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在HSC6.0计算软件热力学分析的基础上,采用正交实验确定了高磷鲕状赤铁矿酸浸脱磷保铁的最佳工艺,并以最佳工艺为基础进行了酸浸过程中脱磷和铁损反应的动力学研究。热力学分析表明H_2SO_4为最佳酸浸用酸。正交实验得出最佳酸浸条件为:H+浓度为0.5mol/L的H_2SO_4溶液、酸浸时间40min、温度298K、液固比200mL∶14g、搅拌速度100r/min。在该条件下,脱磷率可达98.89%,铁损率仅为0.51%。通过SEM-EDS对酸浸前后高磷鮞状赤铁块矿试样分析表征得出:经H_2SO_4浸出后,磷灰石基本完全溶解,含铁矿相未发生明显反应。动力学分析显示:优化条件下,酸浸脱磷反应在298~328K内符合收缩未反应核模型,浸出过程主要受内扩散控制,表观活化能为11.24kJ/mol;铁损反应在298~328K内遵循收缩未反应核模型,浸出过程主要受化学反应控制,表观活化能为42.24kJ/mol。
Based on the thermodynamic analysis of HSC6.0 calculation software, the optimum technics of acid leaching and dephosphorization of high-phosphorus oolitic haematite was determined by orthogonal experiment. The best leaching process was based on the best technology Kinetics of phosphorus and iron loss reactions. Thermodynamic analysis shows that H 2 SO 4 is the best acid leaching acid. Orthogonal experiments showed that the optimal conditions for acid leaching were H 2 SO 4 solution with H + concentration of 0.5 mol / L, acid leaching time of 40 min, temperature of 298 K, liquid-solid ratio of 200 mL:14 g and stirring speed of 100 r / min. Under this condition, the dephosphorization rate can reach 98.89% and the iron loss rate is only 0.51%. The results of SEM-EDS showed that the apatite was almost completely dissolved after H_2SO_4 leaching, and no obvious reaction occurred in the iron-bearing ore. Kinetic analysis shows that under the optimized conditions, the acid leaching and dephosphorization reaction conforms to the contracted and unreacted core model within 298 ~ 328K, the leaching process is mainly controlled by the internal diffusion, the apparent activation energy is 11.24kJ / mol; the iron loss reaction is between 298 ~ 328K follow the contraction of unreacted nuclear model, the leaching process is mainly controlled by chemical reactions, the apparent activation energy of 42.24kJ / mol.