Comprehensive recycling method of electrolytic manganese residues

Abstract

The invention discloses a comprehensive recycling method of electrolytic manganese residues. The method comprises the following steps: treating the electrolytic manganese residues by adopting a pickling and ball-milling process to obtain a leaching solution and leaching residues; treating the leachate by adopting a step-by-step separation process to obtain manganese minerals and struvite; and treating the leached residues by adopting a glass ceramic process to obtain the microcrystalline glass. According to the method, the acid pickling ball-milling process, the step-by-step separation process and the glass ceramic process are combined, the recycling value of the electrolytic manganese residues is greatly improved, and the acid pickling ball-milling and step-by-step separation processes which are low in cost and less in environmental pollution can be used for recycling manganese and ammonia nitrogen and preparing manganese minerals, struvite and other resource materials; in addition, the leached slag can be converted into a ceramic material which can be further utilized through a glass ceramic process. As the manganese ions and the ammonia nitrogen are prepared into insoluble precipitates, and the sulfur element in the electrolytic manganese residues is removed, the sulfur element in the leaching residues cannot enter the air in the process of preparing the glass ceramics, the air pollution is avoided, and the yield of the glass ceramics is increased under the condition of the same energy consumption.

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste treatment and resource utilization, and in particular relates to a comprehensive recycling method for electrolytic manganese slag. Background Art

[0002] In recent years, the recycling of electrolytic manganese slag has received more and more attention and application worldwide. my country is the world's largest producer, consumer and exporter of manganese metal. In 2018, the annual output of China was 1.4 million tons, accounting for 97% of the world's total. On average, every ton of manganese metal produced will produce 6-10 tons of electrolytic manganese slag.

[0003] However, due to the lack of a better method to process electrolytic manganese slag, and the manganese slag reserves continue to increase every year, occupying large areas of land, causing serious waste of resources. The manganese slag after being processed by the existing harmless treatment method of electrolytic manganese slag still contains ions of mercury, cadmium, arsenic, lead and other environmental pollutants, or in the process of calcining, a large amount of alkaline substances are needed to absorb SO3, and the cost is too high. Therefore, the current electrolytic manganese slag treatment method does not solve the problem of environmental pollution, and the treatment problem of electrolytic manganese slag is already imminent. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a comprehensive recycling method of electrolytic manganese slag which has simple process, low cost, environmental friendliness and good benefits.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The invention discloses a comprehensive recycling method for electrolytic manganese slag, which comprises the following steps: treating the electrolytic manganese slag by an acid washing ball milling process to obtain a leaching solution and leaching slag; treating the leaching solution by a step-by-step separation process to obtain manganese minerals and struvite; and treating the leaching slag by a glass ceramic process to obtain glass ceramics.

[0007] The comprehensive recycling method of electrolytic manganese slag is to process the leached slag by glass-ceramic technology to obtain microcrystalline glass.

[0008] The pickling ball milling process is operated as follows: the electrolytic manganese slag is dried and crushed into powder, then mixed with oxalic acid solution, placed in a ball mill for stirring and leaching, and separated to obtain a leaching solution and leaching slag containing manganese, ammonia nitrogen and sulfur.

[0009] The solid-liquid ratio of electrolytic manganese slag to oxalic acid solution is 1:1-50 g / mL, the concentration of oxalic acid solution is 1-250 g / L, the ball milling speed is 250-450 r / min, and the ball milling time is 0.5-3 h.

[0010] The step-by-step separation process is operated as follows: adding ammonia water, magnesium salt and phosphate to the leachate to recover ammonia nitrogen in the solution, stirring and precipitating to separate the solid and liquid, and continuing to add NaOH to the separated solution, stirring and precipitating to separate the solid and liquid.

[0011] The magnesium salt is MgCl2·6H2O, and the phosphate is Na2HPO4·12H2O; the volume ratio of the leachate to the ammonia water is 400:1-15, and the liquid-to-solid ratios of the leachate to MgCl2·6H2O, Na2HPO4·12H2O and NaOH are 25:1-3g / mL, 25:1-4g / mL and 100:1-3g / mL respectively.

[0012] The glass ceramic process is operated as follows: the leached slag is treated at 900°C, mixed with magnesium oxide, silicon dioxide and a nucleating agent, placed in a muffle furnace, poured into a stainless steel mold after melting, cooled and shaped, and then heat treated to obtain glass ceramics.

[0013] The nucleating agent is magnesium aluminum chromium spinel; the leaching residue, magnesium oxide, silicon dioxide and the nucleating agent are prepared according to the following percentages: 75-85wt.% of leaching residue, 8-13wt.% of magnesium oxide, 3-7wt.% of silicon dioxide and 1-5wt.% of nucleating agent.

[0014] The melting temperature is 1200-1450°C, and the heat treatment temperature is 600-950°C.

[0015] In view of the problems existing in the current treatment of electrolytic manganese slag, the inventor has established a comprehensive recycling method for electrolytic manganese slag, wherein the electrolytic manganese slag is treated by an acid-washing ball milling process to obtain a leachate and a leachate slag; the leachate is treated by a step-by-step separation process to obtain manganese ore and struvite; the leachate slag is treated by a glass-ceramic process to obtain microcrystalline glass. The present invention combines the acid-washing ball milling process, the step-by-step separation process and the glass-ceramic process, greatly improving the recycling value of the electrolytic manganese slag, wherein the acid-washing ball milling and step-by-step separation process with low cost and less environmental pollution can recycle manganese and ammonia nitrogen and prepare resource materials such as manganese ore and struvite; in addition, the leached slag can also be converted into a ceramic material (microcrystalline glass) that can be further utilized by a glass-ceramic process. Since manganese ions and ammonia nitrogen are prepared into insoluble precipitation, the sulfur element in the electrolytic manganese slag is removed at the same time, so that the sulfur element in the leachate slag will not enter the air during the preparation of glass-ceramic, avoiding air pollution, and increasing the output of glass-ceramic under the same energy consumption.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention combines acid leaching and ball milling technology to achieve efficient and rapid leaching of manganese in manganese slag, and has the advantages of fast leaching speed, environmental friendliness, short processing time, low energy consumption, etc.

[0018] 2. The process for preparing microcrystalline glass of the present invention is simple, requires less equipment, and uses a large amount of manganese slag, which is suitable for large-scale treatment of electrolytic manganese slag; the produced microcrystalline glass can be used as a building material, providing certain economic benefits and reducing the cost required for manganese slag treatment.

[0019] Therefore, the present invention provides a new direction for the resource utilization of electrolytic manganese slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a process flow chart of the comprehensive recycling method of electrolytic manganese slag.

[0021] Figure 2 It is a TG-DSC curve chart of the electrolytic manganese slag used in the present invention.

[0022] Figure 3 The XRD diagram of the glass in Examples 1-3 of the present invention is

[0023] Figure 4 This is the XRD diagram of the manganese ore produced after adding ammonia water in Example 4 of the present invention and after calcining at 600° C. for 3 hours, in the figure: a manganese ore, b manganese ore after calcination.

[0024] Figure 5 This is the XRD diagram of the struvite precipitate produced by adding MgCl2·6H2O and Na2HPO4·12H2O in Example 4 of the present invention.

[0025] Figure 6 This is the XRD diagram of struvite produced by adding MgCl2·6H2O and Na2HPO4·12H2O, stirring, filtering, and then adding NaOH again in Example 4 of the present invention.

[0026] Figure 7 This is the XRD diagram of the residue after the remaining solution is evaporated after the manganese and ammonia ions are removed in Example 4 of the present invention.

[0027] Figure 8 This is the XRD diagram of the glass-ceramics obtained in Example 4 of the present invention. DETAILED DESCRIPTION

[0028] To further illustrate how to implement the present invention, the following is a specific description through an embodiment, wherein the electrolytic manganese slag comes from Guangxi Daxin Manganese Industry, and its basic composition is SO3, SiO2, CaO, Fe2O3, MnO, MgO and Al2O3, which account for more than 80% of the total mass.

[0029] Example 1

[0030] 1. Dry the electrolytic manganese slag and crush it into powder. Pass it through a 50-mesh sieve. Weigh 5 g of the sample and mix it with 20 g / L oxalic acid solution at a liquid-solid ratio of 20:1 mL / g.

[0031] 2. Place in a ball mill, leaching at 350r / min for 1h, and obtain leachate and leach residue by separation;

[0032] 3. Add 1.5 mL of ammonia water to 50 mL of the leaching solution, stir mechanically for 20 minutes, and then separate the solid and liquid. Then add 5.274 g of MgCl2·6H2O and 6.625 g of Na2HPO4·12H2O, stir mechanically for 15 minutes, and then separate the solid and liquid.

[0033] 4. Add 1g NaOH, stir and filter;

[0034] 5. After calcining the leached residue in a muffle furnace at 900°C for 3 hours, the mixture was uniformly mixed with magnesium oxide, silicon dioxide and magnesium aluminum chromium spinel in the following mass percentages: 83.3230wt.% of leached residue, 10.9941wt.% of magnesium oxide, 4.6829wt.% of silicon dioxide and 1wt.% of nucleating agent;

[0035] 6. Melt at 1400°C for 3 hours and cool naturally at a rate of 10°C / min.

[0036] Example 2

[0037] 1. Dry the electrolytic manganese slag and crush it into powder. Pass it through a 50-mesh sieve. Weigh 5 g of the sample and mix it with 0.02 g / mL oxalic acid solution at a liquid-solid ratio of 20:1 mL / g.

[0038] 2. Place in a ball mill, leaching at 350r / min for 1h, and obtain leachate and leach residue by separation;

[0039] 3. Add 1.5 mL of ammonia water to 50 mL of the leaching solution, stir mechanically for 20 minutes, and then separate the solid and liquid. Then add 5.274 g of MgCl2·6H2O and 6.625 g of Na2HPO4·12H2O, stir mechanically for 15 minutes, and then separate the solid and liquid.

[0040] 4. Add 1 g of NaOH, stir and filter; 5. Place the leached residue in a muffle furnace at 900° C. and calcine for 3 hours, then mix it evenly with magnesium oxide, silicon dioxide and magnesium aluminum chromium spinel according to the mass percentage: leached residue 82.4813wt.%, magnesium oxide 10.8831wt.%, silicon dioxide 4.6356wt.% and nucleating agent 2wt.%, place it in a muffle furnace, melt it at 1400° C. for 3 hours, take it out and pour it into a stainless steel mold to cool.

[0041] Example 3

[0042] 1. Dry the electrolytic manganese slag and crush it into powder. Pass it through a 50-mesh sieve. Weigh 5 g of the sample and mix it with 0.02 g / mL oxalic acid solution at a liquid-solid ratio of 20:1 mL / g.

[0043] 2. Place in a ball mill, leaching at 350r / min for 1h, and obtain leachate and leach residue by separation;

[0044] 3. Add 1.5 mL of ammonia water to 50 mL of the leaching solution, stir mechanically for 20 minutes, and then separate the solid and liquid. Then add 5.274 g of MgCl2·6H2O and 6.625 g of Na2HPO4·12H2O, stir mechanically for 15 minutes, and then separate the solid and liquid.

[0045] 4. Add 1g NaOH, stir and filter;

[0046] 5. After calcining the leached residue in a muffle furnace at 900°C for 3 hours, mix it evenly with magnesium oxide, silicon dioxide and magnesium aluminum chromium spinel in the following mass percentages: leached residue 80.7980wt%, magnesium oxide 10.6610wt%, silicon dioxide 4.5410wt% and nucleating agent 4wt%, place it in a muffle furnace, melt it at 1400°C for 3 hours, take it out and pour it into a stainless steel mold to cool.

[0047] Example 4

[0048] 1. Dry the electrolytic manganese slag and crush it into powder. Pass it through a 50-mesh sieve. Weigh 5 g of the sample and mix it with 0.02 g / mL oxalic acid solution at a liquid-solid ratio of 20:1 mL / g.

[0049] 2. Place in a ball mill, leaching at 350r / min for 1h, and obtain leachate and leach residue by separation;

[0050] 3. Add 1.5 mL of ammonia water to 50 mL of the leaching solution, stir mechanically for 20 minutes, and then separate the solid and liquid. Then add 5.274 g of MgCl2·6H2O and 6.625 g of Na2HPO4·12H2O, stir mechanically for 15 minutes, and then separate the solid and liquid.

[0051] 4. Add 1g NaOH, stir and filter;

[0052] 5. After the leached residue is calcined in a muffle furnace at 900°C for 3 hours, it is evenly mixed with magnesium oxide, silicon dioxide and magnesium aluminum chromium spinel in the following mass percentages: leached residue 83.3230wt.%, magnesium oxide 10.9941wt.%, silicon dioxide 4.6829wt.% and nucleating agent 1wt.%, and placed in a muffle furnace for melting at 1400°C for 3 hours. After being taken out and poured into a stainless steel mold and cooled, it is placed in a muffle furnace for high-temperature heat treatment at 860°C for 5 hours.

[0053] The glass-ceramics in Examples 1-3 were subjected to XRD testing, and the results were as follows: Figure 3 When the nucleating agent content exceeds 2wt.%, the XRD peaks of glass ceramics appear in the unheat-treated glass sample. XRD detection of the products of each step of Example 4 is performed, and the results are as follows: Figure 4-8 The results show that the recovery rates of manganese and sulfur in the manganese slag treated by the pickling and ball milling process of the present invention reach 79.38% and 95.79%, and the recovery rates of manganese ions and ammonia nitrogen in the solution reach 99.98% and 97.42%, respectively. The test results of the prepared glass ceramics are: the glass ceramics have no cracks and damage, and the leaching test results meet the limit values ​​of the technical indicators of solid waste hazardous characteristics specified in GB5085.3-2007 Hazardous Waste Identification Standard.

[0054] The results of other embodiments are similar to this and will not be described in detail.

Claims

1. A comprehensive recycling method for electrolytic manganese slag, characterized in that: The electrolytic manganese slag is treated by an acid washing ball milling process to obtain a leaching solution and a leaching slag; the leaching solution is treated by a step-by-step separation process to obtain manganese ore and struvite.

2. The comprehensive recycling method of electrolytic manganese slag according to claim 1, characterized in that: The leached residue is processed by glass ceramic process to obtain glass-ceramics.

3. The comprehensive recycling method of electrolytic manganese slag according to claim 1, characterized in that The pickling ball milling process is operated as follows: the electrolytic manganese slag is dried and crushed into powder, then mixed with oxalic acid solution, placed in a ball mill for stirring and leaching, and separated to obtain a leaching solution and leaching slag containing manganese, ammonia nitrogen and sulfur.

4. The comprehensive recycling method of electrolytic manganese slag according to claim 3, characterized in that: The solid-liquid ratio of the electrolytic manganese slag to the oxalic acid solution is 1:1-50 g / mL, the concentration of the oxalic acid solution is 1-250 g / L, the ball milling speed is 250-450 r / min, and the ball milling time is 0.5-3 h.

5. The comprehensive recycling method of electrolytic manganese slag according to claim 1, characterized in that The step-by-step separation process is operated as follows: adding ammonia water, magnesium salt and phosphate to the leaching solution, stirring and precipitating, and then separating the solid and liquid; continuously adding NaOH to the separated solution, stirring and precipitating, and then separating the solid and liquid.

6. The comprehensive recycling method of electrolytic manganese slag according to claim 1, characterized in that: The magnesium salt is MgCl2·6H2O, and the phosphate is Na2HPO4·12H2O; the volume ratio of the leachate to aqueous ammonia is 400:1-15, and the liquid-to-solid ratios of the leachate to MgCl2·6H2O, Na2HPO4·12H2O and NaOH are 25:1-3g / mL, 25:1-4g / mL and 100:1-3g / mL respectively.

7. The comprehensive recycling method of electrolytic manganese slag according to claim 1, characterized in that The glass ceramic process is operated as follows: the leached slag is treated at 900°C, mixed with magnesium oxide, silicon dioxide and a nucleating agent, placed in a muffle furnace, poured into a stainless steel mold after melting, cooled and shaped, and then heat treated to obtain microcrystalline glass.

8. The comprehensive recycling method of electrolytic manganese slag according to claim 1, characterized in that: The nucleating agent is magnesium aluminum chromium spinel; the leaching residue, magnesium oxide, silicon dioxide and nucleating agent are prepared according to the following percentages: leaching residue 75-85wt.%, magnesium oxide 8-13wt.%, silicon dioxide 3-7wt.% and nucleating agent 1-5wt.%.

9. The comprehensive recycling method of electrolytic manganese slag according to claim 1, characterized in that: The melting temperature is 1200-1450°C, and the heat treatment temperature is 600-950°C.

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