Method for producing manganese sulfate from low-grade manganese oxide ore

Abstract

The invention provides a method for producing manganese sulfate from low-grade manganese oxide ore, which comprises the following steps: mixing and ball-milling low-grade manganese oxide ore powder and ferric sulfate to obtain a mixture; carrying out heat treatment on the mixture to realize a melting reaction, and cooling after the reaction is finished to obtain a reaction product; the reaction product is subjected to water leaching, and water leaching liquid and water leaching residues are obtained; sulfide is added into the water leaching solution, and a manganese sulfate solution and sulfide slag are obtained after precipitation reaction; and adjusting the pH value of the manganese sulfate solution to 4.0-6.5, and carrying out evaporative crystallization to obtain manganese sulfate. The method is simple in technological process, mild in technological condition, low in energy consumption, low in required cost, high in manganese sulfate recovery rate and high in purity of the recovered manganese sulfate, and the method can effectively utilize the ferric sulfate waste salt and eliminate the environmental protection pressure of the steel and iron material processing industry.

Description

Technical Field

[0001] The invention belongs to the field of resource utilization of difficult-to-treat minerals, and in particular relates to a method for producing manganese sulfate by using low-grade manganese oxide ore. Background Art

[0002] As an important strategic metal element, manganese is mainly used in special steel, non-ferrous metal alloys, battery materials, magnetic materials, building materials, fertilizers, feed additives, environmental management materials and drug manufacturing. It is widely used in aerospace, infrastructure construction, environmental protection and life and health fields. It is an indispensable key raw material for the development of strategic emerging industries such as special equipment, new energy devices, and electronic communications. In recent years, with the rapid development of new energy vehicles and electronic communications, the demand for metallic manganese and manganese-containing compounds has continued to increase. As the world's largest producer and consumer of metallic manganese and manganese-containing compounds, my country must achieve efficient utilization and development of existing manganese ore resources in order to meet development needs.

[0003] The quality of manganese ore in my country is generally poor, mainly poor ore, accounting for about 93% of the total reserves, and there are almost no rich ore deposits that meet the international commercial grade (Mn content ≥ 48%). At the same time, the ore types are mainly a combination of manganese carbonate and manganese oxide, of which manganese carbonate ores account for about 74%. According to YB / T5084-2005, the Mn content of manganese oxide ore used for industrial production shall not be less than 45%. However, most of the manganese oxide ores mined in my country are low-grade manganese oxide ores. Compared with high-grade ores, their gangue content is high, so they are difficult to process, the recovery rate of effective components is low, and the cost of using traditional processes is high, the consumption of reducing agents is large, and they cannot be effectively utilized. Except for a small amount used for electrolytic manganese solution iron removal and flue gas desulfurization, most of them are stored in the open air in the form of tailings. The idle storage of low-grade manganese oxide ores not only occupies a large amount of land, but also causes the associated heavy metal elements to enter the surrounding soil and water bodies due to long-term weathering and rain erosion, causing serious pollution to the surrounding ecological environment. More importantly, under the current situation of global changes, the import of foreign manganese ore is restricted, domestically produced ore cannot meet production needs, and the idle low-grade manganese oxide ore is a serious waste of resources. Therefore, realizing the low-cost and efficient utilization of low-grade manganese oxide ore resources is of great significance to meet the growing demand for manganese-based materials and fertilizers, promote the sustainable development of aerospace, new energy vehicles, electronic communications and hydrogen energy utilization industries, eliminate environmental pollution, and realize the clean production of manganese sulfate. Summary of the invention

[0004] In response to the above technical problems, the present application provides a method for producing manganese sulfate using low-grade manganese oxide ore.

[0005] To achieve the above objectives, this application proposes the following technical solutions: The present invention provides a method for producing manganese sulfate by using low-grade manganese oxide ore, comprising: mixing and ball-milling low-grade manganese oxide ore powder and ferric sulfate to obtain a mixed material; The mixture is subjected to heat treatment to achieve a melting reaction, and after the reaction is completed, it is cooled to obtain a reaction product; soaking the reaction product in water to obtain a water soaking liquid and a water soaking residue; Adding sulfide to the water extract, and obtaining manganese sulfate solution and sulfide slag after precipitation reaction; The pH value of the manganese sulfate solution is adjusted to 4.0-6.5, and the solution is evaporated and crystallized to obtain manganese sulfate.

[0006] Furthermore, the temperature of the heat treatment is 400-800° C., preferably 600-700° C.; the time of the heat treatment is 30-180 min, preferably 60-120 min.

[0007] Furthermore, the atmosphere of the heat treatment is an oxygen-containing gas; preferably, the oxygen partial pressure of the oxygen-containing gas is 21 to 100%.

[0008] Furthermore, the low-grade manganese oxide ore powder and ferric sulfate are mixed in a molar ratio of Mn to sulfate of 1:1 to 2.5.

[0009] Furthermore, the ball-to-material mass ratio of the ball milling is 2.5:1-20:1, and the ball milling time is 30-120 min.

[0010] Furthermore, the water immersion temperature is 40-100° C., preferably 60-90° C.; the water immersion time is 45-180 min, preferably 60-90 min; and the liquid-to-solid ratio of the water immersion is 5:1-2:1 mL / g.

[0011] Furthermore, the sulfide is one or more of hydrogen sulfide, calcium sulfide, sodium sulfide, ammonium sulfide, and manganese sulfide.

[0012] Furthermore, the molar ratio of the sulfide to the impurity ions contained in the water extract is 1.4:1 to 3:1.

[0013] Furthermore, the temperature of the precipitation reaction is 25-100° C., preferably 50-60° C.; the time of the precipitation reaction is 45-150 min, preferably 60-120 min.

[0014] Furthermore, the method also includes washing the water-leached slag with water to obtain water-washed slag and water washing liquid; the water washing liquid is used as a solvent for water leaching; and the water-washed slag is used as iron ore for producing steel.

[0015] Furthermore, the number of water washing is 1 to 3 times; the temperature of the water washing is 25 to 100° C.; the slurry-solid ratio of the water washing is 2:1 to 5:1 mL / g; and the stirring time of the water washing is 5 to 30 min.

[0016] Furthermore, the method also includes washing the sulfide slag with water to obtain washed slag and washing liquid; the washing liquid is used as a solvent for water immersion.

[0017] Furthermore, the number of water washing is 1 to 3 times; the temperature of the water washing is 25 to 100° C.; the slurry-solid ratio of the water washing is 2:1 to 5:1 mL / g; and the stirring time of the water washing is 5 to 30 min.

[0018] Furthermore, the manganese content of the low-grade manganese oxide ore is 15-19wt.%; and the manganese sulfate is battery-grade manganese sulfate.

[0019] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects: The provided method for producing manganese sulfate using low-grade manganese oxide ore has the advantages of simple process, mild process conditions, low energy consumption, low required cost, high recovery rate of manganese sulfate, and high purity of recovered manganese sulfate. The method can efficiently utilize waste iron sulfate salt and eliminate the environmental pressure of the steel material processing industry.

[0020] The provided method for producing manganese sulfate by using low-grade manganese oxide ore can recover manganese sulfate with a purity as high as battery grade, and a recovery rate of more than 98%.

[0021] The provided method for producing manganese sulfate using low-grade manganese oxide ore does not generate secondary waste, is clean and environmentally friendly, can reduce the environmental pressure of related enterprises and increase economic benefits, and is suitable for large-scale industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 The present invention is a process flow chart of the method for producing manganese sulfate using low-grade manganese oxide ore. DETAILED DESCRIPTION

[0024] The present invention provides a method for producing manganese sulfate by using low-grade manganese oxide ore, comprising: mixing and ball-milling low-grade manganese oxide ore powder and ferric sulfate to obtain a mixed material; The mixture is subjected to heat treatment to achieve a melting reaction, and after the reaction is completed, it is cooled to obtain a reaction product; soaking the reaction product in water to obtain a water soaking liquid and a water soaking residue; Adding sulfide to the water extract, and obtaining manganese sulfate solution and sulfide slag after precipitation reaction; The pH value of the manganese sulfate solution is adjusted to 4.0-6.5, and the solution is evaporated and crystallized to obtain manganese sulfate.

[0025] The applicant has found through research that when processing low-grade manganese oxide ore, it is heat-treated with ferric sulfate. When the heat treatment temperature is above the melting point of ferric sulfate, that is, when ferric sulfate exists in the form of molten salt, it can undergo molten salt replacement reaction with manganese oxide in the low-grade manganese oxide ore to obtain manganese sulfate and iron ore raw materials, and the manganese recovery rate in this process is high.

[0026] In some preferred embodiments, the temperature of the heat treatment is 400-800°C, preferably 600-700°C, such as 600°C, 620°C, 650°C, 680°C, 700°C, etc. It is found that when the heat treatment temperature is too high, the self-decomposition of ferric sulfate increases, and the effective utilization rate of ferric sulfate is low. At the same time, the manganese sulfate generated by the reaction will also undergo secondary decomposition. If the heat treatment temperature is too low, the conversion efficiency per unit time is low. The time of the heat treatment is 30-180min, preferably 60-120min, such as 60min, 75min, 90min, 105min, 120min, etc. It is found that the conversion rate is low when the heat treatment time is too short, and the heat treatment time is too long to easily cause the secondary decomposition of manganese sulfate, reduce the subsequent manganese leaching rate and then reduce the recovery rate of manganese.

[0027] In some embodiments, the heat treatment atmosphere is an oxygen-containing gas; preferably, the oxygen partial pressure of the oxygen-containing gas is 21 to 100%.

[0028] In some preferred embodiments, the low-grade manganese oxide ore powder and ferric sulfate are mixed in a molar ratio of Mn to sulfate of 1:1 to 2.5. If the amount of ferric sulfate added is too high, the risk of incomplete reaction of ferric sulfate increases, which is not conducive to subsequent water leaching for iron removal and sulfide precipitation for impurity removal. If the amount of ferric sulfate added is too low, the effective conversion rate of Mn in the low-grade manganese oxide ore is low.

[0029] In some preferred embodiments, the ball-to-material mass ratio of the ball mill is 2.5:1~20:1. A large ball-to-material ratio is beneficial to increasing the activation effect, but affects the processing efficiency, and the single processing volume is small. A small ball-to-material ratio has a poor activation effect, such as 2.5:1, 5:1, 7.5:1, 10:1, 12.5:1, 15:1, 17.5:1, 20:1, etc. The ball milling time is 30~120min. If the ball milling time is too long, the energy consumption increases. If the ball milling time is too short, the mechanical activation effect cannot be achieved, such as 30min, 45min, 60min, 75min, 90min, 105min, 120min, etc.

[0030] In some preferred embodiments, the water immersion temperature is 40-100°C, preferably 60-90°C, for example 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C. The applicant has found through research that by conducting water immersion at a higher temperature (i.e., water can be directly used as a leaching agent without acid adjustment), although the leaching efficiency of manganese will be reduced, the iron removal effect can be improved, thereby reducing the loss of manganese during impurity removal. Too low water immersion temperature will result in poor iron removal effect, resulting in a high manganese loss rate in the subsequent impurity removal process; the water immersion time is 45-180min, preferably 60-90min, for example 60min, 70min, 80min, 90min, etc. Too short water immersion time affects the iron precipitation effect, resulting in a large subsequent Mn loss, and too long water immersion time reduces the treatment efficiency.

[0031] In some preferred embodiments, the sulfide is one or more of hydrogen sulfide, calcium sulfide, sodium sulfide, ammonium sulfide, and manganese sulfide. In a further preferred embodiment, when the sulfide is hydrogen sulfide, ammonia water or ammonia gas needs to be added to the solution to maintain the pH value of the sulfidation system at an alkaline level.

[0032] In some preferred embodiments, the molar ratio of the sulfide to the impurity ions contained in the water extract is 1.4:1-3:1, for example, 1.4:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, etc.

[0033] In some preferred embodiments, the precipitation reaction temperature is 25-100°C, preferably 50-60°C, for example 50°C, 55°C, 60°C, etc.; the precipitation reaction time is 45-150min, preferably 60-120min, for example 60min, 75min, 90min, 105min, 120min, etc.

[0034] In some preferred embodiments, the process further comprises washing the leached slag with water to obtain washed slag and washing liquid; the washing liquid is used as a solvent for leaching; and the washed slag is used as iron ore for producing steel.

[0035] In some preferred embodiments, the water washing is performed 1 to 3 times; the water washing temperature is 25 to 100° C.; the slurry-to-solid ratio of the water washing is 2:1 to 5:1 mL / g; and the stirring time of the water washing is 5 to 30 min.

[0036] In some preferred embodiments, the process further comprises washing the sulfide slag with water to obtain washed slag and a washing liquid; the washing liquid is used as a solvent for water immersion.

[0037] In some preferred embodiments, the water washing is performed 1 to 3 times; the water washing temperature is 25 to 100° C.; the slurry-to-solid ratio of the water washing is 2:1 to 5:1 mL / g; and the stirring time of the water washing is 5 to 30 min.

[0038] In some preferred embodiments, the manganese content of the low-grade manganese oxide ore is 15-19 wt.%.

[0039] In some preferred embodiments, the manganese sulfate is battery grade manganese sulfate.

[0040] In some preferred embodiments, the pH value of the clean manganese sulfate solution is adjusted to 4.0-6.5 using concentrated sulfuric acid.

[0041] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the specification, but the protection scope of the present invention is not limited to the following specific embodiments.

[0042] Example 1 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate, the process flow chart is as follows: Figure 1 As shown, the following steps are included: (1) Dry the low-grade manganese oxide ore and ferric sulfate, crush them to less than 100 mesh with a pulverizer or crusher, and mix them according to the molar ratio of SO4 2- : Mn=1.5 Mix iron sulfate with low-grade manganese oxide ore.

[0043] (2) The mixture obtained in step (1) was placed in a ball mill with a ball-to-material ratio of 10:1 g / g and a ball milling time of 60 min.

[0044] (3) The ball-milled mixture obtained in step (2) was placed in a muffle furnace at 600° C. for reaction for 90 min (in air atmosphere). During the reaction, iron sulfate existed in the form of molten salt and there was slight smoke during the reaction. A reaction product was obtained. It was confirmed that a molten salt replacement reaction occurred in the process and a partial thermal decomposition reaction also occurred.

[0045] (4) The reaction product obtained in step (3) was slurried with deionized water at a liquid-to-solid ratio of 5:1 mL / g, and the obtained slurry was then placed in a 90°C water bath for stirring and immersion. The reaction was carried out for 60 minutes, and the leaching rate of Mn was 98.6%, and the Fe content in the leachate was 0.83 mg / L. The leaching residue and manganese sulfate leachate were then filtered to obtain leaching residue and manganese sulfate leachate.

[0046] (5) The leached residue obtained in step (4) is slurried with deionized water at a liquid-to-solid ratio of 2:1 mL / g, and the resulting slurry is then placed in a 50° C. water bath and stirred for 10 min. The washing is repeated three times and then filtered. The obtained washed slag is dried and can be used as an iron ore raw material for steel production. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0047] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 60°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 2, react for 60 minutes, filter after the reaction to obtain a precipitated liquid and a precipitated residue, wherein the precipitated liquid is a clean manganese sulfate solution, and ICP detection shows that the contents of Fe, Al, Zn, Cd and Cu in the precipitated solution are less than 0.001 mg / L, and the contents of residual Co and Ni are less than 0.2 mg / L, and the precipitated residue is sulfides of Zn, Cd, Cu, Co and Ni and oxides of Fe, Al and Mn.

[0048] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 10 min. The washing is repeated three times and then filtered. The washed slag obtained is dried and can be used as a raw material for the recovery of other valuable elements. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0049] (8) The clean manganese sulfate solution obtained in step (6) is adjusted to pH 6 using concentrated sulfuric acid, and the manganese-containing leaching solution is evaporated and crystallized to obtain a MnSO4·H2O product that meets the requirements of HG / T 4823-2015. The comprehensive recovery rate of manganese is 98.5% (the comprehensive recovery rate is the total recovery rate, and the calculation formula is comprehensive recovery rate of Mn = (the mass of Mn contained in the MnSO4·H2O product / the mass of Mn contained in the low-grade manganese oxide ore) × 100%).

[0050] Example 2 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate comprises the following steps: (1) to (3) are the same as step (1), step (2), and step (3) of Example 1.

[0051] (4) The reaction product obtained in step (3) was slurried with deionized water at a liquid-to-solid ratio of 5:1 mL / g, and the obtained slurry was then placed in a water bath at 30°C for stirring and immersion. The reaction was carried out for 60 minutes, and the leaching rate of Mn was 98.9%, and the Fe content in the leachate was 126.74 mg / L. The leaching residue and manganese sulfate leachate were then filtered to obtain leaching residue and manganese sulfate leachate.

[0052] (5) The leached residue obtained in step (4) is slurried with deionized water at a liquid-to-solid ratio of 2:1 mL / g, and the resulting slurry is then placed in a 50° C. water bath and stirred for 10 min. The washing is repeated three times and then filtered. The obtained washed slag is dried and can be used as an iron ore raw material for steel production. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0053] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 60°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 2, react for 60 minutes, filter after the reaction to obtain a precipitated liquid and a precipitated residue, wherein the precipitated liquid is a clean manganese sulfate solution, and ICP detection shows that the contents of Fe, Al, Zn, Cd and Cu in the precipitated solution are less than 0.001 mg / L, and the contents of residual Co and Ni are less than 0.2 mg / L, and the precipitated residue is sulfides of Zn, Cd, Cu, Co and Ni and oxides of Fe, Al and Mn.

[0054] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 10 min. The washing is repeated three times and then filtered. The washed slag obtained is dried and can be used as a raw material for the recovery of other valuable elements. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0055] (8) The clean manganese sulfate solution obtained in step (6) is adjusted to pH 6 using concentrated sulfuric acid, and the manganese-containing leaching solution is evaporated and crystallized to obtain a MnSO4·H2O product that meets the requirements of HG / T 4823-2015. The comprehensive recovery rate of manganese is 96.3%.

[0056] Compared with Example 1, when the leaching temperature in step (4) is reduced from 90°C to 30°C, although the leaching rate of Mn increases, the Fe content in the leachate increases, which ultimately leads to a decrease in the comprehensive recovery rate of Mn.

[0057] Example 3 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate, the process flow chart is as follows: Figure 1 As shown, the following steps are included: (1) Dry the low-grade manganese oxide ore and ferric sulfate, crush them to less than 100 mesh with a pulverizer or crusher, and mix them according to the molar ratio of SO4 2- : Mn = 2 Mix iron sulfate with low-grade manganese oxide ore.

[0058] (2) The mixture obtained in step (1) was placed in a ball mill with a ball-to-material ratio of 8:1 g / g and a ball milling time of 90 min.

[0059] (3) The ball-milled mixture obtained in step (2) was placed in a muffle furnace at 650° C. for reaction for 120 min (in air atmosphere) to obtain a molten salt reaction product.

[0060] (4) The molten salt reaction product obtained in step (3) was slurried with deionized water at a liquid-to-solid ratio of 2.5:1 mL / g, and the obtained slurry was then placed in a water bath at 80°C for stirring and immersion. The reaction lasted for 120 minutes, and the leaching rate of Mn was 99.3%. The leaching residue and manganese sulfate leaching solution were then obtained by filtration.

[0061] (5) The leached residue obtained in step (4) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 80° C. and stirred and washed for 15 min. The washing is repeated three times and then filtered. The washed slag obtained can be dried and used as an iron ore raw material for steel production. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0062] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 60°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 2.5, react for 60 minutes, filter after the reaction to obtain a precipitated liquid and a precipitated residue, wherein the precipitated liquid is a clean manganese sulfate solution, and ICP detection shows that the contents of Fe, Al, Zn, Cd and Cu in the precipitated solution are less than 0.001 mg / L, and the contents of residual Co and Ni are less than 0.1 mg / L, and the precipitated residue is sulfides of Zn, Cd, Cu, Co and Ni and oxides of Fe, Al and Mn.

[0063] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 2:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 15 min. The washing is repeated three times and then filtered. The washed slag is dried and can be used as a raw material for the recovery of other valuable elements. The washed liquid can be used as a leaching agent for the molten salt product in step (4).

[0064] (8) The clean manganese sulfate solution obtained in step (7) is adjusted to pH 6 using concentrated sulfuric acid, and the manganese-containing leaching solution is evaporated and crystallized to obtain a MnSO4·H2O product that meets the requirements of HG / T 4823-2015. The comprehensive recovery rate of manganese is 99.1%.

[0065] Example 4 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate comprises the following steps: (1) to (3) are the same as step (1), step (2), and step (3) of Example 3.

[0066] (4) The reaction product obtained in step (3) was slurried with deionized water at a liquid-to-solid ratio of 2.5:1 mL / g, and the obtained slurry was then placed in a water bath at 80°C for stirring and immersion. The reaction was carried out for 30 minutes, and the leaching rate of Mn was 98.6%, and the Fe content in the leachate was 29.09 mg / L. The leaching residue and manganese sulfate leachate were then filtered to obtain leaching residue and manganese sulfate leachate.

[0067] (5) The leached residue obtained in step (4) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 80° C. and stirred and washed for 15 min. The washing is repeated three times and then filtered. The washed slag obtained can be dried and used as an iron ore raw material for steel production. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0068] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 60°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 2.5, react for 60 minutes, filter after the reaction to obtain a precipitated liquid and a precipitated residue, the precipitated liquid is a clean manganese sulfate solution, and ICP detection shows that the contents of Fe, Al, Zn, Cd, and Cu in the precipitated solution are less than 0.001 mg / L, and the contents of residual Co and Ni are less than 0.2 mg / L, and the obtained sulfide precipitation products are sulfides of Zn, Cd, Cu, Co, and Ni and oxides of Fe, Al, and Mn.

[0069] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 2:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 15 min. The washing is repeated three times and then filtered. The washed slag is dried and can be used as a raw material for the recovery of other valuable elements. The washed liquid can be used as a leaching agent for the molten salt product in step (4).

[0070] (8) The clean manganese sulfate solution obtained in step (7) is adjusted to pH 6 using concentrated sulfuric acid, and the manganese-containing leaching solution is evaporated and crystallized to obtain a MnSO4·H2O product that meets the requirements of HG / T 4823-2015. The comprehensive recovery rate of manganese is 97.9%.

[0071] In Example 4, compared with Example 3, the leaching time in step (4) is reduced, resulting in a slight decrease in the leaching rate of Mn and a significant increase in the Fe content in the leachate, thereby resulting in a significant decrease in the final comprehensive recovery rate of Mn.

[0072] Example 5 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate, the process flow chart is as follows: Figure 1 As shown, the following steps are included: (1) Dry the low-grade manganese oxide ore and ferric sulfate, crush them to less than 100 mesh with a pulverizer or crusher, and mix them according to the molar ratio of SO4 2- : Mn = 1.5 Mix iron sulfate with low grade manganese oxide ore.

[0073] (2) The mixture obtained in step (1) was placed in a ball mill with a ball-to-material ratio of 8:1 g / g and a ball milling time of 60 min.

[0074] (3) The ball-milled mixture obtained in step (2) was placed in a muffle furnace at 650° C. and reacted for 120 min (in air atmosphere). During the reaction, the iron sulfate existed in the form of molten salt and there was slight smoke during the reaction. A reaction product was obtained. It was confirmed that a molten salt replacement reaction occurred in the process, and a partial thermal decomposition reaction also occurred.

[0075] (4) The reaction product obtained in step (3) was slurried with deionized water at a liquid-to-solid ratio of 5:1 mL / g, and the obtained slurry was then placed in a 60°C water bath for stirring and immersion. The reaction lasted for 180 minutes, and the leaching rate of Mn was 99.1%, and the Fe content in the leaching solution was 0.94 mg / L. The leaching residue and manganese sulfate leaching solution were then filtered to obtain leaching residue and manganese sulfate leaching solution.

[0076] (5) The leached residue obtained in step (4) is slurried with deionized water at a liquid-to-solid ratio of 2:1 mL / g, and the resulting slurry is then placed in a 50° C. water bath and stirred for 10 min. The washing is repeated three times and then filtered. The obtained washed slag is dried and can be used as an iron ore raw material for steel production. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0077] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 60°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 2, react for 60 minutes, filter after the reaction to obtain a precipitated liquid and a precipitated residue, wherein the precipitated liquid is a clean manganese sulfate solution, and ICP detection shows that the contents of Fe, Al, Zn, Cd and Cu in the precipitated solution are less than 0.001 mg / L, and the contents of residual Co and Ni are less than 0.2 mg / L, and the precipitated residue is sulfides of Zn, Cd, Cu, Co and Ni and oxides of Fe, Al and Mn.

[0078] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 10 min. The washing is repeated three times and then filtered. The washed slag obtained is dried and can be used as a raw material for the recovery of other valuable elements. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0079] (8) The clean manganese sulfate solution obtained in step (6) is adjusted to pH 6 using concentrated sulfuric acid, and the manganese-containing leaching solution is evaporated and crystallized to obtain a MnSO4·H2O product that meets the requirements of HG / T 4823-2015. The comprehensive recovery rate of manganese is 98.5%.

[0080] Comparative Example 1 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate comprises the following steps: (1) to (5) are the same as steps (1), (2), (3), (4), and (5) of Example 5.

[0081] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 60°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 2, reaction time 30min, ICP detection showed that the contents of Fe, Al, Zn, Cd and Cu in the precipitated solution were less than 0.001 mg / L, the residual Co content was 2.6 mg / L, and the Ni content was about 3.3 mg / L. The sulfide precipitation products obtained were sulfides of Zn, Cd, Cu, Co and Ni and oxides of Fe, Al and Mn.

[0082] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 10 min. The washing is repeated three times and then filtered. The washed slag obtained is dried and can be used as a raw material for the recovery of other valuable elements. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0083] (8) The clean manganese sulfate solution obtained in step (7) is adjusted to a pH value of 6 using concentrated sulfuric acid, and the manganese-containing leaching solution is evaporated and crystallized to obtain a MnSO4·H2O product, wherein the Ni content is 0.021 wt.%, and the Co content is 0.018 wt.%.

[0084] Compared with Example 5, when the reaction time of step (6) is reduced to 30 min, the impurity removal is not thorough, resulting in a decrease in the impurity content of the recovered manganese sulfate.

[0085] Example 6 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate, the process flow chart is as follows: Figure 1 As shown, the following steps are included: (1) Dry the low-grade manganese oxide ore and ferric sulfate, crush them to less than 100 mesh with a pulverizer or crusher, and mix them according to the molar ratio of SO4 2- : Mn=1.5 Mix iron sulfate with low-grade manganese oxide ore.

[0086] (2) The mixture obtained in step (1) was placed in a ball mill with a ball-to-material ratio of 8:1 g / g and a ball milling time of 60 min.

[0087] (3) The ball-milled mixture obtained in step (2) was placed in a muffle furnace at 650° C. and reacted for 120 min (in air atmosphere). During the reaction, the iron sulfate existed in the form of molten salt and there was slight smoke during the reaction. A reaction product was obtained. It was confirmed that a molten salt replacement reaction occurred in the process, and a partial thermal decomposition reaction also occurred.

[0088] (4) The reaction product obtained in step (3) was slurried with deionized water at a liquid-to-solid ratio of 5:1 mL / g, and the obtained slurry was then placed in a 60°C water bath for stirring and immersion. The reaction lasted for 180 minutes, and the leaching rate of Mn was 99.1%, and the Fe content in the leaching solution was 0.94 mg / L. The leaching residue and manganese sulfate leaching solution were then filtered to obtain leaching residue and manganese sulfate leaching solution.

[0089] (5) The leached residue obtained in step (4) is slurried with deionized water at a liquid-to-solid ratio of 2:1 mL / g, and the resulting slurry is then placed in a 50° C. water bath and stirred for 10 min. The washing is repeated three times and then filtered. The obtained washed slag is dried and can be used as an iron ore raw material for steel production. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0090] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 50°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 2, react for 120 minutes, filter after the reaction to obtain a precipitated liquid and a precipitated residue, the precipitated liquid is a clean manganese sulfate solution, and ICP detection shows that the contents of Fe, Al, Zn, Cd, and Cu in the precipitated solution are less than 0.001 mg / L, and the contents of residual Co and Ni are less than 0.2 mg / L, and the obtained sulfide precipitation products are sulfides of Zn, Cd, Cu, Co, and Ni and oxides of Fe, Al, and Mn.

[0091] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 10 min. The washing is repeated three times and then filtered. The washed slag obtained is dried and can be used as a raw material for the recovery of other valuable elements. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0092] (8) The clean manganese sulfate solution obtained in step (6) is adjusted to pH 6 using concentrated sulfuric acid, and the manganese-containing leaching solution is evaporated and crystallized to obtain a MnSO4·H2O product that meets the requirements of HG / T 4823-2015. The comprehensive recovery rate of manganese is 98.4%.

[0093] Example 7 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate comprises the following steps: (1) to (5) are the same as steps (1), (2), (3), (4), and (5) of Example 6.

[0094] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 50°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 2, react for 150 min, filter after the reaction to obtain a precipitated liquid and a precipitated residue, wherein the precipitated liquid is a clean manganese sulfate solution, and ICP detection shows that the contents of Fe, Al, Zn, Cd, and Cu in the precipitated solution are less than 0.001 mg / L, and the contents of residual Co and Ni are less than 0.1 mg / L, and the precipitated residue is sulfides of Zn, Cd, Cu, Co, and Ni and oxides of Fe, Al, and Mn.

[0095] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 10 min. The washing is repeated three times and then filtered. The washed slag obtained is dried and can be used as a raw material for the recovery of other valuable elements. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0096] (8) The clean manganese sulfate solution obtained in step (6) is adjusted to pH 6 using concentrated sulfuric acid, and the manganese-containing leaching solution is evaporated and crystallized to obtain a MnSO4·H2O product that meets the requirements of HG / T 4823-2015. The comprehensive recovery rate of manganese is 93.7%.

[0097] Compared with Example 6, when the reaction time in step (6) is increased to 150 min, the comprehensive recovery rate of manganese is significantly reduced.

[0098] Example 8 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate, the process flow chart is as follows: Figure 1 As shown, the following steps are included: (1) Dry the low-grade manganese oxide ore and ferric sulfate, crush them to less than 100 mesh with a pulverizer or crusher, and mix them according to the molar ratio of SO4 2- : Mn=1.5 Mix iron sulfate with low-grade manganese oxide ore.

[0099] (2) The mixture obtained in step (1) was placed in a ball mill with a ball-to-material ratio of 8:1 g / g and a ball milling time of 60 min.

[0100] (3) The ball-milled mixture obtained in step (2) was placed in a muffle furnace at 650° C. and reacted for 120 min (in air atmosphere). During the reaction, the iron sulfate existed in the form of molten salt and there was slight smoke during the reaction. A reaction product was obtained. It was confirmed that a molten salt replacement reaction occurred in the process, and a partial thermal decomposition reaction also occurred.

[0101] (4) The reaction product obtained in step (3) was slurried with deionized water at a liquid-to-solid ratio of 5:1 mL / g, and the obtained slurry was then placed in a 60°C water bath for stirring and immersion. The reaction lasted for 180 minutes, and the leaching rate of Mn was 99.1%, and the Fe content in the leaching solution was 0.94 mg / L. The leaching residue and manganese sulfate leaching solution were then filtered to obtain leaching residue and manganese sulfate leaching solution.

[0102] (5) The leached residue obtained in step (4) is slurried with deionized water at a liquid-to-solid ratio of 2:1 mL / g, and the resulting slurry is then placed in a 50° C. water bath and stirred for 10 min. The washing is repeated three times and then filtered. The obtained washed slag is dried and can be used as an iron ore raw material for steel production. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0103] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 60°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 1.5, react for 60 minutes, filter after the reaction to obtain a precipitated liquid and a precipitated residue, the precipitated liquid is a clean manganese sulfate solution, and ICP detection shows that the contents of Al, Fe, Zn, Cd, and Cu in the precipitated solution are less than 0.001 mg / L, and the contents of residual Co and Ni are less than 0.3 mg / L, and the obtained sulfide precipitation products are sulfides of Zn, Cd, Cu, Co, and Ni and oxides of Fe, Al, and Mn.

[0104] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 10 min. The washing is repeated three times and then filtered. The washed slag obtained is dried and can be used as a raw material for the recovery of other valuable elements. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0105] (8) The clean manganese sulfate solution obtained in step (6) is adjusted to a pH value of 6 using concentrated sulfuric acid, and the manganese-containing leaching solution is evaporated and crystallized to obtain a MnSO4·H2O product that meets the requirements of HG / T 4823-2015, and the comprehensive recovery rate of manganese is 98.1%.

[0106] Comparative Example 2 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate comprises the following steps: (1) to (5) are the same as steps (1), (2), (3), (4), and (5) of Example 8.

[0107] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 70°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 1.5, the reaction took 60 minutes, and an obvious rotten egg smell could be smelled during the reaction, which was verified to be hydrogen sulfide gas. After the reaction, the liquid after precipitation and the precipitated residue were obtained by filtration. The liquid after precipitation was a clean manganese sulfate solution. ICP detection showed that the contents of Fe, Zn, Cd and Cu in the precipitated solution were less than 0.001 mg / L, the residual Al content was 5.8 mg / L, the Co content was 4.7 mg / L, and the Ni content was 5.2 mg / L. The obtained sulfide precipitation products were sulfides of Zn, Cd, Cu, Co, and Ni and oxides of Fe, Al, and Mn.

[0108] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 10 min. The washing is repeated three times and then filtered. The washed slag obtained is dried and can be used as a raw material for the recovery of other valuable elements. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0109] (8) The clean manganese sulfate solution obtained in step (6) was adjusted to a pH value of 6 using concentrated sulfuric acid, and the manganese-containing leaching solution was evaporated and crystallized to obtain a MnSO4·H2O product, wherein the Ni content was 0.058 wt.%, and the Co content was 0.049 wt.%.

[0110] The only difference between this comparative example and Example 8 is that the reaction temperature in step (6) is increased to 70° C., and the content of impurities Ni, Co, and Al in the solution after precipitation is too high, resulting in too high content of impurities such as Ni and Co in the final manganese sulfate product. The phenomenon generated during the comprehensive reaction process is analyzed. This is because when the reaction temperature in step (6) is too high, CaS is dissolved in water and hydrolyzed to produce hydrogen sulfide, resulting in a decrease in the effective sulfur content in the solution, resulting in a decrease in the impurity removal effect.

[0111] Comparative Example 3 A method for producing manganese sulfate by treating low-grade manganese oxide ore with molten iron sulfate comprises the following steps: Steps (1) to (5) are the same as steps (1), (2), (3), (4), and (5) of Example 8.

[0112] (6) The manganese sulfate leaching solution obtained in step (4) was placed in a 60°C water bath and stirred, and calcium sulfide was added in an amount according to a molar ratio of S 2- / Me = 1, react for 60 minutes, filter after the reaction to obtain a precipitated liquid and a precipitated residue, the precipitated liquid is a clean manganese sulfate solution, and ICP detection shows that the contents of Fe, Zn, Cd and Cu in the precipitated solution are less than 0.001 mg / L, the residual Al content is 24.3 mg / L, the Co content is 18.7 mg / L, and the Ni content is 21.1 mg / L. The obtained sulfide precipitation products are sulfides of Zn, Cd, Cu, Co and Ni and oxides of Fe, Al and Mn.

[0113] (7) The sulfide precipitated slag obtained in step (6) is slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g, and the resulting slurry is then placed in a water bath at 25° C. and stirred and washed for 10 min. The washing is repeated three times and then filtered. The washed slag obtained is dried and can be used as a raw material for the recovery of other valuable elements. The obtained washing liquid can be used as a leaching agent for the molten salt product in step (4).

[0114] (8) The clean manganese sulfate solution obtained in step (6) was adjusted to a pH value of 6 using concentrated sulfuric acid, and the manganese-containing leaching solution was evaporated and crystallized to obtain a MnSO4·H2O product, wherein the Ni content was 0.083 wt.%, and the Co content was 0.076 wt.%.

[0115] Comparison of Example 8 and Comparative Example 3 shows that when S 2- / Me is reduced to 1:1, resulting in incomplete impurity removal, and the impurity content in the final manganese sulfate product increases, resulting in reduced product quality.

[0116] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for producing manganese sulfate using low-grade manganese oxide ore, characterized in that: include: mixing and ball-milling low-grade manganese oxide ore powder and ferric sulfate to obtain a mixed material; The mixture is subjected to heat treatment to achieve a melting reaction, and after the reaction is completed, it is cooled to obtain a reaction product; soaking the reaction product in water to obtain a water soaking liquid and a water soaking residue; Adding sulfide to the water extract, and obtaining manganese sulfate solution and sulfide slag after precipitation reaction; The pH value of the manganese sulfate solution is adjusted to 4.0-6.5, and the solution is evaporated and crystallized to obtain manganese sulfate.

2. The method for producing manganese sulfate using low-grade manganese oxide ore according to claim 1, characterized in that: The heat treatment temperature is 400-800°C, preferably 600-700°C; the heat treatment time is 30-180min, preferably 60-120min; The atmosphere of the heat treatment is an oxygen-containing gas; preferably, the oxygen partial pressure of the oxygen-containing gas is 21 to 100%.

3. The method for producing manganese sulfate using low-grade manganese oxide ore according to claim 1, characterized in that: The low-grade manganese oxide ore powder and ferric sulfate are mixed in a molar ratio of Mn to sulfate of 1:1-2.

5.

4. The method for producing manganese sulfate using low-grade manganese oxide ore according to claim 1, characterized in that: The ball-to-material mass ratio of the ball milling is 2.5:1-20:1, and the ball milling time is 30-120 min.

5. The method for producing manganese sulfate using low-grade manganese oxide ore according to claim 1, characterized in that: The water immersion temperature is 40-100°C, preferably 60-90°C; the water immersion time is 45-180 min, preferably 60-90 min; the liquid-to-solid ratio of the water immersion is 5:1-2:1 mL / g.

6. The method for producing manganese sulfate using low-grade manganese oxide ore according to claim 1, characterized in that: The sulfide is one or more of hydrogen sulfide, calcium sulfide, sodium sulfide, ammonium sulfide, and manganese sulfide; The molar ratio of the sulfide to the impurity ions contained in the water leaching solution is 1.4:1 to 3:

1.

7. The method for producing manganese sulfate using low-grade manganese oxide ore according to claim 1, characterized in that: The temperature of the precipitation reaction is 25-100° C., preferably 50-60° C.; the time of the precipitation reaction is 45-150 min, preferably 60-120 min.

8. The method for producing manganese sulfate using low-grade manganese oxide ore according to claim 1, characterized in that: The invention also includes washing the water-soaked residue with water to obtain the washed residue and the washing liquid; The water washing liquid is used as a solvent for water immersion; the water washing slag is used as iron ore for producing steel; The number of water washing is 1 to 3 times; the temperature of the water washing is 25 to 100° C.; the slurry-solid ratio of the water washing is 2:1 to 5:1 mL / g; and the stirring time of the water washing is 5 to 30 min.

9. The method for producing manganese sulfate using low-grade manganese oxide ore according to claim 1, characterized in that: The invention also includes washing the sulfide slag with water to obtain washed slag and washing liquid; The water wash liquid is used as a solvent for water immersion; The number of water washing is 1 to 3 times; the temperature of the water washing is 25 to 100° C.; the slurry-solid ratio of the water washing is 2:1 to 5:1 mL / g; and the stirring time of the water washing is 5 to 30 min.

10. The method for producing manganese sulfate using low-grade manganese oxide ore according to claim 1, characterized in that: The manganese content of the low-grade manganese oxide ore is 15-19wt.%; The manganese sulfate is battery grade manganese sulfate.

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