Studies on adsorption of guar gum onto biotite mica

The interaction of guar gum with biotite mica has been investigated through adsorption, flotation and electrokinetic measurements. The adsorption densities of guar gum increase with increase of pH and the isotherms exhibit Langmuirian behaviour. Pretreatment of mica with a complexing agent such as EDTA results in a decrease in the adsorption density, highlighting the contribution of metal ions to the adsorption process. An increase in the surface face-to-edge ratio leads to an increase in the adsorption density. The flotation recoveries decrease as a function of pH, complementing the adsorption results. However, polymer depressant ability is reduced in the case of EDTA treated mica, consequent to reduction of metallic sites. Electrokinetic measurements portray conformational rearrangements of macromolecules with the loading, resulting in the shift of the shear plane, further away from the interface. Dissolution experiments indicate release of metal ions from mica, while co-precipitation tests confirm polymer-metal ion interaction in the bulk solution. The adsorption process is governed by hydrogen bonding as well as chemical interaction between guar gum and the surface metal hydroxide groups of mica.     

Cu-S flotation separation via the combination of sodium humate and lime in a low pH medium

The flotation separation of chalcopyrite and pyrite was studied in the presence of sodium humate. The results of flotation tests indicated that pyrite can be selectively depressed by sodium humate, and the activity of sodium humate was strongly affected by the pH of the pulp. At high pH values, pyrite was strongly depressed by sodium humate; however, the content of chalcopyrite was not affected. Ore flotation tests were successfully conducted in the laboratory and at the Dexing Copper Mine by applying sodium humate as a pyrite depressant. By adding 40-60 g/t of sodium humate to the pulp and adjusting the pH to 10-10.5 with CaO, a concentrate with a Cu content of 24% was obtained without reducing the Cu recovery rate. In addition, the dosage of CaO was reduced, and the recovery of Au, Ag and Mo in the copper concentrate was enhanced due to the reduced pH of the pulp. The zeta potential, adsorption of xanthate and contact angle of the mineral surface were measured, and the results from surface measurements indicated that there was a strong hydrophilic interaction between sodium humate and the surface of pyrite. Moreover, the results revealed that the interaction between sodium humate and chalcopyrite was weak. Infrared (IR) spectra of pyrite and sodium humate were obtained, and the results indicated that sodium humate was chemically adsorbed on the surface of pyrite.     

The effect of acrylamide-co-vinylpyrrolidinone copolymer on the depression of talc in mixed nickel mineral flotation

Copolymers of acrylamide and vinylpyrrolidinone with varying compositions have been synthesised and employed to depress talc in a model flotation system with process plant operation conditions. Adsorption isotherms indicated that the hydrophilic acrylamide homopolymer has a very low affinity for the hydrophobic talc surface, whereas vinylpyrrolidinone homopolymer strongly adsorbs onto the talc surface. Micro-flotation experiments revealed that the copolymer system can induce stronger talc depression than the homopolymer variants, with the most effective copolymer depressant having 25-30% vinylpyrrolidinone incorporation. The copolymer system is observed to have inherited the strong talc affinity of vinylpyrrolidinone polymer and the strong hydrophilic property from polyacrylamide. This combined effect facilitates the desired strong talc depression in single mineral flotation. However, this copolymer system has similar adsorption affinity on both the talc and pentlandite, hence depressing both talc and pentlandite in the mixed mineral flotation system. This research shows that a sufficient hydrophobic balance on the polymer is necessary for the adsorption and subsequent depression for talc. However, polymer with high adsorption selectivity is required to be a successful synthetic talc depressant for mixed mineral system.     

The development of a composite collector for the flotation of rutile

A study was carried out to find a replacement for benzyl arsenic acid (BAA) that was used in the rutile flotation circuit of a hard rock rutile mine in China. Several types of oxide collectors were tested, including sodium oleate, sodium laurate, sodium dodecyl sulphate, amino acids, diphosphonic acid and styryl phosphonic acid. It was found that styryl phosphonic acid (SPA) was the most effective, and that an aliphatic alcohol (e.g., octanol) was required to maintain the effectiveness of SPA.However, octanol was insoluble in water. The composite collector that was mixed with SPA and octanol had to be well emulsified before addition to flotation pulp. Poorly emulsified composite collectors destroyed flotation froths. Several surfactants were tested as emulsifiers and one was found to have the least adverse effects on the selectivity of the composite collector. By using the composite collector that contained SPA, octanol and the emulsifier, a rutile rougher concentrate assaying 71.3% TiO₂ was floated at 81.6% recovery from a feed containing 8.78% Ti0₂ in a single stage rougher flotation.     

氧化锌矿浮选药剂研究概况

从捕收剂、调整剂、起泡剂等方面总结了近年来国内外氧化锌矿浮选药剂的研究进展,强调了氧化锌浮选捕收剂的重要性.     

Removal of titanium impurities from feldspar ores by new flotation collectors

The principal impurities in some feldspar ores are titanium and iron, which impart color and in turn degrade the quality of the ore. Mineralogical investigations on the majority of Turkish feldspar ores indicate that rutile and, scarcely, sphene are the major titanium minerals and iron mainly originates from mica minerals. Conventionally, fatty acids, and particularly sodium oleate, are extensively used to float discoloring minerals from feldspar ores with reasonable success. In this study, new collectors, oleoyl sarcosine and hydroxamate, reported for the first time in the literature, have been used to float titanium impurities. It is found that compared to fatty acids these reagents achieve superior results. The mechanism of the action is elaborated on the basis of experimental data.     

Recovery of indium from sphalerite ore and flotation tailings by bioleaching and subsequent precipitation processes

Flotation tailings dump material of the former lead–zinc mine near Freiberg (Germany) consists of fine grained quartz, feldspar, mica as well as the sulphide minerals pyrite, galena and sphalerite not recovered by flotation. Sphalerite contains, aside from iron, copper and cadmium, significant amounts of indium (up to 0.38% (w/w)) leading to indium contents up to 70 mg/kg in the mine tailings. Preliminary thermodynamic assessment showed a comparatively small Eh–pH-range where bioleaching is possible and indium is not hydrolytically precipitated. Shake flask bioleaching of original polymetallic sphalerite ore from the Freiberg mining district (400 mg/kg indium) showed maximum zinc and indium recovery rates of almost 100% or 80%, respectively. First bioleaching tests on tailings material achieved zinc and indium yields of up to 80%. A stepwise precipitation process is being developed for indium recovery from the PLS (pregnant leaching solution) consisting of combined iron/indium precipitation and subsequent processing of the indium pre-precipitate.     

The effect of frother blends on the flotation performance of selected PGM bearing ores

Concentrators processing PGM bearing ores make use of polysaccharide depressants to reduce the recovery of the undesired naturally floatable gangue minerals, mainly silicates, present in the ore. Recent work has shown that high depressant dosages can completely depress naturally floatable gangue and thus prevent it from reporting to the concentrate. These high depressant dosages can, however, have a negative effect on the recovery of valuable minerals present in the ore by reducing the stability of the froth. In order to counterbalance the effects of depressant addition, frothers are added. It is, however, preferable to maintain independent control over bubble size and froth stability which is difficult to achieve with only one frother. An alternative strategy is to use a blend of frothers, e.g. a weaker frother in combination with a stronger frother. Such a system allows an additional degree of freedom: changing the ratio of the two frothers provides more independent control of bubble size and froth stability. This study demonstrates through the use of batch flotation tests how blending low molecular weight alcohols with commercially available frothers impacts the solids and water recovery, as well as the valuable mineral recovery and concentrate grade in different PGM ores. Higher water and solids recoveries together with higher valuable mineral recoveries (>90% copper and >70% nickel) were obtained from tests using frother blends.     

二聚酸副产物单体酸对鞍山式赤铁矿浮选试验研究

为了提高二聚酸副产物单体酸的价值,分析了单体酸成分,主要含有饱和、不饱和和异构脂肪酸。采用尿素包合法获得含量较高的异构脂肪酸,分别与原料、油酸复配后构成了一系列捕收剂,并用于鞍山齐大山铁矿石浮选试验。通过实验室开路和闭路浮选试验结果表明:浮选温度为25℃时,精矿铁品位66.38%,尾矿铁品位14.90%,铁回收率84.19%。与KS-Ⅱ浮选药剂相比,在降尾、铁回收率和降低药剂用量方面有优势。     

锂辉石矿浮选理论与药剂研究的新进展

随着锂资源需求的日益增大,作为锂资源提取的主要来源,锂辉石的选别技术需要不断发展与完善。如何扩大锂辉石与脉石矿物的可浮性差异,是提高锂辉石浮选效率的关键。本文概括分析了锂辉石与脉石矿物晶面的各向异性,以及近年来锂辉石矿浮选研究的最新进展。分析表明,锂辉石解理面具有很强的各向异性和表面组分选择性溶蚀行为。调控锂辉石优势解理面比例和表面组分选择性溶蚀,以及阴阳离子组合捕收剂的使用,可进一步强化锂辉石的浮选,同时加强脉石矿物选择性抑制剂的开发,这些将成为锂辉石矿浮选工艺研究的重要方向。     

我国重晶石选矿与提纯研究现状及展望

重晶石是一种重要的战略性非金属矿产,我国重晶石资源丰富,储量、产量和出口量均居世界首位,但出口价格偏低的局面长期存在。基于现阶段重晶石矿的特点,介绍了国内重晶石矿的不同选矿方法,评述了重晶石矿浮选过程中捕收剂和抑制剂的种类、特点及应用现状,并对影响浮选精矿质量的因素进行了分析;论述了重晶石化学提纯增白的方法,指出制备高纯度和高白度的重晶石、提高产品附加值将是实现资源高效利用的重要途径之一。     

2-mercaptobenzothiazole and derivatives in the flotation of galena, chalcocite and sphalerite: A study of flotation, adsorption and microcalorimetry

The results of flotation, using 2-mercaptobenzothiazole (MBT) and its derivatives, 6-methyl-MBT (MMBT), 6-methyloxy-MBT (MOMBT), 6-propyloxy-MBT (PrOMBT), and 6-pentyloxy-MBT (POMBT) on pure mineral samples showed some important advantages in the flotation of galena at neutral pH and low collector dosages. It has been found that MBT shows a high affinity towards surfaces containing lead and copper but no selectivity. The introduction of a pentyloxy ring substituent led to a change in the adsorption kinetics, as shown by microcalorimetry, and an improvement of the affinity towards galena.The basic mechanism of adsorption of MBT on galena and chalcocite has been studied by thermochemical measurements, showing that the adsorption mechanisms of MBT on both minerals are comparable in the initial step, involving the chemisorption of the collector. At concentrations above monolayer a second surface reaction of MBT on galena has been observed and attributed to an oxidative dimerisation.Comparative experiments on adsorption properties of mercapto-benzo-oxazole (MBO) show the important role of the endocyclic element composition on the sorption process. The endocyclic O-atom in MBO prevents chemisorption on galena whereas strong coordinative bonds will be formed on Cu containing surfaces.     

Collection zone kinetic model for industrial flotation columns

The collection zone recovery of a flotation column was modeled using a rectangular distribution function for the kinetic rate constant and a tank in series model with different vessel sizes for the residence time distribution. It was demonstrated that an analytical expression can be obtained and that data from large industrial columns fits well, keeping the parsimony principle by using a simple and practical solution. An example for the estimation of the maximum kinetic rate constant, useful for scale-up purposes, is shown using data from industrial flotation columns.     

Column flotation simulation: A dynamic framework

Since the introduction of column flotation in mineral processing plants in the early 1980s, modelling of this process has become a prevailing field of investigation. Even if significant progresses have been made with every new attempt, most of the proposed models or simulators have been restricted to the steady-state behaviour. When dynamic mass balance equations were considered, a constant pulp level during the simulation was always assumed. The objective of this paper is to present a framework for the fully dynamic simulation of column flotation. The emphasis is placed on the simulation of water, solids and gas flows and their effect on the pulp level and output flow rates.     

An experimental study of the recovery of hydrophilic silica fines in column flotation

This paper presents results of tests performed to investigate the effect of gas rate (1.2–2.5 cm/s), hydrophilic fines content (5–20% w/w silica) and froth depth (10–30 cm) on fines recovery in a laboratory-scale flotation column operating without wash-water addition and absence of floatable particles. A model was developed based on the entrainment coefficients presented by [Trahar, W.J., 1981. A rational interpretation of the role of particle size in flotation. International Journal of Mineral Processing 8, 289–327], which describes the mass contribution of the different size classes to the solids recovered in the concentrate. The entrainment model of [Zheng, X., Johnson, N.W., Franzidis, J.P., 2006. Modelling of entrainment in industrial flotation cells: water recovery and degree of entrainment. Minerals Engineering 19, 1191–1203] was also tested. The results show both models described well the dependence of the mass flow rate of hydrophilic solids in the concentrate.     

Temperature sensitive polymers as efficient and selective flotation collectors

This study investigates both the efficacy and selectivity temperature responsive of poly(N-isopropylacrylamide) PNIPAM as a flotation collector. The results of this study showed that charged poly(N-isopropylacrylamide) polymers selectively increased both the probability particle/bubble attachment as well as the floatability of coarse alumina and quartz particles respectively. These results provide a basis for considering PNIPAM as both an effective and selective collector in a flotation system. Coupled with previous studies that demonstrate the efficacy of PNIPAM as a flocculant in mineral suspensions, these results clearly demonstrate the potential use of PNIPAM as a dual function reagent which acts as both selective flotation collector and flocculant in the flotation of ultrafine particles.     

选矿废水对浮选的影响

介绍了选矿废水来源、特点及危害,综述了废水中的固体悬浮物、重金属离子和残留药剂对浮选工艺影响的研究进展。     

铜矿峪矿应用诱导浮选试验研究

探讨铜矿峪矿应用诱导浮选试验研究,寻找降低选矿成本,提高铜精矿品位的技术途径.