, and first iron slag and a sodium silicate solution are obtained; s3, mixing the leached filtrate with a first precipitant, and carrying out iron and aluminum removal reaction to obtain iron and aluminum slag and first filtrate; s4, mixing the first filtrate with a second precipitant for nickel-cobalt precipitation reaction to obtain a nickel-cobalt product and a magnesium-containing solution; and S5, the iron-aluminum slag is subjected to pressurized acid leaching treatment, and second iron slag and an aluminum-containing solution are obtained. According to the treatment method, particularly the pressurized alkaline leaching treatment is performed on the iron-silicon slag and the pressurized acid leaching treatment is performed on the iron-aluminum slag, so that the purity of the first iron slag and the second iron slag is improved, the problem of common landfill treatment on other metal valuable elements in the serpentine in the form of waste slag is solved, and the overall utilization rate of the serpentine is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrometallurgy, and more particularly, to a method for treating serpentine. Background Art

[0002] Serpentine is a natural hydrous magnesium silicate mineral with a layered structure. The main valuable elements are Mg and Si, and in addition, there are also components such as Al, Fe, Mn, Cr, and Ni. Serpentine has rich reserves in China and has high comprehensive development and utilization value after deep processing.

[0003] At present, the processing methods of serpentine include atmospheric acid leaching method and pyrometallurgical roasting, with the acid leaching method being the main one. The technological process of acid leaching and wet smelting of serpentine is: raw material leaching, impurity removal, and magnesium precipitation; the pyrometallurgical roasting process uses serpentine powder mixed with ammonium salt for roasting, water dissolution, impurity removal and other processes to prepare magnesium hydroxide products. The above two serpentine smelting processes are both aimed at producing magnesium products, and other valuable metal elements in serpentine are generally landfilled in the form of waste residue, resulting in great waste of resources and environmental pollution.

[0004] With the increasing depletion of resources and the increasingly strict requirements for the discharge of industrial three wastes, it is very necessary to develop a simple operation comprehensive development process for serpentine. On the one hand, it can solve the problem of industrial three wastes, and on the other hand, it can avoid the waste of high-value nickel, cobalt resources and additional products such as silicon and iron, and improve the comprehensive utilization value of serpentine. Summary of the Invention

[0005] The main object of the present invention is to provide a method for treating serpentine to solve the problem of resource waste caused by the common landfill treatment of high-value nickel, cobalt resources and additional products such as silicon and iron in serpentine in the prior art in the form of waste residue.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided a method for treating serpentine, the treatment method comprising: step S1, subjecting serpentine to acidification treatment and oxygen pressure leaching treatment in sequence to obtain iron-silicon slag and leaching filtrate; step S2, subjecting the iron-silicon slag to pressurized alkali leaching treatment to obtain first iron slag and sodium silicate solution; step S3, mixing the leaching filtrate with a first precipitant to carry out iron and aluminum removal reaction to obtain iron-aluminum slag and a first filtrate; step S4, mixing the first filtrate with a second precipitant to carry out nickel and cobalt precipitation reaction to obtain nickel-cobalt products and magnesium-containing solution; step S5, subjecting the iron-aluminum slag to pressurized acid leaching treatment to obtain second iron slag and aluminum-containing solution.

[0007] Further, in the above step S2, the alkaline solution used in the pressurized alkaline leaching is a sodium hydroxide solution. Preferably, the concentration of the sodium hydroxide solution is 5 - 10 mol / L; the mass ratio of the sodium hydroxide solution to the iron-silicon slag is 1.1 - 1.5:1, and the liquid-solid mass ratio in the pressurized alkaline leaching treatment is 6 - 10:1; the temperature of the pressurized alkaline leaching treatment is 110 - 150 °C, and the time of the pressurized alkaline leaching treatment is 2 - 4 h.

[0008] Further, in the above step S2, the iron content in the first iron slag is 36 - 70 wt.%, preferably 52 - 70 wt.%; the moisture content is 35 - 50 wt.%.

[0009] Further, in the above step S5, the acid solution used in the pressurized acid leaching is a sulfuric acid solution. Preferably, the mass fraction of the sulfuric acid solution is 85 - 98 wt.%; the mass ratio of the sulfuric acid solution to the iron-aluminum slag is 0.3 - 0.6:1, and the liquid-solid mass ratio in the pressurized acid leaching treatment is 4 - 8:1; the temperature of the pressurized acid leaching treatment is 110 - 130 °C, and the time of the pressurized acid leaching treatment is 2 - 4 h.

[0010] Further, in the above step S5, the iron content in the second iron slag is 43 - 70 wt.%, preferably 55 - 70 wt.%; the moisture content is 35 - 50 wt.%.

[0011] Further, in the above step S1, the acid solution used in the acidification treatment is a sulfuric acid solution. Preferably, the mass fraction of the sulfuric acid solution is 75 - 98 wt.%; the mass ratio of the sulfuric acid solution to the serpentine is 0.9 - 1.2:1; the liquid-solid mass ratio in the acidification treatment is 4 - 6:1, the temperature of the acidification treatment is 60 - 80 °C, and the time of the acidification treatment is 2 - 3 h.

[0012] Further, in the above step S1, the temperature of the oxygen pressure leaching treatment is 140 - 180 °C, and the time of the oxygen pressure leaching treatment is 3 - 6 h; the partial oxygen pressure in the oxygen pressure leaching treatment is 0.2 - 0.5 MPa.

[0013] Further, in the above step S3, during the iron and aluminum removal reaction, the pH value of the reaction system is controlled to be 4.0 - 5.0 by adjusting the dosage of the first precipitant, and the temperature of the iron and aluminum removal reaction is 65 - 80 °C; the first precipitant is selected from one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate.

[0014] Further, in the above step S4, during the nickel and cobalt precipitation reaction, the pH value of the reaction system is controlled to be 6.5 - 8.5 by adjusting the dosage of the second precipitant, and the temperature of the nickel and cobalt precipitation reaction is 45 - 60 °C; the second precipitant is selected from one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate.

[0015] Further, in the above step S4, the nickel content in the nickel-cobalt product is 35-65 wt.%, the cobalt content in the nickel-cobalt product is 0.5-5 wt.%, and the water content in the nickel-cobalt product is 30-70 wt.%.

[0016] Applying the technical solution of the present invention, the present application discloses a comprehensive development process for the pressure treatment of serpentine. Considering the whole process from the acidification treatment of the original ore to the oxygen pressure leaching, and then to the precipitation of the filtrate and the treatment and recovery of the leaching residue, after the low-value serpentine is effectively treated, high-value iron slag, sodium silicate solution, nickel-cobalt product, magnesium-containing solution and aluminum-containing solution are obtained, improving the overall utilization rate of serpentine, solving the problem of ordinary landfill treatment of other valuable metal elements in serpentine in the form of waste residue, resulting in a great waste of resources and environmental pollution, having good social benefits, and at the same time having a short production cycle, high product purity and remarkable economic benefits, which has important practical significance for the comprehensive utilization of serpentine. In particular, the pressure alkali leaching treatment of iron-silicon slag and the pressure acid leaching treatment of iron-aluminum slag not only improve the purity of the first iron slag and the second iron slag, but also solve the problem of ordinary landfill treatment of silicon and aluminum resources in serpentine in the form of waste residue, resulting in a great waste of resources and environmental pollution, and at the same time the generated sodium silicate solution and aluminum-containing solution also have high economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The specification drawings forming a part of the present application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0018] Figure 1 The flow chart of preparing nickel-cobalt-silicon-iron products using serpentine in Example 1 of the present application is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0020] As analyzed in the background art, the main elements in serpentine are magnesium and silicon, and in addition, there are also components such as Al, Fe, Mn, Cr, Ni, etc. However, in the existing technology, most of the smelting processes of serpentine aim to produce magnesium products, while the high-value nickel, cobalt resources and additional products such as silicon and iron in serpentine are treated by ordinary landfill in the form of waste residue, resulting in a great waste of resources and environmental pollution. To solve the above problems, the present application provides a method for treating serpentine.

[0021] In a typical embodiment of the present application, a method for treating serpentine is provided. The method includes: Step S1, subjecting serpentine to acidification treatment and oxygen pressure leaching treatment in sequence to obtain an iron-silicon slag and a leaching filtrate; Step S2, subjecting the iron-silicon slag to pressurized alkali leaching treatment to obtain a first iron slag and a sodium silicate solution; Step S3, mixing the leaching filtrate with a first precipitant to carry out an iron-aluminum removal reaction to obtain an iron-aluminum slag and a first filtrate; Step S4, mixing the first filtrate with a second precipitant to carry out a nickel-cobalt precipitation reaction to obtain a nickel-cobalt product and a magnesium-containing solution; Step S5, subjecting the iron-aluminum slag to pressurized acid leaching treatment to obtain a second iron slag and an aluminum-containing solution.

[0022] The present application discloses a comprehensive process for pressurized treatment of serpentine. Considering the whole process from the acidification treatment of the raw ore to oxygen pressure leaching, and then to the precipitation of the filtrate and the treatment and recovery of the leaching residue, after effectively treating the low-value serpentine, high-value iron slag, sodium silicate solution, nickel-cobalt product, magnesium-containing solution and aluminum-containing solution are obtained, improving the overall utilization rate of serpentine, solving the problem of ordinary landfill treatment of other valuable metal elements in serpentine in the form of waste residue, resulting in great waste of resources and environmental pollution, and having good social benefits. At the same time, the production cycle of this process is short, the product purity is high, the economic benefits are remarkable, and it has important practical significance for the comprehensive utilization of serpentine. In particular, the pressurized alkali leaching treatment of the iron-silicon slag and the pressurized acid leaching treatment of the iron-aluminum slag not only improve the purity of the first iron slag and the second iron slag, but also solve the problem of ordinary landfill treatment of silicon and aluminum resources in serpentine in the form of waste residue, resulting in great waste of resources and environmental pollution. At the same time, the generated sodium silicate solution and aluminum-containing solution also have high economic value.

[0023] In an embodiment of the present application, in the above Step S2, the alkali solution used for pressurized alkali leaching is a sodium hydroxide solution. Preferably, the concentration of the sodium hydroxide solution is 5 - 10 mol / L; the mass ratio of the iron-silicon slag to the sodium hydroxide solution is 1.1 - 1.5:1, and the liquid-solid mass ratio of the pressurized alkali leaching treatment is 6 - 10:1; the temperature of the pressurized alkali leaching treatment is 110 - 150 °C, and the time of the pressurized alkali leaching treatment is 2 - 4 h.

[0024] By controlling the range of the above conditions, it is beneficial to improve the dissolution efficiency and effect of silicon elements in the iron-silicon slag in the alkali solution, thereby being more conducive to the separation of iron and silicon. It not only solves the problem of ordinary landfill treatment of silicon elements in serpentine in the form of waste residue, resulting in great waste of resources and environmental pollution, but also the generated sodium silicate solution has high economic value, and is also beneficial to improving the purity of the first iron slag.

[0025] In an embodiment of the present application, in the above Step S2, the iron content in the first iron slag is 36 - 70 wt.%, preferably 52 - 70 wt.%; the moisture content is 35 - 50 wt.%.

[0026] Optimizing the iron content and moisture content of the first iron slag is not only beneficial to the effective recovery of iron elements, but also improves the quality of the first iron slag, thereby enhancing the market competitiveness of the product.

[0027] In an embodiment of the present application, in the above step S5, the acid solution used in the pressure acid leaching is a sulfuric acid solution. Preferably, the mass fraction of the sulfuric acid solution is 85-98 wt.%; the mass ratio of the iron-aluminum slag to the sulfuric acid solution is 0.3-0.6:1, and the liquid-solid mass ratio in the pressure acid leaching treatment is 4-8:1; the temperature of the pressure acid leaching treatment is 110-130 °C, and the time of the pressure acid leaching treatment is 2-4 h.

[0028] Preferably, controlling the conditions of the pressure acid leaching within the above range is beneficial to the efficient leaching of aluminum in the iron-aluminum slag. At the same time, it also solves the problem of the great waste of resources and environmental pollution caused by the ordinary landfill treatment of aluminum elements in serpentine in the form of waste slag. At the same time, the produced aluminum-containing solution also has high economic value.

[0029] In an embodiment of the present application, in the above step S5, the iron content in the second iron slag is 43-70 wt.%, preferably 55-70 wt.%; the water content is 35-50 wt.%.

[0030] Preferably, controlling the iron content and water content in the second iron slag is beneficial to improving the quality of the second iron slag, thereby enhancing its acceptance and value in the market.

[0031] In an embodiment of the present application, in the above step S1, the acid solution used in the acidification treatment is a sulfuric acid solution. Preferably, the mass fraction of the sulfuric acid solution is 75-98 wt.%; the mass ratio of the serpentine to the sulfuric acid solution is 0.9-1.2:1; the liquid-solid mass ratio in the acidification treatment is 4-6:1, the temperature of the acidification treatment is 60-80 °C, and the time of the acidification treatment is 2-3 h.

[0032] Preferably, controlling the conditions of the acidification treatment within the above range is beneficial to improving the dissolution efficiency and effect of metal elements in the serpentine.

[0033] In an embodiment of the present application, in the above step S1, the temperature of the oxygen pressure leaching treatment is 140-180 °C, the time of the oxygen pressure leaching treatment is 3-6 h; the partial oxygen pressure in the oxygen pressure leaching treatment is 0.2-0.5 MPa.

[0034] Preferably, controlling the conditions of the oxygen pressure leaching treatment within the above range is beneficial to accelerating the dissolution and separation of metal elements, improving the leaching efficiency and purity, and thus facilitating the subsequent recovery of metal elements.

[0035] In an embodiment of the present application, in the above step S3, during the iron and aluminum removal reaction, by adjusting the dosage of the first precipitant, the pH value of the reaction system is controlled to be 4.0 - 5.0, and the temperature of the iron and aluminum removal reaction is 65 - 80 °C; the first precipitant is selected from one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate.

[0036] Preferably, controlling the pH value of the reaction system within the above range is beneficial to promoting the precipitation of iron and aluminum elements in the leaching filtrate, while avoiding the precipitation loss of other metal elements, and can maximize the recovery of iron and aluminum and reduce resource waste. Preferably, controlling the temperature of the iron and aluminum removal reaction within the above range is beneficial to increasing the reaction rate. In addition, the present application has no special limitation on the type of the first precipitant, as long as it can adjust the pH value and avoid generating metal impurities.

[0037] In an embodiment of the present application, in the above step S4, during the nickel and cobalt precipitation reaction, by adjusting the dosage of the second precipitant, the pH value of the reaction system is controlled to be 6.5 - 8.5, and the temperature of the nickel and cobalt precipitation reaction is 45 - 60 °C; the second precipitant is selected from one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate.

[0038] Preferably, controlling the pH value of the reaction system within the above range is beneficial to the precipitation of nickel and cobalt elements, thereby improving their recovery rate. If the pH value is too high, a large amount of magnesium elements will be entrained in the nickel and cobalt slag. If the pH value is too low, it is easy to cause insufficient precipitation of nickel and cobalt elements and loss of nickel and cobalt elements, thereby reducing their recovery rate. Controlling the temperature of the nickel and cobalt precipitation reaction within the above range is beneficial to increasing the reaction rate. The present application has no special limitation on the type of the second precipitant, as long as it can adjust the pH value and avoid generating metal impurities.

[0039] In an embodiment of the present application, in the above step S4, the nickel content in the nickel and cobalt product is 35 - 65 wt.%, the cobalt content in the nickel and cobalt product is 0.5 - 5 wt.%, and the moisture content in the nickel and cobalt product is 30 - 70 wt.%.

[0040] Preferably, controlling the nickel, cobalt content, and moisture content in the nickel and cobalt product within the above range is beneficial to improving the quality of the nickel and cobalt product, thereby increasing its market value, and can meet the high-purity metal requirements of industries such as electronics and batteries, bringing significant economic benefits to the enterprise.

[0041] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0042] The composition of the serpentine used in the embodiments of the present application is shown in Table 1.

[0043] Table 1

[0044]

[0045] Example 1

[0046] The serpentine is acidified. Among them, the acid solution in the acidification treatment is a 98 wt.% sulfuric acid solution, the mass ratio of serpentine to sulfuric acid solution is 1.0:1, the liquid-solid mass ratio of the acidification treatment is 5:1, the reaction temperature is 70 °C. After reacting for 2.5 h, the obtained pulp is directly subjected to oxygen pressure leaching treatment. Under the condition of an oxygen partial pressure of 0.3 MPa, the temperature is raised to 160 °C and then reacted for 4 h, and an iron-silicon slag and a leaching filtrate are obtained by filtration.

[0047] The iron-silicon slag is subjected to pressure alkaline leaching treatment. Among them, the alkaline solution in the pressure alkaline leaching is a sodium hydroxide solution with a concentration of 7 mol / L, the mass ratio of the iron-silicon slag to the sodium hydroxide solution is 1.2:1, the liquid-solid mass ratio of the pressure alkaline leaching treatment is 8:1, the reaction temperature is 120 °C. After reacting for 3 h, a first iron slag and a sodium silicate solution are obtained; the first iron slag contains 60 wt.% iron and a water content of 50 wt.%.

[0048] A 10 wt.% first MgO solution is added to the leaching filtrate for iron and aluminum removal reaction. The reaction temperature is 80 °C. After adjusting the pH value to 5.0 with the first MgO solution, an iron-aluminum slag and a first filtrate are obtained by filtration; a 5 wt.% second MgO solution is added to the above first filtrate for nickel and cobalt precipitation reaction. The reaction temperature is 45 °C. After adjusting the pH value to 6.5 with the first MgO solution, a nickel-cobalt product and a magnesium sulfate solution are obtained by filtration; the nickel-cobalt product contains 50 wt.% nickel, 3.5 wt.% cobalt and a water content of 30 wt.%.

[0049] The iron-aluminum slag is further subjected to pressure acid leaching treatment. Among them, the acid solution in the acidification treatment is an 85 wt.% sulfuric acid solution, the mass ratio of the iron-aluminum slag to the sulfuric acid solution is 0.6:1, the liquid-solid mass ratio of the pressure acid leaching treatment is 8:1, the reaction temperature is 130 °C. After reacting for 4 h, a second iron slag and an aluminum sulfate solution are obtained; the second iron slag contains 60 wt.% iron and a water content of 50 wt.%.

[0050] Example 2

[0051] The serpentine is acidified. Among them, the acid solution in the acidification treatment is a 95 wt.% sulfuric acid solution, the mass ratio of serpentine to sulfuric acid solution is 0.9:1, the liquid-solid mass ratio of the acidification treatment is 4:1, the reaction temperature is 60 °C. After reacting for 3 h, the obtained pulp is directly subjected to oxygen pressure leaching treatment. Under the condition of an oxygen partial pressure of 0.4 MPa, the temperature is raised to 180 °C and then reacted for 3 h, and an iron-silicon slag and a leaching filtrate are obtained by filtration.

[0052] The iron-silicon slag is subjected to pressure alkaline leaching. Among them, the alkaline solution concentration in the pressure alkaline leaching is 10 mol / L sodium hydroxide solution, the mass ratio of the iron-silicon slag to the sodium hydroxide solution is 1.1:1, the liquid-solid mass ratio of the pressure alkaline leaching treatment is 6:1, the reaction temperature is 110 °C, and after reacting for 4 h, the first iron slag and sodium silicate solution are obtained; the first iron slag contains 55 wt.% iron and 40 wt.% moisture content.

[0053] An iron and aluminum removal reaction is carried out by adding a first MgO solution with a mass fraction of 8 wt.% to the leaching filtrate, and the reaction temperature is 80 °C. After adjusting the pH value to 4.0 with the first MgO solution, an iron and aluminum slag and a first filtrate are obtained by filtration; a nickel and cobalt precipitation reaction is carried out by adding a second MgO solution with a mass fraction of 10 wt.% to the above-mentioned first filtrate, and the reaction temperature is 55 °C. After adjusting the pH value to 8.0 with the first MgO solution, a nickel and cobalt product and a magnesium sulfate solution are obtained by filtration; the nickel and cobalt product contains 40 wt.% nickel, 0.5 wt.% cobalt, and 60 wt.% moisture content.

[0054] The iron and aluminum slag is further subjected to pressure acid leaching treatment. Among them, the acid solution in the acidification treatment is 90 wt.% sulfuric acid solution, the mass ratio of the iron and aluminum slag to the sulfuric acid solution is 0.3:1, the liquid-solid mass ratio of the pressure acid leaching treatment is 4:1, the reaction temperature is 110 °C, and after reacting for 2 h, the second iron slag and aluminum sulfate solution are obtained; the second iron slag contains 65 wt.% iron and 40 wt.% moisture content.

[0055] Example 3

[0056] The serpentine is subjected to acidification treatment. Among them, the acid solution in the acidification treatment is 90 wt.% sulfuric acid solution, the mass ratio of the serpentine to the sulfuric acid solution is 1.1:1, the liquid-solid mass ratio of the acidification treatment is 6:1, the reaction temperature is 75 °C, and after reacting for 2 h, the obtained pulp is directly subjected to oxygen pressure leaching treatment. Under the condition of an oxygen partial pressure of 0.5 MPa, after heating to 170 °C, the reaction is carried out for 5 h, and an iron-silicon slag and a leaching filtrate are obtained by filtration.

[0057] The iron-silicon slag is subjected to pressure alkaline leaching. Among them, the alkaline solution in the pressure alkaline leaching is 5 mol / L sodium hydroxide solution, the mass ratio of the iron-silicon slag to the sodium hydroxide solution is 1.5:1, the liquid-solid mass ratio of the pressure alkaline leaching treatment is 10:1, the reaction temperature is 140 °C, and after reacting for 2.5 h, the first iron slag and sodium silicate solution are obtained; the first iron slag contains 70 wt.% iron and 50 wt.% moisture content.

[0058] Add a first MgO solution with a mass fraction of 15 wt.% to the leaching filtrate for the iron and aluminum removal reaction. The reaction temperature is 65 °C. After adjusting the pH value to 4.5 with the first MgO solution, filter to obtain iron and aluminum slag and a first filtrate; add a second MgO solution with a mass fraction of 8 wt.% to the above first filtrate for the nickel and cobalt precipitation reaction. The reaction temperature is 60 °C. After adjusting the pH value to 8.5 with the first MgO solution, filter to obtain nickel and cobalt products and magnesium sulfate solution; the nickel and cobalt products contain 65 wt.% nickel, 5.0 wt.% cobalt, and 70 wt.% water content.

[0059] Perform pressure acid leaching on the iron and aluminum slag again. Among them, the acid solution in the acidification treatment is a 98 wt.% sulfuric acid solution. The mass ratio of the iron and aluminum slag to the sulfuric acid solution is 0.4:1. The liquid-solid mass ratio of the pressure acid leaching treatment is 6:1. The reaction temperature is 120 °C. After reacting for 3 h, obtain a second iron slag and aluminum sulfate solution; the second iron slag contains 55 wt.% iron and 50 wt.% water content.

[0060] Example 4

[0061] Perform acidification treatment on serpentine. Among them, the acid solution in the acidification treatment is an 85 wt.% sulfuric acid solution. The mass ratio of serpentine to the sulfuric acid solution is 1.2:1. The liquid-solid mass ratio of the acidification treatment is 4.5:1. The reaction temperature is 80 °C. After reacting for 2 h, directly perform oxygen pressure leaching on the obtained pulp. Under the condition of an oxygen partial pressure of 0.2 MPa, heat up to 140 °C and react for 6 h, then filter to obtain iron and silicon slag and a leaching filtrate.

[0062] Perform pressure alkali leaching on the iron and silicon slag. Among them, the alkali solution in the pressure alkali leaching is a sodium hydroxide solution with a concentration of 6 mol / L. The mass ratio of the iron and silicon slag to the sodium hydroxide solution is 1.3:1. The liquid-solid mass ratio of the pressure alkali leaching treatment is 7:1. The reaction temperature is 150 °C. After reacting for 2 h, obtain a first iron slag and sodium silicate solution; the first iron slag contains 65 wt.% iron and 35 wt.% water content.

[0063] Add a first MgO solution with a mass fraction of 12 wt.% to the leaching filtrate for the iron and aluminum removal reaction. The reaction temperature is 70 °C. After adjusting the pH value to 4.8 with the first MgO solution, filter to obtain iron and aluminum slag and a first filtrate; add a second MgO solution with a mass fraction of 12 wt.% to the above first filtrate for the nickel and cobalt precipitation reaction. The reaction temperature is 55 °C. After adjusting the pH value to 7.5 with the first MgO solution, filter to obtain nickel and cobalt products and magnesium sulfate solution; the nickel and cobalt products contain 35 wt.% nickel, 2.0 wt.% cobalt, and 40 wt.% water content.

[0064] The iron-aluminum slag is further subjected to pressure acid leaching. Among them, the acid solution in the acidification treatment is a 95 wt.% sulfuric acid solution, the mass ratio of the iron-aluminum slag to the sulfuric acid solution is 0.5:1, the liquid-solid mass ratio in the pressure acid leaching treatment is 5:1, the reaction temperature is 125 °C, and after reacting for 3.5 h, a second iron slag and an aluminum sulfate solution are obtained; the second iron slag contains 70 wt.% iron and has a moisture content of 35 wt.%.

[0065] Example 5

[0066] The difference from Example 1 is that the mass ratio of the iron-silicon slag to the alkali solution is 1.5:1 to complete the treatment of serpentine.

[0067] Example 6

[0068] The difference from Example 1 is that the mass ratio of the iron-silicon slag to the alkali solution is 1:1 to complete the treatment of serpentine.

[0069] Example 7

[0070] The difference from Example 1 is that the liquid-solid mass ratio in the pressure alkali leaching treatment is 10:1 to complete the treatment of serpentine.

[0071] Example 8

[0072] The difference from Example 1 is that the liquid-solid mass ratio in the pressure alkali leaching treatment is 5:1 to complete the treatment of serpentine.

[0073] Example 9

[0074] The difference from Example 1 is that the mass ratio of the iron-aluminum slag to the acid solution is 0.3:1 to complete the treatment of serpentine.

[0075] Example 10

[0076] The difference from Example 1 is that the mass ratio of the iron-aluminum slag to the acid solution is 0.2:1 to complete the treatment of serpentine.

[0077] Example 11

[0078] The difference from Example 1 is that the liquid-solid mass ratio in the pressure acid leaching treatment is 4:1 to complete the treatment of serpentine.

[0079] Example 12

[0080] The difference from Example 1 is that the liquid-solid mass ratio in the pressure acid leaching treatment is 3:1 to complete the treatment of serpentine.

[0081] Test the recovery rates of nickel and cobalt elements, the purity of the first iron slag, the purity of the second iron slag, the concentration of sodium silicate in the sodium silicate solution, the concentration of magnesium ions in the magnesium sulfate solution, and the concentration of aluminum ions in the aluminum sulfate solution in the nickel-cobalt products in the above embodiments, and list the test results in Table 2.

[0082] List the iron content rate and water content rate of the first iron slag, the iron content rate and water content rate of the second iron slag, the nickel content rate, cobalt content rate, and water content rate of the nickel-cobalt products in the above embodiments in Table 3 respectively.

[0083] Table 2

[0084]

[0085] Table 3

[0086]

[0087]

[0088] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0089] The present application discloses a comprehensive development process for the pressure treatment of serpentine. Considering the whole process from the acidification treatment of the original ore to the oxygen pressure leaching, and then to the precipitation of the filtrate and the treatment and recovery of the leaching residue, after the low-value serpentine is effectively treated, high-value iron slag, sodium silicate solution, nickel-cobalt products, magnesium-containing solution, and aluminum-containing solution are obtained, improving the overall utilization rate of serpentine, solving the problem of ordinary landfill treatment of other valuable metal elements in serpentine in the form of waste residue, resulting in a great waste of resources and environmental pollution, having good social benefits, and at the same time having a short production cycle and high product purity, with significant economic benefits, and having important practical significance for the comprehensive utilization of serpentine. In particular, the pressure alkaline leaching treatment of the iron-silicon slag and the pressure acid leaching treatment of the iron-aluminum slag not only improve the purity of the first iron slag and the second iron slag, but also solve the problem of ordinary landfill treatment of silicon and aluminum resources in serpentine in the form of waste residue, resulting in a great waste of resources and environmental pollution, and at the same time the generated sodium silicate solution and aluminum-containing solution also have high economic value.

[0090] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for treating serpentine, characterized in that, The described treatment method includes: Step S1: subject the serpentine to acidification treatment and oxygen pressure leaching treatment in sequence to obtain an iron-silicon slag and a leaching filtrate; Step S2: subject the iron-silicon slag to pressurized alkali leaching treatment to obtain a first iron slag and a sodium silicate solution; Step S3: mix the leaching filtrate with a first precipitant for iron and aluminum removal reaction to obtain an iron-aluminum slag and a first filtrate; Step S4: mix the first filtrate with a second precipitant for nickel and cobalt precipitation reaction to obtain nickel-cobalt products and a magnesium-containing solution; Step S5: subject the iron-aluminum slag to pressurized acid leaching treatment to obtain a second iron slag and an aluminum-containing solution.

2. The processing method according to claim 1, wherein In the said Step S2, the alkali solution used for the pressurized alkali leaching is a sodium hydroxide solution, preferably with a concentration of 5 - 10 mol / L for the sodium hydroxide solution; the mass ratio of the sodium hydroxide solution to the iron-silicon slag is 1.1 - 1.5:1, and the liquid-solid mass ratio for the pressurized alkali leaching treatment is 6 - 10:1; the temperature for the pressurized alkali leaching treatment is 110 - 150 °C, and the time for the pressurized alkali leaching treatment is 2 - 4 h.

3. The processing method according to claim 1 or 2, characterized in that, In the said Step S2, the iron content in the first iron slag is 36 - 70 wt.%, preferably 52 - 70 wt.%; the water content is 35 - 50 wt.%.

4. The processing method according to any one of claims 1 to 3, characterized in that In the said Step S5, the acid solution used for the pressurized acid leaching is a sulfuric acid solution, preferably with a mass fraction of 85 - 98 wt.% for the sulfuric acid solution; the mass ratio of the sulfuric acid solution to the iron-aluminum slag is 0.3 - 0.6:1, and the liquid-solid mass ratio for the pressurized acid leaching treatment is 4 - 8:1; the temperature for the pressurized acid leaching treatment is 110 - 130 °C, and the time for the pressurized acid leaching treatment is 2 - 4 h.

5. The processing method according to any one of claims 1 to 4, characterized in that In the said Step S5, the iron content in the second iron slag is 43 - 70 wt.%, preferably 55 - 70 wt.%; the water content is 35 - 50 wt.%.

6. The processing method according to any one of claims 1 to 5, characterized in that, In the said Step S1, the acid solution used for the acidification treatment is a sulfuric acid solution, preferably with a mass fraction of 75 - 98 wt.% for the sulfuric acid solution; the mass ratio of the sulfuric acid solution to the serpentine is 0.9 - 1.2:1; the liquid-solid mass ratio for the acidification treatment is 4 - 6:1, the temperature for the acidification treatment is 60 - 80 °C, and the time for the acidification treatment is 2 - 3 h.

7. The processing method according to any one of claims 1 to 6, characterized in that, In the said Step S1, the temperature for the oxygen pressure leaching treatment is 140 - 180 °C, the time for the oxygen pressure leaching treatment is 3 - 6 h; the oxygen partial pressure for the oxygen pressure leaching treatment is 0.2 - 0.5 MPa.

8. The processing method according to any one of claims 1 to 7, characterized in that, In the said Step S3, during the iron and aluminum removal reaction, the pH value of the reaction system is controlled at 4.0 - 5.0 by adjusting the dosage of the first precipitant, and the temperature for the iron and aluminum removal reaction is 65 - 80 °C; the first precipitant is selected from one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate.

9. The processing method according to any one of claims 1 to 8, characterized in that In the said Step S4, during the nickel and cobalt precipitation reaction, the pH value of the reaction system is controlled at 6.5 - 8.5 by adjusting the dosage of the second precipitant, and the temperature for the nickel and cobalt precipitation reaction is 45 - 60 °C; the second precipitant is selected from one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate.

10. The processing method according to any one of claims 1 to 9, characterized in that, In the step S4, the nickel content in the nickel-cobalt product is 35-65 wt.%, the cobalt content in the nickel-cobalt product is 0.5-5 wt.%, and the moisture content in the nickel-cobalt product is 30-70 wt.%.

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