碳酸盐型硫化物尾矿酸化及其研究意义

Application and Acidification of Carbonate-Type Sulfide Tailings

碳酸盐型硫化物矿尾矿因富含碱性碳酸盐,其酸化(尾矿中所含的硫化物氧化并释放出酸性水)问题一直不为人们所重视。通过对桂北(及邻区)碳酸盐岩区金属硫化物矿山尾矿污染的调研后发现:碳酸盐型尾矿酸化具有遍在性;尾矿能否发生酸化不能仅根据尾矿中碱性碳酸盐的含量简单地进行判断。经初步分析表明,在尾矿酸化过程中,碳酸盐颗粒的表面所形成的次生矿物(高价铁氢氧化物及石膏等)包壳可降低尾矿中碳酸盐中和酸的有效性,此即为"富含碱性碳酸盐的硫化物尾矿仍可发生酸化"的原因之一。深入研究碳酸盐型尾矿酸化机制,对于完善硫化物尾矿AMD的成因理论和预测评价体系,以及指导碳酸盐岩地区金属硫化物矿山AMD污染的防治,具有理论和实际意义。

As carbonate-type tailings are rich in the alkaline carbonates,the tailings acid problem（The sulfides in the tailings oxidize and release acidic water） is usually ignored.However,based on the pollution investigation of the tailings in the metal sulfide mines,situated in the carbonate area in northern Guangxi（and adjacent areas）,southern China,it is found that the acidification of the carbonate-type tailings is ubiquitous in the area.The alkaline carbonate content in tailings may not be a simple criterion to judge if the tailings will be acidified or not.Preliminary analysis in the paper shows that during the tailings acidification process,the secondary minerals（such as high iron hydroxide and gypsum,etc.） precipitate and tightly adhere to the surface of carbonate particles as cladding（Armor）,thus reduce the effectiveness of carbonate to neutralize acid—as one of explanations for ＂the acidification in the sulphide tailings rich in alkaline carbonate＂.The acidification mechanism study of carbonate-type tailings is of theoretical and practical significance to improve the original knowledge on sulfide tailings acidification and the forecast-evaluation system,and helpful for the prevention and control of AMD pollution in metallic sulfide mines in carbonate area.