Method for utilizing serpentine

Abstract

The invention relates to the technical field of ore resource utilization, in particular to a serpentine utilization method. The method comprises the following steps: mixing serpentine powder, calcium oxide powder and water, carrying out hydrothermal reaction to obtain a hydrothermal reaction mixed solution, carrying out thermal solid-liquid separation on the hydrothermal reaction mixed solution to obtain a solid phase and a liquid phase, carrying out magnetic separation on the solid phase to obtain a solid rich in iron oxide and magnetic separation residues, and carrying out flotation on the magnetic separation residues to obtain the iron oxide. Solid rich in nickel oxide and flotation residues are obtained, and the flotation residues are used as cement raw materials. According to the utilization method provided by the invention, full resource utilization of serpentine is realized, the technological process is reduced, no waste gas or waste liquid is generated, and the pollution to the environment is eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of ore resource utilization, and particularly to a method for utilizing serpentine. Background Art

[0002] Serpentine is a layered silicate mineral formed by the alternation of silicon oxygen octahedra and magnesium oxide, with the chemical formula MgSiO3˙nH2O. Its main components include 35%-40% MgO, 28%-37% SiO2, 12%-15% crystal water, 8%-11% Fe3O4, 0.5%-2% calcium oxide, 0.11%-0.3% nickel, and 0.01% chromium. Some also contain small amounts of elements such as copper, manganese, and aluminum.

[0003] Serpentine is a relatively abundant mineral resource on the earth. Currently, there are two ways to utilize serpentine. One is to simply use it as a whole, such as as a building decoration material, refractory material, raw material for calcium magnesium phosphate fertilizer, metallurgical flux, roadbed raw material, etc. The added value of this kind of utilization is relatively low. The other utilization method is to extract the useful components from it. Due to the high added value of this utilization method, it has become a current research hotspot. The existing high-added-value utilization methods include mixing ammonium sulfate with serpentine fine powder and calcining, and then obtaining magnesium raw materials by water leaching, but this method has large pollution and the residue is difficult to treat; another example is to perform magnetic separation on the iron in it to extract the iron resources, but this method has a long process and the residue after magnetic separation is harmful to the environment; in addition, in recent years, it has also been reported that serpentine is treated by acid leaching to obtain magnesium raw materials, and the acid leaching residue is treated with alkali to obtain silicon raw materials, but this method is also difficult to put into actual production and operation due to many technological procedures and high costs. More importantly, the transportation, storage of raw materials during the use of acids and alkalis, and the emission treatment after production are all cost problems faced by enterprises. Therefore, how to provide a green environmental protection technology that can fully utilize the useful components of serpentine and does not produce waste liquid and waste gas has become an urgent problem to be solved. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for utilizing serpentine, which can fully extract the useful components in serpentine, and the waste residue can be used as a cement raw material, without generating waste, and the process is simple and easy to operate.

[0005] The present invention provides a method for utilizing serpentine, comprising the following steps:

[0006] (1) Mix serpentine powder, calcium oxide powder and water, and carry out hydrothermal reaction to obtain a hydrothermal reaction mixture;

[0007] (2) Perform thermal solid-liquid separation on the hydrothermal reaction mixture to obtain a solid phase and a liquid phase;

[0008] (3) Perform magnetic separation on the solid phase to obtain a solid rich in iron oxide and magnetic separation residue;

[0009] (4) Perform flotation on the magnetic separation residue to obtain a solid rich in nickel oxide and flotation residue, and use the flotation residue as a cement raw material.

[0010] Optionally, in the step (1), the particle size of the serpentine powder is 150 - 200 mesh, and the particle size of the calcium oxide powder is 50 mesh.

[0011] Optionally, the mass ratio of the serpentine powder to the calcium oxide powder is 1.3 - 1.7:1, and the mass ratio of the sum of the masses of the serpentine powder and calcium oxide powder to the mass of water is 1:3.5 - 4.5.

[0012] Optionally, the temperature of the hydrothermal reaction is 95 - 100 °C, and the time is 2 - 3 h.

[0013] Optionally, after obtaining the solid phase in the step (2), wash the solid phase with water at a temperature of 70 - 90 °C, perform subsequent steps on the washed solid phase, and incorporate the washing liquid obtained from the washing into the liquid phase.

[0014] Optionally, the washing method is stirring washing or spraying washing, and the number of washing times is 2 - 3 times.

[0015] Optionally, remove the moisture from the liquid phase obtained in the step (2) to obtain magnesium hydroxide.

[0016] Optionally, calcine the magnesium hydroxide to obtain magnesium oxide.

[0017] Optionally, the magnetic field strength for magnetic separation in the step (3) is ≥4200 mT.

[0018] Optionally, the temperature of the thermal solid-liquid separation is above 40 °C.

[0019] The present invention provides a method for utilizing serpentine. Serpentine powder, calcium oxide powder and water are mixed and then subjected to hydrothermal reaction. During the hydrothermal reaction, the silicate radical of serpentine combines with calcium ions to form more stable calcium silicate, thereby displacing the magnesium combined with the silicate radical. At the same time, iron oxide and nickel oxide existing in the form of silicides are also displaced from the serpentine structure, which is beneficial to improving the extraction rate of iron oxide and nickel oxide in the subsequent extraction; under hydrothermal reaction conditions, the magnesium hydroxide obtained by the reaction can dissolve in the aqueous phase. Therefore, after the hydrothermal reaction mixture is subjected to thermal solid-liquid separation, magnesium hydroxide can be separated out, and the solid phase is the oxides of other metals with relatively low solubility; then the solid phase is subjected to magnetic separation and flotation in sequence, and iron oxide and nickel oxide can be separated out. The main chemical components in the remaining flotation residue are silicon dioxide and calcium oxide, which can be used as cement raw materials, thus realizing the full resource utilization of serpentine. The method provided by the present invention can fully utilize serpentine resources. Magnesium, iron and nickel can be extracted from serpentine, and the remaining flotation residue can be used as cement raw materials. The process flow is short, the pollution is small, and there is no generation of waste gas and waste liquid. It can be seen from the examples that the content of iron oxide in the obtained product is 57% - 75%, the content of nickel oxide is 4.7% - 8%, and the content of magnesium oxide is 66% - 85%. The main components of the obtained flotation residue are all components required for cement raw materials. Detailed implementation manners

[0020] The present invention will be described below through specific implementation manners. Those skilled in the art can understand that the following specific implementation manners are only for the purpose of illustration and do not limit the scope of the present invention in any way. In addition, in the following implementation manners, unless otherwise specified, the reagents and equipment used are commercially available. If the specific treatment conditions and treatment methods are not clearly described in the following implementation manners, the conditions and methods well known in the art can be used for treatment.

[0021] The present invention provides a method for utilizing serpentine on the one hand, including the following steps:

[0022] (1) Mix serpentine powder, calcium oxide powder and water and then carry out hydrothermal reaction to obtain a hydrothermal reaction mixture;

[0023] (2) Carry out thermal solid-liquid separation on the hydrothermal reaction mixture to obtain a solid phase and a liquid phase;

[0024] (3) Carry out magnetic separation on the solid phase to obtain a solid rich in iron oxide and a magnetic separation residue;

[0025] (4) Carry out flotation on the magnetic separation residue to obtain a solid rich in nickel oxide and a flotation residue, and the flotation residue is used as a cement raw material.

[0026] The method for utilizing serpentine provided by the present invention can comprehensively utilize serpentine, reduce the technological process, generate no waste gas or waste liquid, and eliminate environmental pollution.

[0027] In the present invention, serpentine powder, calcium oxide powder and water are first mixed and stirred to carry out a hydrothermal reaction to obtain a hydrothermal reaction mixture.

[0028] In some embodiments of the present invention, the particle size of the serpentine powder is 150 - 200 mesh (that is, the serpentine can pass through any mesh screen between 150 - 200 mesh (including 150 mesh and 200 mesh)), and the particle size of the calcium oxide powder is 50 mesh (that is, the calcium oxide powder can pass through a 50 - mesh screen). The above particle size is conducive to the full mixing of the serpentine powder and the calcium oxide powder. The mixed ore powder obtained by mixing the serpentine powder and the calcium oxide powder becomes slurry when encountering water in the subsequent reaction, which is conducive to the full progress of the subsequent hydrothermal reaction, facilitating the full replacement of magnesium, and at the same time grinding it to the above range can reduce the grinding cost. When the particle sizes of the serpentine powder and the calcium oxide powder are not within the above range, those skilled in the art can use conventional methods to grind them to the above range.

[0029] The present invention has no special limitation on the source of the serpentine, and its main component is serpentine, such as serpentine ore, asbestos tailings, etc.

[0030] In some embodiments of the present invention, the serpentine powder, calcium oxide powder and water are mixed by mixing the serpentine powder and the calcium oxide powder to obtain a mixed ore powder, and then mixing the mixed ore powder with water to obtain a raw material mixture.

[0031] In some embodiments of the present invention, the mass ratio of the serpentine powder to the calcium oxide powder is 1.3 - 1.7:1, specifically it can be 1.3:1, 1.5:1 or 1.7:1. The amount of silicon dioxide present as silicate in serpentine accounts for about 35% of serpentine. The above mass ratio of the serpentine powder to the calcium oxide powder can ensure that calcium ions fully replace metal ions and the magnesium oxide product has few impurities. When the ratio is greater than this value (too little calcium oxide), the metal ion replacement is incomplete; when the ratio is less than this value (too much calcium oxide), the calcium content of impurities in the obtained magnesium product increases.

[0032] In some embodiments of the present invention, the mass ratio of the sum of the masses of the serpentine powder and the calcium oxide powder (i.e., the mass of the mixed ore powder) to the mass of water is 1:3.5 - 4.5, specifically it can be 1:3.5, 1:4 or 1:4.5. The above amount of water can ensure that as much magnesium hydroxide as possible dissolves in water. At the same time, the amount of water is appropriate, which can smoothly carry out pressure filtration, is conducive to industrial application, and the concentration of magnesium hydroxide is appropriate, which is conducive to the subsequent product recovery.

[0033] In some embodiments of the present invention, the hydrothermal reaction temperature is 95 - 100 °C, specifically it can be 95 °C, 97 °C or 100 °C; the time of the hydrothermal reaction is 2 - 3 h, specifically it can be 2 h, 2.5 h or 3 h. In some embodiments of the present invention, the hydrothermal reaction is carried out under stirring conditions; the present invention has no special limitation on the specific rotation speed of the stirring, as long as it can ensure uniform mixing of the reactants. At this hydrothermal reaction temperature, calcium ions displace other metal ions (magnesium, iron and nickel) combined with silicate radicals in serpentine, and the calcium silicate formed is solid; among them, the generated magnesium hydroxide dissolves in hot water, and iron hydroxide and nickel hydroxide are further converted into iron oxide and nickel oxide, which are extracted in the subsequent magnetic separation and flotation processes.

[0034] After obtaining the hydrothermal reaction mixture, the present invention performs thermal solid-liquid separation on the hydrothermal reaction mixture to obtain a solid phase and a liquid phase.

[0035] The thermal solid-liquid separation described in the present invention means that after the hydrothermal reaction is completed, without cooling, direct solid-liquid separation is carried out, and the temperature of this solid-liquid separation is higher than room temperature to ensure that magnesium hydroxide is dissolved in the liquid phase as much as possible. In some embodiments of the present invention, the temperature during the thermal solid-liquid separation is above 40 °C, specifically it can be 40 - 90 °C, such as 50 °C, 60 °C, 70 °C, 80 °C or 90 °C. The present invention has no special limitation on the method of the thermal solid-liquid separation, and conventional solid-liquid separation methods can be used as long as the solid phase and the liquid phase can be separated. In some embodiments of the present invention, the method of the thermal solid-liquid separation is pressure filtration. In the present invention, after solid-liquid separation, the main component in the obtained liquid phase is the displaced magnesium hydroxide, and the solid phase is the remaining part of serpentine and the calcium silicate formed by the hydrothermal reaction.

[0036] In some embodiments of the present invention, after obtaining the solid phase, water with a temperature of 70 - 90 °C (specifically it can be 70 °C, 80 °C, 85 °C or 90 °C) is used to wash the solid phase, and the washed solid phase is processed in the subsequent steps, and the washing liquid obtained from the washing is incorporated into the liquid phase. When the temperature is 25 °C, the solubility product constant Ksp of magnesium hydroxide is 9.6×10 -3 , with a relatively low solubility. Above 25 °C, the dissolution rate of magnesium hydroxide increases with the increase of temperature, and above 70 °C, magnesium hydroxide is completely dissolved in the water defined in this application. The water in the above temperature range can dissolve the undissolved magnesium hydroxide in the solid phase into the water sufficiently without dissolving other substances, so as to separate magnesium hydroxide from the solid phase.

[0037] The present invention has no special limitation on the washing method and the amount of water used, as long as the magnesium hydroxide in the solid phase can be removed; in the embodiments of the present invention, the magnesium content in the washing liquid is reduced to less than 3%. In some embodiments of the present invention, the washing method is shower washing, the number of washing times is 2 - 3 times, and the amount of water used for each shower washing is 20% of the water used for mixing with the ore powder. After shower washing, the magnesium content in the residue drops to less than 3%.

[0038] After obtaining the solid phase, the present invention performs magnetic separation on the solid phase to obtain a solid rich in iron oxide and magnetic separation residue.

[0039] Those skilled in the art can select the magnetic field strength for magnetic separation according to the specific situation of the solid phase. In some embodiments of the present invention, the magnetic field strength for magnetic separation is ≥4200 mT, specifically it can be 4200 mT or 4500 mT. In the embodiments of the present invention, the above magnetic field strength can ensure the sufficient separation of iron oxide from the solid phase, and the iron oxide content in the obtained solid rich in iron oxide can reach 60 wt%.

[0040] After obtaining the magnetic separation residue, the present invention performs flotation on the magnetic separation residue to obtain a solid rich in nickel oxide and flotation residue, and the flotation residue is used as a cement raw material.

[0041] The present invention has no special limitation on the flotation method, and conventional commercially available flotation machines and their supporting flotation agents can be used. In some embodiments of the present invention, the flotation machine for flotation is an XCF type air - agitated flotation machine or a BF type mechanical - agitated flotation machine. In the embodiments of the present invention, the flotation machine and its supporting flotation agents are purchased from Shandong Xinhai Mining Technology and Equipment Co., Ltd. The above flotation conditions can fully separate nickel oxide from the magnetic separation residue.

[0042] In some embodiments of the present invention, the utilization method further includes removing the moisture in the liquid phase to obtain magnesium hydroxide.

[0043] The present invention has no special limitation on the method for removing moisture, as long as the moisture can be removed. In some embodiments of the present invention, the method for removing moisture is evaporation.

[0044] In some embodiments of the present invention, the utilization method further includes calcining the magnesium hydroxide to obtain magnesium oxide.

[0045] The present invention has no special limitation on the calcination conditions, and the conditions well - known in the art can be adopted as long as magnesium hydroxide can be decomposed into magnesium oxide.

[0046] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0047] Example 1

[0048] (1) Grind serpentine into serpentine powder with a mesh size of 150 (silicon dioxide 38.5%, magnesium oxide 39.1%, nickel oxide 0.55%, iron oxide 11.1%, others 11.55%), grind calcium oxide into calcium oxide powder with a mesh size of 50. Mix 600 kg of serpentine powder and 400 kg of calcium oxide powder to obtain a mixed ore powder. Mix the mixed ore powder with 4000 kg of water, heat it to 95 °C under stirring conditions, react for 3 h, and then directly filter the obtained reaction product (the temperature of the reaction product during filtration is 85 °C) to obtain filter residue and filtrate. Wash the filter residue 3 times with water at 70 °C, with the amount of water used for each washing being 800 kg. Detect the magnesium content in the washing liquid after each washing. The magnesium content concentration in the first washing liquid is 10%, the magnesium content concentration in the second washing liquid is 2%, and the magnesium content concentration in the third washing liquid is 0.5%. Collect the washing liquid and merge it with the filtrate to form a mixed liquid phase.

[0049] (2) Conduct magnetic separation on the washed filter residue under a magnetic field intensity of 4200 mT to obtain a solid rich in iron oxide and magnetic separation residue. Weigh the dried solid rich in iron oxide, which is 81.5 kg.

[0050] (3) Use an XCF type aerated stirring flotation machine and its supporting flotation agent to conduct flotation on the magnetic separation residue to select nickel, obtaining a solid rich in nickel oxide and flotation residue. Weigh the dried solid rich in nickel oxide, which is 64.7 kg.

[0051] (4) Naturally dry the flotation residue to obtain 548.8 kg of dried flotation residue.

[0052] (5) Evaporate the mixed liquid phase obtained in step (1) to recover the water therein, and calcine the obtained solid to obtain 305 kg of a solid rich in magnesium oxide.

[0053] Use the volumetric method to respectively test the amounts of iron oxide, nickel oxide, and magnesium oxide in the solid rich in iron oxide, the solid rich in nickel oxide, and the solid rich in magnesium oxide. The results are 60 wt%, 5 wt%, and 71 wt% respectively.

[0054] Example 2

[0055] Use the method of Example 1 to treat asbestos tailings (silicon dioxide 38.3%, magnesium oxide 39.8%, nickel oxide 0.65%, iron oxide 10.4%, others 11.85%). The process conditions are the same as those in Example 1, obtaining 75.6 kg of a solid rich in iron oxide, 77.1 kg of a solid rich in nickel oxide, 534.8 kg of dried flotation residue, and 312.5 kg of a solid rich in magnesium oxide.

[0056] The method in Example 1 was used to detect the content of metal oxides in the obtained solid, and the amounts of iron oxide, nickel oxide, and magnesium oxide in the solid rich in iron oxide, the solid rich in nickel oxide, and the solid rich in magnesium oxide were measured. The results were 60 wt%, 5 wt%, and 70 wt% in sequence.

[0057] Example 3

[0058] Serpentine (silicon dioxide 37.5%, magnesium oxide 41%, nickel oxide 0.62%, iron oxide 12.1%, others 8.78%) was processed according to the method of Example 1, and 87.8 kg of solid rich in iron oxide, 74.2 kg of solid rich in nickel oxide, 512.9 kg of flotation residue, and 325.1 kg of solid rich in magnesium oxide were obtained.

[0059] The method in Example 1 was used to detect the content of metal oxides in the obtained solid, and the amounts of iron oxide, nickel oxide, and magnesium oxide in the solid rich in iron oxide, the solid rich in nickel oxide, and the solid rich in magnesium oxide were measured. The results were 61 wt%, 4.9 wt%, and 70 wt% in sequence.

[0060] Example 4

[0061] Serpentine was processed according to the method of Example 1, except that the serpentine was ground into serpentine powder with a mesh size of 175. 81.1 kg of solid rich in iron oxide, 61.3 kg of solid rich in nickel oxide, 554.6 kg of dry flotation residue, and 303.0 kg of solid rich in magnesium oxide were obtained.

[0062] The method in Example 1 was used to detect the content of metal oxides in the obtained solid, and the amounts of iron oxide, nickel oxide, and magnesium oxide in the solid rich in iron oxide, the solid rich in nickel oxide, and the solid rich in magnesium oxide were measured. The results were 61 wt%, 5.3 wt%, and 72 wt% in sequence.

[0063] Example 5

[0064] Serpentine was processed according to the method of Example 1, except that the serpentine was ground into serpentine powder with a mesh size of 200. 80.6 kg of solid rich in iron oxide, 59.1 kg of solid rich in nickel oxide, 557.9 kg of dry flotation residue, and 302.4 kg of solid rich in magnesium oxide were obtained.

[0065] The method in Example 1 was used to detect the content of metal oxides in the obtained solid, and the amounts of iron oxide, nickel oxide, and magnesium oxide in the solid rich in iron oxide, the solid rich in nickel oxide, and the solid rich in magnesium oxide were measured. The results were 62 wt%, 5.5 wt%, and 73 wt% in sequence.

[0066] Example 6

[0067] Treat the serpentine according to the method of Example 1, except that the reaction temperature is 90 °C. 82.5 kg of a solid rich in iron oxide, 65.9 kg of a solid rich in nickel oxide, 533.9 kg of dry flotation residue, and 317.7 kg of a solid rich in magnesium oxide are obtained.

[0068] Use the method in Example 1 to detect the metal oxide content in the obtained solid, and measure the amounts of iron oxide, nickel oxide, and magnesium oxide in the solid rich in iron oxide, the solid rich in nickel oxide, and the solid rich in magnesium oxide. The results are 59 wt%, 4.9 wt%, and 68 wt% in sequence.

[0069] Example 7

[0070] Treat the serpentine according to the method of Example 1, except that the reaction temperature is 100 °C. 80.4 kg of a solid rich in iron oxide, 62.4 kg of a solid rich in nickel oxide, 555.5 kg of dry flotation residue, and 301.7 kg of a solid rich in magnesium oxide are obtained.

[0071] Use the method in Example 1 to detect the metal oxide content in the obtained solid, and measure the amounts of iron oxide, nickel oxide, and magnesium oxide in the solid rich in iron oxide, the solid rich in nickel oxide, and the solid rich in magnesium oxide. The results are 61 wt%, 5.2 wt%, and 72 wt% in sequence.

[0072] Comparative Example 1

[0073] (1) Grind the serpentine into serpentine powder with a mesh size of 150 (silicon dioxide 38.5%, magnesium oxide 39.1%, nickel oxide 0.55%, iron oxide 11.1%, others 11.55%), and grind calcium oxide into calcium oxide powder with a mesh size of 50. Mix 600 kg of serpentine powder and 400 kg of calcium oxide powder to obtain a mixed ore powder.

[0074] (2) Perform magnetic separation on the mixed ore powder under a magnetic field intensity of 4200 mT to obtain 79.7 kg of a solid rich in iron oxide and a magnetic separation residue.

[0075] (3) Use an XCF type aerated stirring flotation machine and its supporting flotation agent to perform flotation on the magnetic separation residue to select nickel, obtaining a solid rich in nickel oxide and a flotation residue. After drying the solid rich in nickel oxide, weigh it to be 68.8 kg.

[0076] (4) Mix the flotation residue with 4000 kg of water, heat it to 95 °C under stirring conditions, react for 3 h, and then directly perform hot filtration on the obtained reaction product (when filtering, the temperature of the reaction product is 85 - 90 °C) to obtain a filter residue and a filtrate. Wash the filter residue 3 times with water at 70 °C, with the amount of water used for each wash being 800 kg, and collect the washing liquid and combine it with the filtrate to form a mixed liquid phase.

[0077] (5) The filter residue was naturally dried to obtain 540.5 kg of dry filter residue.

[0078] (6) The mixed liquid phase was evaporated to recover the water therein, and the obtained solid was calcined to obtain 310.9 kg of a solid rich in magnesium oxide.

[0079] The amounts of iron oxide, nickel oxide and magnesium oxide in the solid rich in iron oxide, the solid rich in nickel oxide and the solid rich in magnesium oxide were respectively measured by volumetric method, and the results were 55 wt%, 4.3 wt% and 63 wt% in sequence.

[0080] Calculate the extraction rates of iron oxide, nickel oxide and magnesium oxide in Examples 1-6 and Comparative Example 1. The results are shown in Table 1:

[0081] Table 1 Extraction rates of iron oxide, nickel oxide and magnesium oxide in Examples 1-6 and Comparative Example 1

[0082] Example Iron Oxide / % Nickel Oxide / % Magnesium Oxide / % Example 1 73.4 98.1 92.3 Example 2 72.7 98.8 91.6 Example 3 73.8 97.7 92.5 Example 4 74.3 98.4 93.0 Example 5 75.0 98.5 94.1 Example 6 73.1 97.8 92.1 Example 7 73.6 98.3 92.6 Comparative Example 1 65.8 89.7 83.5

[0083] According to GB / T 176-2017 "Methods of Chemical Analysis of Cement" and volumetric chemical method, the chemical compositions of the dried flotation residues obtained in Examples 1-6 and the dried filter residue obtained in Comparative Example 1 were tested. The results are shown in Table 2. From the chemical compositions in Table 2, it can be seen that the main components of the dried flotation residues obtained in Examples 1-6 are all necessary components required for cement, and the contents of magnesium oxide and iron oxide are low, so they can be used as cement raw materials; the contents of magnesium oxide and iron oxide in the dried filter residue obtained in Comparative Example 1 are too high and cannot be used as cement additive raw materials.

[0084] Table 2 Chemical compositions in the dried flotation residue

[0085]

[0086]

[0087] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for utilizing serpentine, comprising the following steps: (1) Mix serpentine powder, calcium oxide powder and water and carry out hydrothermal reaction to obtain a hydrothermal reaction mixture; (2) Carry out thermal solid-liquid separation on the hydrothermal reaction mixture to obtain a solid phase and a liquid phase; (3) Carry out magnetic separation on the solid phase to obtain a solid rich in iron oxide and a magnetic separation residue; (4) Carry out flotation on the magnetic separation residue to obtain a solid rich in nickel oxide and a flotation residue, and use the flotation residue as a cement raw material.

2. The method for utilizing serpentine according to claim 1, characterized in that, The particle size of the serpentine powder is 150-200 mesh, and the particle size of the calcium oxide powder is 50 mesh.

3. The method for utilizing serpentine according to claim 1, characterized in that, The mass ratio of the serpentine powder to the calcium oxide powder is 1.3-1.7:1, and the mass ratio of the sum of the masses of the serpentine powder and the calcium oxide powder to the mass of water is 1:3.5-4.

5.

4. The utilization method of serpentine according to any one of claims 1-3, characterized in that, The temperature of the hydrothermal reaction is 95-100 °C, and the time is 2-3 h.

5. The method for utilizing serpentine according to claim 1, characterized in that, In step (2), after obtaining the solid phase, wash the solid phase with water at a temperature of 70-90 °C, carry out subsequent steps on the washed solid phase, and incorporate the washing liquid obtained from the washing into the liquid phase.

6. The method for utilizing serpentine according to claim 5, characterized in that The washing method is stirring washing or shower washing, and the number of washing times is 2-3 times.

7. The method for utilizing serpentine according to any one of claims 1 and 5-6, characterized in that, The utilization method further includes removing the water in the liquid phase to obtain magnesium hydroxide.

8. The method for utilizing serpentine according to claim 7, characterized in that, The utilization method further includes calcining the magnesium hydroxide to obtain magnesium oxide.

9. The method for utilizing serpentine according to claim 1, wherein The magnetic field intensity of the magnetic separation is ≥4200 mT.

10. The method for utilizing serpentine according to claim 1, characterized in that, The temperature of the thermal solid-liquid separation is above 40 °C.

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