Efficient leaching method for manganese ions in low-grade manganese ore

Abstract

The invention discloses an efficient leaching method for manganese ions in low-grade manganese ore. According to the method, thiourea and sodium sulfite (or sodium hydrogen sulfite) are introduced to serve as a composite reducing agent on the basis of a traditional acid leaching process for manganese extraction, high-valence manganese oxide is effectively reduced into divalent manganese ions, and the manganese leaching rate is remarkably increased. After the composite reducing agent is added, the leaching rate of manganese ions is greatly increased to 95.24% from 10.70%. And after the acid leaching reaction, the wastewater obtained by washing the leaching residues is reused for preparing ore pulp in the acid leaching treatment, so that the residual manganese ions and sulfuric acid in the leaching residues are recovered, the water resource is saved, and the production cost is reduced. According to the method, the compound reducing agent is reasonably designed, so that the manganese leaching rate is increased, and the efficient extraction of the manganese resource in the low-grade manganese ore is realized by a simple process.

Description

Technical Field

[0001] This invention relates to the field of low-grade manganese ore utilization and manganese extraction technology, specifically to a highly efficient leaching method for manganese ions in low-grade manganese ore. Background Technology

[0002] Manganese, as a critical strategic metal resource, plays an irreplaceable role in various industrial sectors, including steel metallurgy, battery materials, and chemical products. With the rapid development of the new energy industry, the demand for battery-grade manganese sulfate has increased significantly. However, long-term large-scale mining has led to the depletion of global high-grade manganese ore resources, further exacerbating the supply-demand imbalance. In recent years, my country's manganese industry has become increasingly reliant on imported manganese ore. Furthermore, in practical applications, the leaching process for extracting manganese from low-grade manganese ore still faces significant technological bottlenecks.

[0003] Manganese ores can be classified into manganese oxide ores, manganese carbonate ores, polymetallic symbiotic ores, and manganese sulfate ores, among which manganese oxide ores are the most important type, accounting for 26% of my country's total proven manganese reserves. Low-grade manganese oxide ores suffer from complex composition and structure, and high slime content, making it difficult to achieve efficient utilization of manganese. Furthermore, manganese in manganese oxide ores mainly exists in the high-valence state (Mn) which is poorly soluble in acids. 4+ and Mn 3+ High-valent manganese (Mn) exists in the form of ions, making it difficult to achieve ideal leaching results using conventional acid leaching methods. Therefore, in the acid leaching process, technologies such as roasting reduction and wet reduction are introduced to remove high-valent manganese (Mn). 4+ and Mn 3+ ) is reduced to divalent manganese (Mn) 2+ This method improves the leaching rate while directly obtaining the target product, manganese sulfate. Wet reduction leaching involves adding a reducing agent under acidic conditions to reduce high-valence manganese in situ and dissolve it simultaneously. Compared to roasting reduction leaching, wet reduction leaching eliminates the high-temperature roasting process, significantly reducing energy consumption while improving production efficiency.

[0004] Among organic and inorganic reducing agents, sulfur-containing reducing agents can effectively reduce high-valence metal ions. Ferrous sulfate, ferrous sulfide, and sulfur dioxide have been proven to effectively reduce high-valence manganese in manganese oxide ores (Chinese Journal of Nonferrous Metals, DOI: 10.11817 / j.ysxb.1004.0609.2025-45820). The two-ore process is currently the most widely used manganese leaching technology in industry, utilizing the Fe produced by the reaction of sulfuric acid and pyrite. 2+ This method achieves the reductive leaching of high-valence, insoluble manganese oxide ores. Chinese patent CN119614906A utilizes microwave treatment to improve the manganese extraction rate in the two-ore method. However, under reaction conditions with different proportions of pyrite, manganese oxide, and sulfuric acid, elemental sulfur (S) may be generated. 0The reducing agent, which covers the surface of manganese ore, inhibits the leaching process, reducing manganese extraction efficiency and increasing the demand for reducing agents (Chemical Metallurgy, 1998, (02): 66-70). This makes it difficult to optimize the process conditions for manganese ores from different sources in actual production. Therefore, it is necessary to design new reducing agents to achieve efficient and stable leaching of manganese ions from low-grade manganese ores. In addition, sodium sulfite and thiourea, as reducing agents, have been widely used in the separation of precious metals such as gold and silver (Gold, 2014, 35(01): 48-51; CN103276206A), which also provides a new design idea for reducing agents for wet reduction leaching of manganese ions. In actual production, due to the influence of reducing agents and reaction conditions, wet reduction leaching still cannot achieve efficient leaching of manganese, and further optimization is urgently needed. Summary of the Invention

[0005] To address the aforementioned problems, this invention aims to provide a highly efficient leaching method for manganese ions in low-grade manganese ore, thereby improving the manganese leaching rate of low-grade manganese ore.

[0006] The main technical solutions adopted in this invention include: A highly efficient leaching method for manganese ions in low-grade manganese ore, characterized by comprising the following steps: (1) The low-grade manganese ore was dried at 105 °C for 2 h to remove moisture, then ball-milled for 15 min and sieved with a 60 mesh screen to obtain manganese ore powder.

[0007] (2) The obtained manganese ore powder is mixed with 98 wt% concentrated sulfuric acid and water at a mass ratio of 1:(0.5~1):(5~10) to prepare a slurry;

[0008] (3) Add a composite reducing agent consisting of thiourea and sodium sulfite (or sodium bisulfite) to the obtained slurry, wherein the mass ratio of manganese ore powder, thiourea and sodium sulfite (or sodium bisulfite) is 1: (0.1~0.5): (0.1~0.3), and then carry out an acid leaching reaction at a temperature of 60~80 ºC, a reaction time of 200~300 min, and a stirring speed of 500 rpm;

[0009] (4) After the acid leaching reaction is completed, the mixed slurry is separated into solid and liquid by vacuum filtration to obtain manganese ion leaching solution and leaching residue;

[0010] (5) The obtained leaching residue is washed with water and then filtered again to separate the slag and washing wastewater, wherein the washing wastewater is reused for slurry preparation in step (2).

[0011] Preferably, in step (2), the mass ratio of manganese ore powder, 98 wt% concentrated sulfuric acid and water is 1 : 0.72 : 6.87.

[0012] Preferably, the composite reducing agent added to the slurry in step (3) consists of thiourea and sodium bisulfite, wherein the mass ratio of manganese ore powder, thiourea and sodium bisulfite is 1:0.325:0.2, the reaction temperature of the acid leaching reaction is 70 ºC, and the reaction time is 240 min.

[0013] The beneficial effects of this invention are as follows: (1) This invention introduces a composite reducing agent into the traditional acid leaching technology for manganese extraction, achieving efficient leaching of manganese ions from low-grade manganese ore. For high-valent manganese oxides in low-grade manganese ore that are difficult to extract directly by acid leaching, thiourea is innovatively introduced, significantly improving the manganese leaching rate. The use of sodium sulfite (or sodium bisulfite) reduces the amount of thiourea used and further improves the manganese leaching rate, simultaneously reducing production costs and increasing manganese extraction efficiency.

[0014] (2) In the high-efficiency manganese ion leaching technology route based on composite reducing agent of the present invention, thiourea and sodium sulfite (or sodium bisulfite) synergistically improve the manganese ion leaching rate in low-grade manganese ore, while acting as composite reducing agent, effectively removing high-valence manganese oxides (Mn) 4+ and Mn 3+ ) Restored to Mn 2+ This makes it easier to obtain the target product, manganese sulfate.

[0015] (3) This invention emphasizes the recycling of resources, and reuses the washing wastewater of the leaching residue for the preparation of slurry in acid leaching treatment. This not only recovers the residual manganese ions and sulfuric acid in the leaching residue, but also saves water resources and reduces production costs. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the method of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described and illustrated below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the scope of protection of the invention.

[0018] Example 1 A highly efficient leaching method for manganese ions in low-grade manganese ore includes the following steps: (1) The low-grade manganese ore was dried at 105 °C for 2 h to remove moisture, then ball-milled for 15 min and sieved with a 60 mesh screen to obtain manganese ore powder.

[0019] (2) The obtained manganese ore powder was mixed with 98 wt% concentrated sulfuric acid and water at a mass ratio of 1:0.72:6.87 to prepare a slurry;

[0020] (3) Add a composite reducing agent consisting of thiourea and sodium bisulfite to the obtained slurry, wherein the mass ratio of manganese ore powder, thiourea and sodium bisulfite is 1:0.325:0.2. Then carry out an acid leaching reaction at a reaction temperature of 70 ºC, a reaction time of 240 min and a stirring speed of 500 rpm.

[0021] (4) After the acid leaching reaction is completed, the mixed slurry is separated into solid and liquid by vacuum filtration to obtain manganese ion leaching solution and leaching residue;

[0022] (5) The obtained leaching residue is washed with water and then filtered again to separate the slag and washing wastewater, wherein the washing wastewater is reused for slurry preparation in step (2).

[0023] The total manganese content of the low-grade manganese ore used in this embodiment is 23.29%, and the manganese content in the leachate was tested, and the manganese leaching rate reached 95.24%.

[0024] Example 2 A highly efficient leaching method for manganese ions in low-grade manganese ore includes the following steps: (1) The low-grade manganese ore was dried at 105 °C for 2 h to remove moisture, then ball-milled for 15 min and sieved with a 60 mesh screen to obtain manganese ore powder.

[0025] (2) The obtained manganese ore powder was mixed with 98 wt% concentrated sulfuric acid and water at a mass ratio of 1:0.72:6.87 to prepare a slurry;

[0026] (3) Add a composite reducing agent composed of thiourea and sodium sulfite to the obtained slurry, wherein the mass ratio of manganese ore powder, thiourea and sodium sulfite is 1:0.325:0.25. Then carry out an acid leaching reaction at a reaction temperature of 70 ºC, a reaction time of 240 min and a stirring speed of 500 rpm.

[0027] (4) After the acid leaching reaction is completed, the mixed slurry is separated into solid and liquid by vacuum filtration to obtain manganese ion leaching solution and leaching residue;

[0028] (5) The obtained leaching residue is washed with water and then filtered again to separate the slag and washing wastewater, wherein the washing wastewater is reused for slurry preparation in step (2).

[0029] The total manganese content of the low-grade manganese ore used in this embodiment is 23.29%, and the manganese content in the leachate was tested, and the manganese leaching rate reached 94.64%.

[0030] Example 3 A highly efficient leaching method for manganese ions in low-grade manganese ore includes the following steps: (1) The low-grade manganese ore was dried at 105 °C for 2 h to remove moisture, then ball-milled for 15 min and sieved with a 60 mesh screen to obtain manganese ore powder.

[0031] (2) The obtained manganese ore powder was mixed with 98 wt% concentrated sulfuric acid and water at a mass ratio of 1:0.5:10 to prepare a slurry;

[0032] (3) Add a composite reducing agent composed of thiourea and sodium sulfite to the obtained slurry, wherein the mass ratio of manganese ore powder, thiourea and sodium sulfite is 1:0.1:0.3, and then carry out an acid leaching reaction at a reaction temperature of 60 ºC, a reaction time of 200 min and a stirring speed of 500 rpm.

[0033] (4) After the acid leaching reaction is completed, the mixed slurry is separated into solid and liquid by vacuum filtration to obtain manganese ion leaching solution and leaching residue;

[0034] (5) The obtained leaching residue is washed with water and then filtered again to separate the slag and washing wastewater, wherein the washing wastewater is reused for slurry preparation in step (2).

[0035] The total manganese content of the low-grade manganese ore used in this embodiment is 23.29%, and the manganese content in the leachate was tested, and the manganese leaching rate reached 92.19%.

[0036] Example 4 A highly efficient leaching method for manganese ions in low-grade manganese ore includes the following steps: (1) The low-grade manganese ore was dried at 105 °C for 2 h to remove moisture, then ball-milled for 15 min and sieved with a 60 mesh screen to obtain manganese ore powder.

[0037] (2) The obtained manganese ore powder was mixed with 98 wt% concentrated sulfuric acid and water in a mass ratio of 1:1:5 to prepare a slurry;

[0038] (3) Add a composite reducing agent consisting of thiourea and sodium bisulfite to the obtained slurry, wherein the mass ratio of manganese ore powder, thiourea and / or sodium bisulfite is 1:0.5:0.1, and then carry out an acid leaching reaction at a reaction temperature of 80 ºC, a reaction time of 300 min, and a stirring speed of 500 rpm.

[0039] (4) After the acid leaching reaction is completed, the mixed slurry is separated into solid and liquid by vacuum filtration to obtain manganese ion leaching solution and leaching residue;

[0040] (5) The obtained leaching residue is washed with water and then filtered again to separate the slag and washing wastewater, wherein the washing wastewater is reused for slurry preparation in step (2).

[0041] The total manganese content of the low-grade manganese ore used in this embodiment is 23.29%, and the manganese content in the leachate was tested, with a manganese leaching rate of 95.17%.

[0042] Comparative Example 1 The difference from Example 1 is that no composite reducing agent is added, and the method includes the following steps: (1) The low-grade manganese ore was dried at 105 °C for 2 h to remove moisture, then ball-milled for 15 min and sieved with a 60 mesh screen to obtain manganese ore powder.

[0043] (2) The obtained manganese ore powder was mixed with 98 wt% concentrated sulfuric acid and water at a mass ratio of 1:0.72:6.87 to prepare a slurry;

[0044] (3) The obtained slurry was subjected to acid leaching reaction at a reaction temperature of 70 ºC, a reaction time of 240 min, and a stirring speed of 500 rpm;

[0045] (4) After the acid leaching reaction is completed, the mixed slurry is separated into solid and liquid by vacuum filtration to obtain manganese ion leaching solution and leaching residue;

[0046] (5) The obtained leaching residue is washed with water and then filtered again to separate the slag and washing wastewater, wherein the washing wastewater is reused for slurry preparation in step (2).

[0047] The total manganese content of the low-grade manganese ore used in this comparative example was 23.29%, and the manganese content in the leachate was tested, with a manganese leaching rate of 10.70%.

[0048] Comparative Example 2 The difference from Example 1 is that only thiourea is added, including the following steps: (1) The low-grade manganese ore was dried at 105 °C for 2 h to remove moisture, then ball-milled for 15 min and sieved with a 60 mesh screen to obtain manganese ore powder.

[0049] (2) The obtained manganese ore powder was mixed with 98 wt% concentrated sulfuric acid and water at a mass ratio of 1:0.72:6.87 to prepare a slurry;

[0050] (3) Thiourea was added to the obtained slurry, wherein the mass ratio of manganese ore powder to thiourea was 1:0.48, and then acid leaching was carried out at a reaction temperature of 70 ºC, a reaction time of 240 min, and a stirring speed of 500 rpm.

[0051] (4) After the acid leaching reaction is completed, the mixed slurry is separated into solid and liquid by vacuum filtration to obtain manganese ion leaching solution and leaching residue;

[0052] (5) The obtained leaching residue is washed with water and then filtered again to separate the slag and washing wastewater, wherein the washing wastewater is reused for slurry preparation in step (2).

[0053] The total manganese content of the low-grade manganese ore used in this comparative example was 23.29%, and the manganese content in the leachate was tested, with a manganese leaching rate of 91.80%.

[0054] As can be seen, the present invention employs thiourea and sodium sulfite (or sodium bisulfite) as a composite reducing agent to achieve a high-efficiency leaching process for manganese ions in low-grade manganese ore. This process effectively improves the manganese leaching rate, which can reach up to 95.24%. This is a significant improvement compared to the leaching process without the composite reducing agent in Comparative Example 1 (10.70%) and the leaching process with only thiourea in Comparative Example 2 (91.80%).

Claims

1. A highly efficient leaching method for manganese ions in low-grade manganese ore, characterized in that, Includes the following steps: (1) The low-grade manganese ore was dried at 105 °C for 2 h to remove moisture, then ball-milled for 15 min and sieved with a 60 mesh screen to obtain manganese ore powder. (2) The obtained manganese ore powder is mixed with 98 wt% concentrated sulfuric acid and water at a mass ratio of 1:(0.5~1):(5~10) to prepare a slurry; (3) Add a composite reducing agent consisting of thiourea and sodium sulfite (or sodium bisulfite) to the obtained slurry, wherein the mass ratio of manganese ore powder, thiourea and sodium sulfite (or sodium bisulfite) is 1: (0.1~0.5): (0.1~0.3), and then carry out an acid leaching reaction at a temperature of 60~80 ºC, a reaction time of 200~300 min, and a stirring speed of 500 rpm; (4) After the acid leaching reaction is completed, the mixed slurry is separated into solid and liquid by vacuum filtration to obtain manganese ion leaching solution and leaching residue; (5) The obtained leaching residue is washed with water and then filtered again to separate the slag and washing wastewater, wherein the washing wastewater is reused for slurry preparation in step (2).

2. The method for efficient leaching of manganese ions from low-grade manganese ore according to claim 1, characterized in that, In step (2), the mass ratio of manganese ore powder, 98 wt% concentrated sulfuric acid and water is 1 : 0.72 : 6.

87.

3. The method for efficient leaching of manganese ions from low-grade manganese ore according to claim 1, characterized in that, In step (3), the composite reducing agent added to the slurry consists of thiourea and sodium bisulfite, wherein the mass ratio of manganese ore powder, thiourea and sodium bisulfite is 1:0.325:0.2, the reaction temperature of the acid leaching reaction is 70 ºC, and the reaction time is 240 min.

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