【作者】 刘俊；

【导师】 龚文琪；

【作者基本信息】 武汉理工大学 ， 矿物加工， 2008， 博士

【摘要】 磷是工业和农业生产的重要原料,我国的磷矿资源总量虽多,但平均品位低,采用传统生产工艺加工低品位的磷矿石经济效益极差。而生物浸矿技术具有污染小、能耗少、操作费用低等无可比拟的优点,为低品位磷矿石的开发利用开辟了新的途径。本研究采用生物湿法冶金技术中常用的嗜酸氧化硫硫杆菌（At.t）和嗜酸氧化亚铁硫杆菌（At.f）,从安徽某矿山酸性废水中提取的At.t和At.f菌,经过长时间的富集和纯化培养后,对其在不同的培养液初始pH值和能源物质条件下的产酸能力进行了实验研究,发现对于At.t菌,在初始pH值为2.35、以单质硫为能源物质的Starkey培养基中的产酸能力较强;对At.t菌而言,在初始pH值为3.01,以黄铁矿能源的9K培养基中的产酸能力较强。采用紫外线照射和微波诱变育种的方法对At.t和At.f菌进行产酸诱导实验,以提高它们的产酸能力。实验结果表明:对At.t菌采用微波和紫外线照射的方法都能够加强其产酸能力,尤其是以微波处理10 s和紫外线照射5 min时效果最好,其培养液的最低pH值可分别达到1.45和1.52;对于At.f菌采用微波诱变的方法,对其产酸能力有一定的加强,在微波诱变10 s时,其菌液最低pH值为1.82,而采用紫外线诱变处理的At.f菌,其产酸能力变化不明显。At.t和At.f菌对低品位磷矿浸出实验表明,磷的浸出率会随浸矿时间的增长而增加;在相同的浸出时间内,经过诱变育种后产酸能力强的菌种,其对磷矿的浸出率比原菌的更高。在同样条件下25天内,经过紫外诱变5 min的At.t菌浸磷率可达到39.14%,微波诱变10 s的At.f菌的浸出率达到38.12%,而At.t和At.f原菌的浸出率分别只有30.12%和28.13%。添加合适种类和用量的吐温类表面活性剂可以促进硫杆菌对磷矿的浸出,At.t菌添加0.001%（v/v）的吐温60可以将磷的浸出率提高到41.12%;添加0.001%（v/v）的吐温80可以将At.f菌的浸磷率提高到38.25%。不过,对诱变后的菌种添加相应的吐温类表面活性剂,只能对浸磷率起到微弱的提升效果。为了解释影响At.t和At.f菌产酸和浸磷效果的原因,进行了Zeta电位和FTIR分析,发现At.t菌在经过紫外线诱变后,其等电点比原菌要低;微波诱变后的At.f菌的IEP也会稍小于原菌。以黄铁矿为能源物质生长的At.f菌比以FeSO₄为能源物质的IEP要高。经过At.t菌作用后的硫粉颗粒和经过At.f菌作用过的黄铁矿其等电点会随着作用时间的增加而升高,加入吐温60后的硫粉颗粒同细菌作用后的IEP也会增加。对At.t和At.f菌的的FTIR研究表明,其表面经过物理诱变后化学官能团或振动方式发生了变化,这表明其表面的氢键作用强弱改变了,这可能是导致诱变后的菌种表面性质的发生变化的重要原因。综合分析Zeta电位和FTIR测试结果,可以对At.t和At.f菌在产酸和浸矿方面的实验结果做出较合理的解释。更多还原

【Abstract】 Phosphors were important raw material of industry and agriculture,although the total amounts of phosphate ore were plentiful,but the average grade was very low. The economic effectiveness was very poor when adopt tradition technique process low grade phosphate ore,on the contrary,the bioleaching technique have overwhelming advantages such like small pollution,less energy consumption,low cost of operation etc.all these cast new lights on exploiting and using low grade phosphate ore.Acidithiobacillus thiooxidans（At.t） and Acidithiobacillusferrooxidans（At.f） which were been widely use in biological hydrometallurgy were be adopted in this study.At.t and At.f were spperate from the acid drainage of a coal mine in Anhui province,after they be enriched and purfied a long time,the produce acide ability were been test on different substrate original pH value and differemt energy materals. At.t was found have stronger produce acid ability when the sbustrate original pH value was 2.35 and sulfur as the energy source in Starkey substrate.When the substrate original pH value was 3.01 and pyrite as energy source the At.f produce more acide in 9K sbustrate.Ultraviolet irradiation and Microwave inducement were applied to the bacterial cultivation process to produce At.t and At.f able to generate more acide.As a result: At.t generate acid capacity were be enhanced after induced by Ultraviolet irradiation and Microwave,especiallly when Microwave induced 10 second（MW 10 s） and Ultraviolet irradiation induced 5 minute（UV 5 min）,the lowest pH value of the substrate were 1.45 and 1.52.When Mivrowave was applied to induce At.f 10 s,their generate acide capacity also improved,the lowest pH value of substrate were 1.82. At.f induced by Ultravioled irradiation had unconspicuous change on their generate acide capacity.The experiment of low grade phosphate ore leached by At.t and At.f indicated the phosphorus leached rate increased with the leached time in general.The mutagenesis with stronge generate acide capacity had more leached rate than the original bacterium during the same period.UV 5rain At.t leached rate can reach 39.14%,MW 10 s At.f phosphate leached rate was 38.12%,the original At.t and At.f correspond leached rate were 30.12%and 28.13%.The phosphate leached rate can improve by the addition of suitable kinds and quaintity of Tween series surfactant,At.t leached rate was increased to 41.12%when 0.001%（v/v） Tween 60 was added,At.f leached rate was increased to 38.25%when 0.001%（v/v） Tween 80 was added.The corresponded mutagenesis leahed rate only improved a little when Tween series surfactant was added.In order to find out the reasons affect the At.t and At.f phospate leached rate,the zeta potential and FTIR test were carried out.The IEP were smaller than the original At.t when they were induced cultivating by ultraviolet irradiation.The same change happened to At.f when they induced by microwave 10 s.The At.f grown with pryite has higher IEP than At.f grown with FeSO₄.The sulfur and pyrite particles IEP will increase with interaction times when they interacted with corresponding At.t and At.f The IEP of sulfur particles also increase when interatced with At.t in presence of Tween 60.The FTIR study on At.t and At.f cells surface substances shown that the chemical function group or the vibration mode of group had been changed,these means the hydrogen bond action changed on the surface,they maybe was the main reason cause the mutagenes surface characteristic changed.The reasonable interpretation to At.t and At.f leaching posphate ore and genetate acide experiment reuslts can be found out from the synthetically analyzed the results of zeta potential and FTIR experiments.更多还原