铁矾渣预氧化—煤基直接还原过程脱砷研究

摘要

针对铁矾渣综合回收过程脱砷问题,在分析砷物相基础上提出一种预氧化—煤基直接还原的脱砷方案.结果表明,预氧化升温阶段(25～800℃),砷总挥发率为24.45％;预氧化温度为800℃、预氧化气氛为02(5％)+N2(95％),预氧化时间为10 min时,最优脱砷率为26.34％;外配15％煤粉的预氧化铁矾渣含碳球团在弱还原升温阶段(25 ～1 075 ℃),砷总挥发率为45.90％;弱还原阶段适宜配碳量为10％ ～ 15％;还原温度1 075℃、外配10％煤粉,还原30 min时,砷挥发率达到68.2％;调整碱度、提高温度后,最优脱砷效率提高到78.34％.%Based on analysis of arsenic phase,a novel method to remove arsenic by pre-oxidationcoal-based direct reduction was proposed address arsenic removal in comprehensive recovery of jarosite residue.The results show that total volatilization rate of arsenic is 24.45％ in pre-oxidation and heating process (25 ～800 ℃).The optimum elimination efficiency of arsenic is 26.34％ under the conditions including pre-oxidation temperature of 800 ℃,oxidizing atmosphere of O2 (5％) + N2 (95％),and oxidation time of 10 min.Total volatilization rate of arsenic for pre-oxidized pellets with 15％ pulverized coal is 45.90％ in weak reduction and heating process (25 ～ 1 075 ℃).The suitable additional carbon of coal-based weak reduction removing arsenic is 10％ ～ 15％.Volatilization rate of arsenic is 68.2％ under the conditions including temperature of 1 075 ℃,pulverized coal dosage of 10％,and reduction time of 30min.The optimum volatilization rate of arsenic is 78.34％ after adjusting basicity of carboncontaining pellets and improving temperature.