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通过“硫酸-硝酸法”浸出实验,以砷的浸出浓度为控制指标,选用Fe Cl2为稳定药剂,对矿区砷渣进行药剂稳定化研究。考察Fe/As摩尔比、p H值、粒度、温度及稳定时间对砷浸出浓度的影响,通过研究稳定化前后砷形态的变化,探讨重金属迁移转化规律。结果表明:砷浸出浓度随Fe Cl2投加量增加而降低,当Fe/As摩尔比为1,p H=6.5~7.5时,常温下稳定化1 h后,砷浸出浓度低于2.5 mg/L且基本达到稳定,达到《危险废物填埋污染控制标准》(GB 18598-2001)的入场要求;随反应温度升高,砷浸出浓度略有升高;矿渣稳定化处理后,砷从生物有效性高和毒性大的形态逐渐转化为毒性小、稳定性强的形态,但矿物组成和化学组成不同,砷形态的迁移转化也略有不同。
Through the “sulfuric acid - nitric acid” leaching experiment, taking the leaching concentration of arsenic as the control index, selecting FeCl2 as the stable medicament, the arsenic residue in the mining area was studied for drug stabilization. The effect of Fe / As molar ratio, p H value, particle size, temperature and stabilization time on arsenic leaching concentration was investigated. The change of arsenic species before and after stabilization was also investigated to discuss the migration and transformation rules of heavy metals. The results showed that the arsenic leaching concentration decreased with the increase of FeCl 2 dosage. When the Fe / As molar ratio was 1 and p H = 6.5-7.5, the arsenic leaching concentration was lower than 2.5 mg / L after being stabilized at room temperature for 1 h And basically reached a stable, to “hazardous waste landfill pollution control standards” (GB 18598-2001) admission requirements; as the reaction temperature increases, the arsenic leaching concentration slightly increased; Slag stabilization, arsenic from the bio-effective Sexual high and toxic form gradually into toxic little, strong stability of the form, but the mineral composition and chemical composition is different, the migration and transformation of arsenic form is also slightly different.