A rhodochrosite pre-throw tailings-mineral phase conversion-magnetic separation deep impurity removal process

Abstract

The application discloses a rhodochrosite pre-throwing tailings-mineral phase conversion-magnetic separation deep impurity removal process and belongs to the technical field of mineral processing.The application removes the ore with high calcium and magnesium content in advance through X-ray sorting technology, then carries out powdering and one-stage magnetic separation, feeds one-stage magnetic separation manganese concentrate into a suspension roasting furnace, and generates magnetite (MnO) with stronger magnetism than rhodochrosite (MnCO3) in a suspension flow state under a nitrogen atmosphere and through a decomposition reaction, more effectively separates the magnetite (MnO) with relatively strong magnetism and non-magnetic calcium and magnesium impurities through two-stage magnetic separation, and improves the grade of the manganese concentrate.The application realizes efficient comprehensive utilization of the rhodochrosite with high calcium and magnesium, has a simple process flow, high heat and mass transfer efficiency, good reaction effect, good production continuity, high manganese grade and manganese recovery rate in the product, and remarkable calcium and magnesium removal effect.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology and relates to a process for pre-tailing of rhodochrosite, mineral phase transformation, and deep impurity removal by magnetic separation. Background Technology

[0002] Manganese plays an irreplaceable role in the production of high-performance, high-quality steel materials, with approximately 90% of its usage in the steel industry, second only to iron. Simultaneously, manganese has wide applications in the electronics, chemical, aerospace, and medical industries.

[0003] Currently, commonly used methods for processing rhodochrosite include direct leaching (CN106745290A) and roasting-leaching (CN116926347A). However, impurities such as calcium and magnesium form a passivation layer during the leaching process, affecting leaching efficiency. Therefore, developing a deep impurity removal process for rhodochrosite is of great significance. To address the above situation, this invention provides a deep impurity removal process for rhodochrosite involving pre-tailings disposal, mineral phase transformation, and magnetic separation. Summary of the Invention

[0004] 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.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A process for pre-tailings removal, phase transformation, and deep magnetic separation of rhodochrosite involves crushing the rhodochrosite and then pre-selecting it. The pre-selected concentrate is then ground and subjected to a first-stage magnetic separation to obtain a first-stage magnetic manganese concentrate and a first-stage magnetic tailings. The first-stage magnetic manganese concentrate undergoes phase transformation in a suspension roaster, and the resulting phase transformation product is subjected to a second-stage magnetic separation to obtain a second-stage magnetic concentrate and a second-stage magnetic tailings. The pre-selected tailings, the first-stage magnetic tailings, and the second-stage magnetic tailings are combined into a total tailings, and the second-stage magnetic concentrate is the final product.

[0006] Rhodochrosite is crushed to a particle size ≤130mm; Pre-selection is achieved using an X-ray intelligent sorting machine; The pre-selected concentrate is crushed and ground to a particle size ≤0.15mm and then fed into the silo, of which -0.074mm mineral powder accounts for ≥60% of the total mass; The chemical composition of the rhodochrosite includes: Mn 22.00wt%~33.50wt%, MgO 3.00wt%~10.00wt%, and CaO 4.00wt%~12.00wt%.

[0007] The magnetic field strength of a single magnetic separation section is 12000 Oe to 16000 Oe.

[0008] During the mineral phase transformation process, the roasting temperature is 500℃~700℃; the roasting time is 15min~30min; and nitrogen is used as a protective gas during the mineral phase transformation process.

[0009] The main chemical reaction that occurs during the mineral phase transformation is: MnCO3 MnO + CO2↑ The magnetic field strength during the two-stage magnetic separation process is 2000 Oe to 7000 Oe.

[0010] In the method described, the magnesium ion removal rate is above 75%, and the calcium ion removal rate is above 73%.

[0011] This invention provides a pre-tailings removal-phase transformation-magnetic separation deep impurity removal process for rhodochrosite. The key principle and technical points are as follows: Due to the high content of calcium and magnesium impurities in rhodochrosite, these impurities easily form a passivation layer during leaching, severely affecting leaching efficiency. This invention uses X-ray separation technology to pre-remove ores with high calcium and magnesium content, thereby improving subsequent leaching efficiency. After pre-selection, the rhodochrosite (MnCO3) is in a suspended flow state under a nitrogen atmosphere during roasting and undergoes a decomposition reaction to generate rhodochrosite (MnO), which has stronger magnetic properties than rhodochrosite (MnCO3). This facilitates more effective separation of the relatively strong magnetic MnO and non-magnetic calcium and magnesium impurities through magnetic separation, improving the grade of manganese concentrate. Furthermore, rhodochrosite (MnCO3) belongs to the trigonal crystal system, while rhodochrosite (MnO) belongs to the cubic crystal system. During the crystal structure transformation process, numerous pores and microcracks are formed in the ore particles, transforming the originally dense mineral into a loose and porous structure, providing favorable conditions for subsequent leaching operations.

[0012] Compared with existing electrolytic manganese waste residue treatment processes, the features and advantages of this invention are as follows: 1. This invention achieves efficient and comprehensive utilization of high-calcium and high-magnesium rhodochrosite, with high manganese grade and recovery rate in the product, and significant calcium and magnesium removal effects.

[0013] 2. The mineral phase transformation process of this invention uses a suspension roasting furnace to roast rhodochrosite powder. Compared with the traditional rotary kiln roasting device, it has higher heat and mass transfer efficiency, better reaction effect, and better production continuity.

[0014] 3. The process of pre-tailings disposal, phase transformation and magnetic separation for deep impurity removal of rhodochrosite proposed in this invention is simple, the related technologies are relatively mature, and it is easy to promote industrialization. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the process of pre-tailings removal, mineral phase transformation, and magnetic separation for deep impurity removal of rhodochrosite according to the present invention. Detailed Implementation

[0016] 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.

[0017] Example 1: In this embodiment, the rhodochrosite comes from Akto County and Wuqia County in Xinjiang Uygur Autonomous Region, with a Mn content of 29.82 wt%, an MgO content of 5.14 wt%, and a CaO content of 6.64 wt%.

[0018] This embodiment provides a method for pre-tailing removal, morphological phase transformation, and deep impurity removal from rhodochrosite ore using magnetic separation. The process flow is as follows: Figure 1 As shown; Rhodochrosite is fed into a primary crusher for pulverization, yielding a crushed product with a particle size less than 90 mm. The crushed product is then conveyed to an X-ray intelligent sorting device for pre-selection, yielding X-ray intelligent pre-selected concentrate and pre-selected tailings. The X-ray pre-selected concentrate is further ground to a particle size below 0.15 mm, with -0.074 mm ore powder accounting for 60% of the total mass. The crushed sample is then fed into a vertical ring high-intensity magnetic separator with a magnetic field strength of 12000 Oe, yielding a first-stage magnetic concentrate and a first-stage magnetic tailings. The first-stage magnetic product is dried in a dryer and then fed into a suspension roaster with preheated nitrogen for mineral phase transformation. The temperature inside the suspension roaster is stabilized at 500℃, and the roasting time is 15 minutes, ultimately yielding a synergistic mineral phase transformation product. The material discharged from the suspension roaster is cooled by a cooling cyclone and then fed into a second-stage magnetic separator with a magnetic field strength of 3000 Oe, yielding a second-stage magnetic concentrate and a second-stage magnetic tailings. In this embodiment, the two-stage magnetic separation concentrate is the final concentrate. The tailings from the X-ray intelligent pre-selection, the first-stage magnetic separation tailings, and the second-stage magnetic separation tailings are combined into the final tailings. The final concentrate obtained has a manganese grade of 39.78 wt%, an MgO content of 3.77 wt%, and a CaO content of 3.21 wt%. The manganese recovery rate is 85.92%, and the demagnesification and decalcification rates are 75.31% and 74.84%, respectively.

[0019] Example 2: The method is the same as the rhodochrosite pre-tailings disposal-phase transformation-magnetic separation deep impurity removal method in Example 1, except that: 1. In this embodiment, the rhodochrosite has a Mn content of 29.97 wt%, an MgO content of 6.25 wt%, and a CaO content of 5.98 wt%.

[0020] 2. Grind the X-ray pre-selected concentrate to a particle size of less than 0.15 mm, of which -0.074 mm mineral powder accounts for 60% of the total mass.

[0021] 3. The crushed sample is fed into a vertical ring high-intensity magnetic separator with a magnetic field strength of 13000 Oe to obtain a first-stage magnetic concentrate and a first-stage magnetic tailings.

[0022] 4. After the magnetic separation product is dried in a dryer, it is sent to a suspension roasting furnace with preheated nitrogen for mineral phase transformation. The temperature inside the suspension roasting furnace is stabilized at 550℃ and the roasting time is 15 minutes, finally obtaining a synergistic mineral phase transformation product.

[0023] 5. The material discharged from the suspension roaster is cooled by a cooling cyclone and then fed into a two-stage magnetic separator with a magnetic field strength of 2000 Oe to obtain two-stage magnetic concentrate and two-stage magnetic tailings.

[0024] In this embodiment, the two-stage magnetic separation concentrate is the final concentrate. The tailings from the X-ray pre-selection, the first-stage magnetic separation, and the second-stage magnetic separation are combined into the final tailings. The final manganese concentrate obtained has a manganese grade of 40.57 wt%, an MgO content of 3.41 wt%, and a CaO content of 2.88 wt%. The manganese recovery rate is 83.84%, and the demagnesification and decalcification rates are 76.77% and 74.81%, respectively.

[0025] Example 3: The method is the same as the rhodochrosite pre-tailings disposal-phase transformation-magnetic separation deep impurity removal method in Example 1, except that: 1. In this embodiment, the rhodochrosite has a Mn content of 31.54 wt%, an MgO content of 6.88 wt%, and a CaO content of 6.14 wt%.

[0026] 2. Grind the X-ray pre-selected concentrate to a particle size of less than 0.15 mm, of which -0.074 mm mineral powder accounts for 70% of the total mass.

[0027] 3. The crushed sample is fed into a vertical ring high-intensity magnetic separator with a magnetic field strength of 2000 Oe to obtain a first-stage magnetic concentrate and a first-stage magnetic tailings.

[0028] 4. After the magnetic separation product is dried in a dryer, it is sent to a suspension roasting furnace along with preheated nitrogen for mineral phase transformation. The temperature inside the suspension roasting furnace is stabilized at 600℃ and the roasting time is 20 minutes, finally yielding a synergistic mineral phase transformation product.

[0029] 5. The material discharged from the suspension roaster is cooled by a cooling cyclone and then fed into a two-stage magnetic separator with a magnetic field strength of 3000 Oe to obtain two-stage magnetic concentrate and two-stage magnetic tailings.

[0030] In this embodiment, the two-stage magnetic separation concentrate is the final concentrate. The tailings from the X-ray pre-selection, the first-stage magnetic separation, and the second-stage magnetic separation are combined into the final tailings. The final manganese concentrate obtained has a manganese grade of 41.10 wt%, an MgO content of 3.78 wt%, and a CaO content of 3.11 wt%. The manganese recovery rate is 82.49%, and the demagnesification and decalcification rates are 78.17% and 75.28%, respectively.

[0031] Example 4: The method is the same as the rhodochrosite pre-tailings disposal-phase transformation-magnetic separation deep impurity removal method in Example 1, except that: 1. In this embodiment, the rhodochrosite has a Mn content of 30.89 wt%, an MgO content of 7.78 wt%, and a CaO content of 6.91 wt%.

[0032] 2. Grind the X-ray pre-selected concentrate to a particle size of less than 0.15 mm, of which -0.074 mm mineral powder accounts for 75% of the total mass.

[0033] 3. The crushed sample is fed into a vertical ring high-intensity magnetic separator with a magnetic field strength of 13000 Oe to obtain a first-stage magnetic concentrate and a first-stage magnetic tailings.

[0034] 4. After the magnetic separation product is dried in a dryer, it is sent to a suspension roasting furnace with preheated nitrogen for mineral phase transformation. The temperature inside the suspension roasting furnace is stabilized at 700℃ and the roasting time is 25 minutes, finally obtaining a synergistic mineral phase transformation product.

[0035] 5. The material discharged from the suspension roaster is cooled by a cooling cyclone and then fed into a two-stage magnetic separator with a magnetic field strength of 4000 Oe to obtain two-stage magnetic concentrate and two-stage magnetic tailings.

[0036] In this embodiment, the two-stage magnetic separation concentrate is the final concentrate. The tailings from the X-ray pre-selection, the first-stage magnetic separation, and the second-stage magnetic separation are combined into the final tailings. The final manganese concentrate obtained has a manganese grade of 39.78 wt%, an MgO content of 2.88%, and a CaO content of 2.15 wt%. The manganese recovery rate is 77.83%, and the demagnesification and decalcification rates are 78.89% and 77.41%, respectively.

[0037] Example 5: The method is the same as the rhodochrosite pre-tailings disposal-phase transformation-magnetic separation deep impurity removal method in Example 1, except that: 1. The rhodochrosite in this embodiment comes from South Africa, with a Mn content of 23.78 wt%, an MgO content of 4.73 wt%, and a CaO content of 8.61 wt%.

[0038] 2. Grind the X-ray pre-selected concentrate to a particle size of less than 0.15 mm, of which -0.074 mm mineral powder accounts for 75% of the total mass.

[0039] 3. The crushed sample is fed into a vertical ring high-intensity magnetic separator with a magnetic field strength of 15000 Oe to obtain a first-stage magnetic concentrate and a first-stage magnetic tailings.

[0040] 4. After the magnetic separation product is dried in a dryer, it is sent to a suspension roasting furnace with preheated nitrogen for mineral phase transformation. The temperature inside the suspension roasting furnace is stabilized at 700℃ and the roasting time is 30 minutes, finally obtaining a synergistic mineral phase transformation product.

[0041] 5. The material discharged from the suspension roaster is cooled by a cooling cyclone and then fed into a two-stage magnetic separator with a magnetic field strength of 6000 Oe to obtain two-stage magnetic concentrate and two-stage magnetic tailings.

[0042] In this embodiment, the two-stage magnetic separation concentrate is the final concentrate. The tailings from the X-ray pre-selection, the first-stage magnetic separation, and the second-stage magnetic separation are combined into the final tailings. The final manganese concentrate obtained has a manganese grade of 43.10 wt%, an MgO content of 2.10 wt%, and a CaO content of 2.02 wt%. The manganese recovery rate is 81.76%, and the demagnesification and decalcification rates are 77.99% and 73.23%, respectively.

[0043] Example 6: The method is the same as the rhodochrosite pre-tailings disposal-phase transformation-magnetic separation deep impurity removal method in Example 1, except that: 1. The rhodochrosite in this embodiment comes from Guangxi Zhuang Autonomous Region, with a Mn content of 29.75 wt%, an MgO content of 3.45 wt%, and a CaO content of 11.53 wt%.

[0044] 2. Grind the X-ray pre-selected concentrate to a particle size of less than 0.15 mm, of which -0.074 mm mineral powder accounts for 80% of the total mass.

[0045] 3. The crushed sample is fed into a vertical ring high-intensity magnetic separator with a magnetic field strength of 15000 Oe to obtain a first-stage magnetic concentrate and a first-stage magnetic tailings.

[0046] 4. After the magnetic separation product is dried in a dryer, it is sent to a suspension roasting furnace with preheated nitrogen for mineral phase transformation. The temperature inside the suspension roasting furnace is stabilized at 700℃ and the roasting time is 30 minutes, finally obtaining a synergistic mineral phase transformation product.

[0047] 5. The material discharged from the suspension roaster is cooled by a cooling cyclone and then fed into a two-stage magnetic separator with a magnetic field strength of 7000 Oe to obtain two-stage magnetic concentrate and two-stage magnetic tailings.

[0048] In this embodiment, the two-stage magnetic separation concentrate is the final concentrate. The tailings from the X-ray pre-selection, the first-stage magnetic separation, and the second-stage magnetic separation are combined into the final tailings. The final manganese concentrate obtained has a manganese grade of 43.21 wt%, an MgO content of 2.57 wt%, and a CaO content of 1.80 wt%. The manganese recovery rate is 80.12%, and the demagnesification and decalcification rates are 78.06% and 74.23%, respectively.

Claims

1. A process for pre-tailings removal, morphological phase transformation, and deep magnetic separation of rhodochrosite, characterized in that, Rhodochrosite is crushed and pre-selected. The pre-selected concentrate is then ground and subjected to a first-stage magnetic separation to obtain a first-stage magnetic manganese concentrate and a first-stage magnetic tailings. The first-stage magnetic manganese concentrate undergoes mineral phase transformation in a suspension roaster. The resulting mineral phase transformation product is then subjected to a second-stage magnetic separation to obtain a second-stage magnetic concentrate and a second-stage magnetic tailings. The pre-selected tailings, the first-stage magnetic tailings, and the second-stage magnetic tailings are combined into a total tailings, and the second-stage magnetic concentrate is the final product. The composition of rhodochrosite, by mass percentage, includes: Mn 22.00wt%~33.50wt%, MgO 3.00wt%~10.00wt%, and CaO 4.00wt%~12.00wt%. During the mineral phase transformation process, the roasting temperature is 500℃~700℃, and the mineral phase transformation time is 15min~30min; nitrogen is used as a protective atmosphere during the mineral phase transformation process. The removal rate of magnesium ions in rhodochrosite is over 75%, and the removal rate of calcium ions is over 73%. Pre-selection is achieved using an X-ray intelligent separator; the pre-selected concentrate is ground to a particle size ≤0.15mm and then fed into the hopper, of which -0.074mm mineral powder accounts for ≥60% of the total mass; During a single magnetic separation process, the magnetic field strength is 12000 Oe to 16000 Oe; During the two-stage magnetic separation process, the magnetic field strength is 3000 Oe to 7000 Oe; After being dried in a dryer, the first-stage magnetic separation manganese concentrate is fed into a suspension roasting furnace along with preheated nitrogen for mineral phase transformation. The mineral phase transformation product discharged from the suspension roasting furnace is cooled by a cooling cyclone and then fed into the second-stage magnetic separation operation.

2. The process for pre-tailings disposal, facies transformation, and deep magnetic separation of rhodochrosite as described in claim 1, characterized in that, Rhodochrosite is crushed to a particle size of ≤130mm.

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