An efficient magnesium reduction process for high-magnesium nickel concentrate

Abstract

The present invention relates to the technical field of hydrometallurgy, and particularly to an efficient magnesium reduction process for high-magnesium nickel concentrate. The high-magnesium nickel concentrate (400 mesh fineness) after grinding and flotation is fed into a cyclone separator for multi-stage air separation of serpentine, talc, and chlorite according to certain technical parameters. The air pressure is 0.5 - 3 Pa, and the relative concentration of air powder is 0.5 - 3%. The high-magnesium minerals in gangue minerals are separated to the maximum extent. When the magnesium content is reduced to below 8%, it can meet the smelting requirements. The present invention realizes the removal of magnesium-containing mineral impurities through multi-stage separation. The invention process is simple, the treatment cost is low, and there is no environmental pollution problem. A series of acid leaching processes are respectively carried out on the materials selected by the cyclone separator to comprehensively recover magnesium. The present invention can not only overcome the problem of magnesium reduction in the beneficiation of high-magnesium ores, but also improve the comprehensive utilization rate of ore resources, generating obvious economic and social benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrometallurgy, and particularly relates to an efficient magnesium reduction process for high-magnesium nickel concentrate. Background Art

[0002] The Jinchuan nickel mine is one of the world-famous large sulfide copper-nickel deposits with multiple metal symbiosis. The ore type of its deposit is serpentine sulfide copper-nickel ore. The mineral composition in the ore is complex: the metal minerals are mainly composed of symbiotic pyrrhotite, pentlandite, and chalcopyrite, and the gangue minerals are mainly serpentine, followed by altered minerals such as olivine, pyroxene, tremolite, mica, chlorite, and talc. During the mineralization process, magnesium is mainly contained in the gangue minerals. The Jinchuan Company uses advanced flash furnace technology for smelting, requiring that the magnesium oxide content in the concentrate does not exceed 6%, while the magnesium oxide content in the existing concentrate is above 12%. For nickel, copper sulfide ores or precious metal sulfide ores with severely altered serpentine as the main gangue, it is difficult to obtain low-magnesium high-quality concentrates that are easy to smelt only through physical beneficiation such as flotation. The problem of magnesium reduction in the beneficiation of such ores has not been broken through yet.

[0003] In view of the problems existing in the above-mentioned prior art, it is necessary to accurately separate magnesium-containing minerals from high-magnesium nickel concentrate by using cyclone dust collection technology according to the ore deposit genesis process and mineral composition properties, and then adopt processes such as acid leaching for magnesium reduction and magnesium recovery to solve the new method for the problem of magnesium reduction in the beneficiation of the above high-magnesium ores. Summary of the Invention

[0004] The purpose of the present invention is to provide an efficient magnesium reduction process for high-magnesium nickel concentrate in view of the problems existing in the prior art.

[0005] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0006] An efficient magnesium reduction process for high-magnesium nickel concentrate, characterized by comprising the following steps:

[0007] Step 1: Prepare high-magnesium nickel concentrate materials;

[0008] Step 2: Feed the high-magnesium nickel concentrate materials prepared in Step 1 into a cyclone separator after grinding and flotation to maximize the separation of high-magnesium minerals in the gangue minerals, and obtain nickel concentrate materials and high-magnesium low-nickel concentrate materials;

[0009] Step 3: Subject the high-magnesium low-nickel concentrate materials obtained in Step 2 to pre-leaching pulping, pre-leaching, and pressure filtration to obtain nickel concentrate with qualified magnesium content and filtrate containing nickel and magnesium;

[0010] Step 4: The nickel concentrate with qualified magnesium content obtained in Step 3 is flash-dried to obtain nickel concentrate materials that meet the requirements for both water content and magnesium content;

[0011] Step 5: Feed the filtrate containing nickel and magnesium obtained in Step 3 into a slurring tank for cyclic leaching;

[0012] Step 6: When the magnesium ions in the leaching solution during the cyclic leaching in Step 5 reach a certain concentration, add an appropriate amount of magnesium hydroxide to the third stage of the leaching tank to adjust the pH value, so as to promote the transfer of iron, copper, and cobalt in the solution into the concentrate. After filtration, a filter cake and a filtrate are obtained. The filter cake is sent to flash drying to obtain a nickel concentrate with qualified magnesium content, and the filtrate is a leaching solution containing nickel and magnesium;

[0013] Step 7: Selectively exchange the leaching solution containing nickel and magnesium obtained in Step 6 through a resin column to obtain a nickel solution and a magnesium solution;

[0014] Step 8: Add high-purity hydrochloric acid to the nickel solution obtained in Step 7 to prepare nickel chloride, and use ultrasonic spray drying technology (abbreviation: USP technology) to produce nickel oxide;

[0015] Step 9: Prepare anhydrous magnesium sulfate from a part of the magnesium solution obtained in Step 7 by high-temperature crystallization or spray pyrolysis;

[0016] Step 10: Use another part of the magnesium solution obtained in Step 7 to prepare magnesium hydroxide for self-use in the leaching in Step 6.

[0017] Preferably, in Step 1, the high-magnesium nickel concentrate material includes serpentine, talc, chlorite, etc.

[0018] Preferably, in Step 2, the air pressure of the cyclone separator is 0.5 - 3 Pa, and the relative air-powder concentration of the cyclone separator is 0.5 - 3%.

[0019] Preferably, in Step 2, the fineness of the high-magnesium nickel concentrate after grinding and flotation is 400 mesh.

[0020] Preferably, in Step 2, the magnesium oxide content of the nickel concentrate material is less than 8%.

[0021] Preferably, in Step 3, use a forklift to feed the high-magnesium low-nickel concentrate material obtained in Step 2 into a hopper, and then quantitatively add it to the slurring tank through a metering screw conveyor. According to a liquid-solid ratio of 3:1, add a certain amount of fresh water, sulfuric acid, and mother liquor from the magnesium sulfate process through a metering pump, and stir and mix evenly while adding. The pulp is pumped into the leaching tank through a chemical pump. The leaching system is divided into three stages for leaching, and the process is continuous leaching. The leaching process is heated with steam to maintain a certain temperature; put the qualified leaching pulp into an intermediate tank, and then transport it to two plate filters for pressure filtration by a slurry pump. The filter cake is a nickel concentrate with qualified magnesium content, and the filtrate is a solution containing nickel and magnesium.

[0022] Preferably, in Step Nine, the high-temperature crystallization is as follows: Pump a part of the magnesium solution into a crystallization tank, add sulfuric acid, adjust the pH to 4, stir and heat. When the Baume degree reaches 39-40 °Bé, add crystal seeds for crystallization. After filtering and drying magnesium sulfate monohydrate, it is metered, packaged and sold; the magnesium sulfate mother liquor is returned to leaching.

[0023] Preferably, in Step Nine, the spray pyrolysis is as follows: Let a part of the magnesium solution enter a spray drying system and be heated with natural gas, control the temperature at about 300 °C, and collect magnesium sulfate monohydrate products by cyclone; the liquid and heat after the tail gas is sprayed and absorbed enter the pulping and leaching process.

[0024] Preferably, in Step Ten, add a part of the crystallized magnesium sulfate mother liquor into a reaction tank, continuously stir, and heat up to 50-80 degrees, add liquid caustic soda, and carry out a synthesis reaction to obtain magnesium hydroxide, which is used to adjust the pH value during the leaching process to remove heavy metal ions such as copper and iron; the mother liquor for the preparation of magnesium hydroxide is a sodium sulfate solution, which is discharged or crystallized to produce mirabilite;

[0025] Main reaction chemical equations:

[0026] (1). MgO + H2SO4 = MgSO4 + H2O

[0027] (2). MgSO4 + 2NaOH = Mg(OH)2 + Na2SO4.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. The present invention feeds the high-magnesium nickel concentrate (400 mesh fineness) after grinding and flotation into a cyclone separator for multi-stage air separation of serpentine, talc, and chlorite according to certain technical parameters. The air pressure is 0.5-3 Pa, and the relative concentration of air powder is 0.5-3%. The high-magnesium minerals in the gangue minerals are separated to the greatest extent, and when it is reduced to less than 8%, it can meet the smelting requirements.

[0030] 2. The present invention undergoes multi-stage separation to remove magnesium-containing mineral impurities. The invention process is simple, the treatment cost is low, and there is no environmental pollution problem. A series of acid leaching processes are carried out on the materials selected by the cyclone separator to comprehensively recover magnesium.

[0031] 3. The present invention can not only overcome the problem of reducing magnesium in the beneficiation of high-magnesium ores, but also improve the comprehensive utilization rate of ore resources, generating obvious economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the process flow diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] Example 1

[0035] Prepare a high-magnesium nickel concentrate material. After grinding and flotation, the high-magnesium nickel concentrate material is fed into a cyclone separator according to certain technical parameters, and serpentine, talc, and chlorite are subjected to multi-stage air separation to maximize the separation of high-magnesium minerals in gangue minerals, and the magnesium oxide content is reduced to less than 8%.

[0036] Main equipment process parameters of the cyclone separator: the wind pressure is 0.5 - 3 Pa, the relative concentration of air and powder is 0.5 - 3%; the fineness of the high-magnesium nickel concentrate after grinding and flotation is 400 mesh.

[0037] Example 2

[0038] Acid leaching and magnesium recovery process

[0039] 1) The nickel concentrate separated by the cyclone separator is fed into a hopper by a forklift, and then quantitatively added to a pulping tank through a metering screw conveyor. According to a liquid-solid ratio of 3:1, a certain amount of fresh water, sulfuric acid, and mother liquor from the magnesium sulfate process are added through a metering pump, and stirred and mixed evenly while adding. The pulp is pumped into a leaching tank by a chemical pump. The leaching system is divided into three stages of leaching, and the process is continuous leaching. The leaching process is heated by steam to maintain a certain temperature; the qualified pulp after leaching is put into an intermediate tank, and then transported to two filter presses by a slurry pump for filtration. The filter cake is a nickel concentrate with qualified magnesium content. The nickel concentrate with qualified magnesium content is then flash-dried to meet the requirements of the nickel smelter concentrate for furnace charging in terms of both water content and magnesium content; the filtrate is a solution containing nickel and magnesium, which is sent back to the pulping tank for circulating leaching. When the magnesium content in the leaching solution reaches a certain level, it is sent to the next process for nickel-magnesium separation;

[0040] 2) Purification of the leaching solution

[0041] When the magnesium ions in the leaching solution reach a certain concentration during the circulating leaching, an appropriate amount of magnesium hydroxide is added to the third stage of the leaching tank to adjust the pH value, so as to promote the transfer of iron, copper, and cobalt in the solution into the concentrate. After filtration, the filter cake is sent to flash drying, and the filtrate is sent to resin exchange for nickel extraction;

[0042] 3) Nickel-magnesium separation

[0043] The leaching solution containing nickel and magnesium is selectively exchanged through a resin column respectively to produce a nickel solution and a magnesium solution. The nickel solution enters the nickel solution to prepare nickel chloride by adding high-purity hydrochloric acid, and nickel oxide is produced by using ultrasonic spray drying technology (abbreviated as USP technology). Part of the exchanged solution (magnesium solution) is used to prepare magnesium hydroxide (for self-use in leaching), and the other part is used to prepare anhydrous magnesium sulfate by high-temperature crystallization or spray pyrolysis.

[0044] Example 3

[0045] Preparation of intermediate product magnesium hydroxide

[0046] Part of the crystallized magnesium sulfate mother liquor is added to the reaction tank, continuously stirred, and heated to 50 - 80 °C. Then caustic soda is added for synthesis reaction. The obtained magnesium hydroxide is used to adjust the pH value during the leaching process to remove heavy metal ions such as copper and iron. The mother liquor for preparing magnesium hydroxide is sodium sulfate solution, which is discharged or crystallized to produce mirabilite.

[0047] Main reaction chemical equations:

[0048] (1) MgO + H2SO4 = MgSO4 + H2O

[0049] (2) MgSO4 + 2NaOH = Mg(OH)2 + Na2SO4

[0050] Example 4

[0051] Magnesium product preparation process

[0052] (1) High - temperature crystallization

[0053] Part of the post - exchange liquid (magnesium solution) is pumped into the crystallization tank by a pump, sulfuric acid is added to adjust the pH = 4, stirred and heated. When the Baume degree reaches 39 - 40 °Bé, crystal seeds are added for crystallization. After the monohydrate magnesium sulfate is filtered and dried, it is metered, packaged and sold; the mother liquor is returned to the leaching process.

[0054] (2) Spray crystallization

[0055] Another part of the post - exchange liquid (magnesium solution) enters the spray drying system and is heated by natural gas, controlling the temperature at about 300 °C. The monohydrate magnesium sulfate product is collected by a cyclone. The liquid and heat after the tail gas is spray - absorbed enter the pulping and leaching process.

[0056] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An efficient magnesium reduction process for high-magnesium nickel concentrate, characterized in that, It includes the following steps: Step 1: Prepare high-magnesium nickel concentrate materials; the high-magnesium nickel concentrate materials include serpentine, talc, and chlorite; Step 2: Feed the high-magnesium nickel concentrate materials prepared in Step 1 into a cyclone separator after grinding and flotation to maximize the separation of high-magnesium minerals in gangue minerals, obtaining nickel concentrate materials and high-magnesium low-nickel concentrate materials; the fineness of the high-magnesium nickel concentrate after grinding and flotation is 400 mesh; the air pressure of the cyclone separator is 0.5 - 3 Pa, and the relative concentration of air powder in the cyclone separator is 0.5 - 3%; the magnesium oxide content of the nickel concentrate materials is less than 8%; Step 3: Subject the high-magnesium low-nickel concentrate materials obtained in Step 2 to pre-impregnation pulping, pre-impregnation, and pressure filtration to obtain nickel concentrate with qualified magnesium content and filtrate containing nickel and magnesium; specifically, use a forklift to feed the high-magnesium low-nickel concentrate materials obtained in Step 2 into a hopper, and then quantitatively add them to a pulping tank through a metering screw conveyor. According to a liquid-solid ratio of 3:1, add a certain amount of fresh water, sulfuric acid, and mother liquor from the magnesium sulfate process through a metering pump, and stir and mix evenly while adding. The pulp is pumped into a leaching tank by a chemical pump. The leaching system is divided into three stages of leaching, and the process is continuous leaching. The leaching process is heated by steam to maintain a certain temperature; put the qualified leached pulp into an intermediate tank, and then transport it to two plate filters for pressure filtration by a slurry pump. The filter cake is nickel concentrate with qualified magnesium content, and the filtrate is a solution containing nickel and magnesium; Step 4: The nickel concentrate with qualified magnesium content obtained in Step 3 is nickel concentrate materials that meet the requirements of both water content and magnesium content after flash drying; Step 5: Feed the filtrate containing nickel and magnesium obtained in Step 3 into the pulping tank for cyclic leaching; Step 6: When the magnesium ions in the leaching solution during cyclic leaching in Step 5 reach a certain concentration, add an appropriate amount of magnesium hydroxide to the third stage of the leaching tank to adjust the pH value, prompting iron, copper, and cobalt in the solution to transfer into the concentrate. After filtration, obtain a filter cake and a filtrate. The filter cake is sent for flash drying to obtain nickel concentrate with qualified magnesium content, and the filtrate is a leaching solution containing nickel and magnesium; Step 7: Selectively exchange the leaching solution containing nickel and magnesium obtained in Step 6 through a resin column to obtain a nickel solution and a magnesium solution; Step 8: Add high-purity hydrochloric acid to the nickel solution obtained in Step 7 to prepare nickel chloride, and use ultrasonic spray drying technology to produce nickel oxide; Step 9: Prepare anhydrous magnesium sulfate from a part of the magnesium solution obtained in Step 7 through high-temperature crystallization or spray pyrolysis; Step 10: Use another part of the magnesium solution obtained in Step 7 to prepare magnesium hydroxide for self-use in the leaching in Step 6.

2. The efficient magnesium reduction process for high-magnesium nickel concentrate according to claim 1, characterized in that: In Step 9, the high-temperature crystallization is as follows: Pump a part of the magnesium solution into a crystallization tank, add sulfuric acid, adjust the PH = 4, stir and heat. When the Baume degree reaches 39 - 40 °Bé, add crystal seeds for crystallization. After filtering and drying monohydrate magnesium sulfate, it is measured, packaged, and sold; the magnesium sulfate mother liquor is returned to leaching.

3. The efficient magnesium reduction process for high-magnesium nickel concentrate according to claim 1, characterized in that: In Step 9, the spray pyrolysis is as follows: A part of the magnesium solution enters a spray drying system and is heated by natural gas, controlling the temperature at about 300 °C, and the monohydrate magnesium sulfate product is collected by a cyclone; the liquid and heat after the tail gas is sprayed and absorbed enter the pulping and leaching process.

4. The efficient magnesium reduction process for high-magnesium nickel concentrate according to claim 1, characterized in that: In step ten, part of the partially crystallized magnesium sulfate mother liquor is added to the reaction tank, continuously stirred, heated to 50 - 80 °C, and liquid alkali is added for synthesis reaction. The obtained magnesium hydroxide is used to adjust the pH value during the leaching process to remove heavy metal ions such as copper and iron. The mother liquor for the preparation of magnesium hydroxide is sodium sulfate solution, which is discharged or crystallized to produce mirabilite. Main reaction chemical equation: (1). MgO + H2SO4 = MgSO4 + H2O (2), MgSO4 + 2NaOH = Mg(OH)2 + Na2SO 4。

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