A method for resource-based treatment of manganese slag

Abstract

The present invention belongs to the technical field of industrial solid waste resource treatment, and provides a resource treatment method for manganese slag. The method comprises the following steps: mixing phosphate tailings and kaolin, calcining to obtain a calcined phosphate tailings-kaolin composite material; mixing manganese slag, water and calcined phosphate tailings-kaolin composite material, reacting, filtering to obtain filter residue and filtrate after the reaction is completed; mixing the filtrate with sodium hydroxide solution, performing electro-oxidation, and completing the resource treatment of manganese slag. The present invention selects the composite material obtained by mixing and calcining phosphate tailings and kaolin as a stabilizer, and the two materials cooperate with each other to efficiently stabilize the manganese in the manganese slag, thereby avoiding the adverse effects of subsequent manganese on ammonia nitrogen removal; then electro-oxidation is used to remove ammonia nitrogen in the filtrate, so that the electrolytic manganese slag is converted into a filter residue and a qualified filtrate that can be used for building materials. The treatment process of the present invention is simple and efficient, and provides a new way to achieve resource treatment of manganese slag.

Description

Technical Field

[0001] This invention relates to the field of industrial solid waste resource utilization technology, and in particular to a method for the resource utilization of manganese slag. Background Technology

[0002] Electrolytic manganese slag is the waste residue produced during the electrolytic manganese production process after manganese carbonate ore undergoes acid leaching, neutralization, and pressure filtration. As an industrial waste, electrolytic manganese slag has a high moisture content, fine particles, and contains large amounts of heavy metals such as ammonia nitrogen and manganese, making it highly susceptible to environmental pollution. Currently, most electrolytic manganese enterprises dispose of the waste residue by sending it to stockpiles and using a wet storage method with dams. Due to rainfall, large amounts of manganese ions and ammonia nitrogen in the electrolytic manganese slag will seep into surrounding water bodies and soil through surface runoff, polluting the environment, wasting resources, and posing a threat to human health.

[0003] Therefore, increasing the resource utilization of electrolytic manganese slag is of great significance to both the electrolytic manganese industry and economic development. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a method for the resource-based treatment of manganese slag.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for the resource-based treatment of manganese slag, comprising the following steps:

[0007] (1) Mix phosphorus tailings and kaolin and calcine them to obtain calcined phosphorus tailings-kaolin composite material;

[0008] (2) Mix manganese slag, water and calcined phosphorus tailings-kaolin composite material, react them, and filter them after the reaction to obtain filter residue and filtrate.

[0009] (3) Mix the filtrate with sodium hydroxide solution and perform electro-oxidation to complete the resource utilization of manganese slag.

[0010] Preferably, the mass ratio of phosphorus tailings to kaolin in step (1) is 0.5-1.5:0.5-1.5.

[0011] Preferably, the heating rate of the calcination in step (1) is 8-12℃ / min, the calcination temperature is 800-1100℃, and the holding time after reaching the target temperature is 1-3h.

[0012] Preferably, the mass ratio of manganese slag, water and calcined phosphorus tailings-kaolin composite material in step (2) is 1:2 to 6:0.05 to 0.3.

[0013] Preferably, the reaction temperature in step (2) is 50-60°C, the stirring speed is 200-400 r / min, and the reaction time is 2-5 h.

[0014] Preferably, the concentration of the sodium hydroxide solution in step (3) is 0.3 to 0.7 mol / L, and the pH value of the mixed solution is 10 to 11.

[0015] Preferably, the current density of the electro-oxidation in step (3) is 23–29 mA / cm². 2 .

[0016] Preferably, the electrode spacing in step (3) of the electro-oxidation is 1 to 2 cm.

[0017] Preferably, the electro-oxidation time in step (3) is 1 to 2 hours.

[0018] The beneficial effects of this invention are:

[0019] This invention provides a method for the resource-based treatment of manganese slag, comprising the following steps: mixing phosphorus tailings and kaolin, and calcining them to obtain a calcined phosphorus tailings-kaolin composite material; mixing manganese slag, water, and the calcined phosphorus tailings-kaolin composite material, reacting them, and filtering them after the reaction to obtain filter residue and filtrate; mixing the filtrate with sodium hydroxide solution and performing electro-oxidation to complete the resource-based treatment of manganese slag. This invention uses the composite material obtained by calcining phosphorus tailings and kaolin as a stabilizer. The two materials work synergistically to efficiently stabilize manganese in the manganese slag, thus avoiding the adverse effects of manganese on ammonia nitrogen removal. Then, sodium hydroxide solution is used to remove phosphorus from the filtrate, and electro-oxidation is used to remove ammonia nitrogen from the filtrate, transforming the electrolytic manganese slag into filter residue and compliant filtrate that can be used in building materials. This invention has a simple and efficient processing method, providing a new approach for the resource-based treatment of manganese slag. Detailed Implementation

[0020] This invention provides a method for the resource-based treatment of manganese slag, comprising the following steps:

[0021] (1) Mix phosphorus tailings and kaolin and calcine them to obtain calcined phosphorus tailings-kaolin composite material;

[0022] (2) Mix manganese slag, water and calcined phosphorus tailings-kaolin composite material, react them, and filter them after the reaction to obtain filter residue and filtrate.

[0023] (3) Mix the filtrate with sodium hydroxide solution and perform electro-oxidation to complete the resource utilization of manganese slag.

[0024] In this invention, the mass ratio of phosphorus tailings and kaolin in step (1) is preferably 0.5-1.5:0.5-1.5, more preferably 0.7-1.3:0.7-1.3, and even more preferably 0.8-1.0:0.8-1.0.

[0025] In this invention, the heating rate of the calcination in step (1) is preferably 8-12℃ / min, more preferably 9-11℃ / min, and even more preferably 10-10.5℃ / min; the calcination temperature is preferably 800-1100℃, more preferably 900-1000℃, and even more preferably 950-970℃; the holding time after reaching the target temperature is preferably 1-3h, more preferably 1.5-2.5h, and even more preferably 1.8-2h.

[0026] In this invention, after the calcination in step (1) is completed, the material is cooled in the furnace, and then ground and sieved in sequence to obtain the calcined phosphorus tailings-kaolin composite material. The target temperature for cooling in the furnace is preferably 20-30°C, more preferably 22-28°C, and even more preferably 25-26°C. The mesh size of the sieve is preferably 40-80 mesh, more preferably 50-70 mesh, and even more preferably 60 mesh.

[0027] In this invention, the mass ratio of manganese slag, water and calcined phosphorus tailings-kaolin composite material in step (2) is preferably 1:2 to 6:0.05 to 0.3, more preferably 1:3 to 5:0.1 to 0.25, and even more preferably 1:4 to 4.5:0.15 to 0.2.

[0028] In this invention, the reaction temperature in step (2) is preferably 50-60°C, more preferably 52-58°C, and even more preferably 55-56°C; the stirring speed is preferably 200-400 r / min, more preferably 250-350 r / min, and even more preferably 300-320 r / min; and the reaction time is preferably 2-5 h, more preferably 3-4 h, and even more preferably 3.3-3.5 h.

[0029] In this invention, the filter residue obtained from step (2) can be processed using conventional techniques in the field, and is preferably used in the preparation of building materials.

[0030] In this invention, the concentration of the sodium hydroxide solution in step (3) is preferably 0.3 to 0.7 mol / L, more preferably 0.4 to 0.6 mol / L, and even more preferably 0.5 to 0.55 mol / L; the pH value of the mixed solution is preferably 10 to 11, more preferably 10.2 to 10.8, and even more preferably 10.5 to 10.6.

[0031] In this invention, the anode plate for electro-oxidation in step (3) is preferably a DSA anode plate, and the cathode plate is preferably a graphite cathode plate.

[0032] In this invention, the current density of the electro-oxidation in step (3) is preferably 23-29 mA / cm². 2 More preferably 25–28 mA / cm 2 More preferably 26–27 mA / cm 2 .

[0033] In this invention, the electrode spacing of the electro-oxidation in step (3) is preferably 1 to 2 cm, more preferably 1.2 to 1.8 cm, and even more preferably 1.5 to 1.6 cm.

[0034] In this invention, the electro-oxidation time in step (3) is preferably 1 to 2 hours, more preferably 1.2 to 1.8 hours, and even more preferably 1.5 to 1.6 hours.

[0035] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0036] Example 1

[0037] Phosphate tailings and kaolin were mixed (mass ratio of phosphate tailings to kaolin was 1.0:1.0), heated to 950℃ at a heating rate of 10℃ / min, and calcined. The holding time for calcination was set to 2 hours. After calcination, the mixture was cooled to 25℃ in the furnace, then ground and passed through a 60-mesh sieve to obtain the calcined phosphate tailings-kaolin composite material. Manganese slag, water, and the calcined phosphate tailings-kaolin composite material were then mixed (mass ratio of manganese slag, water, and the calcined phosphate tailings-kaolin composite material was 1:4:0.2). The reaction was carried out at 55℃ and 300 r / min for 3.5 h. After the reaction, the mixture was filtered to obtain filter residue and filtrate. The filter residue was treated using conventional techniques in the field and used for the preparation of building materials. The filtrate was mixed with a 0.5 mol / L sodium hydroxide solution (the pH of the resulting solution was 10.6) and subjected to electro-oxidation. The electro-oxidation conditions were as follows: the anode plate was a DSA anode plate, the cathode plate was a graphite cathode plate, and the current density was 27 mA / cm². 2 The electrode spacing was 1.6 cm, and the time was 1.5 h. After the electro-oxidation was completed, the treated filtrate was obtained, thus completing the resource utilization treatment of manganese slag.

[0038] According to the Chinese standard for testing the leaching toxicity of solid waste (GB5085.3-2007), the leaching amounts of manganese and ammonia nitrogen in the filtrate after treatment in this embodiment were tested, and the manganese fixation rate and ammonia nitrogen removal rate were calculated. The results showed that the treated filtrate met the national standard for wastewater discharge GB8978-1996; the manganese fixation rate was 99.98%, and the ammonia nitrogen removal rate was 96.26%.

[0039] Example 2

[0040] Phosphate tailings and kaolin were mixed (mass ratio of phosphate tailings to kaolin was 1.0:0.8) and calcined at 10℃ / min to 1000℃. The holding time for calcination was set to 1.5h. After calcination, the mixture was cooled to 25℃ in the furnace, then ground and passed through a 60-mesh sieve to obtain a calcined phosphate tailings-kaolin composite material. Manganese slag, water, and the calcined phosphate tailings-kaolin composite material were then mixed (mass ratio of manganese slag, water, and the calcined phosphate tailings-kaolin composite material was 1:3:0.1). 5) The reaction was carried out at 56℃ and 250 r / min for 3 hours. After the reaction, the mixture was filtered to obtain filter residue and filtrate. The filter residue was treated using conventional techniques in the field and used for the preparation of building materials. The filtrate was mixed with a 0.6 mol / L sodium hydroxide solution (the pH of the resulting solution was 10.5) and subjected to electro-oxidation. The electro-oxidation conditions were as follows: the anode plate was a DSA anode plate, the cathode plate was a graphite cathode plate, and the current density was 25 mA / cm². 2 The electrode spacing was 1.5 cm, and the time was 1.8 h. After the electro-oxidation was completed, the treated filtrate was obtained, thus completing the resource utilization treatment of manganese slag.

[0041] Using the same test method as in Example 1, the filtrate treated in this example meets the national wastewater discharge standard GB8978-1996; the manganese fixation rate is 99.99%, and the ammonia nitrogen removal rate is 96.37%.

[0042] Example 3

[0043] Phosphate tailings and kaolin were mixed (mass ratio of phosphate tailings to kaolin was 1.0:0.5) and calcined at 900℃ at a heating rate of 9℃ / min. The holding time for calcination was set to 2.5h. After calcination, the mixture was cooled to 25℃ in the furnace, then ground and passed through a 60-mesh sieve to obtain a calcined phosphate tailings-kaolin composite material. Manganese slag, water, and the calcined phosphate tailings-kaolin composite material were mixed (mass ratio of manganese slag, water, and the calcined phosphate tailings-kaolin composite material was 1:4.5:0.2). 5) The reaction was carried out at 52℃ and 200 r / min for 5 h. After the reaction, the mixture was filtered to obtain filter residue and filtrate. The filter residue was treated using conventional techniques in the field and used for the preparation of building materials. The filtrate was mixed with a 0.4 mol / L sodium hydroxide solution (the pH of the resulting solution was 10.8) and subjected to electro-oxidation. The electro-oxidation conditions were as follows: the anode plate was a DSA anode plate, the cathode plate was a graphite cathode plate, and the current density was 29 mA / cm². 2 The electrode spacing was 1.8 cm, and the time was 1.2 h. After the electro-oxidation was completed, the treated filtrate was obtained, thus completing the resource utilization treatment of manganese slag.

[0044] Using the same test method as in Example 1, the filtrate treated in this example meets the national wastewater discharge standard GB8978-1996; the manganese fixation rate is 99.96%, and the ammonia nitrogen removal rate is 96.09%.

[0045] Comparative Example 1

[0046] Keeping other conditions unchanged in Example 3, the calcined phosphate tailings-kaolin composite material was replaced with calcined phosphate tailings, and the treated filtrate was finally obtained, thus completing the treatment of manganese slag. The preparation method of calcined phosphate tailings is as follows: the phosphate tailings were heated to 900°C at a heating rate of 9°C / min for calcination, and the holding time for calcination was set to 2.5h. After calcination, the tailings were cooled to 25°C in the furnace, then ground and passed through a 60-mesh sieve to obtain calcined phosphate tailings.

[0047] Using the same test method as in Example 1, the manganese fixation rate in this comparative example was 95.22%, and the ammonia nitrogen removal rate was 89.31%.

[0048] Comparative Example 2

[0049] Keeping other conditions unchanged in Example 2, the calcined phosphorus tailings-kaolin composite material was replaced with calcined kaolin, and the treated filtrate was finally obtained, thus completing the treatment of manganese slag. The preparation method of calcined kaolin is as follows: the kaolin was heated to 1000℃ at a heating rate of 10℃ / min and calcined. The holding time for calcination was set to 1.5h. After calcination, it was cooled to 25℃ with the furnace, then ground and passed through a 60-mesh sieve to obtain calcined kaolin.

[0050] Using the same test method as in Example 1, the manganese fixation rate in this comparative example was 93.85%, and the ammonia nitrogen removal rate was 86.66%.

[0051] Comparative Example 3

[0052] Manganese slag, water, and a 0.5 mol / L sodium hydroxide solution were mixed (the mass ratio of manganese slag to water was 1:4, and the pH of the resulting solution was 10.6). Electro-oxidation was then performed under the following conditions: a DSA anode plate, a graphite cathode plate, and a current density of 27 mA / cm². 2 The electrode spacing was 1.6 cm, and the time was 1.5 h. After the electro-oxidation was completed, the treated filtrate was obtained, thus completing the treatment of manganese slag.

[0053] Using the same test method as in Example 1, the manganese fixation rate in this comparative example was 75.02%, and the ammonia nitrogen removal rate was 72.15%.

[0054] As shown in the above embodiments, this invention provides a method for the resource-based treatment of manganese slag. The method includes the following steps: mixing phosphorus tailings and kaolin, calcining them to obtain a calcined phosphorus tailings-kaolin composite material; mixing manganese slag, water, and the calcined phosphorus tailings-kaolin composite material, reacting them, and filtering after the reaction to obtain filter residue and filtrate; mixing the filtrate with sodium hydroxide solution and performing electro-oxidation to complete the resource-based treatment of manganese slag. This invention uses the composite material obtained by calcining phosphorus tailings and kaolin as a stabilizer. The two materials synergistically stabilize manganese in the slag, thus avoiding the adverse effects of manganese on ammonia nitrogen removal. Then, sodium hydroxide solution is used to remove phosphorus from the filtrate, and electro-oxidation removes ammonia nitrogen from the filtrate, transforming the electrolytic manganese slag into filter residue and compliant filtrate that can be used in building materials. This invention has a simple and efficient processing method, providing a new approach for the resource-based treatment of manganese slag.

[0055] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for the resource-based treatment of manganese slag, characterized in that, Includes the following steps: (1) Mix phosphorus tailings and kaolin and calcine them to obtain calcined phosphorus tailings-kaolin composite material; (2) Mix manganese slag, water and calcined phosphorus tailings-kaolin composite material, react them, and filter them after the reaction to obtain filter residue and filtrate. (3) Mix the filtrate with sodium hydroxide solution and perform electro-oxidation to complete the resource utilization of manganese slag; The mass ratio of phosphorus tailings to kaolin in step (1) is 0.5–1.5:0.5–1.5; The mass ratio of manganese slag, water, and calcined phosphate tailings-kaolin composite material in step (2) is 1:2-6:0.05-0.3; The concentration of the sodium hydroxide solution in step (3) is 0.3 to 0.7 mol / L, and the pH value of the mixed solution is 10 to 11.

2. The method for resource-based treatment of manganese slag as described in claim 1, characterized in that, The heating rate of the calcination in step (1) is 8-12℃ / min, the calcination temperature is 800-1100℃, and the holding time after reaching the target temperature is 1-3h.

3. The method for resource-based treatment of manganese slag as described in claim 1, characterized in that, The reaction temperature in step (2) is 50-60℃, the stirring speed is 200-400 r / min, and the reaction time is 2-5 h.

4. The method for resource-based treatment of manganese slag as described in claim 1, characterized in that, The current density for electro-oxidation in step (3) is 23–29 mA / cm². 2 .

5. The method for resource-based treatment of manganese slag as described in claim 4, characterized in that, The electrode spacing in step (3) of the electro-oxidation is 1 to 2 cm.

6. The method for resource-based treatment of manganese slag as described in claim 5, characterized in that, The electro-oxidation time in step (3) is 1 to 2 hours.