The effect of surface oxidation of copper sulfide minerals on clay slime coating in flotation

The industry is well aware of the difficulty in treating copper ores in the presence of clay minerals. In this study, the effect of bentonite on the flotation of chalcopyrite (a primary copper sulfide mineral) and chalcocite (a secondary copper sulfide mineral) was investigated in terms of surface coating. Based on the flotation of copper ores containing both chalcopyrite and chalcocite, the flotation of chalcopyrite and chalcocite single minerals in the presence and absence of bentonite, and the zeta potential measurement of chalcopyrite, chalcocite and bentonite, it was found that the oxidation of chalcopyrite and chalcocite had a different effect on their interaction with bentonite. Under the normal grinding and flotation condition, significant oxidation occurred on the surface of chalcocite which was electrostatically attractive to bentonite resulting in bentonite slime coating and the depressed flotation of chalcocite. The reduction of oxidation on chalcocite could mitigate bentonite slime coating due to electrostatic repulsion between unoxidized chalcocite and bentonite. Unlike chalcocite, chalcopyrite with and without surface oxidation exhibited an electrostatic repulsion to bentonite. Its flotation was less affected by bentonite slimes.     

Effect of clay minerals on pulp rheology and the flotation of copper and gold minerals

In this study, the effect of bentonite and kaolinite minerals with low and high crystallinity on pulp rheology and the flotation of copper and gold minerals was investigated. It was found that clay minerals modified the pulp rheology depending on the type of clay minerals present. Bentonite, a 2:1 structured clay mineral increased pulp viscosity more significantly than kaolinite, a 1:1 structured clay mineral, and poorly crystallized kaolinite increased pulp viscosity more than well crystallized kaolinite. It was also found that pulp rheology modified by clay minerals was strongly correlated with copper and gold flotation. The higher pulp viscosity corresponded to the lower copper recovery. While high pulp viscosity was related to the decreased gold flotation, slightly increased pulp viscosity by clay minerals enhanced gold flotation.     

The interaction of clay minerals with gypsum and its effects on copper–gold flotation

The interaction of two clay minerals, kaolinite and bentonite with gypsum and its effects on the flotation of a copper–gold ore was investigated in this study. It was found that bentonite increased the viscosity more than kaolinite when mixed with the copper–gold ore at low shear rates. The detrimental effect of these clay minerals on flotation was attributed to the entrainment of clay particles when kaolinite was added to the ore and to a decrease in true flotation by bentonite. Bentonite formed a sponge-like structure with predominant edge–edge (E–E) interactions which might affect hydrodynamics in the flotation cell and have a detrimental effect on flotation recovery. Kaolinite did not form a particular network structure and its aggregates mostly consisted of face–face (F–F) type associations which did not affect flotation hydrodynamics. The addition of gypsum to the ore–bentonite mixture inhibited the formation of interconnected network structures. This led to lower viscosity values with flotation behaviour similar to that of mixtures with kaolinite. In this case, there was an improvement in recovery, but the grade decreased due to entrainment. The addition of gypsum to the ore–kaolinite mixture created aggregates with long strings further enhancing particle entrainment with more mass transported to the froth.     

The separation of chalcopyrite and chalcocite from pyrite in cleaner flotation after regrinding

In this study, the differences between the separation of chalcopyrite and chalcocite from pyrite in cleaner flotation after regrinding were investigated. In the rougher flotation prior to regrinding, high chalcopyrite and chalcocite recovery were obtained in conjunction with high pyrite flotation recovery due to the activation of pyrite by copper ions during primary grinding. The rougher flotation concentrate was reground in a rod mill before cleaner flotation. It was found that chalcopyrite and chalcocite exhibited different flotation behavior and also affected pyrite flotation differently in cleaner flotation. The mechanism underpinning these phenomena was investigated by a range of techniques including the polarization of mineral electrodes, X-ray photoelectron spectroscopy (XPS) analyses and ethylene diamine tetraacetic acid (EDTA) extraction. It was found that the flotation behavior of both copper minerals and their effect on pyrite flotation after regrinding were governed by their electrochemical activities and galvanic coupling with pyrite.     

Quantifying accidental activation. Part I. Cu ion production

Accidental activation is a function of metal ion production, transfer and resultant flotation response. In Part I copper ion production from chalcocite and chalcopyrite was determined for single minerals and ores as a function of particle size using an EDTA extraction method. Copper ion production was inversely proportional to particle size. For single minerals, chalcocite produced about 50 times more Cu than chalcopyrite. The chalcopyrite-bearing ores gave higher copper ion production than for mineral alone, ascribed to galvanic interaction. A model was derived to predict surface concentration of Cu. The Cu production is compared to the resultant flotation effect in Part II.     

The effect of biopolymer dispersants on copper flotation in the presence of kaolinite

In this study, three lignosulfonate-based biopolymers, DP1775, DP1777 and DP1778 with different compositions were examined as dispersants in copper flotation in the presence of kaolinite. While rheological measurements indicated that these biopolymers dispersed the kaolinite aggregates, flotation results revealed that the three biopolymers increased the copper recovery, with a decline in copper grade, which was attributed to an interaction of biopolymers with the frother modifying the froth and enhancing the mechanical entrainment. Two-phase foam characterisation revealed a larger height in the blends of biopolymer and frother, which in turn promoted the mechanical entrainment in flotation. The dispersing and foaming abilities of biopolymers were governed by their structural features such as the content of functional groups, the molecular weight and counterions. This study indicates that when selecting a polymeric dispersant in flotation to deal with clay minerals, its froth property should also be taken into consideration.     

The effect of grinding conditions on the flotation of a sulphide copper ore

The challenge of process development for the beneficiation of Salobo’s copper ore started in 1978 and the studies still go on. Copper is predominantly present as secondary minerals, such as chalcocite, bornite, and digenite, and liberation requires very fine grinding. These minerals may undergo rapid oxidation at the alkaline pH range and under mildly oxidising conditions. The oxidation products may adsorb onto the minerals altering their surface characteristics, flotation behaviour, and may also significantly modify the mechanisms of interaction between the minerals and the collector. These facts impair the flotation process performance and increase the reagents consumption, the required flotation cells volume, and the overall processing costs. This paper describes the effect of grinding conditions on the flotation performance. Different media and mill construction materials were tested at bench scale aiming at evaluating the effects of the pulp electrochemical potential and the availability of iron oxide and hydroxide compounds on the flotation response. The results indicated that the grinding process affects significantly the flotation metallurgical performance of Salobo’s ore. The conditions that yielded the highest levels of copper recovery and the fastest flotation kinetics were rubber lined steel mill and stainless steel media.     

Effect of saline water on the flotation of fine and coarse coal particles in the presence of clay minerals

This research addresses two important issues confronting coal flotation plants in Australia, the use of saline water and the processing of clayey coal. Two coal samples obtained from BHP Billiton Mitsubishi Alliance (BMA) and Xstrata were tested to represent coarse coal flotation and fine coal flotation, respectively. Saline water with low, medium and high ionic strengths and individual electrolytes encountered in the flotation plants were used. It was found that saline water had a more pronounced effect on fine coal flotation than coarse coal flotation despite similar mineral compositions and clay mineral types present. Although saline water increased froth stability in both fine and coarse coal flotation, coal particle aggregation only occurred between fine coal particles resulting in an increased recovery of coal particles as well as the entrapment of fine gangue minerals.     

Effects of aluminosilicate minerals on copper-molybdenum flotation from Sarcheshmeh porphyry ores

The presence of aluminosilicate minerals adversely affects the floatability of copper during processing of Sarcheshmeh porphyry ores. In this work, ores containing different types and quantities of aluminosilicate minerals, as well as copper sulfides (i.e., chalcopyrite and chalcocite), were examined in the laboratory to determine how aluminosilicate minerals affect the floatability of copper and to find ways to decrease their unwanted effects. It was shown that ore types that contain muscovite and vermiculite have the greatest effect on the floatability of copper sulfides. To overcome this problem, two reagent strategies were used: (a) dextrin at 100, 200, and 600 g/ton and (b) a mixture of dextrin, sodium silicate, and sodium hexametaphosphate (20%, 40%, and 40% by weight, respectively) at 200 and 300 g/ton. The reagent mixture (case b) at a dosage of 200 g/ton improved the copper recovery and decreased the grade and the recovery of Al₂O₃ and SiO₂ in the flotation concentrate. As an alternative solution, flotation at reduced pulp density (24%) improved the grade and the recovery of copper and molybdenum and decreased the grade and recovery of Al₂O₃ and SiO₂ in comparison to the currently used pulp density (29%) in the Sarcheshmeh flotation plant.     

Gemini trisiloxane surfactant: Synthesis and flotation of aluminosilicate minerals

In this paper, an amino-trisiloxane Gemini cationic surfactant, butane-1,4-bis(dimethyl-(3-(3-aminopropyl trisiloxane-3-yl)-propyl)-ammonium bromide) (BBAB) was prepared, and its flotation potential was assessed on kaolinite, pyrophyllite and illite minerals. The flotation results showed that changes to the pulp pH did not significantly influence BBAB’s collecting power in floating three aluminosilicate minerals. In addition, BBAB was a stronger collector than the conventional monomeric surfactant dedecyl trimethylammonium bromide (DTAB) or dodecylamine (DDA). The results of FTIR spectra, zeta potential measurements and density functional theory (DFT) calculations indicated that the interaction of BBAB with the three aluminosilicates was mainly through electrostatic attraction. BBAB’s unique properties, such as high positive grouping Mulliken charge of –CH₂N⁺(CH₃)₂(CH₂)₄(CH₃)₂N⁺CH₂–, and “parachute” shape structure of [(CH₃)₃SiO]₂SiCH₃, resulted in superior collecting powers for the aluminosilicate minerals.     

黏土矿物的结构性质及其对浮选的影响

黏土矿物属于层状硅酸盐矿物，其中高岭石、蒙脱石是两类最为常见的脉石矿物，是矿物浮选分离的重大挑战之一。从黏土矿物结构和物理化学性质分析了其对浮选的影响及其机理，并综述了常见的黏土处理方法及其机理。由于黏土矿物的表面电性，当其分散在水中时会水化膨胀并剥离成为片层，组成不同的聚集体，改变矿浆流变性质从而影响浮选。黏土还会与其他矿物颗粒相互作用，造成细泥罩盖和机械夹带，影响精矿品位。为消除黏土矿物对浮选的不利影响，可采用预先脱泥、高剪切调浆、超声预处理等物理方法和添加黏土抑制剂、使用电解质溶液等化学方法进行处理。对黏土矿物在浮选中的影响和处理方法进行总结和展望，有利于为含黏土的矿石浮选理论及工艺研究提供参考。      

六偏磷酸钠对浮选中煤泥与黏土颗粒间相互作用的影响

通过浮选试验、Zeta 电位测试、吸附量试验和扩展的DLVO理论计算,考察六偏磷酸钠对浮选中煤泥与黏土颗粒间相互作用的影响,研究六偏磷酸钠的作用机理。结果表明:高岭石含量较多时会对煤泥浮选产生不利影响,高岭石含量达到20%,精煤回收率降低18.70%;低用量的六偏磷酸钠会抑制高岭石上浮而对煤影响较小,高用量的六偏磷酸钠会失去选择抑制性;六偏磷酸钠用量为1000g/t时,能使煤和高岭石的Zeta电位分别从-25mV、-39mV移至-32mV、-57mV,增强了颗粒间静电排斥作用;同时,六偏磷酸钠水解形成的大分子吸附于高岭石表面,当颗粒相互靠近时产生较强的排斥力,增强了颗粒之间的空间稳定化作用能。     

某低品位金铜矿石浮选柱应用试验研究

某低品位金铜矿石含铜0.46%、金0.18 g/t,矿石中铜矿物主要以蓝辉铜矿、辉铜矿、铜蓝、硫砷铜矿等次生铜矿物存在,其可浮性好但容易过磨,造成浮选时细粒级损失较高,试验采用浮选柱+浮选机联合选别与单独采用浮选机相比,其它指标相当的情况下,铜精矿品位提高9.6%,硫精矿回收率提高9.23%,试验表明浮选柱对提高精矿品质、简化流程和强化细粒级回收方面具有较为明显地优势。     

Effect of mechanical and chemical clay removals by hydrocyclone and dispersants on coal flotation

Fine minerals, mostly clays, are known to have a detrimental effect on coal flotation. This paper focuses on the effect of mechanical and chemical removals of fine minerals by hydrocyclone and dispersants on coal flotation. The experimental results showed that the flotation recovery slightly increased from medium acidic to medium alkaline ranges. The flotation experiments carried out with dispersants at different dosages showed that the dispersants did not enhance the flotation recovery significantly. However, the removal of the fine fraction from the feed using a hydrocyclone significantly increased the flotation recovery. The bubble–particle attachment tests also indicated that the attachment time between an air bubble and the coal particles increased in the presence of clay particles. These attachment time results clearly showed that the clay particles adversely affected the flotation of coal particles by covering the coal surfaces which reduced the efficiency of bubble–coal attachment. An analysis based on the colloid stability theory showed that the clay coating was governed by the van der Waals attraction and that the double-layer interaction played a secondary role. It was also concluded that the best way to increase the flotation recovery in the presence of clays was to remove these fine minerals by mechanical means such as hydrocylones.     

Classification of the Major Copper Sulphides into semiconductor types,and associated flotation characteristics

Recoverable economic copper sulphide minerals such as chalcopyrite, bornite, chalcocite and covellite often occur together in varying proportions in the major copper-bearing ores, and have individual flotation requirements and characteristics. Pyrite also occurs in these ores to varying extents as the sulphide gangue, and is problematic because of its natural tendency to float quickly and easily. In a bulk sulphide float, selectivity against pyrite is desirable, particularly if it does not host other paymetals such as gold or silver. At the same time it is a requirement to float all of the copper sulphides despite their electrochemical differences. The electrochemistry and semiconductor properties of these minerals are reviewed, together with implications for flotation with and without collector addition. Mixed collector systems for the improved flotation of these sulphides are proposed as a solution. The use of xanthate and dithiophosphate in the collector suite allows the co-existence of dixanthogen and free dithiophosphate radical because the latter has a higher redox potential requirement than xanthate to oxidize to the dithiolate. Because some of these minerals require dixanthogen, and others, free thiolate, to generate surface hydrophobicity, a bulk flotation of all the species becomes possible in the overlapping area of Eh and pH between the two dithiolate equilibrium lines on the Pourbaix Diagram. The arsenic-signature copper minerals are added to the study, since many copper operations encounter arsenic as a penalty element in the saleable concentrate. It is shown that the addition of arsenic to the copper and iron sulphides alters the semiconductor and electrochemistry properties, and in turn, its flotation characteristics. The degree of mineral association and liberation between these minerals can be a complicating factor due to textural associations, and should also be considered in the process as a next step.     

新型钼捕收剂JJ-4#在斑岩型铜钼矿的试验研究与应用

内蒙古某大型斑岩型铜钼矿属细脉浸染型低品位贫矿石,原矿含铜0.35%,含钼0.02%,有价矿物主要是黄铜矿、辉钼矿和辉铜矿,脉石矿物以石英、绢云母和长石为主。小型试验研究及工业试验表明,在铜钼混合浮选阶段,即使是嵌布粒度较细,裸露面较小的钼矿物,也能在捕收剂JJ-4#的作用下很好地矿化捕收,因此该捕收剂具有矿化效果好、捕收能力强、作用时间持久的特点。工业生产中也取得了很好的选矿指标。混合浮选段铜、钼回收率分别由86.59%和76.29%提高到88.08%和80.94%,混合精矿铜钼品位未受影响,选矿效果理想,对同类矿山的生产具有一定实践指导意义。     

氟化钠在铝硅酸锌矿石物浮选新工艺试验研究

在季铵盐捕收剂体系中，氟化钠活化了层状硅酸盐矿物高岭石、伊利石和叶蜡石的浮选，而对一水硬铝石的浮选没有影响，可以作为铝土矿反浮选的有效调整剂。氟化钠在矿物表面上发生特性吸附作用，显著降低硅酸盐矿物的Zeta电位，而对一水硬铝石的电位影响不大。AES研究表明，氟离子扩散至硅酸盐矿物颗粒内部，使得其在硅酸盐矿物颗粒上的吸附量很高，而只在一水硬铝石表面发生较低量的吸附。氟离子在硅酸盐矿物颗粒的表面和内部的高吸附量显著降低矿物的动电位，增强捕收剂与矿物的静电作用，从而起到活化作用。     

A preliminary rheological classification of phyllosilicate group minerals

With the increased exposure to progressively complex ores, there is growing concern over the effects of phyllosilicate gangue minerals. These minerals present challenges during ore beneficiation, with issues such as reduced flotation performance and complex tailings treatment arising. Often broadly classified as ‘clays’, the understanding of the distinct behaviour of phyllosilicates remains poor. This work focusses on talc, illite and kaolinite, and forms part of an ongoing study which aims at investigating the entire phyllosilicate group, categorised as serpentine, micas; talc/pyrophillite, kaolinites, illites, smectites and vermiculite. Using pure minerals belonging to each phyllosilicate type, a comprehensive surface charge and rheological analysis was conducted, incorporating their charge anisotropy and non-spherical morphology. The mineralogy was discussed, based on pre-existing knowledge of the minerals. Talc, kaolinite and illite suspensions are characterised by high yield stresses and low viscosities, with differences in their behaviour attributed to variations in charge anisotropy, aspect ratio and surface morphology. A comparison with other phyllosilicates showed that muscovite (mica) results in the least rheologically complex suspensions, while the fibrous nature of chrysotile (serpentine) leads to suspensions with the highest yield stresses and viscosities. The other minerals demonstrate intermediate rheological behaviour. Such a classification may be foundational to geometallurgical advances which can enable process performance predictions based on mineralogy.     

采用CCF浮选柱回收某尾矿中铜的实验研究

本文以湖北某磁选尾矿中铜的综合回收为研究对象,通过工艺矿物学研究表明,该磁选尾矿组分较为复杂,铜含量较低为0.38%,嵌布粒度较细,铜主要赋存于原生硫化铜中,分布率为74.08%,铜矿物主要是黄铜矿,少量铜蓝、辉铜矿等,脉石矿物主要是石英,其次为方解石、白云石、绢云母,少量长石、高岭石等。针对尾矿中铜矿物“贫、细、杂”的特点,采用CCF浮选柱进行回收铜的选矿实验研究,研究结果表明,经过一次粗选一次扫选和两次精选作业,可从含铜0.38%的尾矿中获得铜品位16%以上,铜回收率76% 以上的铜精矿,实验指标良好,实现矿产资源综合回收利用。      

煤层夹矸型黏土矿物对甲烷的吸附研究

黏土矿物是煤层中最重要的矿物质,煤层中有机质与黏土矿物复合能改善黏土矿物对甲烷的吸附能力,因而煤储层中黏土矿物对甲烷的吸附不容忽视。分别选取黏土矿物含量较高的煤层夹矸和纯黏土样品,采用X-射线衍射、红外光谱及扫描电镜表征,并进一步分析了样品中总有机碳(TOC)含量、有机质的类型和成熟度,结合孔径、孔隙体积和比表面积测定结果,探讨造成夹矸型和非煤黏土矿物甲烷吸附能力差异的主要原因,研究影响夹矸型黏土矿物吸附能力的控制因素。结果表明:夹矸型黏土矿物对甲烷的吸附能力依次为铵伊利石高岭石伊利石金云母;单纯的外表面积大小并不能完全反应出黏土矿物的甲烷吸附特性,需结合不同黏土矿物层间域等多方面因素综合考虑;有机质含量较高的夹矸型黏土矿物样品比纯黏土样品具有更多的微小孔隙,尤其是孔径小于6 nm的孔隙,对样品比表面积的增加起到了关键作用,进而也增强了其甲烷吸附能力。通过分析黏土矿物的甲烷吸附贡献率发现,黏土矿物及其有机复合体具有较强的甲烷吸附能力,在煤层夹矸中对甲烷的吸附贡献较大。