水悬浮体系中凹凸棒石与Cu2+作用机理

研究矿物吸附重金属性能和机理,对正确认识矿物吸附性质、环境矿物材料应用研究以及重金属环境化学行为具有重要理论和实际意义。凹凸棒石是重要粘土矿物之一,也是重要的环境矿物材料,其吸附净化功能潜在应用受到广泛关注。在制备凹凸棒石纯样基础上,进行了凹凸棒石吸附Cu^2 单因素实验,吸附前后溶液pH值变化观测和吸附Cu^2 后凹凸棒石表面结构高分辨透射电镜调查。结果表明,从表面来看,凹凸棒石对Cu^2 的吸附性能主要受振荡速度、吸附时间、初始溶液pH值、吸附剂用量等因素影响,但实际上,凹凸棒石对Cu^2 的吸附作用主要是凹凸棒石诱导的Cu^2 水解沉淀作用以及凹凸棒石(带负电荷)与氢氧化铜(带正电荷)正负电荷胶体颗粒的互相作用,这有别于严格意义的矿物界面吸附作用。产生这种作用的机制在于凹凸棒石属于天然纳米矿物材料,具有较高的表面化学活性,凹凸棒石一水悬浮体系中凹凸棒石表面水解呈现出碱性,结果导致吸附平衡水溶液pH值较初始水溶液有较大程度的升高,达到Cu^2 水解基本完全的pH条件.     

国内矿物治理重金属废水研究进展与展望

综述了我国利用天然矿物治理重金属废水方面的研究新成果。天然铁的硫化物、天然铁锰的氧化物、方解石与磷灰石等具有良好的表面吸附与氧化还原化学活性;不同介质中它们能不同程度地表现出对Cr^6 、Pb^2 、Hg^2 、Cd^2 等重金属离子的吸附作用,可广泛用于重金属废水处理。矿物吸附重金属离子机理的研究表明,矿物对重金属的吸附是矿物表面与无机重金属离子之间的表面作用过程,包括矿物表面功能基与重金属离子的配位反应、矿物表面氧化还原反应和沉淀转化作用,以及矿物表面离子交换吸附作用等。     

石英与钠长石浮选分离的研究

用十八胺(阳离子捕收剂)和十二烷基磺酸钠(阴离子捕收剂,SDS)作浮选为捕收剂分离石英与钠长石,研究了浮选条件对分离效果的影响以及捕收剂在矿物表面的吸附行为.结果表明,最佳浮选条件是浮选液的pH=2,阴、阳离子捕收剂的浓度分别为3.0×10-6 mol/L和4.0×10-6 mol/L;阴阳离子捕收剂在石英与钠长石两种矿物上表现出相同的吸附行为.在最佳浮选条件下,对不同配比的石英和钠长石混合物进行浮选,石英回收率为14%,钠长石回收率达80%,分离效果显著;对含微量长石的石英矿粉进行浮选,分离效果与石英与钠长石混合物相近.     

钙镁离子对胶磷矿表面电性及可浮性的影响

本文选取贵州典型磷矿区海相沉积型磷矿石为研究对象,通过ξ电位测定和纯矿物浮选试验,考察了Ca2+、Mg2+对胶磷矿表面电性及可浮性的影响。结果表明:加入Ca2+、Mg2+后,胶磷矿表面负电性降低,由此可推知,胶磷矿是优先吸附溶液中的Ca2+、Mg2+而使表面负电性降低。Mg2+在胶磷矿表面的吸附使其表面形成类似白云石的覆盖层,从而会降低分选的选择性。在酸性条件下,Ca2+、Mg2+对胶磷矿浮选影响不大,但在中性及碱性条件下,金属离子的加入会明显地抑制胶磷矿的上浮,其原因可能是金属离子与脂肪酸类捕收剂发生沉淀反应,从而消耗捕收剂,并且在碱性条件下形成氢氧化物沉淀,并吸附罩盖在矿物表面,使矿物表面亲水,不易上浮。     

混合捕收剂去除高岭土中含铁矿物试验研究

文章根据高岭土中含铁矿物的浮选试验研究,采用胺类与皂化油酸表面活性剂组合作为高岭土中含铁矿物的捕收剂。高岭土中铁的赋存状态表明,采用分段阳离子/阴离子捕收剂组合试剂,当pH=8～10时,十八胺乳化液以静电力吸附形式捕收含铁硅酸盐;当pH=5～7时,皂化油酸和少量十二烷基磺酸钠通过表面活化反应捕收氧化铁矿,使北海高岭土精矿自然白度达到85%～86%,煅烧白度（1 200℃）达到88%～89%。     

含钼白钨矿的矿物学特征、晶体结构与可浮性

针对白钨矿-钼钙矿系列矿物在选矿实践中浮选行为的差异,本文在对某钨钼矿床中的典型钨矿物——含钼白钨矿进行工艺矿物学研究的基础上,从矿物晶体化学角度出发,探讨矿物晶体结构和浮选行为之间的关系,为该类型矿物的浮选行为以及浮选药剂的选择提供理论指导。结果表明,该矿石中的含钼白钨矿为钨的主要回收矿物,WO₃占有率达99%,矿物晶格中约25%的W被Mo呈类质同象替代,导致Ca-O的键合能力降低,造成矿物表面与捕收剂作用的活性质点减少,晶格中阴离子基团[MoO₄]^2-的存在,不利于矿物表面与捕收剂的有效吸附,从而使含钼白钨矿的可浮性降低。     

微生物矿化成因的铁硫酸盐矿物表面特征初探

研究表明，生物一矿物相互作用是地球表层系统演化的重要地质营力之一。微生物与矿物岩石之间进行着活跃的物质交换，微生物通过营造微观地球化学环境和提供吸附、成核中心影响着矿物的溶解和结晶，其中生物一矿物界面是物质交换和化学反应最为活跃的场所，矿物表界面记录着丰富的微生物作用信息。在综述前人微生物一矿物相互作用界面研究的基础上，利用气体吸附技术，对比分析了微生物矿化成因和无机合成含水铁硫酸盐矿物的表面积、表面分形和表面吸附能特征，初步讨论了微生物矿化成因铁硫酸盐矿物的表面特征和控制机理。     

高岭石和硅／铝-氧化物对腐殖酸的吸附实验研究

矿物结合的腐殖质可改变矿物的表面性质,矿物对腐殖酸的吸附强度与矿物的吸附位性质、密度、荷电性及比表面积有关.若按比表面积计算,矿物对腐殖酸的吸附强度顺序为氢氧化铝>高岭石>石英;按单位质量计算,吸附强度顺序为高岭石>氢氧化铝>石英.研究表明,矿物表面活性受水溶液pH值的调控,且当pH值在4～7时,上述3种矿物对腐殖酸的吸附机理为石英主要表现为氢键作用;氢氧化铝主要表现为配体交换表面配位作用;高岭石表现为多种形式并存,包括氢键、配体交换表面配位和疏水性作用以及金属离子桥键作用.     

水环境中腐殖质对重金属吸附行为的影响

水环境中金属离子-腐殖质-矿物（或细菌）之间的相互作用能够显影响金属离子在地质体中的迁移和归宿。本综述了水环境中腐殖质对金属离子在矿物、微生物等表面只附行为影响的研究现状，分析讨论了复合型表面的基本特点、腐殖质对金属吸附到矿物表面的影响因素、腐殖质影响细菌表面吸附金属离子的机理，以及对三相体系不同研究的研究思路与结论等。     

矿物粉尘对人体血清物质的吸附行为研究

通过测定吸附后人体血清的成分,并利用红外光谱研究了几种矿物粉尘对血清中物质的吸附作用,结果表明,矿物粉尘对血清中物质的吸附具有选择性,主要是吸附了血清中的蛋白质和脂类等生物大分子。不同矿物吸附生物大分子的选择性不同,这主要与矿物的结构和表面海性等因素有关。红外光谱研究表明,吸附机理主要是物理吸附,可能也存在化学吸附。另一方面,矿物粉尘在血清中发生了一定程度的阳离子交换和溶解作用。     

Rejection of arsenic minerals in sulfide flotation — A literature review

Arsenic is one of the most dangerous inorganic pollutants and thus a penalty element in many base metal concentrates. Arsenic removal in sulphide flotation has been studied extensively with various approaches, including pre-oxidation of flotation pulp, E_h control during flotation and the use of selective depressants/collectors. Pre-oxidation of flotation pulp using oxidizing agents or aeration conditioning represents a simple approach in arsenic removal and was found effective in many cases. Selective flotation of arsenic minerals through E_h control has made significant advances in recent years with promising results achieved. In addition, various depressants and collectors have also been studied in arsenic removal. In this communication, the various approaches used in selective flotation of arsenic minerals are reviewed with emphasis on the development in recent years.     

The adsorption of polysaccharides onto mineral surfaces: an acid/base interaction

Natural polysaccharides such as starch, dextrin, guar gum, cellulose and their derivatives are promising non-toxic organic depressants. Although generally perceived as non-selective, these polymers have found use in commercial processes or have been tested in laboratories in practically all flotation systems involving every type of minerals. In this communication, the adsorption mechanisms of natural polysaccharides are reviewed, with the objective of promoting the wider applications of the polymers. While it seems generally accepted that natural polysaccharides interact with minerals via surface metal-hydroxylated species, an acid/base interaction model between the natural polysaccharides and mineral surfaces is proposed to explain many observed adsorption and flotation phenomena.     

Interaction of thionocarbamate and thiourea collectors with sulphide minerals: a flotation and adsorption study

The ability of O-isopropyl-N-ethyl thionocarbamate (IPETC), O-isobutyl-N-ethoxycarbonyl thionocarbamate (IBECTC) and butyl ethoxycarbonyl thiourea (BECTU) collectors to increase the flotation of the sulphide minerals, chalcopyrite, galena and pyrite, has been studied. For each collector, the flotation characteristics of these minerals, flotation rate constant and flotation recovery maximum, have been calculated from the flotation data and compared as a function of pH and collector concentration. Overall, the flotation performance of these collectors is stronger for chalcopyrite than for galena and pyrite. Flotation increases with collector concentration and decreasing pH values. For chalcopyrite, the collector performances of BECTU are slightly better than those of IPETC but far superior to those of IBECTC, especially at high pH values or at low collector concentrations. The flotation performance of these collectors has been shown to be in good agreement with the amount of collector adsorbed at the mineral surface. The affinity of BECTU for the various minerals has been calculated using a multilayer adsorption model.     

Two-stage reverse flotation process for removal of carbonates and silicates from phosphate ore using anionic and cationic collectors

Phosphate rock contains various gangue minerals including silicates and carbonates which need to be reduced in content in order to meet the requirements of the phosphate industry. Froth flotation has become an integral part of phosphate concentration process. In this study, double reverse flotation was applied to recover apatite from phosphate ore. H₃PO₄ and CaO were used as phosphate depressants, in acidic and alkaline conditions. Fatty acids and amines were added as carbonate and silicate collectors respectively. An experimental protocol devised to optimize the grade and recovery of phosphate using anionic–cationic method was found effective. Consequently, a required high quality of phosphate concentrate containing 30.1% P₂O₅ was obtained, with a recovery of 94%. X-ray diffraction and optical microscopy studies were performed to define the main minerals.     

新型捕收剂RA-92在低品位碳酸锰矿选矿中的应用

微细粒低品位锰矿由于颗粒间的非选择性聚集、浮选药剂用量大、浮选效率低等技术难题而致使其利用困难,造成大量浪费。在品位低于13%的锰矿浮选技术研究中,捕收剂最受关注,前人已研究了多种类型的捕收剂,所得精矿品位在16.9%~18.3%之间,回收率为56%~97%,回收率比较理想,但精矿品位总体不高。本文将新型捕收剂RA-92应用于湖南凤凰-花垣地区低品位碳酸锰矿(锰品位为10.7%)的选矿工艺中,实验研究了磨矿细度、pH值、抑制剂和捕收剂用量对浮选效果的影响,在最佳工艺条件下,精矿品位由原矿的10.7%提升至17.4%,回收率达到80.2%。研究表明RA-92对碳酸锰矿具有良好的捕收性能,浮选工艺相对简单且捕收剂用量少,浮选成本较低,可为此种捕获剂在微细粒低品位碳酸盐锰矿选矿中的应用得到推广。     

Influence of adsorbed polysaccharides and polyacrylamides on talc flotation

The adsorption and action of various polymers on talc has been investigated. Two families of polymers (starch-based polysaccharides and synthetic polyacrylamides) with specific molecular weights and functional group chemistry were studied. Adsorption isotherms, acoustophoresis, and contact angle studies enabled polymer adsorption behaviour, adsorbed layer thickness, and the hydrophilicity of the polymer-treated talc surface to be determined. Flotation testing on the treated talc revealed a hierarchy of effectiveness within the group of polymers studied. The observed trends in flotation performance are discussed with reference to the measured polymer layer properties. A 3D correlation plot of adsorbed layer thickness and contact angle against flotation recovery indicates that it may be feasible to predict an order of effectiveness for polymeric depressants based solely on measurements of the adsorbed layer properties, without recourse to flotation testing. This approach would be desirable when screening large numbers of potential depressants.     

Removal of lead minerals from copper industrial flotation concentrates by xanthate flotation in the presence of dextrin

Potato starch and dextrins resulting from thermolysis of potato starch in the absence of reagents and presence of -amino acids are promising depressants for separation of lead and copper minerals present in the Polish industrial copper concentrates. The polysaccharides were used for differential xanthate flotation of the final industrial concentrates produced by flotation with sulfhydryl collectors in the absence of depressants. The polysaccharides depressed galena and provided froth concentrate rich in chalcocite and other copper minerals as well as cell product containing lead minerals. The best results of separation were obtained in the presence of plain dextrin prepared by a thermal degradation of potato starch. The industrial concentrate containing 18.5% Cu and 5.5% Pb was divided into a froth product containing 38.1% Cu with 77% recovery of copper and a cell product assaying 7.3% Pb with 83% recovery of lead. It was accomplished using 2500 g/t of dextrin, 50g/t of potassium ethyl xanthate, and 50 g/t of frother (α-terpineol). The pH of flotation was 8.0–8.2.     

Flotation of calcareous Mussorie phosphate ore

Separation of Mussorie rock phosphate (P₂O₅ = 20%) from Uttar Pradesh, India, containing pyrite, calcite and other carbonaceous impurities by flotation has been successfully attempted to upgrade the phosphate values. Based on Hallimond cell flotation results of single and synthetic mineral mixtures of calcite and apatite using oleic acid and potassium phosphate, conditions were obtained for the separation of calcite from apatite which is considered to be the most difficult step in the beneficiation of calcareous phosphates. Further studies using 250 g of the mineral (?60 +150 and ?150 mesh fractions, deslimed) in laboratory size Fagergren subaeration machine employed a stagewise flotation viz. carbonaceous materials using terpineol, pyrite using potassium-ethyl xanthate and calcite using oleic acid respectively. Separation was, however, found to be unsatisfactory in the absence of a depressant.Among starch, hydrofluosilicic acid and dipotassium hydrogen phosphate, which were tried as depressants for apatite in the final flotation stage, dipotassium hydrogen phosphate proved to be superior to others. However, the tests with the above fractions did not yield the required grade. This was possibly due to insufficient liberation of the phosphate mineral from the ore body and different experimental conditions due to scale up operations. Experiments conducted using ?200 mesh deslimed fractions has yielded an acceptable grade of 27.6% P₂O₅ with a recovery of about 60%. The results have been explained in terms of the specific adsorption characteristics of phosphate ions on apatite and the liberation size of the mineral.     

Solution chemistry studies and flotation behaviour of apatite,calcite and fluorite minerals with sodium oleate collector

The maximum flotation response for three naturally occurring calcium minerals, apatite, calcite and fluorite with sodium oleate collector correlated directly with the minimum interfacial tension of the air/solution interface. For fluorite and apatite the minimum surface tension occurred about the mid-pH region and was attributed to the formation of pre-micellar associated species in solution. In the case of calcite the minimum was observed at high pH since the presence of high concentrations of calcium ions in solution appeared to reduce the concentration of amphililic species in the low and mid-pH regions.Microelectrophoresis data demonstrated that the three minerals acquired a negative charge in sodium oleate solution, resulting from adsorption of oleate species on the mineral surfaces.The flotation behaviour of the systems were shown to be related to the species distribution diagrams suggesting that the role of the acid soap dimer, soap dimer, molecular and lattice species could make a significant contribution to the character and composition of the interfacial films.High flotation response was explained by strong adhesion between the hydrophobic particle and bubble. It was suggested that the reduction in surface tension may not be the major factor contributing to the flotation efficiency but indicated the presence of associated surfactant species in solution which could also synergistically adsorb at the solid/liquid interface, increasing the hydrophobic character of the mineral surface. This would maximize the magnitude of the contact angle and hence the strength of the adhesion between particle and bubble. This adsorption behaviour is not in general agreement with conventionally non-hydrolyzable collector theory which is usually based on electrostatic models.     

Depression of galena by slime gangue in an agitated pulp

The effect of gangue on mineral behaviour in a miniature batch version of an industrial flotation machine was examined. The flotation systems consisted of a sulphide, galena, with a specific collector, potassium ethyl xanthate, and a particular non-sulphide gangue in each case. Three gangue minerals were selected: corundum, fluorite and quartz. Flotation experiments were augmented with spectrophotometric adsorption and zeta potential measurements. Based on this data, the validity and significance of the slime-coating hypothesis in the context of the environment characteristic of industrial flotation processes were assessed.