硅酸盐细菌代谢产物对不同结构硅酸盐矿物风化作用的影响

选用一株硅酸盐细菌,采用摇瓶发酵培养,对比分析不同结构硅酸盐矿物刺激与促进细菌产代谢产物的差异;采用摇瓶浸矿试验,研究细菌代谢产物及细菌对石英、斜长石与高岭石的风化分解作用。结果表明,硅酸盐矿物可促进细菌产草酸、酒石酸、苹果酸等有机酸、氨基酸与多糖,同时可刺激细菌代谢产生特定的柠檬酸与氨基酸,高岭石对细菌代谢产有机酸与多糖促进作用最强,斜长石对细菌代谢产生氨基酸促进作用最明显;各代谢产物均对硅酸盐矿物具有一定的风化分解作用,其中多糖对矿物分解作用最强,混合代谢产物对矿物具有更强的风化作用;具层状结构的高岭石较架状结构的斜长石更易被细菌及代谢产物所风化分解;3种代谢产物的混合物在风化矿物过程中具有明显协同作用;细菌对矿物分解作用明显较混合代谢产物强,表明细菌对矿物风化分解作用是生物物理及化学等多种因素共同作用的结果。     

硅酸盐细菌代谢产物对硅酸盐矿物的浸溶作用研究

研究发现，硅酸盐细菌JXF菌株在含有石英粉的培养基中能合成有机酸、氨基酸、多糖等各种代谢产物并分泌释放到发酵液中。随着发酵时间的延长，发酵液中4种有机酸（草酸、柠檬酸、酒石酸、苹果酸）含量逐渐降低，说明细菌又以它们为营养物质进行生长繁殖；在菌种的不同发酵期，合成氨基酸的种类不同，在无氮或含石英粉的培养基中，有利于细菌大量合成多糖类物质。摇瓶试验表明，有机酸、氨基酸、多糖均具有破坏高岭石晶格结构的能力而释放出其中的铝、硅，原因是这些有机物具有络合矿物中各种金属离子的有机基团并有一定的酸溶作用。试验还表明，各种代谢产物在浸出硅酸盐矿物中具有协同作用，三者的混合物的浸矿效果明显好于它们各自对矿物的作用效果。     

铝土矿的细菌浸出及微生物代谢产物试验研究

就细菌浸出方式、矿物品格结构、菌种的不同来源及其分解代谢物种类、数量、能力等四个方面对铝土矿的硅酸盐细菌浸硅效果的影响进行了试验研究和分析。结果表明,五种不同来源的硅酸盐细菌都能较好地从各种铝土矿中浸出硅,硅浸出率范围为35.3%-65.3%,其中JXF-1菌株浸出硅的效果最好;试验采用了四种不同的浸出方式,其中,利用预先在有被浸矿样且含蔗糖的培养基中培养的菌种,然后在有糖培养基质中对矿样进行浸出,硅的浸出率最好,从各种矿样中浸出硅的范围为25.7%-65.3%,比其它浸出方式高10%以上。在各种类型的被浸矿样中,细菌对层状结构的绿泥石浸出效果最好,可浸出其中65.3%的硅,而架状结构的正长石被细菌浸出的硅只有25.7%。硅酸盐细菌在不同的培养基中可以合成大部分的氨基酸、多糖和酒石酸、柠檬酸、苹果酸等四种主要的有机酸,各种代谢产物均对高岭石中的硅有一定的浸溶作用,试验表明,氨基酸、有机酸、多糖三者混合物溶解高岭石中硅的量比单独代谢产物的溶解硅的量分别高357.99%、291.89%、1186.1%。     

含硅尾渣常压碱浸及浸出液制备白炭黑的研究

采用常压碱浸法对含硅尾渣中的Si、Al、Fe元素进行了有效分离,得到了优质硅酸钠浸出液。结果表明： 碱浸实验中,浸出温度108 ℃,浸出时间1 h,碱硅比0.5,液固比1.3 mL/g时浸出效果最佳。得到了Si、Al、Fe 元素含量 分别为140 g/L、140 mg/L和71 mg/L,模数2.26的硅酸钠浸出液。进一步采用化学沉淀法从浸出液中制备了白炭黑,使 用X射线衍射仪和扫描电镜对白炭黑进行了表征,结果表明：白炭黑产品为无定型结构,SiO₂含量为99.35%,一次粒子 粒径在50 nm左右,颗粒形貌为葡萄状集合体。     

四种羟基羧酸对含钙矿物浮选的影响

通过浮选试验、Zeta 电位测定、X 射线光电子能谱(XPS)分析、溶液化学计算,研究柠檬酸、酒石酸、苹果 酸、水杨酸 4 种羟基羧酸对稀土尾矿中萤石、磷灰石和方解石浮选行为的影响,结果表明:油酸钠作为捕收剂时,四种 羟基羧酸的抑制能力大小为萤石(柠檬酸>酒石酸>苹果酸>水杨酸),磷灰石(柠檬酸>酒石酸 =苹果酸>水杨酸)以及 方解石(柠檬酸>苹果酸>酒石酸 =水杨酸)。 柠檬酸对萤石和方解石具有选择性抑制效果。 在 pH = 6. 8 时,1. 6×10^-4 mol / L 柠檬酸和 1. 0×10^-4 mol / L 油酸(约等于 30 mg / L 油酸钠)都以阴离子形式存在,并以矿物表面的 Ca 为作用位 点,产生竞争吸附。 矿物表面 Ca 的电子结合能大小决定了柠檬酸对矿物抑制能力的大小,萤石>磷灰石>方解石。     

胶质芽孢杆菌JXF菌株代谢产物与脱硅作用研究

采用摇瓶振荡培养和电镜分析, 研究了胶质芽孢杆菌JXF菌株在发酵培养过程中产生代谢产物的种类、能力及其对钾长石中硅的浸出效果。结果表明, 在含有石英粉的培养基中, JXF菌株可合成有机酸、氨基酸、多糖等代谢产物并析释于发酵液中。发酵液中4种有机酸(草酸、柠檬酸、酒石酸、苹果酸)的含量随发酵时间延长逐渐降低, 说明细菌又以它们为营养物进行生长繁殖; 在不同发酵期JXF合成的氨基酸种类不同, 而无氮或含石英粉的培养基有利于细菌大量合成多糖类物质。代谢产物摇瓶浸矿试验表明, 有机酸、氨基酸、多糖等均具有配合矿物中各种金属离子的有机基团并有一定的酸溶作用, 均可破坏钾长石晶格结构, 并释放出其中的铝、硅。在浸出硅酸盐矿物时, 代谢产物具有协同作用, 三者的混合物的浸矿效果明显优于它们单独作用时的效果。     

新疆某铀矿矿石浸出性能研究

为探索适合新疆某砂岩铀矿床的地浸采铀工艺,在室内开展了分别以不同质量浓度的硫酸和碳酸氢盐溶液作为浸出剂的搅拌浸出试验。结果表明：该矿铀矿石的浸出性能好,硫酸、碳酸氢盐搅拌浸出均取得了较好的溶浸效果；酸法搅拌浸出,硫酸浓度为2.79 g/L时,铀浸出率达87.65%,铀浓度峰值199.5 mg/L；硫酸浓度为7.04g/L时,铀浸出率达95.06%,浸出液峰值铀浓度达250.20mg/L；碳酸氢盐搅拌浸出,HCO_3^-浓度为5.07g/L时,铀浸出率达83.17%,浸出液峰值铀浓度达213.46mg/L,浸出液中的Ca^₂₊、Mg^₂₊含量仅30~40mg/L,浸出的Ca^₂₊、Mg^₂₊再次沉淀。综合考虑溶浸工艺对矿层孔隙堵塞的风险、生产成本等因素,建议该矿床在地浸采铀条件试验中采用低酸浸出工艺,硫酸酸度建议为2~3g/L。     

异极矿在氨性体系中浸出锌的动力学

本文考察了异极矿在NH₃-(NH₄)₂SO₄体系作中浸出Zn的动力学,探讨了温度和液固比对浸出率的影响。结果表明：最佳的浸出温度为55 ℃,最佳浸出液固比为20;该浸出过程属于扩散控制,反应的活化能为16.1 kJ/mol。     

(Cr,Fe)7C3颗粒原位自生的Fe3Al基金属陶瓷涂层磨损行为

本文研究了一种以Fe₃Al金属间化合物为基相,原位自生(Cr,Fe)₇C₃颗粒为陶瓷相的新型低成本金属陶瓷涂层及其摩擦磨损性能。通过投料成分的精准设计,采用真空冶金+堕气雾化的冶金方法直接制备了(Cr,Fe)₇C₃/Fe₃Al新型复合粉末,获得碳化物原位自生于Fe₃Al基相且呈弥散分布的(Cr,Fe)₇C₃/Fe₃Al金属陶瓷涂层原料;采用超音速火焰喷涂(HVOF)制备(Cr,Fe)₇C₃/Fe₃Al涂层,并通过销-盘往复干摩擦摩擦磨损试验,研究了具有原位自生(Cr,Fe)₇C₃颗粒弥散强化的(Cr,Fe)₇C₃/Fe₃Al金属陶瓷涂层在室温及400℃下的耐摩擦磨损性能。结果表明：(Cr,Fe)₇C₃/Fe₃Al涂层的结合强度达到60.51Mpa,涂层硬度随温度升高衰减较慢,且在室温和400℃相应实验条件下的摩擦系数分别为0.7722和0.5634,均明显低于RuT350铸铁基体摩擦系数,400℃下其摩擦副的总磨损量仅为RuT350基体摩擦副总磨损量的50.4%,耐磨性优于Fe₃Al涂层和NiCr-Mo-Cr₃C₂涂层。(Cr,Fe)₇C₃/Fe₃Al具有较高的中高温耐磨性主要源于金属间化合物Fe₃Al粘结相在特定的温度范围具有异于普通合金的R现象,促使(Cr,Fe)₇C₃/Fe₃Al具有较高的高温硬度,并存在大量弥散分布的细小(Cr,Fe)₇C₃晶粒,不易造成陶瓷颗粒从金属相中脱落在磨损表面形成第三粒的协同机制。研制的(Cr,Fe)₇C₃/Fe₃Al涂层新材料在400℃左右的中低温下具有优异的耐摩擦磨损性能,且原材料成本低,具有工业应用潜力。     

石煤型低品位钒矿提钒试验研究

该矿样中含V₂O₅ 0.506%,全碳36.56%,属于低品位钒石煤矿,其发热量13.27 MJ/kg,可利用其燃烧热能进行焙烧。对焙烧温度、焙烧时间、矿物粒度、浸出时间、浸出温度、浸出酸度、助浸剂选择等进行详细试验研究,最终确定采用空白焙烧—烧渣添加助浸剂—酸浸工艺流程,V₂O₅的浸出率70.41%。     

Utilization of soluble starch as a depressant for the reverse flotation of diaspore from kaolinite

The utilization of a non-toxic natural polysaccharide, soluble starch, in the flotation of diaspore and kaolinite with emphasis on depression of diaspore in the reverse flotation of bauxite ores by using a Gemini cationic collector, is reported in this work. Firstly, the depressant effect of soluble starch was studied by pure mineral micro-flotation of diaspore and kaolinite as functions of the depressant dosage and pulp pH. The results show that soluble starch depresses diaspore much better than kaolinite. When pH is over 10, a satisfactory separation of the alumina and the silicate minerals can be approached. Moreover, micro-flotation tests of artificial mixed minerals and bench scale reverse flotation of the diasporic bauxite ore was complementing conducted. The non-charged starch is highly proved to be an effective and selective depressant for the reverse flotation of diaspore from the gangue minerals like kaolinite. By zeta potential measurement, adsorption studies and D-IR spectra analysis, the mechanism of interaction between starch and the diaspore surfaces is established, which is the formation of a five membered ring complexes on mineral substrates. The number of broken Al–O bonds of diaspore is much more than that of kaolinite, so the selectivity separation of diaspore from kaolinite in this system is feasible.     

含钒粘土矿两段浸出提钒工艺

采用碱浸预处理-酸浸提钒的两段浸出工艺从含钒粘土矿中浸出钒, 考察了碱浸预处理工序中NaOH用量和浸出时间、预处理后酸浸工序中H₂SO₄用量、浸出温度、浸出时间、液固比等因素对钒浸出率的影响。碱浸预处理能部分溶解Si、Al矿物, 从而破坏含钒矿物晶体结构, 为酸浸提钒时提高钒浸出率并降低酸耗创造条件。实验结果表明, 在95 ℃温度下用20%NaOH对矿样浸出24 h后, 酸浸工序中H₂SO₄用量30%, 温度95 ℃, 液固比1.5∶1, 浸出时间12 h, 钒浸取率达到了80%以上。     

Role of crystal structure in flotation separation of diaspore from kaolinite,pyrophyllite and illite

Wettability and electrokinetics of kaolinite, illite, pyrophyllite and diaspore were measured in the context of reverse flotation using cationic collectors. The results were interpreted by crystal structure analysis of the minerals. The point of zero charge (PZC) was calculated using crystallographic parameters of the minerals and compared well with the corresponding iso-electrical point (IEP) determined experimentally. The decreasing order of the measured IEP or calculated PZC from diaspore to kaolinite, illite and finally pyrophyllite correlated well with decreasing the number of broken Al–O bonds and the ratio of broken Al–O to Si–O bonds. The electrostatic interaction was identified as the main driving force for cationic collector adsorption on the minerals. Satisfactory separation of aluminosilicates from diaspore was achieved by reverse flotation.     

A novel depressor useful for flotation separation of diaspore and kaolinite

The floatation of the minerals diaspore and kaolinite was investigated using dodecylamine as the collector.Separating diaspore and kaolinite in a neutral pH pulp is difficult since they then have similar floatability.A depressor consisting of an AlCl3/Na2SiO3 mixture is demonstrated to solve this problem.Diaspore sinking may be seen when the ratio of AlCl3 to Na2SiO3 is 3:1.We refer to this mixture as ATNO.The influence of Al/Si ratio in the feedstock and the grain size of fed minerals on separation was exa...     

刚果（金）某氧化钴矿还原酸浸试验

采用亚硫酸钠为还原剂对来自刚果（金）某钴含量为1.10%的氧化钴矿进行了还原酸浸试验研究，考察了还原剂用量、硫酸用量、浸出温度、液固比等因素对浸出率的影响。结果显示：最优浸出条件为：反应温度70 ℃，液固比1.5，还原剂用量为钴锰完全还原理论用量1.8倍，在此条件下钴的浸出率可达94.86%，锰浸出率97.43%，铁浸出率15.56%，铝浸出率42.53%，浸渣含钴0.059%。对浸出前后的物料进行分析表明，还原酸浸过程充分破坏了金属矿物结构，使有价金属以离子形式进入溶液，实现了有价元素的选择性浸出。     

柠檬酸对蓝晶石浮选行为的影响研究

通过纯矿物浮选试验,研究了柠檬酸对蓝晶石浮选的调整作用。结果表明,在油酸钠浮选体系中,柠檬酸在不同的pH值条件下能不同程度的抑制蓝晶石的上浮,在十二胺浮选体系中,柠檬酸在不同的pH值条件下能不同程度的活化蓝晶石的上浮。利用量子化学计算前线轨道能量和分子动力学模拟研究水和柠檬酸在蓝晶石表面的吸附差异,模拟结果表明柠檬酸与蓝晶石的作用强于水与蓝晶石的作用,通过浮选溶液化学计算,分析了柠檬酸对蓝晶石的调整机理,柠檬酸组分可以与蓝晶石表面的铝离子络合,其中C_6H_7O_7~-和C_6H_6O_7~(2-)的作用效果比C_6H_6O_7~(3-)明显,同时增强了蓝晶石表面的负电性,抑制油酸钠在蓝晶石表面的吸附,而有利于十二胺在蓝晶石表面的吸附。     

Recovery of manganese from electric arc furnace dust of ferromanganese production units by reductive leaching

Recovery of manganese from electric arc furnace dust (EAFD) of a ferromanganese production unit was investigated using reductive leaching in sulfuric acid (H₂SO₄). Three different reducing reagents, oxalic acid, hydrogen peroxide and glucose, were tested. Effect of different leaching parameters on the leaching and separation selectivity of manganese from iron was investigated. Iron concentration in solution was also determined, since iron was the major contaminant in the leach liquor. From the results complete leaching of manganese was achieved at 0.31 mol/L oxalic acid concentration, 2 mol/L H₂SO₄, a liquid/solid ratio of 30/1 at 70 °C and with 90 min leaching time.     

The effects of mineralogy on the biological leaching of nickel laterite ores

The amenability of limonite ore, the iron rich nickel laterite phase, was observed to be less than saprolite, the silicate rich phase, when subjected to biological leaching with heterotrophic microorganisms. To understand this difference, controlled leaching of the various nickel laterite minerals was conducted using citric acid to mimic the chemical action of the organisms and subsequent characterisation of the leached residues. The raw ore and the leached mineral residues were examined using high-resolution synchrotron based X-ray diffraction and optical microscopy. The possible contribution of electrosorption and solid porosity was also considered. The results suggest that although electrosorption contributes to nickel and cobalt losses, it is the structural changes induced by the acid in the minerals which effects the recovery of the metals. Citric acid was found to dehydroxylate saprolite minerals resulting in an unstable nickel oxide and thus making it susceptible to acid attack. This behaviour was not observed in the limonite ore, which was found to be poorly leached by citric acid.     

The role of citric acid in the flotation separation of rare earth from the silicates

The Nechalacho project is the most advanced large heavy rare earth elements (HREE) project outside of China. Open circuit and locked cycle flotation tests along with pilot plant testing of rare earth elements (REE) concentration from the host rocks are accomplished with collectors of alkyl phosphates and the modifier of citric acid. In this study, the function of citric acid in the separation of rare metals against silicates is investigated by a combination of micro-flotation tests and time of flight secondary ion mass spectrometry (ToF-SIMS) surface chemical analysis. It was observed that there was little effect of citric acid on the REE recovery in the micro-flotation tests conditioned with de-ionized water (DIW). To evaluate the flotation response with excess secondary ions in the pulp, micro-flotation tests were performed to look at changes in recovery as a result of adding Al ions and the subsequent presence of citric acid. The results from three micro-flotation tests (DIW, DIW with the addition of 100 mg/L Al and DIW + 100 mg/L Al and 500 g/t citric acid) revealed that the addition of Al ions led to a decrease of REE grade, a lower REE minerals recovery and/or an unexpected promotion of silicates to the concentrate. Citric acid reduced the negative effect generated by the Al ions in the flotation, which was shown by an improvement in REE grade. ToF-SIMS surface analysis of undifferentiated grains from the tests with and without citric acid revealed that grains reporting to the concentrate are doing so in response to collector attachment in combination with having more secondary Al on their surface. Citric acid may partially form aqueous soluble metal–ligand complexes resulting in less Al ions on the grains surface, which were rejected to the tailings. Citric acid also may form chelation competing for adsorption on gangue minerals, resulting in a diminished effectiveness of the activation site.