Research On Stabilization Process Of Soluble Manganses From Manganese Acid Leaching Residue

Manganese acid leaching residue is a kind of solid waste produced in the process of using sulfuric acid leaching manganese ore, which was commonly used to be sample landfill or piled up directly. In recent years, with the development of manganese industry in china, the rich manganese ore resources have dried up, most of the factories have to use low grade manganese ore to production, with the more manganese acid leaching residue increasing, the more environmental problems were growing. The manganese acid leaching residue stabilization process, not only eliminates the pollution of the environment, but also provides a new thought for the sustainable development of manganese industry.The manganese acid leaching residue was from a plant in Guangxi. In order to study the manganese acid leaching residue, various analytic methods were required to analyzes its basic properties. The results show that:The average pH of manganese residue used in this thesis was around 6.5, weak acid, the total manganese content was 6.08%, the content of soluble manganese was about 25% of the total and the manganese carbonate content was 3.39%. Leaching toxicity test results showed that the soluble manganese concentration in the leaching solution is 378.0 mg/L, which is the integrated wastewater discharge standard GB8978-1996 maximum allowable emission concentration standard (2.0 mg/L) 189 times. Therefore, soluble manganese is the main pollutants in manganese residue.In the stabilization research experiment of manganese residue, the calcium oxide, sodium silicate and sodium phosphate as stabilizing agent to dispose manganese acid leaching residue process were explored. The results showed that: (1) Using the manganese residue after drying, the amount of calcium oxide was 1.50 g, moisture content was 100%, no ventilation, no sunshine, placed time 0.5 h, under this conditions the soluble manganese concentration by leaching toxicity test was 1.22 mg/L. (2) The optimum conditions could get the soluble manganese curing rate about 97.11%, through adjust the liquid-solid ratio 5:1, pH 8.0, sodium silicate dosage 0.50 g, at the conditions stirring speed 250 r/min, temperature 30℃ react 15 min. The soluble manganese concentration of manganese filtrate which obtained by leaching toxicity test is 1.12 mg/L. (3) And with the sodium phosphate dosage 1.25 g, adjust the liquid-solid ratio 6:1, pH 8.0, at the conditions reaction temperature 30℃, reaction time 15 min, stirring speed 200 r/min, could get the curing rate about 95.83%, The soluble manganese concentration of manganese filtrate which obtained by leaching toxicity test is 1.42 mg/L. All three kinds of treatment showed above, the soluble manganese concentration was lower than the national standard.The mechanism of stable manganese by stabilizer was studied, through the analytic methods, such as XRD, SEM and chemical analysis. The research shows that:The stabilizing agent and soluble manganese react to generate silicate, phosphate precipitations and gel-forming were the main reason for reducing the soluble manganese, the oxygen in the air also could react with manganese hydroxide generate manganese compound MnO2 also have some effect to stabilizing soluble manganese.