Method for high-efficiency impurity removal and purification of high-calcium high-magnesium rhodochrosite

Abstract

The application discloses a method for efficiently removing impurities and purifying high-calcium and high-magnesium rhodochrosite, and belongs to the technical field of mineral processing. The method comprises the following steps: removing calcium and magnesium impurities by X-ray intelligent sorting and magnetic separation; then, converting the rhodochrosite into chlorinated manganese by a chlorination mineral phase conversion process, and then placing the chlorinated manganese in deionized water for leaching; adding manganese sulfate solution to promote the formation of calcium ion precipitation and remove calcium impurities in the solution; meanwhile, adding ammonium fluoride solution to further remove magnesium ion impurities; adding a precipitant to the obtained leaching solution of the chlorinated manganese, and after reaction, performing precipitation, washing and drying to obtain high-purity rhodochrosite. The method realizes efficient and deep removal of impurities and purification of high-calcium and high-magnesium rhodochrosite, realizes efficient recycling of resources, reduces the overall cost and environmental impact of the process, is suitable for large-scale continuous production, and is convenient for industrialization and popularization.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a method for efficient removal and purification of high-calcium and high-magnesium rhodochrosite. Background Technology

[0002] Electrolytic manganese is an important metallic material widely used in steel manufacturing, alloys, chemical products, and batteries. In the production of electrolytic manganese, rhodochrosite, due to its high manganese content and good solubility, is one of the main raw materials. However, the high calcium and magnesium content in rhodochrosite significantly affects production efficiency. These impurities, along with manganese ions, enter the electrolyte, reducing the effective concentration of manganese and leading to a decrease in reduction efficiency and metal yield. Furthermore, in acidic environments, calcium and magnesium may form insoluble salts (such as calcium sulfate and magnesium sulfate), forming precipitates, increasing the difficulty of solid-liquid separation, and even clogging the electrolytic cell. These problems restrict the production efficiency and quality of electrolytic manganese products. Therefore, controlling the calcium and magnesium content is crucial.

[0003] Extensive research has been conducted on the purification of rhodochrosite. Patent CN104928469A discloses a method for removing magnesium from rhodochrosite by leaching with sulfuric acid, significantly reducing the magnesium content using concentrated sulfuric acid. However, concentrated sulfuric acid is highly corrosive to equipment during the leaching process, and rhodochrosite typically contains high concentrations of calcium ions, so this method fails to effectively address the calcium removal problem. Patent CN101985365A proposes a method for preparing manganese carbonate, adjusting the pH of an acidic manganese solution to 7-8 using ammonia water, followed by the introduction of carbon dioxide, thereby obtaining manganese carbonate with lower impurity content. However, while this method effectively reduces the sodium content, other impurities remain high, resulting in limited purification efficiency.

[0004] In response to sustainable development policies, improving the purity of rhodochrosite to reduce waste generated during the production of electrolytic manganese is an effective way to achieve green production. Therefore, developing a deep impurity removal process for rhodochrosite that can efficiently remove impurities such as calcium and magnesium is particularly important. To address this issue, this invention proposes a highly efficient impurity removal and purification method suitable for high-calcium and high-magnesium rhodochrosite. Summary of the Invention

[0005] The primary objective of this invention is to provide a method for pre-deep impurity removal from rhodochrosite, which aims to improve the manganese leaching rate in subsequent leaching operations and ultimately produce high-quality manganese concentrate.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for efficient removal and purification of high-calcium, high-magnesium rhodochrosite includes the following steps:

[0008] Coarse crushing: crush rhodochrosite to a particle size ≤140mm;

[0009] Intelligent pre-selection: The crushed products are pre-selected by an X-ray intelligent separator to obtain intelligent pre-selected concentrate and pre-selected tailings;

[0010] Fine crushing and grinding: The intelligent pre-selection concentrate is crushed and ground to a particle size ≤0.2mm to obtain the crushed and ground product, wherein the -0.074mm mineral powder in the crushed and ground product accounts for ≥60% of the total mass of the X-ray intelligent pre-selection concentrate;

[0011] Magnetic separation: The crushed and ground products are subjected to magnetic separation to obtain magnetic manganese concentrate and magnetic tailings;

[0012] Chlorinated mineral phase conversion: After drying, the magnetically separated manganese concentrate is conveyed to the mixing bin by a conveyor belt. Ammonium chloride is added to mix the material evenly, and then it is conveyed into the mineral phase conversion furnace for chlorinated mineral phase conversion.

[0013] Cooling: The material discharged from the mineral phase conversion furnace is cooled once by a multi-stage cooling cyclone. During the first cooling process, the material exchanges heat with the protective gas, and the temperature is reduced to below 150°C. The product after the first cooling is fed into a fluidized bed cooler for a second cooling. The temperature of the product after the second cooling is reduced to below 60°C, and the chloride mineral phase conversion product after the second cooling is obtained.

[0014] Leaching: The chloride mineral phase conversion product after secondary cooling is subjected to leaching operation. The leaching product is filtered by pressure to obtain leachate and leaching residue.

[0015] Purification and impurity removal: Add manganese sulfate solution to the leachate to form calcium sulfate precipitate, and then perform solid-liquid separation; add ammonium fluoride solution to the liquid obtained from solid-liquid separation, stir and let stand, and then perform solid-liquid separation to remove calcium and magnesium impurities to a deeper level, and obtain manganese chloride purified solution.

[0016] Preparation of high-purity rhodochrosite: Add ammonium bicarbonate solution to manganese chloride purification solution and let it stand to allow the reaction to occur fully. After filtration, washing and drying, high-purity rhodochrosite is obtained.

[0017] Furthermore, the composition of the rhodochrosite, by mass percentage, includes: Mn 23.00wt% to 33.50wt%, SiO2 12.00wt% to 28.50wt%, MgO 3.00wt% to 12.00wt%, and CaO 4.00wt% to 13.00wt%.

[0018] Furthermore, during the intelligent pre-selection process, the width of the conveyor belt of the X-ray intelligent sorting machine is 1.2m to 2m, and the conveyor belt speed is 2m / s to 4m / s.

[0019] Furthermore, pre-selected tailings and magnetically separated tailings are tailings that are pre-discarded.

[0020] Furthermore, the magnetic field strength during the magnetic separation process is 8000 Oe to 16000 Oe.

[0021] Furthermore, the mass ratio of ammonium chloride to rhodochrosite added during the chlorination phase transformation process is (0.5:1) to (1.5:1), the chlorination phase transformation temperature is 400℃ to 700℃, the chlorination phase transformation time is 10 min to 40 min, and nitrogen is used as a protective gas during the chlorination phase transformation process.

[0022] Furthermore, the chemical reactions that occur during the chloride mineral phase transformation process include:

[0023]

[0024] Furthermore, during the leaching process, deionized water is used to leach the chloride mineral phase conversion product after secondary cooling. The leaching temperature is 25℃~60℃, the leaching time is 0.5h~1.5h, and the leaching liquid-to-solid ratio is 3mL / g~10mL / g.

[0025] Furthermore, during purification and impurity removal, the molar ratio of the added manganese sulfate to calcium ions in the leachate is n(Ca). 2+ The ratio of manganese sulfate solution to magnesium ions in the leachate is 1:(1.0–2.0), with a concentration of 0.5 mol / L to 1.5 mol / L. The molar ratio of added ammonium fluoride to magnesium ions in the leachate is n(Mg). 2+ ):n(NH4F)=1:(1.5~3.0), and the concentration of ammonium fluoride solution is 0.2mol / L~1.2mol / L.

[0026] Furthermore, in the preparation of high-purity rhodochrosite, the concentration of NH3HCO3 is 1 mol / L to 2 mol / L, the pH of the solution is 6.6 to 7.3, and the reaction time is 0.8 h to 1.2 h.

[0027] Furthermore, the chemical reactions that occur during the preparation of high-purity rhodochrosite include:

[0028]

[0029] This invention provides a method for efficient removal and purification of high-calcium and high-magnesium rhodochrosite. The key principle and technical points are: the core technology of this invention is to efficiently remove calcium and magnesium impurities from rhodochrosite through a chemical process, thereby preparing high-purity rhodochrosite. First, X-ray intelligent sorting technology is used to pre-select ores with lower calcium and magnesium content, improving the efficiency of subsequent processing. Before the chloride phase conversion, calcium and magnesium impurities are removed a second time through magnetic separation. After the rhodochrosite is converted to manganese chloride through the chloride phase conversion process, it is leached in deionized water. In the subsequent leaching process, manganese sulfate solution is added to promote the precipitation of calcium ions, removing calcium impurities from the solution. Simultaneously, ammonium fluoride solution is added to effectively remove magnesium ion impurities, ultimately obtaining a purified manganese chloride solution. Finally, NH4HCO3, a precipitant, is added to the manganese chloride leaching solution to promote the precipitation of Mn. 2+ With CO3 2- Ionic reactions form manganese carbonate particles. This invention, through precise control of the solution reaction conditions, relies on the solubility product of manganese carbonate to achieve the desired Mn content. 2+ and CO3 2- After the crystal nucleus is formed, ions continuously precipitate onto the surface of the crystal nucleus through diffusion, eventually forming high-purity rhodochrosite.

[0030] Compared with existing electrolytic manganese waste residue treatment processes, the features and advantages of this invention are as follows:

[0031] 1. This invention achieves efficient and deep purification of high-calcium and high-magnesium rhodochrosite, obtaining high-purity rhodochrosite products with significantly improved manganese grade and remarkable calcium and magnesium removal effects.

[0032] 2. In this invention, the CO2, NH3, and HCl tail gases generated during the chloride mineral phase conversion process can all be recovered and reused. Specifically, NH3 and CO2 can be used to supplement ammonium bicarbonate, NH4Cl can be used as an additive in the chloride mineral phase conversion, and HCl can be recovered to prepare industrial hydrochloric acid, achieving efficient resource recycling and reducing the overall process cost and environmental impact.

[0033] 3. The method for efficient removal and purification of high-calcium and high-magnesium rhodochrosite proposed in this invention has a simple process, smooth connection, and relatively mature related technologies. It is suitable for large-scale continuous production and easy to promote industrialization. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the process for efficient impurity removal and purification of high-calcium and high-magnesium rhodochrosite according to the present invention. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; the reagents and materials described are commercially available unless otherwise specified; and the preferred embodiments described are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0036] The high-calcium, high-magnesium rhodochrosite used in this invention comprises, by mass percentage, Mn 23.00wt%–33.50wt%, SiO2 12.00wt%–28.50wt%, MgO 3.00wt%–12.00wt%, and CaO 4.00wt%–13.00wt%.

[0037] In the method provided by this invention, during the chlorination phase transformation process, the mass ratio of ammonium chloride to rhodochrosite is (0.5:1) to (1.5:1); the chlorination phase transformation temperature is 400℃ to 700℃, and the time is 10 min to 40 min. Nitrogen gas is used as a protective gas during the chlorination phase transformation process. The tail gas generated by the reaction contains CO2, NH3, and HCl, which can be recovered. The NH3 and CO2 are passed into the manganese chloride solution in the process of preparing high-purity rhodochrosite, thereby reducing the amount of NH3HCO3 used; the recovered HCl is used to prepare industrial hydrochloric acid.

[0038] In the efficient method for removing impurities and purifying high-calcium and high-magnesium rhodochrosite provided by this invention, the X-ray intelligent sorting machine is used with a conveyor belt width of 1.2m to 2m and a conveyor belt speed of 2m / s to 4m / s.

[0039] In the efficient method for removing impurities and purifying high-calcium and high-magnesium rhodochrosite provided by this invention, the pre-selected tailings and magnetic separation tailings are combined into pre-discharged tailings.

[0040] This invention uses deionized water to leach the chloride mineral phase conversion product after secondary cooling. The leaching temperature is 25℃~60℃, the leaching time is 0.5h~1.5h, and the leaching liquid-to-solid ratio is 3mL / g~10mL / g.

[0041] In the efficient purification and depurification method for high-calcium and high-magnesium rhodochrosite provided by this invention, the amount of manganese sulfate solution added during the purification process is n(Ca 2+ The concentration of the ammonium fluoride solution is 0.5 mol / L to 1.5 mol / L, with a ratio of n(MnSO4) = 1:(1.0–2.0). 2+ ):n(NH4F)=1:(1.5~3.0), with a concentration of 0.2mol / L~1.2mol / L.

[0042] Example 1:

[0043] A highly efficient method for removing impurities and purifying high-calcium, high-magnesium rhodochrosite, such as... Figure 1 As shown, it includes the following steps:

[0044] In this embodiment, the rhodochrosite comes from the Akto-Wuqia region of Xinjiang, with a Mn content of 28.87 wt%, a SiO2 content of 16.39 wt%, a MgO content of 5.14 wt%, and a CaO content of 6.64 wt%.

[0045] Coarse crushing: Rhodochrosite is fed into a coarse crusher to be crushed to obtain crushed products with a particle size of less than 100mm.

[0046] Intelligent pre-selection: The crushed products are pre-selected by an X-ray intelligent separator to obtain intelligent pre-selected concentrate and pre-selected tailings.

[0047] Fine crushing and grinding: The intelligent pre-selected concentrate is crushed and ground to a particle size of less than 0.2 mm, of which -0.074 mm mineral powder accounts for 60% of the total mass.

[0048] Magnetic separation: The crushed sample is fed into a vertical ring high-intensity magnetic separator with a magnetic field strength of 13000 Oe to obtain magnetic concentrate and magnetic tailings. The magnetic tailings and pre-selected tailings are combined into pre-discharged tailings.

[0049] Chlorination-induced mineral phase conversion: After drying, the magnetically separated concentrate is conveyed to a mixing silo via a conveyor belt, where ammonium chloride is added to mix it with rhodochrosite at a mass ratio of 0.8:1. It is then conveyed into a mineral phase conversion furnace for chlorination-induced mineral phase conversion. The temperature inside the furnace is maintained at 450℃, and the roasting time is 20 minutes, allowing the rhodochrosite and ammonium chloride to react fully under a nitrogen protective atmosphere. The HCl produced during the reaction is collected through a gas recovery device and used to prepare industrial hydrochloric acid. CO2 and NH3 gases are introduced into the manganese chloride solution described in step 9, thereby reducing the amount of NH4HCO3 used.

[0050] Cooling: The material discharged from the mineral phase conversion furnace undergoes primary cooling through a multi-stage cooling cyclone separator. The material exchanges heat with the protective gas, reducing its temperature to below 150°C. The product after primary cooling is fed into a fluidized bed cooler, where its temperature is further reduced to below 60°C, yielding the chloride mineral phase conversion product.

[0051] Leaching: The cooled chloride mineral phase conversion product was leached in water at a temperature of 30°C for 0.6 h and a liquid-to-solid ratio of 4 mL / g. The leached product was then filtered by pressure to obtain leachate and leaching residue.

[0052] Purification and impurity removal: Add a 0.8 mol / L manganese sulfate solution to the leachate, according to the calcium ion concentration (Ca). 2+Manganese sulfate was added at a molar ratio of 1:1.5 to manganese sulfate (MnSO4). The pH was adjusted to 5.5 with ammonia water, and the solution temperature was maintained at 35°C, resulting in the formation of calcium sulfate precipitate, which was then separated into solid and liquid components. A 0.6 mol / L ammonium fluoride solution was added to the separated liquid, according to the magnesium ion concentration (Mg... 2+ Ammonium fluoride (NH4F) was added at a molar ratio of 1:2. After stirring for 1 hour and standing for 1 hour, solid-liquid separation was performed to remove calcium and magnesium impurities.

[0053] Preparation of high-purity rhodochrosite: A 1.2 mol / L ammonium bicarbonate solution was added to the manganese chloride purification solution, the pH of the solution was adjusted to 6.8, and the solution was allowed to stand for 0.8 hours to allow for complete reaction. After filtration, washing, and drying, a high-purity rhodochrosite product with a Mn content of 45.10%, SiO2 content of 0.02%, CaO content of 0.08%, and MgO content of 0.06% was finally obtained.

[0054] Example 2:

[0055] The rhodochrosite used in this embodiment has a Mn content of 30.12 wt%, a SiO2 content of 12.78 wt%, a MgO content of 6.66 wt%, and a CaO content of 5.10 wt%.

[0056] Coarse crushing: Rhodochrosite is fed into a coarse crusher to be crushed to obtain crushed products with a particle size of less than 100mm.

[0057] X-ray intelligent pre-selection: The crushed products are pre-selected by an X-ray intelligent separator to obtain intelligent pre-selected concentrate and pre-selected tailings.

[0058] Fine crushing and grinding: The intelligent pre-selected concentrate is crushed and ground to a particle size of less than 0.2 mm, of which -0.074 mm mineral powder accounts for 65% of the total mass.

[0059] Magnetic separation: The crushed sample is fed into a vertical ring high-intensity magnetic separator with a magnetic field strength of 14000 Oe to obtain magnetic concentrate and magnetic tailings. The magnetic tailings and pre-selected tailings are combined into pre-discharged tailings.

[0060] Chlorination-induced mineral phase conversion: After drying, the magnetically separated concentrate is conveyed to a mixing silo via a conveyor belt, where ammonium chloride is added to mix it with rhodochrosite at a mass ratio of 0.9:1. It is then conveyed into a mineral phase conversion furnace for chlorination-induced mineral phase conversion. The temperature inside the furnace is maintained at 480℃, and the roasting time is 30 minutes to ensure complete reaction between the rhodochrosite and ammonium chloride. The HCl produced during the reaction is collected by a gas recovery device and used to prepare industrial hydrochloric acid. CO2 and NH3 gases are introduced into the manganese chloride solution described in step 9, thereby reducing the amount of NH4HCO3 used.

[0061] Cooling: The material discharged from the mineral phase conversion furnace undergoes primary cooling through a multi-stage cooling cyclone separator. The material exchanges heat with the protective gas, reducing its temperature to below 150°C. The product after primary cooling is fed into a fluidized bed cooler, where its temperature is further reduced to below 60°C, yielding the chloride mineral phase conversion product.

[0062] Leaching: The cooled chloride mineral phase conversion product was leached in water at a temperature of 35°C for 0.6 h and a liquid-to-solid ratio of 4 mL / g. The leached product was then filtered by pressure to obtain leachate and leaching residue.

[0063] Purification and impurity removal: Add a 0.7 mol / L manganese sulfate solution to the leachate, according to the calcium ion concentration (Ca). 2+ Manganese sulfate was added at a molar ratio of 1:1.6 to manganese sulfate (MnSO4). The pH was adjusted to 5.7 with ammonia and the solution temperature was maintained at 35°C, resulting in the formation of calcium sulfate precipitate, which was then separated into solid and liquid components. A 0.8 mol / L ammonium fluoride solution was added to the separated liquid, according to the magnesium ion concentration (Mg... 2+ Ammonium fluoride (NH4F) was added at a molar ratio of 1:2. After stirring for 1 hour and standing for 1 hour, solid-liquid separation was performed to remove calcium and magnesium impurities.

[0064] Preparation of high-purity rhodochrosite: A 1.2 mol / L ammonium bicarbonate solution was added to the manganese chloride purification solution, the pH of the solution was adjusted to 6.7, and the solution was allowed to stand for 0.9 h to allow for complete reaction. After filtration, washing, and drying, a high-purity rhodochrosite product with a Mn content of 45.69%, SiO2 content of 0.01%, CaO content of 0.05%, and MgO content of 0.07% was finally obtained.

[0065] Example 3:

[0066] The rhodochrosite used in this embodiment has a Mn content of 29.38 wt%, a SiO2 content of 14.16 wt%, a MgO content of 5.32 wt%, and a CaO content of 6.27 wt%.

[0067] Coarse crushing: Rhodochrosite is fed into a coarse crusher to be crushed to obtain crushed products with a particle size of less than 100mm.

[0068] Intelligent sorting: The crushed products are pre-sorted by an X-ray intelligent separator to obtain intelligent pre-sorted concentrate and pre-sorted tailings.

[0069] Fine crushing and grinding: The intelligent pre-selected concentrate is crushed and ground to a particle size of less than 0.2 mm, of which -0.074 mm mineral powder accounts for 65% of the total mass.

[0070] Magnetic separation: The crushed sample is fed into a vertical ring high-intensity magnetic separator with a magnetic field strength of 14000 Oe to obtain magnetic concentrate and magnetic tailings. The magnetic tailings and pre-selected tailings are combined into pre-discharged tailings.

[0071] Chlorination-induced mineral phase conversion: After drying, the magnetically separated concentrate is conveyed to a mixing silo via a conveyor belt, where ammonium chloride is added to mix it with rhodochrosite at a mass ratio of 1:1. It is then conveyed into a mineral phase conversion furnace for chlorination-induced mineral phase conversion. The temperature inside the stabilizing mineral phase conversion furnace is 500℃, and the roasting time is 35 minutes to ensure complete reaction between the rhodochrosite and ammonium chloride. The HCl produced during the reaction is collected by a gas recovery device and used to prepare industrial hydrochloric acid. CO2 and NH3 gases are introduced into the manganese chloride solution described in step 9, thereby reducing the amount of NH4HCO3 used.

[0072] Cooling: The material discharged from the mineral phase conversion furnace undergoes primary cooling through a multi-stage cooling cyclone separator. The material exchanges heat with the protective gas, reducing its temperature to below 150°C. The product after primary cooling is fed into a fluidized bed cooler, where its temperature is further reduced to below 60°C, yielding the chloride mineral phase conversion product.

[0073] Leaching: The cooled chloride mineral phase conversion product was leached in water at a temperature of 30°C for 1 hour and a liquid-to-solid ratio of 6 mL / g. The leached product was then filtered by pressure to obtain leachate and leaching residue.

[0074] Purification and impurity removal: Add a 1.0 mol / L manganese sulfate solution to the leachate, according to the calcium ion concentration (Ca). 2+ Manganese sulfate was added at a molar ratio of 1:1.8 to manganese sulfate (MnSO4). The pH was adjusted to 5.7 with ammonia water, and the solution temperature was maintained at 45°C, resulting in the formation of calcium sulfate precipitate, which was then separated into solid and liquid components. A 1.0 mol / L ammonium fluoride solution was added to the separated liquid, according to the magnesium ion concentration (Mg... 2+ Ammonium fluoride (NH4F) was added at a molar ratio of 1:2.5. After stirring for 1 hour and standing for 1 hour, solid-liquid separation was performed to remove calcium and magnesium impurities.

[0075] Preparation of high-purity rhodochrosite: A 1 mol / L ammonium bicarbonate solution was added to the manganese chloride purification solution, the pH of the solution was adjusted to 7.0, and the solution was allowed to stand for 1.0 h to allow the reaction to proceed fully. After filtration, washing, and drying, a high-purity rhodochrosite product with a Mn content of 45.57%, SiO2 content of 0.02%, CaO content of 0.05%, and MgO content of 0.04% was finally obtained.

[0076] Example 4:

[0077] The rhodochrosite used in this embodiment has a Mn content of 33.59 wt%, a SiO2 content of 12.37 wt%, a MgO content of 4.77 wt%, and a CaO content of 5.55 wt%.

[0078] Coarse crushing: Rhodochrosite is fed into a coarse crusher to be crushed to obtain crushed products with a particle size of less than 100mm.

[0079] Intelligent pre-selection: The crushed products are pre-selected by an X-ray intelligent separator to obtain intelligent pre-selected concentrate and pre-selected tailings.

[0080] Fine crushing and grinding: The intelligent pre-selected concentrate is crushed and ground to a particle size of less than 0.2 mm, of which -0.074 mm mineral powder accounts for 65% of the total mass.

[0081] Magnetic separation: The crushed sample is fed into a vertical ring high-intensity magnetic separator with a magnetic field strength of 14000 Oe to obtain magnetic concentrate and magnetic tailings. The magnetic tailings and pre-selected tailings are combined into pre-discharged tailings.

[0082] Chlorination-induced mineral phase conversion: After drying, the magnetically separated concentrate is conveyed to a mixing silo via a conveyor belt, where ammonium chloride is added to mix it with rhodochrosite at a mass ratio of 1.1:1. It is then conveyed into a mineral phase conversion furnace for chlorination-induced mineral phase conversion. The temperature inside the stabilizing mineral phase conversion furnace is 500℃, and the roasting time is 35 minutes to ensure complete reaction between the rhodochrosite and ammonium chloride. The HCl produced during the reaction is collected by a gas recovery device and used to prepare industrial hydrochloric acid. CO2 and NH3 gases are introduced into the manganese chloride solution described in step 9, thereby reducing the amount of NH4HCO3 used.

[0083] Cooling: The material discharged from the mineral phase conversion furnace undergoes primary cooling through a multi-stage cooling cyclone separator. The material exchanges heat with the protective gas, reducing its temperature to below 150°C. The product after primary cooling is fed into a fluidized bed cooler, where its temperature is further reduced to below 60°C, yielding the chloride mineral phase conversion product.

[0084] Leaching: The cooled chloride mineral phase conversion product was leached in water at a temperature of 60℃ for 1.4 h and a liquid-to-solid ratio of 9 mL / g. The leached product was then filtered by pressure to obtain leachate and leaching residue.

[0085] Purification and impurity removal: Add a 1.0 mol / L manganese sulfate solution to the leachate, according to the calcium ion concentration (Ca). 2+ Manganese sulfate was added at a molar ratio of 1:2.0 to manganese sulfate (MnSO4). The pH was adjusted to 5.7 with ammonia water, and the solution temperature was maintained at 45℃, resulting in the formation of calcium sulfate precipitate, which was then separated into solid and liquid components. A 1.0 mol / L ammonium fluoride solution was added to the separated liquid, according to the magnesium ion concentration (Mg... 2+Ammonium fluoride (NH4F) was added at a molar ratio of 1:2.8. After stirring for 1 hour and letting stand for 1 hour, solid-liquid separation was performed to remove calcium and magnesium impurities.

[0086] Preparation of high-purity rhodochrosite: A 1 mol / L ammonium bicarbonate solution was added to the manganese chloride purification solution, the pH of the solution was adjusted to 7.2, and the solution was allowed to stand for 1.2 hours to allow for complete reaction. After filtration, washing, and drying, a high-purity rhodochrosite product with a Mn content of 45.93%, SiO2 content of 0.01%, CaO content of 0.02%, and MgO content of 0.02% was finally obtained.

Claims

1. A method for efficient removal and purification of high-calcium, high-magnesium rhodochrosite, characterized in that, Includes the following steps: Coarse crushing: crush rhodochrosite to a particle size ≤140mm; Intelligent pre-selection: The crushed products are pre-selected by an X-ray intelligent separator to obtain intelligent pre-selected concentrate and pre-selected tailings; Fine crushing and grinding: The X-ray intelligent pre-selection concentrate is crushed and ground to a particle size ≤0.2mm to obtain the crushed and ground product; Magnetic separation: The crushed and ground products are subjected to magnetic separation to obtain magnetic manganese concentrate and magnetic tailings; Chlorinated mineral phase conversion: After drying, the magnetically separated manganese concentrate is conveyed to the mixing bin by a conveyor belt. Ammonium chloride is added to mix the material evenly, and then it is conveyed into the mineral phase conversion furnace for chlorinated mineral phase conversion. Cooling: The material discharged from the mineral phase conversion furnace is cooled once by a multi-stage cooling cyclone; the product after the first cooling is fed into a fluidized bed cooler for a second cooling to obtain the chloride mineral phase conversion product; Leaching: The chloride mineral phase conversion product after secondary cooling is subjected to leaching operation. The leaching product is then filtered by pressure to obtain leachate and leaching residue. Purification and impurity removal: Add manganese sulfate solution to the leachate to form calcium sulfate precipitate, and then perform solid-liquid separation; add ammonium fluoride solution to the liquid obtained from solid-liquid separation, stir and let stand, and then perform solid-liquid separation to remove calcium and magnesium impurities to a deeper level, and obtain manganese chloride purified solution. Preparation of high-purity rhodochrosite: Add ammonium bicarbonate solution to manganese chloride purification solution and let it stand to allow it to react fully. After filtration, washing and drying, high-purity rhodochrosite is obtained. The composition of rhodochrosite, by mass percentage, includes Mn 23.00wt%~33.50wt%, SiO2 12.00wt%~28.50wt%, MgO 3.00wt%~12.00wt%, and CaO 4.00wt%~13.00wt%. In the crushing and grinding products, -0.074mm mineral powder accounts for ≥60% of the total mass of intelligent pre-selected concentrate; The magnetic field strength during magnetic separation is 8000 Oe to 16000 Oe; the tailings from magnetic separation and pre-separation are combined into pre-discharged tailings; The mass ratio of ammonium chloride to rhodochrosite added during the chlorination phase transformation process is (0.5:1) to (1.5:1); the chlorination phase transformation temperature is 400℃ to 700℃, and the time is 10 min to 40 min. Nitrogen is used as a protective gas during the chlorination phase transformation process.

2. The method for efficient removal and purification of high-calcium, high-magnesium rhodochrosite according to claim 1, characterized in that, The X-ray intelligent sorting machine has a conveyor belt width of 1.2m to 2m and a conveyor belt speed of 2m / s to 4m / s.

3. The method for efficient removal and purification of high-calcium, high-magnesium rhodochrosite according to claim 1, characterized in that, During the cooling process, the material exchanges heat with the protective gas, and the temperature drops to below 150°C. After secondary cooling, the product temperature drops to below 60℃.

4. The method for efficient removal and purification of high-calcium, high-magnesium rhodochrosite according to claim 1, characterized in that, The chloride mineral phase conversion product after secondary cooling was leached with deionized water at a leaching temperature of 25℃~60℃, a leaching time of 0.5h~1.5h, and a leaching liquid-to-solid ratio of 3mL / g~10mL / g.

5. The method for efficient removal and purification of high-calcium, high-magnesium rhodochrosite according to claim 1, characterized in that, The concentration of the added manganese sulfate solution is 0.5 mol / L to 1.5 mol / L, and the molar ratio of manganese sulfate to calcium ions in the leachate is n(Ca). 2+ ): n(MnSO4)=1: (1.0~2.0); The concentration of the added ammonium fluoride solution is 0.2 mol / L to 1.2 mol / L, and the molar ratio of ammonium fluoride to magnesium ions in the leachate is n(Mg). 2+ ): n(NH4F)=1: (1.5~3.0).

6. The method for efficient removal and purification of high-calcium, high-magnesium rhodochrosite according to claim 1, characterized in that, When preparing high-purity rhodochrosite, the concentration of NH3HCO3 solution is 1mol / L~2mol / L, the pH of the solution is 6.6~7.3, and the reaction time is 0.8h~1.2h.

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