安徽铜陵铜尾矿硫形态及硫同位素分布特征

分析讨论了安徽铜陵水木冲S和SP剖面尾矿砂的理化指标、硫形态变化和硫酸根硫同位素组成与分布特征.结果显示：S和SP剖面整体呈酸性，pH值为2.59~6.12和3.50~6.27，由下而上有明显的降低趋势；Eh随剖面由下至上明显升高，范围为66~457和-37~307mV；酸可挥发性硫（AVS）含量为0~62.36和0~3.44mg/g，黄铁矿硫（CRS）含量为0.70~32.30mg/g和0.17~5.39mg/g；AVS与CRS的变化趋势基本一致，随剖面自下而上减少，且AVS先于CRS被氧化.2个剖面元素硫（ES）含量为0~8.83和0~3.62mg/g，随深度变化无明显规律.硫酸根硫（SO₄^2--S）含量为8.44~66.34和8.48~29.87mg/g，自下而上呈降低趋势，且分别在剖面的氢氧化物薄膜层（11.5~16.5cm和18~54cm）出现高值区.2个剖面总硫（TS）含量为9.18~109.69和12.38~37.72mg/g，表层由于淋滤含量较低，底层变化则不大.位于斜坡上的SP剖面TS及各形态硫含量均低于S剖面，表明淋滤对硫含量影响更明显.硫酸根硫同位素δ³⁴S为-3.32‰~13.43‰和-3.08‰~1.80‰，S-9硫酸根δ³⁴S为13.43‰，指示其来自于伴生硬石膏，其余层位δ³⁴S偏负且变幅较小，指示其硫酸根主要来源于硫化物的氧化.

Distribution characteristics of sulfur species and isotopes in a copper tailing at Tongling,Anhui Province

In this study, the composition and distribution characteristics of physiochemical proxies, sulfur species and sulfur isotope of sulfate in S and SP profiles collected from a copper tailing of Shuimuchong were analyzed and discussed. The results showed that profiles of S and SP were general acidic, with a pH value of 2.59~6.12 and 3.50~6.27, respectively. The oxidation-reduction potential (Eh) of S and SP increased obviously from the bottom up, with an Eh value of 66~457mV and -37~307mV, respectively. The content of acid volatile sulfur (AVS) in S and SP profiles was 0~62.36mg/g and 0~3.44mg/g; while the pyrite sulfur (CRS) was 0.70~32.30mg/g and 0.17~5.39mg/g, respectively. The content of AVS and CRS in these two profiles showed a similar decrease trend from the bottom up, and AVS was oxidized earlier than CRS. The content of elemental sulfur (ES) in S and SP profiles was 0~8.83mg/g and 0~3.62mg/g, without clear trend in depths. The content of sulfate was 8.44~66.34mg/g and 8.48~29.87mg/g, respectively; they decreased from bottom-up in these two profiles. The hardpan (iron hydroxide) at 11.5~16.5cm and 18~54cm in S and SP blocked the transport of oxygen and water from the top down, slowed the oxidation of sulfide in down layers, and formed a sulfate-rich zone. The total sulfur (TS) of these two profiles was 9.18~109.69mg/g and 12.38~37.72mg/g, respectively, and the lower values in up layers were likely due to the surface leaching. Generally, the content of TS and sulfur species in SP profile was lower than those in S, suggested more intense leaching. The δ³⁴S of sulfate in S and SP was -3.32‰~13.43‰ and -3.08‰ ~1.80‰, respectively. An exceptional δ³⁴S of 13.43‰ in S-9layer suggested a source of anhydrite, while others indicated a source of sulfide.