Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第30卷    第7期    总第256期    2020年7月

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文章编号:1004-0609(2020)-07-1667-10
采用复合盐沉淀法从含砷废水中回收三氧化二砷及复合盐的循环利用
徐 蕾1,郑雅杰1,龙 华1,彭映林2,何汉兵1

(1. 中南大学 冶金与环境学院,长沙 410083;
2. 湖南城市学院 材料与化学工程学院,益阳 413000
)

摘 要: 采用复合盐沉淀法处理含砷废水,研究了钙砷比、铜砷比、铁砷比、锌砷比对砷脱除率的影响,并以硫酸浓度、液固比、浸出时间、浸出温度为考察因素,对含砷沉淀渣进行浸出,从浸出液中回收三氧化二砷,同时回用脱砷后母液。结果表明:在n(Ca)/n(As)=1.05、n(Cu)/n(As)=0.45、n(Fe)/n(As)=1.20、n(Zn)/n(As)=1.20的复合盐配比下,处理初始As(Ⅲ)浓度为0.05~9.76 g/L含砷废水时,砷残留浓度均低于14 mg/L,通过增加复合盐用量进行二次脱砷沉淀,滤液中铜、锌、砷浓度在《污水综合排放标准》(GB 8978—1996)范围内。在液固比(mL:g)为3:1、浸出时间为0.5 h、浸出温度为25 ℃、硫酸浓度0.87 mol/L条件下对含砷渣进行浸出,并回收三氧化二砷,可使砷回收率达到72.38%。将回收后母液回用处理初始As(Ⅲ)浓度为50 mg/L的含砷废水,可使砷脱除率达83.65%,复合盐利用率可达80%以上,具有生态与经济双重效益。

 

关键字: 复合盐;二次脱砷;浸出;含砷废水;循环利用

Recovery of arsenic trioxide from arsenic-containing wastewater by using compound salt precipitation and recycling of compound salt
XU Lei1, ZHENG Ya-jie1, LONG Hua1, PENG Ying-lin2, HE Han-bing1

1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. School of Chemistry and Environmental Engineering, Hunan City University, Yiyang 413000, China

Abstract:Arsenic-containing wastewater was treated by compound salt precipitation method. The effects of calcium-arsenic ratio, copper-arsenic ratio, iron-arsenic ratio and zinc-arsenic ratio on arsenic removal rate were studied. Taking sulfuric acid concentration, liquid-solid ratio, leaching time and leaching temperature as factors to investigate, the arsenic-containing precipitated slag was leached, and arsenic trioxide was recovered from the leaching solution, and the mother liquor after arsenic removal was reused. The results show that, under the optimal compound salt ratio conditions of n(Ca)/n(As)=1.05, n(Cu)/n(As)=0.45, n(Fe)/n(As)=1.20 and n(Zn)/n(As)=1.20, the arsenic residual concentration is lower than 14 mg/L when the arsenic-containing wastewater with ρ(As)=0.05-9.7 g/L is treated, the concentrations of Ca, Fe, Cu, Zn and As in the filtrate are less than Integrated Wastewater Discharge Standard (GB 8978—1996) after the second arsenic removal by increasing the amount of compound salt. Under the conditions of liquid-solid ratio of 3:1, leaching time of 0.5 h, leaching temperature of 25 ℃ and sulfuric acid concentration of 0.87 mol/L, the arsenic recovery rate reaches 72.38% when arsenic-containing slag is leached and arsenic trioxide is recovered. The mother liquor after arsenic recovery is used to treat the arsenic-containing wastewater with ρ(As)=50 mg/L, and the arsenic removal rate can reach 83.65% and the compound salt utilization rate can reach over 80%, which has both ecological and economic benefits.

 

Key words: compound salt; secondary arsenic removal; leaching; arsenic-containing wastewater; recycling

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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