细菌亚硝酸钠诱变育种及铝土矿浸矿脱硅

以胶质芽孢杆菌CGMCC11和环状芽孢杆菌CGMCC12为出发菌株,采用亚硝酸钠对其进行诱变育种与浸矿研究。结果表明:菌株CGMCC11和CGMCC12的最适生长温度分别为28和30℃,最适pH值分别为7.2和8.3。采用40和60 mg/L亚硝酸钠分别处理出发菌株CGMCC11和CGMCC12,致死率分别为87%和85%,正突变率分别为18%和20%;筛选获得两株突变菌CGMCC11KP和CGMCC12KP,其达到生长稳定期的时间分别比对应的出发菌株达到生长稳定期的时间缩短了48和24 h,且具有更大的菌体密度、产酸和产大分子胞外聚合物的能力。浸矿15 d,与对应的出发菌株相比,突变菌株CGMCC11KP和CGMCC12KP溶出的SiO2量分别提高了30.47%和29.57%,且达到浸出终点的时间分别提前了5和3 d;混合诱变菌株浸出液中SiO2的量分别比对应的诱变菌株浸出液中SiO2的量提高了20.0%和37.5%,且达到浸出终点的时间比出发菌株达到浸出终点的时间提前了6 d。SEM和XRD结果表明:混合诱变菌株对铝土矿的溶蚀分解最为明显,混合浸出15 d后,诱变前后胶质芽孢杆菌CGMCC11和环状芽孢杆菌CGMCC12的菌落个数比由1:1变为10:1。     

铝土矿脱硅方法及其研究的进展

介绍了铝土矿各种脱硅方法和研究进展,详细阐述了各种方法的基本原理和工艺流程,并对各种方法的脱硅效果和应用前景进行了讨论。     

自制铝土矿脱硅水力分选设备的流场模拟及实验研究

采用Fluent6.3软件对自制水力分选设备的流场进行模拟.模拟结果表明:设备锥体内流体的旋转运动使矿浆在径向分散和分离,向上运动的流体能促使固相尤其是粒度较小和密度较低的含硅相向上运动,实现铝相和硅相在轴向上的分离;斜板能显著提高铝相在上升过程中的沉降效率.在自制设备上进行的实际矿石脱硅试验结果表明:当原矿铝硅比（质量比）为4.7时,在搅拌器转速为150 r/min、斜板高度为16 cm、给矿量为100 mL/min及底流与溢流体积比为1:3.5的条件下,经设备一次脱硅处理,可得到Al2O3回收率为90.64％、铝硅质量比为6.34:1的精矿.     

低铝硅比铝土矿反浮选脱硅的研究

以贵州某低铝硅比铝土矿为研究对象,筛选出BS-3高效反浮选脱硅捕收剂强化捕收含硅脉石矿物,为成功分离高硅低铝硅比铝土矿奠定了基础。试验证明:在磨矿细度为85%的条件下,采用一粗两精两扫工艺和高效捕收剂强化捕收,可以获得较好的精矿指标。对入选原矿A/S为5.60的低铝硅比铝土矿,获得最终精矿A/S为10.08,回收率为83.07%的优良试验指标。     

极难选—水硬铝石型铝土矿反浮选脱硅的研究

为了解决细粒浮选的问题,本文作者采用一水硬铝石型铝土矿进行反浮选脱硅试验研究,并针对高硅型铝土矿首次提出了“强化二次富集”技术并将谈技术成功地应用于实际矿石的浮选,达到了反浮选脱硅的目的.针对一水硬铝石型铝土矿试验结果表明:通过“强化二次富集”技术的应用,在不预先脱除矿泥的情况下直接进行铝土矿的反浮选试验,最终获得了满意的精矿指标:精矿铝硅比10.28,Al2O3回收率85.41％.     

某铝土矿浮选脱硅脱硫工艺矿物学的可行性研究

利用X射线衍射、矿物定量解离系统(MLA)、扫描电镜(SEM)对云南某高硫铝土矿进行了工艺矿物学研究。分析了矿石的元素和物质组成,着重研究了铝、铁、硫的矿物组成、嵌布特征、粒级分布、矿物单体解离度等工艺矿物学性质,并分析了影响选冶工艺的因素,为该铝土矿的选矿除杂和高效利用提供了理论依据。     

环状芽孢杆菌对铝土矿浸出分解行为的影响

微生物对铝硅酸盐矿物的风化分解包含直接作用与间接作用两种方式。采用微孔滤膜将细菌与矿物隔离,在细菌矿物直接接触与间接接触两种模式下,研究环状芽孢杆菌对铝土矿风化分解行为的影响。结果表明:在细菌生长的0~216 h内,细菌及代谢产物能通过直接和间接作用共同促进铝土矿的分解,但直接作用的强度明显大于间接作用的;Al的溶出主要受直接作用的影响,而铝土矿中K、Fe和Si的溶出率主要受间接作用的影响;细菌代谢产物对溶出的Al具有明显的絮凝抑制作用,对Si具有良好的分散性能;细菌对铝土矿中不同晶体结构的硅酸盐矿物具有选择性的分解作用,具层状结构的高岭石、伊利石、绿泥石较架状结构的石英更易被细菌风化分解;在直接作用模式下,细菌在生长过程中会产生大量的胞外多聚物,细菌和矿粉之间会形成菌体矿物聚集体,促进铝土矿的分解。分析认为,细菌对铝土矿的分解过程包括机械破坏、代谢产物溶蚀、络合作用及这3种作用的协同效应。     

平果岩溶堆积型铝土矿地质特征及成矿模式探讨

平果岩溶堆积型铝土矿是我国华南特大型铝土矿矿床，本文主要对其独特的地质特征及成矿模式进行分析探讨。     

高镁石灰对铝土矿预脱硅及溶出性能的影响研究

本文针对高镁石灰对铝土矿预脱硅及溶出性能的影响开展了试验研究。研究结果表明：高镁石灰对原矿浆预脱硅与预脱钛效果的影响规律相反,对于预脱硅效果有一定程度的抑制作用,而对于预脱钛效果有一定程度的促进作用;高镁石灰有利于溶出赤泥钠硅比的降低,但却使赤泥的铝硅比略微升高。     

浅谈阿希金矿引进细菌氧化工艺在矿实验阶段的效果及思考

介绍了阿希金矿针对选冶回收率下降的现状,引进浮选精矿细菌氧化浸出工艺,经过试验、试用,将其推广应用,取得了较好的效果.     

桂西堆积型铝土矿矿物组成及地球化学特征探析

通过对桂西堆积型铝土矿矿石进行手标本观察、室内净矿石化学分析、化学物相分析及X射线粉晶衍射法等多种方法分析,结果显示其矿物组成以一水硬铝石为主,其次为针铁矿、赤铁矿、三水铝石、一水软铝石、高岭石等,其中一水硬铝石、赤铁矿、针铁矿三者之和达到了80%以上。矿石化学成分相对较为简单,A12O3、Fe2O3、SiO2、TiO2和H2O+含量之和在95%以上,表明研究区为低硫高铁型一水硬铝石铝土矿;另含S、Ga、ZrO2、Nb2O5、Ta2O5、Sc2O3及REE等微量元素,其中Ga可在生产氧化铝溶出过程中随循环母液溶出后进行回收利用。充分研究利用区内堆积型铝土矿的典型矿物组合特征和地球化学特征,对今后指导找矿勘探具有十分重要的意义。     

Technology and mechanism of desilication from roasted diasporic bauxite in atmosphere

The leaching desilication technology of roasted diasporic bauxite in atmosphere by caustic soda solution was investigated. The optimum parameters were: the grinding fineness of the roasted bauxite -0. 076 mm and 80 % -85 %,leaching time 2h, Na2Ok100-150g/L, L/S 4-5, leaching temperature 90-95℃. The desilication rate 55.20% and concentrate A/S (mass ratio of A12O3 to SiO2) 9.90, as good as those obtained at pressure, were obtained respectivdy.Investigation of two-stage leaching shows that it can both improve desilication rate of roasted ore and reduce leaching time.When time of the first stage and the second stage is 30 min and 30 min respectively, desilication rate can reach 59.65 %.X-ray diffraction analysis of the concentrate has proved that desilication procedure is accompanied with the formation of sodium aluminosilicate hydrate. X-ray spectra also show that silica removed during leaching is amorphous silica. SiO2 occurrina as ouartz in raw ore or mullite formed during roasting can not dissolve in alkali solution.     

Effect of salinity and acidity on bioleaching activity of mesophilic and extremely thermophilic bacteria

The effects of bacterial strain, salinity and pH on the bioleaching of a complex ore using mesophilic and extremely thermophilic bacteria were investigated and the statistical analysis of the results was performed using ERGUN＇s test. The extreme thermophiles were shown to display superior kinetics of dissolution of zinc compared with the mesophiles as confirmed by the statistical analysis. Bioleaching performance of the extreme thermophiles is found to improve in response to the increase in acidity （pH from 2.0 to 1.0） whilst the activity of the mesophiles is adversely affected by decreasing pH. Statistical analysis of the bioleaching data indicates that the effect of pH is insignificant in the range of pH 1.0-1.2 for the extreme thermophiles and pH 1.4-2.0 for the mesophiles. Salinity is shown to have a suppressing effect on the mesophiles. However, the extreme thermophiles appear to be halophilic in character as they could operate efficiently under saline conditions （1%-4%Cl^- （w/v））.     

三水铝石型铝土矿还原溶出赤泥中铁矿物的富集与分离（英文）

研究3种高铁三水铝石型铝土矿的矿物学特征以及不同拜耳法溶出条件对铁矿物富集与分离的影响。结果表明,添加合适的有机物还原剂,例如甘油,可以促进伴生的一水硬铝石,一水软铝石和铝针铁矿的溶出,同时还可以促进针铁矿向赤铁矿转化。利用拜尔法还原溶出处理高铝硅比三水铝石型铝土矿(A/S=25.41)可直接产出合格铁精矿(TFe>56%),实现赤泥的零排放。对于中低A/S的矿石(7.82和3.35),通过重选获得的铁精矿中相应全铁含量分别为52.05%和50.16%,铁回收率分别为65.13%和79.13%,赤泥排放量减少约50%以上。     

Flotation techniques for separation of diaspore from bauxite using Gemini collector and starch depressant

The floatability of diaspore and three kinds of silicate minerals,including kaolinite,illite and pyrophyllite,by a cationic Gemini surfactant as collector and starch as depressant was investigated as function of reagents concentration and pulp pH.Further studies of artificially mixed minerals and bauxite ore were also detailedly conducted.At last,the pre-desliming reverse flotation separation process was adopted.It can be concluded that the combinational use of a Gemini cationic collector and the starch dep...     

Thermodynamic properties of bioleaching liquid mixtures with and without mesophilic bacteria at different temperatures

In this work, low-grade copper sulfide mine has been treated by the bioleaching process using native cultures of Acidithiobacillus ferrooxidans. The bioleaching experiments were carried out in shake flasks at pH 2.0, 180 r·min-1 and 30°C for mesophilic bacteria. The conductivity of copper bioleaching liquid was determined by the electric conductivity method at temperatures ranging from 298 K to 313 K. The ionic activity coefficients were estimated using Debye-Hücker and Osager-Falkenlagen equations. Meanwhile, the effects of temperature and concentration on the mean ionic activity co efficients were discussed. The relative partial molar free energies, enthalpies and entropies of copper leaching solution at above experimental temperatures were calculated The behaviors of change of relative partial molar quantities were dis cussed on the basis of electrolytic solution theory. Simultaneously, the thermodynamic characters of bioleaching solution with and without mesophilic bacteria were compared. The existence of mesophilic bacteria changed the Fe3 /Fe2 ratio, which resulted in the difference of ionic interaction. The experimental data show that the determination of the thermody namic properties during the bioleaching processes should be important     

生物浸出体系中中等嗜热菌对锌冶炼窑渣中金属的提取及其电化学特性的影响(英文)

研究中等嗜热菌对锌冶炼窑渣中金属提取的影响以及生物浸出过程中锌冶炼窑渣碳糊电极的电化学特性。结果表明,在矿浆浓度2%、pH1.0、温度65°C、转速为120r/min的浸出条件下,去除生物浸出体系中吸附菌后,废渣中Fe、Cu和Zn的浸出率分别为86.7%、90.3%和66.7%,而在没有去除吸附菌体系中3种金属的浸出率分别为91.9%、96.0%和84.5%。对生物浸出渣和酸浸渣表面细菌分泌物进行FT-IR测试分析可知,生物浸出渣颗粒表面出现了新的官能团振动峰,如1007cm1和1193cm1处的峰,间接说明残渣颗粒表面吸附细菌的存在。生物浸出体系和空白体系的循环伏安曲线和塔菲尔曲线特性进一步表明生物浸出体系中细菌促进了锌冶炼窑渣中有价金属的溶出。     

Removal and recovery of titanium (IV) from leach liquor of high-sulfur bauxite using calcium alginate microspheres impregnated with di-(2-ethylhexyl) phosphoric acid

In the leaching solution of high-sulfur bauxite roasted by sulfuric acid, a high concentration of aluminum presented along with titanium and iron. The present work was to remove Ti(IV) from the leach liquor by calcium alginate microsphere sorbent material (CA-P204) based on natural alginate impregnated with di-(2-ethylhexyl) phosphoric acid (D2EHPA) to purify leaching solution. Cation exchange and chelation make major contributions to the adsorption mechanism according to Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis. The results showed that Ti(IV) was successfully removed by the CA-P204 adsorbent from the Ti(IV)?Al(III)?Fe(III) ternary system with a dynamic column experiment. The removal rate of titanium was nearly 95% under optimal conditions and the maximum adsorption capacity was 66.79 mg/g at pH 1.0. Reusability of CA-P204 was evaluated over three consecutive adsorption/desorption cycles. The adsorption process was simple, low-cost, and had no waste discharge, suggesting that the CA-P204 was promising, efficient, and economical for removing Ti(IV) from high-sulfur bauxite leaching solution.     

Local structure of calcium silicate melts from classical molecular dynamics simulation and a newly constructed thermodynamic model

The distributions of local structural units of calcium silicate melts were quantified by means of classical molecular dynamics simulation and a newly constructed structural thermodynamic model. The distribution of five kinds of Si-O tetrahedra Q_i from these two methods was compared with each other and also with the experimental Raman spectra, an excellent agreement was achieved. These not only displayed the panorama distribution of microstructural units in the whole composition range, but also proved that the thermodynamic model is suitable for the utilization as the subsequent application model of spectral experiments for the thermodynamic calculation. Meanwhile, the five refined regions mastered by different disproportionating reactions were obtained. Finally, the distributions of two kinds of connections between Q_i were obtained, denoted as Q_i-Ca-Q_j and Q_i-[O_b]-Q_j, from the thermodynamic model, and a theoretical verification was given that the dominant connections for any composition are equivalent connections.