酵母菌对锡石、方解石和石英的浮选特性影响研究

针对微细粒锡石难以浮选回收的问题, 以酵母菌为捕收剂, 系统研究了锡石、方解石、石英纯矿物一元体系和二元体系的浮选规律。结果表明, 一元体系下, 在培养时间24 h、pH=6、酵母菌浓度1.25 g/L、作用时间15 min条件下, 锡石回收率为78.83%。酵母菌浓度0.125 g/L时, 锡石和方解石二元混合体系中锡金属回收率为85.66%, 锡石和石英二元混合体系中锡金属回收率为90.71%。测试结果表明, 酵母菌可以大量吸附-5 μm粒级锡石, 但对+38 μm粒级方解石和石英相互作用较小。酵母菌与锡石之间的吸附以化学作用为主。     

Effects of lower surface ocean pH upon the stability of shallow water carbonate sediments

It is predicted that surface ocean pH will reach 7.9, possibly 7.8 by the end of this century due to increased carbon dioxide (CO₂) in the atmosphere and in the surface ocean. While aragonite-rich sediments don't begin to dissolve until a threshold pH of ~ 7.8 is reached, dissolution from high-Mg calcites is evident with any drop in pH. Indeed, it is high-Mg calcite that dominates the reaction of carbonate sediments with increased CO₂, which undergoes a rapid neomorphism process to a more stable, low-Mg calcite. This has major implications for the future of the high-Mg calcite producing organisms within coral reef ecosystems. In order to understand any potential buffering system offered by the dissolution of carbonate sediments under a lower oceanic pH, this process of high-Mg calcite dissolution in the reef environment must be further elucidated.     

微生物固化砂土强度增长机理及影响因素试验研究

微生物诱导碳酸钙沉淀(MICP)可以显著改善砂土的工程力学特性,但其固化效果易受诸多因素影响。基于不同胶结水平微生物固化砂土试样,开展固结排水三轴剪切试验和扫描电镜测试,探讨了MICP技术的固化效果及其相关机理;在此基础上,研究了胶结液浓度、砂土初始密实度、胶结液浓度配比等因素对微生物固化砂土抗剪强度的影响。结果表明:随着胶结水平的提高,微生物固化砂土试样强度提高,试样的脆性也越显著。微生物固化砂土强度的增长主要源于碳酸钙晶体对土体黏聚强度的提高。微生物固化砂土的强度主要包括土骨架强度和碳酸钙晶体胶结强度两部分,前者受土体性质及相关参数影响,后者主要取决于碳酸钙晶体的含量。采用合适的砂土初始密实度,适当提高胶结液浓度以及胶结液中尿素的浓度占比,均可提高微生物固化砂土试样的胶结强度。     

田黄仿制品——“印尼金田黄”的宝石矿物学特征

针对珠宝市场上新近出现的一种田黄仿制品——"印尼金田黄"(市场俗称)进行了XRD,ICP-MS及FTIR等大型仪器的系统分析测试,并对其矿物组成、化学成分等方面进行了系统的分析,并与寿山田黄进行了对比。研究结果发现,"印尼金田黄"主要为方解石矿物组成,与寿山田黄的矿物组成完全不同;其化学全分析结果显示,除Ca外,Mn,Fe等变价金属离子元素的质量分数较高,可能是导致"印尼金田黄"呈现金黄色的主要致色原因。无论其矿物组成、化学成分还是常规宝石学特征,均与传统的、以地开石为主的寿山田黄完全不同。     

Think Positive: Phase Separation Enables a Positively Charged Additive to Induce Dramatic Changes in Calcium Carbonate Morphology

Soluble macromolecules are essential to Nature's control over biomineral formation. Following early studies where macromolecules rich in aspartic and glutamic acid were extracted from nacre, research has focused on the use of negatively charged additives to control calcium carbonate precipitation. It is demonstrated that the positively charged additive poly(allylamine hydrochloride) (PAH) can also cause dramatic changes in calcite morphologies, yielding thin films and fibers of CaCO₃ analogous to those produced with poly(aspartic acid) via a so‐called PILP (polymer‐induced liquid precursor) phase. The mechanism by which PAH induces these effects is investigated using a range of techniques including cryo transmission electron microscopy (TEM), Raman microscopy, and thermogravimetric analysis, and the data show that hydrated Ca²⁺/PAH/CO₃^2? droplets initially form in solution, before coalescing and ultimately crystallizing to give calcite, together with small quantities of vaterite. It is suggested that it is the initial formation of hydrated Ca²⁺/PAH/CO₃^2? droplets that is key to this process, rather than a specific polymer/mineral interaction. These results are discussed in terms of their relevance to biomineralization processes and highlight the opportunity for using counter‐ion‐induced phase separation of polyelectrolytes as a method for generating minerals with non‐crystallographic morphologies.     

准噶尔盆地南缘安集海河组砂岩碳酸盐胶结物特征

准噶尔盆地南缘古近系安集海河组砂岩普遍存在碳酸盐胶结作用,是导致储层物性变差的重要因素.利用镜下观察、碳氧同位素分析等方法,在分析碳酸盐胶结物岩石学特征的基础上,探讨了碳酸盐胶结物形成环境、时期及其对储层物性的影响.安集海河组砂岩碳酸盐胶结物主要为含铁方解石,形成于成岩晚期.受有机质演化及其流体运移的影响,δ13 CPDB值大多为-10‰～-3‰,δ18OPDB值多为-15‰～-10‰.古盐度计算结果表明碳酸盐胶结物形成于淡水环境;大部分方解石为晚期较高温度下形成的.有机酸溶蚀形成的次生孔隙发育带对应于δ13 CPDB值负偏移的井段.碳酸盐胶结物充填粒间孔隙,使储层的有效孔隙度大大降低.     

Cr3+在方解石表面吸附的量子化学研究

采用量子化学计算的方法，研究了重金属Cr^3 在方解石表面不同位置吸附时能量的差异。通过对所选用的Cr^3 在方解石表面5个不同位置的模型进行计算，然后对计算结果进行分析，表明当重金属Cr^3 吸附在方解石表面一个CO3^2-侧面的上方时，比重金属Cr^3 在其它位置上发生的吸附更为稳定，同时也说明重金属Cr^3 与方解石表面发生的吸附为配位吸附。     

Depressing effect of phenoxyl acetic acids on flotation of minerals containing Ca^2＋/Mg^2＋ gangues

Phenoxyl acetic acids were applied to determine their depressing effect on minerals containing Ca2 /Mg2 gangues. Calcite, mixture of calcite and fluorite, and nickel ore were used in the flotation. And the depression mechanism was studied by the determination of contact angle, zeta potential, adsorptive capacity of collector, and IR analysis as well. It is found that 0.1 mmol/L of phenoxyl acetic acid derived from pyrogallol or gallic acid exhibits strong depressing ability on calcite in almost zero yields at pH value of 9.8, and calcite can be depressed in the flotation of calcite/fluorite mixture for approximate 87% yield of fluorite. The flotation result of practical nickel ore containing serpentine indicates that these two depressants may also show better depression performance to serpentine than traditional depressants such as sodium fluosilicate and carboxylmethyl cellulose. Analysis for the depression mechanism reveals that there exists strong chemical interaction between the depressants and minerals.     

有色方解石晶体的光谱分析

为了更好地利用有色方解石晶体,采用X射线荧光光谱仪和X射线衍射仪等仪器对浅黄色和浅紫色方解石成分进行了测试分析,用分光光度计测试了黄色方解石的透射光谱。浅黄色方解石中含有微量的镁元素和锶元素,浅紫色方解石中含有微量的锰、锶和镁元素,有色方解石晶体偏光器件的消光比可达10-6量级。结果表明,有色方解石晶体偏光器件能满足一般光学测试系统的使用要求。     

某高硫细泥锡矿浮选试验研究

针对某细泥锡矿矿石粒度细、硫化矿物和方解石含量高的特点,浮选试验采用先浮选脱除硫化矿,再采用水杨羟肟酸和P86联合捕收浮选锡石的选别工艺,获得了Sn品位18.86%、回收率64.74%的锡精矿,为此类矿产资源的合理利用提供借鉴.