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贵州某金矿石金品位低且嵌布粒度极细(多数小于2μm,且多为硫化物包裹),浮选金精矿硫含量高且含砷,是一种典型的难处理金矿。本文利用混合菌NB对浮选金精矿进行生物预氧化,考察了NB菌的最适生长pH,最佳生长温度。在有菌体系下,采用直接氧化,恒定pH氧化以及分两段氧化3种方法对其预处理,得出以下结论:直接氧化可以得到较好的氧化效果,恒定pH氧化可减少酸积累对微生物活性的影响,提高硫氧化速率,但是与此同时会在矿物表面产生黄钾铁矾沉淀形成二次包裹,分段氧化既可以较少酸积累带来的负面影响,又可以避免矿物表面形成黄钾铁矾。在15%矿浆浓度以及初始pH为1.5的条件下,一段氧化7 d,二段氧化7 d,硫、砷氧化率分别达到89.31%和79.56%。利用荧光定量PCR查明了该混合菌的组成为:Sulfobacillus thermotolerans,Leptospirillum ferriphilum和古菌Ferroplasma acidiphilum,其中古菌Ferroplasma acidiphilum占到98.36%,该古菌在预氧化过程中起到了决定性作用。
A gold grade of gold ore in Guizhou is of low grade and its grain size is very fine (most less than 2μm, mostly sulfide inclusions). The flotation concentrate contains high sulfur content and arsenic content, and is a typical refractory gold ore. In this paper, the mixed bacteria NB bioforteted flotation of biological pre-oxidation, studied the NB bacteria optimal growth pH, the optimal growth temperature. In the presence of bacteria, direct oxidation, constant pH oxidation and two-stage oxidation of three pretreatment methods, the following conclusions: Direct oxidation can get better oxidation, and constant pH oxidation can reduce the accumulation of acid on microorganisms Activity, and improve the oxidation rate of sulfur, but at the same time, it will form jarosite precipitates on the mineral surface to form secondary encapsulation. Segment oxidation can not only have the negative effect of less acid accumulation, but also avoid the formation of yellow on the mineral surface Potash alum. Under the condition of 15% slurry concentration and initial pH of 1.5, the oxidation rates of the first stage of oxidation and the second stage of oxidation for 7 days were 89.31% and 79.56%, respectively. Fluorescent quantitative PCR confirmed that the composition of the mixed bacteria: Sulfobacillus thermotolerans, Leptospirillum ferriphilum and archaeal Ferroplasma acidiphilum, of which archaeal Ferroplasma acidiphilum accounted for 98.36%, the archaea in the pre-oxidation process has played a decisive role.