Townsley C C, Atkins A S, Davis A J
Department of Mining Engineering, North Staffordshire Polytechnic, College Road, Stoke-on-Trent, ST4 2DE, England.
Biotechnol Bioeng. 1987 Jul;30(1):1-8. doi: 10.1002/bit.260300102.
Environmental concern about sulphur dioxide emissions has led to the examination of the possibility of removing pyritic sulphur from coal prior to combustion during froth flotation, a routine method for coal cleaning at the pit-head. The bacterium Thiobacillus ferrooxidans was effective in leaching 80% and 63% -53 mum pyrite at 2% and 6% pulp density in shake flasks in 240 and 340 h, respectively.The natural floatability of pyrite was significantly reduced in the Hallimond tube following 2.5 min of conditioning in membrane-filtered bacterial liquor prior to flotation. The suppression effect was greatly enhanced in the presence of Thiobacillus ferrooxidans. A bacterial suspension in pH 2.0 distilled water showed 85% suppression, whereas in spent growth liquor this value was 95%. The optimum bacterial density was 3.25 x 10(10) cells/g pyrite in 230-ml distilled water (2% pulp density) in the Hallimond tube. The degree of suppression by the cells was related to particle size but not to pH or temperature. The sulphur content of a synthetic coal/pyrite mixture was reduced from 10.9 to 2.1% by flotation after bacterial preconditioning. It is postulated that pyrite removal in coals which are cleaned by froth flotation could be significantly reduced using a bacterial preconditioning stage with a short residence time of 2.5 min.
对二氧化硫排放的环境担忧促使人们研究在泡沫浮选（一种在煤矿井口进行煤炭清洗的常规方法）过程中，在燃烧前从煤中去除黄铁矿硫的可能性。氧化亚铁硫杆菌在摇瓶中分别以2%和6%的矿浆密度，在240小时和340小时内有效地浸出了80%和63%的-53微米黄铁矿。在浮选前，在膜过滤细菌液中调理2.5分钟后，黄铁矿在哈利蒙德管中的天然可浮性显著降低。在氧化亚铁硫杆菌存在的情况下，抑制效果大大增强。在pH值为2.0的蒸馏水中的细菌悬浮液显示出85%的抑制率，而在废生长液中这一数值为95%。在哈利蒙德管中230毫升蒸馏水（2%矿浆密度）中，最佳细菌密度为3.25×10(10)个细胞/克黄铁矿。细胞的抑制程度与颗粒大小有关，但与pH值或温度无关。经过细菌预处理后，通过浮选，合成煤/黄铁矿混合物的硫含量从10.9%降至2.1%。据推测，使用停留时间仅2.5分钟的细菌预处理阶段，通过泡沫浮选清洗的煤中黄铁矿的去除量可显著降低。
