不同因素对黄铜矿、黄铁矿浮选分离动力学影响的研究

以动力学参数K（浮选速率系数）为依据,来评判黄铜矿、黄铁矿快速浮选分离的可能性.首 先,在不同矿浆浓度、浮选粒度及浮选机转速等条件下考察黄铜矿和黄铁矿纯矿物K值的变化,在一 定程度上阐释了黄铜矿、黄铁矿快速浮选分离的动力学机理及其可能性;同时,为使黄铜矿、黄铁矿快 速浮选分离技术在工业上具有适用性,进一步研究黄铜矿与黄铁矿组成的2种粒级的混合矿在适当 浮选条件下的动力学特性.结果表明,适当的浮选条件,可扩大黄铜矿与黄铁矿之间的浮选速率差异,从而实现黄铜矿的快速优先浮选.      

嗜酸氧化亚铁硫杆菌和嗜酸氧化硫硫杆菌联合浸出高锡多金属硫化矿

高锡多金属硫化矿选冶过程中,硫化矿的存在严重影响了锡的回收率,目前国内外对锡矿生物法脱硫的报道极少,针对上述问题,研究采用嗜酸氧化亚铁硫杆菌和嗜酸氧化硫硫杆菌联合浸出高锡硫化矿.通过摇瓶实验考察嗜酸氧化亚铁硫杆菌、嗜酸氧化硫硫杆菌纯菌及混合菌对锡矿脱硫的影响,并采用实时定量PCR技术(qRT-PCR)对生物浸出过程中2种菌的动态变化进行了分析.结果表明:混合菌浸出优于纯、菌浸出,能够有效地提高脱硫率,当pH为2.0,转速170 r/min,温度30 ℃,矿浆密度为10 %时,混合菌在18天内可使锡矿中的硫脱除率达到97 %.混合菌浸矿初期(第6天),嗜酸氧化亚铁硫杆菌是优势菌种,所占比例为69.4 %, 浸矿中后期,嗜酸氧化硫硫杆菌含量逐渐上升,并成为优势菌种,在稳定期(第24天)比例达到58.3 %.以上结果为锡矿生物法脱硫技术的开发提供了一条新的思路.      

Cation self-diffusion in chalcopyrite and pyrite

The self-diffusion coefficient of Fe⁵⁹ was measured in pyrite (FeS₂) and chalcopyrite (CuFeS₂) and found to exhibit an activation energy of 10.0 and 6.4 kcal/mole, respectively, in the temperature range of 100 to 300°C. The self-diffusion of Cu⁶⁴ and Ag^110m in chalcopyrite yielded activation energies of 12.1 and 17.5 kcal/mole in the same temperature range. The technique of nondestructive measurements is described, and diffusion mechanisms and implications for chemical leaching are discussed.     

Adhesion to metal sulfide surfaces by cells of Acidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans

Attachment of four strains of Acidithiobacillus ferrooxidans to pyrite, chalcopyrite, galena, sphalerite or quartz was found to be mineral-selective. The bacterial extracellular polymeric substances (EPS) are responsible for mediating this process. Attachment of cells of A. ferrooxidans as well as of Acidithiobacillus thiooxidans was diminished, when depleted of their EPS. After 5 days of cultivation cells of A. ferrooxidans cover mineral surfaces with a dense biofilm, as visualised by fluorescence microscopy and AFM. Primary attachment was restricted to surface sites with visible defects.Chemical analyses of EPS of A. ferrooxidans, A. thiooxidans and Leptospirillum ferrooxidans indicated neutral sugars, fatty acids and uronic acids. The composition differed with the strain and the growth substrate. IronIII ions were only detectable in EPS of ironII ion- and pyrite-grown cells, but not in EPS of sulfur grown cells. Pyrite oxidation rates correlated with the amount of EPS-complexed ironIII ions in the case of A. ferrooxidans and L. ferrooxidans. Furthermore, pyrite oxidation rates of L. ferrooxidans were correlated with the genetic affiliation of the strains. The data for A. ferrooxidans seem to indicate a similar correlation, however, the results were not as clear-cut as those obtained for L. ferrooxidans. Sulfur oxidation rates of A. thiooxidans did not require EPS complexed ironIII ions.     

黄铁矿促进黄铜矿微生物浸出影响因素

采用摇瓶实验,以氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,At.f)浸出黄铁矿-黄铜矿,重点研究了基础培养基、矿物配比和粒度组成等因素的影响.黄铁矿能促进黄铜矿的微生物浸出,以采用无Fe 9K培养基效果较好,它对应铜浸出率是9K培养基的1.68倍;采用宽粒级矿物时铜浸出效果较好,且铜浸出率与黄铁矿和黄铜矿的质量比有关,当质量比为2:2时铜浸出率最高可达45.58%;黄铁矿含量大小是影响铜浸出率高低的实质,当质量比小于等于5:2时以At.f菌的氧化作用为主,当质量比为10:2时以硫化矿间的原电池效应为主.浸渣的X射线衍射分析表明,采用无Fe 9K培养基时浸渣中生成的钝化物黄钾铁矾较少,故黄铁矿可以很好地替代9K培养基中的FeSO₄,并能与黄铜矿形成原电池效应,从而促进铜的浸出.     

Dissolution kinetics of chalcopyrite containing pyrite in water saturated with chlorine

In this work the dissolution kinetics of chalcopyrite in water saturated with chlorine have been investigated using particle size, reaction temperature and gas flow rate as parameters. It has been found that the dissolution rate decreased with an increase in particle size and reaction temperature, but increased with an increase in gas flow rate. The mechanism by which the dissolution proceeds has been deduced. It has been concluded that the dissolution is controlled by diffusion through the product layer. The activation energy was calculated as 9.06 kJ mol⁻¹.     

乳酸黄原酸钠合成及其对黄铁矿与黄铜矿抑制的作用机理

通过研究不同工艺条件对合成乳酸黄原酸钠的影响,结果显示乳酸黄原酸钠合成的较优工艺条件为乳酸、CS₂和NaOH摩尔比为1:1:2.1,反应温度为40 ℃,反应时间为4 h.在该条件下,产物产率达到59.25 %.利用紫外光谱和红外光谱进一步确认产物为乳酸黄原酸钠.以天然黄铜矿和黄铁矿为研究对象,系统研究了乳酸黄原酸钠对黄铜矿和黄铁矿可浮性的影响.利用Materials Studio软件进行模拟,从分子力学和分子动力学角度研究了乳酸黄原酸钠与黄铜矿、黄铁矿表面作用体系能量变化,模拟结果表明,乳酸黄原酸钠对黄铁矿抑制作用显著,而对黄铜矿抑制作用较差.红外光谱分析进一步验证了模拟结果.      

磨矿和浮选过程中黄铁矿电化学行为的研究进展

综述了黄铁矿在选矿过程中有关的电化学行为及工作机理,重点讨论了黄铁矿结构特性、溶液中氧化、金属离子作用和抑制剂对黄铁矿电化学行为的影响;此外,还讨论了磨矿过程中电偶相互作用、研磨介质形状、介质材料和研磨气氛对研磨中黄铁矿电化学行为的影响。其中黄铁矿晶体结构的不同对黄铁矿表面的氧化具有较大影响,从而间接的影响黄铁矿的可浮性,半导体性质对黄铁矿的导电率具有显著的影响;同时适度的氧化有利于黄铁矿的无捕收剂浮选,而强烈的还原电位或氧化电位会抑制黄铁矿的浮选;电位的增加,对铜活化黄铁矿有不利影响,主要原因是电位增加导致活化Cu+的浓度降低,同时黄铁矿表面被铁氧化物覆盖阻碍了铜离子的吸附。抑制剂的加入可以直接参与捕收剂与黄铁矿之间的氧化还原反应,从而抑制黄铁矿的浮选;同时磨矿介质及气氛条件的不同也会影响黄铁矿电化学行为。      

硫杆菌对污染土壤中锶-90溶出的影响

采用嗜酸氧化硫硫杆菌菌株HT-8对污染土壤中微量放射性锶进行微生物促溶研究。结果表明,HT-8菌株能通过持续产酸等作用显著促进污染土壤中放射性锶的溶出,处理后的土壤,全氮、全磷损失不大,肥力基本保持不变。     

Mechanism of enhanced bioleaching efficiency of Acidithiobacillus ferrooxidans after adaptation with chalcopyrite

To clarify the role and mechanism of bacterial adaptation in bioleaching, the leaching of chalcopyrite by adapted and unadapted Acidithiobacillus ferrooxidans was compared. Three extrinsic factors (adsorption, tolerance to shearing stress and copper tolerance) in relation to bioleaching were investigated. The results showed that there were significant differences in bacterial attachment and tolerance to shearing stress of unadapted and adapted cells due to the variation of cellular wall component and structure. Consequently, there was significant difference in bioleaching rate between unadapted and adapted bacteria. In addition, some differences of copper accumulation and distribution in adapted and unadapted cells also existed, but this was not one of the key factors that affected their bioleaching rates.     

Raman characterization of secondary minerals formed during chalcopyrite leaching with Acidithiobacillus ferrooxidans

Chalcopyrite passivation greatly reduces the yields from leaching and bioleaching but the problem has not been successfully resolved. Passivation involves the formation of a layer of secondary minerals on chalcopyrite surface, which becomes a diffusion barrier to fluxes of reactants and products. This study aims to identify secondary minerals formed during chalcopyrite passivation in the presence of iron- and sulfur-oxidizing bacteria (Acidithiobacillus ferrooxidans) in mineral salts solution. The minerals were characterized with X-ray diffraction, Fourier transform-infrared spectroscopy, and Raman spectroscopy. Potassium jarosite was the initial product covering chalcopyrite grains, followed by the formation of ammonio-jarosite. Covellite and elemental sulfur were also detected in the passivation layer. The results suggest that passivation may be reduced by controlling jarosite precipitation and prior acclimatization of bacteria to oxidize CuS and elemental S in the presence of ferrous and ferric iron.     

Galvanic interaction between chalcopyrite and pyrite during bacterial leaching of low-grade waste

The bacterial leaching of a low-grade chalcopyrite waste rock in a lixiviant containing thermophilic, Sulfolobus-like microorganisms at 60°C and a lixiviant containing Thiobacillus ferrooxidans at 28°C has been compared with the leaching in sterile lixiviant in terms of copper solubilized in elapsed time and the conversion of $\text{Fe}{}^{\mathrm{3+}}\text{Fe}{}^{\mathrm{2+}}$. Bacterial action has been shown to drastically increase the ratio $\text{Fe}{}^{\mathrm{3+}}\text{Fe}{}^{\mathrm{2+}}$ with elapsed time of leaching. Direct observations of the associated pyrite and chalcopyrite surface corrosion, utilizing scanning electron microscopy, showed that during the leaching of these sulfides as separate, non-contacting phases, the pyrite corroded more rapidly than the chalcopyrite in both sterile and inoculated media. This effect was more pronounced at elevated temperature and in the presence of bacteria. When the pyrite and chalcopyrite were in contact, the resulting galvanic interaction caused the chalcopyrite to corrode more rapidly than the pyrite, which was effectively passivated. The leaching of chalcopyrite is thereby enhanced in contact with pyrite. This effect is accelerated in the presence of bacteria. The corrosion of chalcopyrite was also markedly enhanced as a result of the oxidation of elemental sulfur (formed during the reaction) to sulfuric acid. This reaction was also accelerated by bacterial catalysis. The important implications of the enhanced chalcopyrite corrosion by galvanic interaction in the leaching of low-grade chalcopyrite waste and other galvanic-contact regimes involving metal sulfides are identified and discussed.     

黄铜矿浮选体系晶态/无定形二氧化硅的流变特性与夹带行为

硅酸盐类脉石夹带是制约贫杂难选矿高效浮选分离的难题之一。借助分批浮选试验、流变学测试、冷冻扫描电镜测试、颗粒沉降试验,探究了黄铜矿浮选体系晶态/无定形二氧化硅的流变特性与夹带行为。结果显示,随着脉石中无定形二氧化硅含量的增加,矿浆表观黏度呈指数型增大,黄铜矿回收率持续降低,脉石回收率先升高后降低。脉石回收率发生变化是脉石夹带率、水回收率共同作用的结果:在黏度低增长区,脉石夹带率上移对脉石回收率升高起主导作用,而在黏度中、高增长区,水回收率减少是脉石回收率由升转降的主要原因。总脉石夹带率和各粒级脉石夹带率均随无定形二氧化硅含量增加而升高,且各粒级脉石夹带率呈现出明显差异性,细粒脉石夹带率增幅最大。冷冻扫描电镜与沉降试验表明,无定形二氧化硅与石英颗粒形成了聚集体结构,导致矿浆体系黏度增大,因而脉石颗粒沉降减缓、泡沫排液“洗涤”脉石作用弱化,单位泡沫水中的脉石质量增大,脉石夹带率升高。      

Electrochemical bioleaching of high grade chalcopyrite flotation concentrates in a stirred bioreactor

The main objective of this study is to improve the basic understanding of electrochemical bioleaching as an advanced hydrometallurgical process suitable for the treatment of high grade complex sulfide ores and to use this understanding for analyzing the potential of this process for copper recovery from high grade chalcopyrite ores and flotation concentrates. Using a typical flotation concentrate from the Sarcheshmeh copper processing complex (located in the south-east of Iran) and mixed mesophilic as well as moderately thermophilic microorganisms, leaching experiments were performed in a stirred bioreactor. The emphasis was given on the comparison between the results of bioleaching and that of electrochemical bioleaching tests. From the results of this study, it can be pointed out that compared to the conventional bioleaching; the electrochemical bioleaching of chalcopyrite flotation concentrate leads to about 35% more copper recovery. It seems that the main reason for increasing copper recovery by electrochemical bioleaching is the control of redox potential between 400 and 425 mV. Under this condition, the precipitation of iron oxy-hydroxides on the surface of chalcopyrite, which can act as a diffusion barrier and prevents chalcopyrite dissolution, is significantly reduced. This leads to a higher electrochemical reduction of chalcopyrite and its improved dissolution.     

Mixed-control kinetics of oxygen leaching of chalcopyrite and pyrite from porous primary ore fragments

The leaching of individual copper ore fragments was investigated under oxygen pressure of 690 to 3100 kPa. After 500 hours of leaching at 90°C under 3100 kPa oxygen pressure, 50 pct of copper was extracted from an ore particle of 0.57 cm size, while 1300 hours were needed to extract 90 pct of copper under the same experimental conditions. A mathematical model incorporating the intrinsic leaching kinetics of chalcopyrite and pyrite grains and the pore diffusion of dissolved oxygen within the ore fragment was formulated to interpret the experimental results. Both chemical reaction and diffusion were found to be important to the overall leaching rate in the particle size range tested. The model can also be used to predict the leaching behavior of particles of different sizes at different temperatures and oxygen partial pressures. H. K. LIN, formerly Graduate Student in the Department of Metallurgy and Metallurgical Engineering, University of Utah     

Ammoniacal thiosulphate leaching of gold in the presence of pyrite

The effect of pyrite on gold dissolution was investigated in the ammoniacal thiosulphate leaching system using pure gold foils. Special emphasis was placed on gold leaching in association with pyrite dissolution, thiosulphate decomposition and gold leaching passivation. The presence of pyrite retarded gold dissolution and this detrimental effect became more pronounced at higher pyrite contents. Pyrite catalysed the decomposition of thiosulphate to trithionate. The addition of sulphate enhanced gold leaching by retarding the dissolution of pyrite in ammoniacal thiosulphate solutions. XPS analysis indicated the presence of iron hydroxide species at the gold surfaces in the presence of pyrite, which was likely responsible for the reduced gold dissolution. SEM analysis indicated a lesser extent of gold dissolution occurring in the presence of pyrite.     

Toxicity of metal extraction and flotation chemicals to Sulfolobus metallicus and chalcopyrite bioleaching

The effect of chemicals used in preparation of mineral concentrates and subsequent extraction of metals to the thermophilic, acidophilic microorganism Sulfolobus metallicus has been tested. The chemicals tested included collectors and frothers employed during flotation of the ore to produce a mineral concentrate, solvent extraction reagents used to remove metals after leaching, and thiocyanate produced as a decomposition product during cyanidation for gold recovery. The effect of these chemicals to S. metallicus depends on the conditions and time frame that the experiments were carried out due to their mode of toxicity and stability in acid pH. The metal extraction chemical that had the least effect on bioleaching was potassium amyl xanthate that increased the leaching rate, possibly due to solubilization of sulfur that can form passivation layers on the surface of minerals. The frother Flotanol C-7 decreased the chalcopyrite leaching rate, despite having no effect on Fe²⁺ oxidation by S. metallicus resting cells. This is probably due to inhibition of oxygen transfer during bioleaching that had little effect on Fe²⁺ oxidation over 20 min. Solvent extraction chemicals inhibited both Fe²⁺ oxidation and bioleaching suggesting their mode of inhibition is due to Fe²⁺ oxidation. The results suggest that relevant concentrations of metal extraction and flotation chemicals can be toxic to chalcopyrite bioleaching by S. metallicus.     

高碱高钙受抑黄铁矿活化剂的研究现状

黄铁矿在高碱高钙环境中被强烈抑制,对后续黄铁矿的回收造成困难.在新型活化剂的研发过程中应注意其能否有效清除受石灰抑制的黄铁矿表面的CaO、CaSO4、Ca（OH）2、Fe（OH）3等亲水性薄膜,新型活化剂还应该是环保、廉价、来源广及化学性质稳定的产品.文中详细阐述了受抑黄铁矿活化剂的种类、活化机理及实践应用等研究现状,并对高碱高钙受抑黄铁矿新型活化剂的研制进行了展望.     

Effect of particle size distribution on recovery of coarse chalcopyrite and galena in Denver flotation cell

Abstract

The flotation recovery by particle size of single mineral chalcopyrite and galena was studied in a Denver flotation cell, using sodium dicresylthiophosphate (DTP) and sodium isopropyl xanthate (SIPX) as collectors and polypropylene glycol (PPG) as a frother. The study was extended to very coarse particle size (up to 1·6 mm). Froth stability was also measured in parallel to the batch flotation tests, in a specifically designed froth stability column, following the Bikerman approach. It is shown that particles up to 850 μm can be floated successfully, provided they are liberated and hydrophobic. However, the recovery of both chalcopyrite and galena was strongly influenced by the overall particle size distribution, decreasing sharply as the fraction of fines (?106 μm) in the feed also decreased. Rheology measurements showed negligible differences in pulp viscosity, and therefore in the collection zone hydrodynamics, between the different conditions tested. Froth stability, on the contrary, decreased as the feed particle size distribution became coarser. Correlation was found between the amount of fines in the pulp, froth stability and flotation recovery. The recovery of mineral particles is critically dependent on froth stability, which in turn is highly influenced by the overall particle size distribution of the feed material. For these reasons, the study also suggests that it is not possible in batch flotation to determine the rate and recovery of the coarse particle size fractions floating them independently from the fine size fractions.

Dans une cellule de flottation de Denver, on a étudié la récupération par flottation en fonction de la taille de particule d’un minéral unique de chalcopyrite ou de galène, en utilisant du dicrésyle thiophosphate de sodium (DTP) et de l’isopropyle xanthate de sodium (SIPX) comme agents collecteurs et du polypropylène glycol (PPG) comme agent moussant. On a étendu l’étude à la taille de particule très grossière (jusqu’à 1·6 mm). On a également mesuré la stabilité de la mousse en parallèle aux essais de flottation discontinue, dans une colonne de stabilité de la mousse spécialement conçue, d’après l’approche de Bikerman. On montre que l’on peut faire flotter avec succès des particules ayant jusqu’à 850 μm, à la condition qu’elles soient libres et hydrophobes. Cependant, la récupération, tant de la chalcopyrite que de la galène, était fortement influencée par la distribution globale de la taille de particule, diminuant sévèrement à mesure que la fraction de particules fines (?106 μm) dans l’alimentation diminuait. Les mesures de rhéologie montraient des différences négligeables dans la viscosité de la pulpe et ainsi dans l’hydrodynamique de la zone de collection, parmi les différentes conditions évaluées. Au contraire, la stabilité de la mousse diminuait à mesure que la distribution de la taille de particule de l’alimentation devenait plus grossière. On a trouvé une corrélation entre la quantité de particules fines dans la pulpe, la stabilité de la mousse et la récupération par flottation. La récupération des particules minérales dépend, de façon critique, de la stabilité de la mousse qui, à son tour est hautement influencée par la distribution globale de la taille de particule du matériel d’alimentation. Pour ces raisons, l’étude suggère également qu’il n’est pas possible, en flottation discontinue, de déterminer la vitesse et la récupération des fractions de taille de particules grossières, en les faisant flotter indépendamment des fractions de taille fine.