Method for recovering iron ions in low-grade manganese carbonate

Abstract

The invention relates to the technical field of hydrometallurgy, in particular to a method for recovering iron ions in low-grade manganese carbonate. According to the specific technical scheme, the method for recovering the iron ions in the low-grade manganese carbonate comprises the following steps: mixing P204, a synergistic extraction agent, sulfonated kerosene and dichloromethane to obtain an organic phase, mixing a manganese ore leaching solution with the organic phase, oscillating, standing for layering, washing the loaded organic phase with a sulfuric acid solution, reversely extracting the iron ions in the organic phase with an oxalic acid solution, and recovering the iron ions in the low-grade manganese carbonate. And adding ammonia water into the reverse extraction raffinate to adjust the pH value, filtering, and roasting filter residues obtained after filtering at high temperature to obtain ferric oxide. According to the extraction method disclosed by the invention, the solution is directly extracted after acid leaching oxidation, the iron oxide red pigment with high recovery value is obtained, and the extraction method has the characteristics of low treatment energy consumption, convenience and controllability in operation, environmental friendliness, high resource utilization rate and the like.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for recovering iron ions in low-grade manganese carbonate. Background Art

[0002] Due to the characteristics of manganese ore resources being "small, poor, mixed and fine", the development of new manganese ores and the efficient utilization of low-grade manganese ores are increasingly important for ensuring the stable and safe supply of global manganese products. Therefore, the preparation of high-purity manganese salt technology from low-grade manganese carbonate ore and the research and development of efficient resource applications have attracted much attention, which is related to the safe and stable supply of the manganese industry. Natural manganese carbonate ore is often accompanied by a variety of impurities, and iron is more common and has a high content, which affects subsequent processing and product performance. In the development of manganese ore resources and the recovery of battery materials, treatment with sulfuric acid will cause some metals (such as iron) to enter the acidic solution. The existing manganese carbonate ore iron removal technology is divided into physical methods (magnetic separation, gravity separation) and chemical methods (acid leaching, redox iron removal). They each have their own limitations and it is difficult to take into account the requirements of cost, environmental protection, manganese recovery rate and other aspects. It is necessary to further develop more ideal iron removal technology.

[0003] In the prior art, the jarosite method is used to remove iron, and a temperature of more than 85°C and a reaction time of 2h are required to obtain a good iron removal effect; the hematite method requires a temperature of more than 120°C and a certain oxygen partial pressure to achieve iron removal. A method that can quickly remove iron from a solution under mild conditions is very necessary for hydrometallurgical extraction of target metals. Therefore, regardless of the grade of manganese carbonate ore, the iron removal process on the market is mainly neutralization and hydrolysis. The neutralization and hydrolysis method mainly utilizes the characteristics of iron and other metal ions undergoing hydrolysis reactions under different pH conditions. The neutralizer commonly used in the treatment is lime or sodium hydroxide, but the method is inefficient and has a large amount of residue. At the same time, a large amount of valuable metal ions such as manganese and magnesium in the leachate are easily adsorbed by Fe(OH)3 colloid, which not only makes solid-liquid separation difficult, but also causes obvious waste of resources; and the iron-containing slag entrained with various ions is always discarded as solid waste, and the stacking of such solid waste is likely to cause serious pollution to the soil and groundwater.

[0004] Although ion exchange resins have been proven to have advantages in high efficiency and selectivity in iron removal, they are only applicable to situations with very low iron content due to problems such as low mass transfer rate, limited loading capacity and high cost of use. In the current era of efficient resource utilization, how to efficiently remove iron from manganese ore and recycle it into high value-added materials instead of discarding it as waste has gradually received more and more attention. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method for recovering iron ions in low-grade manganese carbonate.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] The invention discloses a method for recovering iron ions in low-grade manganese carbonate. P204, a co-extractant, sulfonated kerosene and dichloromethane are mixed to obtain an organic phase, a manganese ore leaching solution is mixed with the organic phase, the mixture is allowed to stand for stratification after oscillation, the loaded organic phase is washed with a sulfuric acid solution, the iron ions in the organic phase are stripped with an oxalic acid solution, ammonia water is added to the stripping residue to adjust the pH value, the solution is filtered, and the filter residue obtained after filtration is calcined at high temperature to obtain ferric oxide.

[0008] Preferably, the organic phase after stripping is washed with a regeneration agent, recovered, and reused for extraction; the regeneration agent is sulfuric acid with a concentration of 0.5M to 1M.

[0009] Preferably, the concentration of P204 is 0.03 mol / L to 0.15 mol / L, the mass of the co-extractant is 14 to 140% of P204; and the volume ratio of the sulfonated kerosene to dichloromethane is 1:1 to 5:1.

[0010] Preferably, the manganese ore leaching solution and the organic phase are added at an O / A ratio of 1:1 to 1:5.

[0011] Preferably, the concentration of the sulfuric acid solution is 0.05M to 0.1M, and the concentration of the oxalic acid solution is 0.5M.

[0012] Preferably, the pH value is adjusted to 5-6 by ammonia water, and the temperature of the high-temperature calcination is 800-850° C., and the time is 3±2 h.

[0013] Preferably, the preparation process of the manganese ore leaching solution is: reacting manganese ore powder with concentrated sulfuric acid, and obtaining a manganese ore leaching solution after the reaction is completed, the solid-liquid ratio of the manganese ore powder to the manganese ore leaching solution is 1:1.5-3.5, and the pH of the manganese ore leaching solution is 1.4-1.6.

[0014] Preferably, the preparation process of the co-extractant is: adding sodium dibutyl dithiocarbamate to a sulfuric acid solution, stirring and mixing, adjusting the pH value to 2-4, adding n-hexane for extraction, and separating the oil phase and the raffinate; after washing the oil phase, adding 1-6M sulfuric acid to the raffinate and the washed water phase to adjust the pH to 2-4, and then extracting with n-hexane to obtain an organic phase; mixing the organic phase and the washed oil phase and performing reduced pressure distillation to obtain the co-extractant dibutyl dithiocarbamic acid.

[0015] Preferably, the molar ratio of sodium dibutyldithiocarbamate to sulfuric acid is 2:1, and the concentration of sulfuric acid is 0.5M.

[0016] The present invention has the following beneficial effects:

[0017] 1. The present invention discloses a new iron removal process route for low-grade manganese carbonate ore. After acid leaching and oxidation, the solution is directly extracted to obtain iron oxide red pigment with high recovery value. The process has the characteristics of low processing energy consumption, convenient and controllable operation, environmental friendliness, high resource utilization rate, etc.

[0018] 2. The extraction method disclosed in the present invention does not introduce new ions into the leachate, and has high processing efficiency. After extraction, washing and stripping, the desired effect can be achieved. Moreover, after stripping with oxalic acid, iron ions are enriched to obtain iron hydroxide precipitate, which is then calcined at high temperature to obtain pigment-grade iron oxide red, with a recovery rate of 99.1% for iron ions. The entire process is economical and environmentally friendly, and the organic phase can be recycled, with a cycle number of up to 4 times. DETAILED DESCRIPTION

[0019] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0021] The invention discloses a method for recovering iron ions in low-grade manganese carbonate, which specifically comprises the following steps:

[0022] (1) Preparation of synergistic extractant: Sodium dibutyl dithiocarbamate (mass concentration 40%) is added to 0.5M sulfuric acid solution, stirred and mixed, sulfuric acid is used to adjust the pH value to 2-4, n-hexane is added for extraction, the oil phase is separated, and after washing with pure water for 3 times, 1-6M sulfuric acid is added to the raffinate and the washed aqueous phase to adjust the pH to 2-4, and then n-hexane is used for extraction and separation to obtain an organic phase. The organic phases are mixed and then distilled under reduced pressure until the volume of the solution no longer changes, thereby obtaining the synergistic extractant dibutyl dithiocarbamic acid. The molar ratio of sodium dibutyl dithiocarbamate to sulfuric acid is 2:1.

[0023] (2) Preparation of manganese ore leaching solution: Take manganese ore powder and add concentrated sulfuric acid solution to prepare manganese ore leaching solution (the solid-liquid ratio of manganese ore powder to manganese ore leaching solution can be 1:1.5-3.5, preferably 1:2.6), and the pH value of the leaching solution is between 1.4 and 1.6.

[0024] (3) Extraction process: P204, co-extractant, sulfonated kerosene and dichloromethane are mixed at room temperature in the required proportion to obtain an organic phase. The manganese ore leachate and the organic phase are added to the separatory funnel in proportion (the manganese ore leachate and the organic phase are added in an O / A ratio of 1:1 to 1:5, the manganese ore leachate is used as the aqueous phase, the organic phase is used as the oil phase, and the O / A ratio is the volume ratio). After mechanical vibration for a certain period of time, the stratification is allowed to stand, and the loaded organic phase is washed with a 0.05M to 0.1M sulfuric acid solution. Finally, the iron ions in the organic phase are stripped with a 0.5M oxalic acid solution. After the stripped organic phase is washed with a regeneration agent (0.5M to 1M sulfuric acid), it is reused for extraction, and ammonia water is added to the stripping raffinate (ferric oxalate solution) to adjust the pH to between 5 and 6. The filter residue obtained after filtration is placed in a muffle furnace and calcined at a high temperature of 800 to 850°C for 3±2h to obtain pigment-grade ferric oxide.

[0025] The concentration of P204 is 0.03 mol / L to 0.15 mol / L, the mass of the co-extractant is 14 to 140% of P204, and the volume ratio of the sulfonated kerosene to dichloromethane is 1:1 to 5:1.

[0026] The present invention will be further described below in conjunction with specific embodiments.

[0027] Example 1

[0028] A method for recovering iron ions in low-grade manganese carbonate specifically comprises the following steps:

[0029] (1) Preparation of extractant: Weigh 270-290g of sodium dibutyl dithiocarbamate (40%) and add it to 500ml of 0.5M sulfuric acid solution, stir and mix, and then adjust the solution pH to about 3 with 5M sulfuric acid. Then add 100ml of n-hexane, mechanically shake for 10-20min, and separate the oil phase (A) and the raffinate (a). After washing the oil phase (A) 3 times with 50ml of pure water, collect the washing water, combine it with the raffinate (a), and then add 5M sulfuric acid to adjust the pH to about 3. Then extract with 50mL of n-hexane to obtain the oil phase (B). After mixing the oil phases (A, B), perform vacuum distillation until the volume of the solution no longer changes, and obtain the extractant dibutyl dithiocarbamic acid.

[0030] (2) Leaching of acid leaching solution: crush the manganese ore to less than 100 mesh, take 500g of manganese ore powder and add 106ml of concentrated sulfuric acid solution. After the reaction is completed, add 5-8ml of hydrogen peroxide dropwise to obtain 1.3L of leaching solution with a solid-liquid ratio of 1:2.6. The pH value of the leaching solution is between 1.4 and 1.6.

[0031] (3) Extraction process: The whole process is at room temperature. Before extraction, take 0.03 mol / L to 0.15 mol / L of P204 mixed with a co-extractant (the amount of the co-extractant added is 14 to 140% (mass percentage) of P204) to form an extraction system and V 磺化煤油 :V 二氯甲烷 The dilution system is 1:1 to 5:1 and mixed at room temperature. The manganese ore leaching solution and the organic phase are added to the separatory funnel at an O / A ratio of 1:1 to 1:5, and mechanically shaken for 30s to 5min, then allowed to stand and separate the two phases. During the extraction process, under the optimal conditions: room temperature 25°C, 0.09mol / L P204, 71% synergist, V 磺化煤油 :V 二氯甲烷 The ratio of manganese to magnesium is 4:1, and when the pH of the leaching solution is 1.5, the extraction rate of manganese is 2.1%, the extraction rate of magnesium is 3.4%, and the extraction rate of iron is 99.1%.

[0032] The loaded organic phase was washed with 0.05M-0.1M sulfuric acid solution. The optimal washing conditions were: room temperature, 0.05M sulfuric acid, washing time was 10 min, the washing rate of manganese was 96.9%, the washing rate of magnesium was 94.4%, and the washing rate of iron was 0.04%.

[0033] Finally, the iron ions in the organic phase were stripped with 0.5 M oxalic acid solution. Under the optimal stripping conditions: room temperature, 0.5 M oxalic acid, 2 min stripping time, the iron stripping rate was 99.9%.

[0034] The organic phase after stripping is washed with a regeneration agent (0.5M-1M sulfuric acid) and reused for extraction to achieve the circulation of the organic phase (the first extraction rates of manganese, magnesium and iron are 2.1%, 3.4% and 99.1% respectively; the second extraction rates of manganese, magnesium and iron are 3.2%, 4.1% and 98.4% respectively; the third extraction rates of manganese, magnesium and iron are 3.3%, 4.2% and 96.3% respectively; the fourth extraction rates of manganese, magnesium and iron are 4.1%, 5.3% and 93.5% respectively).

[0035] Ammonia water was added to the stripping raffinate (ferric oxalate solution) to adjust the pH to between 5 and 6. The filter residue obtained after filtration was placed in a muffle furnace and calcined at 800 to 850° C. for 3 hours to obtain pigment-grade ferric oxide with an iron recovery rate of up to 99.1%.

[0036] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for recovering iron ions in low-grade manganese carbonate, characterized in that: P204, a co-extractant, sulfonated kerosene and dichloromethane are mixed to obtain an organic phase, the manganese ore leaching solution is mixed with the organic phase, and the mixture is allowed to stand for stratification after oscillation. The loaded organic phase is washed with a sulfuric acid solution, and the iron ions in the organic phase are stripped with an oxalic acid solution. Ammonia water is added to the stripping residue to adjust the pH, and the solution is filtered. After the filtration, the filter residue is calcined at high temperature to obtain ferric oxide.

2. A method for recovering iron ions in low-grade manganese carbonate according to claim 1, characterized in that: The organic phase after stripping is washed with a regeneration agent, recovered, and reused for extraction; the regeneration agent is sulfuric acid with a concentration of 0.5M to 1M.

3. A method for recovering iron ions in low-grade manganese carbonate according to claim 1, characterized in that: The concentration of the P204 is 0.03 mol / L to 0.15 mol / L, the mass of the co-extractant is 14 to 140% of the P204; the volume ratio of the sulfonated kerosene to dichloromethane is 1:1 to 5:

1.

4. A method for recovering iron ions in low-grade manganese carbonate according to claim 3, characterized in that: The manganese ore leaching solution and the organic phase are added at an O / A ratio of 1:1 to 1:

5.

5. A method for recovering iron ions in low-grade manganese carbonate according to claim 1, characterized in that: The concentration of the sulfuric acid solution is 0.05M-0.1M, and the concentration of the oxalic acid solution is 0.5M.

6. A method for recovering iron ions in low-grade manganese carbonate according to claim 1, characterized in that: The pH value is adjusted to 5-6 by ammonia water, and the temperature of the high temperature roasting is 800-850° C., and the time is 3±2 h.

7. A method for recovering iron ions in low-grade manganese carbonate according to claim 4, characterized in that: The preparation process of the manganese ore leaching solution is: reacting manganese ore powder with concentrated sulfuric acid to obtain a manganese ore leaching solution after the reaction is completed, the solid-liquid ratio of the manganese ore powder to the manganese ore leaching solution is 1:1.5-3.5, and the pH of the manganese ore leaching solution is 1.4-1.

6.

8. A method for recovering iron ions in low-grade manganese carbonate according to claim 3, characterized in that: The preparation process of the co-extractant is as follows: sodium dibutyl dithiocarbamate is added to a sulfuric acid solution, stirred and mixed, the pH value is adjusted to 2-4, n-hexane is added for extraction, and an oil phase and a raffinate are separated; after washing the oil phase, 1-6M sulfuric acid is added to the raffinate and the washed water phase to adjust the pH to 2-4, and then n-hexane is used for extraction to obtain an organic phase; the organic phase and the washed oil phase are mixed and then subjected to reduced pressure distillation to obtain the co-extractant dibutyl dithiocarbamic acid.

9. A method for recovering iron ions in low-grade manganese carbonate according to claim 8, characterized in that: The molar ratio of the sodium dibutyl dithiocarbamate to sulfuric acid is 2:1, and the concentration of the sulfuric acid is 0.5M.