胶硫钼矿型难选钼矿的微生物浸出试验研究

以一株嗜酸氧化亚铁硫杆菌(At.f菌)为浸矿菌种,对某胶硫钼矿型难选钼矿的浮选混合粗精矿进行了浸出试验研究,采用摇瓶浸出方法探讨了菌种驯化、浸出体系初始Fe~(2+)含量及矿浆含量等因素对Mo浸出的影响,并对浸出过程中溶液的pH值和氧化还原电位E_h的变化规律进行了研究.结果表明:生物浸出效果明显优于酸浸,且驯化后的At.f菌对Mo的浸出率显著提高;初始Fe~(2+)较高含量有利于At.f菌对Mo的浸出,在9K浸出体系下浸出83d后Mo的浸出率可达95.65%;矿浆含量对Mo的浸出速率影响明显,但对最终浸出率影响不大;浸出过程中E_h不断升高并维持在700mV以上,pH值逐渐减小到1.3,有利于Mo的浸出.     

含磷铁矿石生物除磷试验研究

研究利用嗜酸氧化亚铁硫杆菌(At.f菌)和嗜酸氧化硫硫杆菌(At.t菌)从某含磷铁矿石中除磷的主要影响因素。研究结果表明:1)At.f菌对该铁矿石的除磷效果比At.t菌的更好,而未接种任何细菌的铁矿石除磷率在第26 d时只有11.76%;2)不同摇床转速中,140 r/min最利于At.f菌去除铁矿石中的磷;3)随着矿浆浓度的增加,除磷率逐渐降低;4)加入一定量的黄铁矿能提高除磷率,当黄铁矿与铁矿石的质量比超过10%时,除磷率能提高到90%以上;5)经浸矿驯化过的At.f菌,其除磷性能比未驯化前有了一定程度的提高;6)At.f菌浸矿后产生的主要物质为黄铵铁矾[NH4Fe3(SO4)2(OH)6]。     

硫酸和氧化亚铁硫杆菌浸出低品位磷矿

研究了硫酸和氧化亚铁硫杆菌(At.f.)浸出低品位磷矿过程中初始pH值和底物成分对磷的浸出率的影响.实验结果表明:在初始pH值为1.50～3.50时,硫酸和At.f.都能有效提高细菌培养液中磷的浸出率,且当pH值为2.00、培养底物为混合矿时,At.f.浸出磷矿中磷的浸出率最大,达到9.50%.     

混合嗜酸硫杆菌浸出低品位磷矿的正交实验研究

以某矿酸性矿土中分离的嗜酸氧化亚铁硫杆菌和嗜酸氧化硫硫杆菌形成的混合菌为浸磷菌种、黄铁矿为能源物质、无磷无铁9K培养基为浸矿培养基,对混合菌浸出低品位磷矿石（w（P2O5）为22.8%）的浸磷条件进行了单因素优化和正交实验研究。结果表明,最优浸磷的适宜条件是,矿浆浓度为15 g/L,菌种体积浓度为15%,初始pH值为1.5,磷的浸出率为51.07%。     

起始pH值对序批式反应器中强化生物除磷系统的影响研究

通过3个序批式反应器(SBR)的连续运行,研究了污水不同起始pH值对强化生物除磷系统(EBPR)的影响(SBR1:pH=6.5;SBR2:pH=7.0;SBR3:pH=7.5).结果表明:随着pH值的提高,厌氧释磷量和好氧吸磷量都逐渐增加,释磷速率和吸磷速率也在增加;除磷效率分别为82.69%、93.87%和98.50%.运用荧光原位杂交技术(FISH)鉴定EBPR中的功能菌为聚磷菌(PAO)并计算出其含量,即SBR3>SBR2>SBR1,得到在一定的pH值范围内pH值越高聚磷菌的含量越高.比较不同pH值下EBPR系统中脱氢酶活性的变化规律,在pH=6.5～7.5范围内,脱氢酶的活性随着pH的增加而线性增加,表明较高的pH有利于PAO的生长和提高PAO的活性,从而提高了除磷效率.因此,通过控制污水起始pH值的方法可以达到显著提高强化生物除磷效果的目的.     

超声波强化酸浸高磷铁矿石除磷试验研究

针对某焙烧-磁选后的高磷铁精矿(铁品位54.92%,磷含量0.83%),采用超声波强化硫酸浸出其中的磷。试验结果表明:随着超声时间的延长,除磷率逐渐降低,当超声时间为60min时,矿石的铁品位有一定波动,但比原来都有一定程度的提高,可达到58%以上,而铁回收率会随着超声时间的延长呈下降趋势,但都在92%以上;随着矿浆浓度的增加,浸出后矿石中的磷含量也逐渐增加,当矿浆浓度低于6%时,超声波除磷效果显著,固体中磷含量都低于0.24%;铁品位呈下降的趋势,但相对铁精矿都有一定程度的提高,而铁回收率也呈波动增加趋势,从最低的91.89%上升至95.50%。     

硫杆菌的驯化育种及对低品位磷矿的浸出

利用从广西某温泉采集的水样分离嗜酸氧化亚铁硫杆菌(Atf菌)和嗜酸氧化硫硫杆菌(Att)并进行纯化,然后将分离纯化后的Atf、Att菌菌株用于低品位磷矿中磷的浸出,并与经过磷矿驯化后的菌株进行浸磷效果对比和分析。研究结果表明:1)Att、Atf菌经过驯化后其生长活性有所提高,Att菌菌液平均pH比原菌有所降低,Atf菌经5~10 g/L磷矿粉驯化后菌液pH降低较明显;2)进行浸矿试验时,驯化菌株对磷矿粉有较强的适应能力,其pH下降较快,且30 d浸出率比原菌均有提高。其中Att菌在有磷培养基和无磷培养基中经过驯化后浸出率均有明显提高,最大提高了近11%;Atf菌在有磷培养基中经2~8 g/L磷矿粉驯化后浸出率提高显著,最大达28%,而在无磷培养基中经过10~15g/L磷矿粉驯化后浸磷效果最优,浸出率比原菌提高了1倍。     

有机物、亚硝酸盐和pH值对反硝化脱氮除磷的影响

目的 研究不同有机物质量浓度、亚硝酸盐质量浓度和pH值对反硝化脱氮除磷效果的影响.方法 以实际生活污水为试验水样,通过控制有机物质量浓度、亚硝酸盐质量浓度和pH值,采用静态试验进行对比研究.结果 在COD质量浓度为200 mg/L时,反硝化脱氮除磷的效果最好,氮和磷的去除率分别为97.63％和92.38％;在亚硝酸盐质量浓度为30 mg/L时获得了较好的脱氮除磷效果;在pH值为7.0 ～8.0时反硝化聚磷菌的脱氮除磷效果最好,磷的平均去除率为90.54％.结论 COD、亚硝酸盐质量浓度和pH值对反硝化脱氮除磷影响显著.     

两株芽孢杆菌对磷矿粉中磷的浸出能力研究

以巨大芽孢杆菌和多粘芽孢杆菌为实验菌种,研究了不同磷矿粉用量、培养时间以及碳源物质和氮源物质的质量分数对细菌培养液中的磷浸出率和pH值的影响.结果表明:两株菌种均显著提高了细菌培养液中磷的浸出率,最高达到3.3%,且多粘芽孢杆菌的溶磷能力比巨大芽孢杆菌稍强.随着磷矿粉用量增加,磷的浸出率显著降低,pH值逐渐升高,但当磷矿粉用量超过10 g/L后,pH值稳定在一定水平.培养时间越长,磷的浸出率越高,到培养的第15 d达到最高值,此后不再明显升高.另外,碳源物质和氮源物质的质量分数在3%时磷的浸出率最高,质量分数过高或过低均抑制了磷的浸出.     

几株黑曲霉菌株的溶磷能力初探

利用固体无机磷培养基和固体有机磷培养基对5株黑曲霉溶磷菌株进行筛选,根据溶磷透明圈与菌落直径大小的比值筛选出两株高效溶磷菌株分别命名为A82和A92。同时对这两株菌株进行无机磷和有机磷液体培养,根据培养过程中菌液的pH值、生物量、溶解磷及消化磷含量的变化探讨黑曲霉的溶磷特性。结果表明：A82和A92黑曲霉菌液pH随着溶磷能力的提高而下降;A82黑曲霉在有机磷液体培养基中培养5d后生物量达到最大;在无机磷液体培养基中培养第4d后溶磷能力达到最大值64mg/L。     

Modeling and process optimization for microbial desulfurization of coal by using a two-level full factorial design

The microbial sulfur removal was investigated on high sulfur content (1.9%) coal concentrate from Tabas coal preparation plant. A mixed culture of ferrooxidans microorganisms was isolated from the tailing dam of the plant. Full factorial method was used to design laboratory test and to evaluate the effects of pH, particle size, iron sulfate concentration, pulp density, and bioleaching time on sulfur reduction. Statistical analyses of experimental data were considered and showed increases of pH and particle size had negative effects on sulfur reduction, whereas increases of pulp density and bioleaching time raised microbial desulfurization rate. According to results of designing, and regarding statistical factors, the optimum values for maximum sulfur reduction were obtained; pH (1.5), particle size (?180 μm), iron sulfate concentration (2.7 mmol/L), pulp density (10%) and bioleaching time (14 d), which leaded to 51.5% reduction from the total sulfur of sample.     

Optimizing conditions for bacterial leaching of copper from discarded mines

1. IntroductionMany high-grade, easily exploited mineral depositsare becoming more and more scarce. Using biotech-nology to study discarded mines for the recovery ofmetallic values could present new business opportuni-ties and have a significant impact on…     

Effect of coal levels during direct reduction roasting of high phosphorus oolitic hematite ore in a tunnel kiln

The effect of coal levels on phosphorus removal from a high phosphorus oolitic hematite ore after direct reduction roasting have been investigated. Raw ore, coal, and a dephosphorization agent were mixed and the mixture was then roasted in a tunnel kiln. The roasted products were treated by two stages of grinding followed by magnetic separation. XRD and SEM–EDS examination of the products was used to analyze differences in the roasted products. The results show that coal is one of the most important factors affecting the direct reduction roasting process. When the inner coal levels increased from 0% to 15% the iron grade decreased linearly from 94.94% to 88.81% and the iron recovery increased from 55.94% to 92.94%. At the same time the phosphorus content increased from 0.045% to 0.231%. Increasing the inner coal levels also caused more hematite to be reduced to metallic iron but the oolitic structure of the roasted product was preserved in the presence of high coal loading. The phase of the phosphorus in raw ore was not changed after direct reduction roasting. The effect of coal on the phosphorus content in the H-concentrate arises from changes in the difficulty of mechanically liberating the metallic iron from the phosphorus bearing minerals.     

铁强化微生物除磷的效能及机理

从深海菌中筛选出一株高效除磷菌,并研究了铁强化此除磷菌在高盐合成废水中的除磷效能及机理。通过批次试验研究了铁磷物质的量比、初始pH值对除磷效率的影响以及铁强化生物除磷的动力学,并利用扫描电镜和能谱分析对微生物表面形貌进行了研究。结果表明,与单独铁盐和生物除磷相比,铁强化微生物除磷效率更高效且稳定在95%以上。当n(Fe(III)):n(P)=1:1时,铁强化微生物除磷的最大效率达98.50%,相比单纯生物除磷提高30%,而单独铁盐除磷n(Fe(III)):n(P)=2:1～3:1时,除磷率仅90%;当n(Fe(III)):n(P)≤1:1时,铁强化微生物除磷以微生物除磷为主,铁盐辅助,处理后水pH中性且稳定;当物质的量比n(Fe(III)):n(P)>1:1时,由于Fe(III)水解造成pH降低至5.50以下,微生物生长受抑,磷的去除主要靠化学沉淀。废水初始pH在6.0～9.0范围内,铁强化生物除磷去除率均在95%以上。准一级动力学模型能够很好地模拟生物除磷过程;准二级动力学模型能够很好地模拟铁强化生物除磷,且较长时间内无磷释放现象。铁强化生物除磷的机理包括:(1)细菌生长除磷以及胞外聚合物对磷的吸附;(2)在混合液中形成了羟基磷酸铁络合物;(3)在细菌表面形成了由细菌诱导的铁磷微沉淀。     

Removal of phosphorus from iron ores by chemical leaching

1 INTRODUCTION With the rise of the price of iron ores in the global market, the iron and steel companies in China have to increase the proportion of domestic iron ores in iron-making production. However, iron ores produced in China commonly contain many impurities, such as phosphorus, sulphur, silica, etc[1]. Phosphorus is one of the main harmful elements to ferrous metallurgy, and it will affect the quality of iron and steel products[2]. At present, China has explored some large mines,…     

Zinc bioleaching from an iron concentrate using Acidithiobacillusferrooxidans strain from Hercules Mine of Coahuila, Mexico

The iron concentrate from Hercules Mine of Coahuila,Mexico,which mainly contained pyrite and pyrrhotite,was treated by the bioleaching process using native strain Acidithiobacillus ferrooxidans(A.ferrooxidans)to determime the ability of these bacteria on the leaching of zinc.The native bacteria were isolated from the iron concentrate of the mine.The bioleaching experiments were carried out in shake flasks to analyze the effects of pH values,pulp density,and the ferrous sulfate concentration on the bioleaching process.The results obtained by microbial kinetic analyses for the evaluation of some aspects of zinc leaching show that the native bacteria A.ferrooxidans,which is enriched with a 9K Silverman medium under the optimum conditions ofpH 2.0,20 g/L pulp density,and 40 g/L FeSO4,increases the zinc extraction considerably observed by monitoring duringl 5 d,i.e.,the zinc concentration has a decrease of about 95％ in the iron concentrate.     

Removing iron by magnetic separation from a potash feldspar ore

A new permanent magnetic separator was introduced to treat the ores with the characteristics of weak magnetic iron minerals and in a fine size range. The new machine was applied to the iron removal from potash feldspar. The effects of the magnetic field intensity, pulp density and grinding fineness on the iron removal were investigated. The optimized operation parameters were achieved and listed as follows: the ?0.074 mm content is 85%, the pulp density is 45% and the magnetic field strength is 2T. A close test of middles regrinding was also carried out to improve concentrate yield. The data show that the grade of TFe(total iron) in potash feldspar product decreased from 1.31% to 0.21% and the concentrate yield reached 85.32%. All the results indicated that the traditonal high-intensity electromagnetic separators can be betterly substituted by the new permanent magnetic separator. This study may provide the theoretical evidence for iron removal from potash feldspar.     

3DBER-S-Fe深度脱氮除磷效果

为强化三维电极生物膜(3DBER)工艺深度脱氮除磷性能,提高污水厂尾水质量,将硫磺和海绵铁作为混合填料,构建硫铁复合填料三维电极生物膜(3DBER-S-Fe)脱氮除磷工艺;在不同ρ( C)/ρ( N)、I和水力停留时间( HRT)运行条件下,探究工艺深度脱氮除磷效果.分别从反应器填料和阴极上取生物膜,通过Miseq高通量测序,构建细菌16S rRNA基因克隆文库.结果表明：在运行条件为ρ(C)/ρ(N)=2、I=150 mA和HRT=4 h时,3DBER-S-Fe对总氮和总磷的去除率分别可达85.59%和97.43%;适当增加ρ( C)/ρ( N)、I和HRT均能不同程度提高系统脱氮除磷效率.在填料和阴极上丰度最大的均为具有硫自养反硝化功能的Thiobacillus,分别占40.62%和44.75%;具有氢自养反硝化功能的Rhodocyclaceae在阴极的分布明显多于填料.因此,3DBER-S-Fe具有较高的脱氮性能主要是硫自养反硝化和氢自养反硝化共同作用的结果,且氢自养反硝化过程主要发生在阴极.