Assessment of the floatability of chalcopyrite,molybdenite and pyrite using biosolids and their main components as collectors for greening the froth flotation of copper sulphide ores

Biosolids and representative compounds of their main components – humic acids, sugars, and proteins – have been tested as possible environment-friendly collectors and frothers for the flotation of copper sulphide ores. The floatability of chalcopyrite and molybdenite – both valuable sulphide minerals present in these ores – as well as non-valuable pyrite was assessed through Hallimond tube flotation tests. Humic acids exhibit similar collector ability for chalcopyrite and molybdenite as that of a commercial collector (Aero 6697 promoter). Biosolids show more affinity for pyrite. The copper recovery (85.9%) and copper grade (6.7%) of a rougher concentrate obtained using humic acids as main collector for the flotation of a copper sulphide ore from Chile, were very similar to those of a copper concentrate produced by froth flotation under the same conditions with a xanthate type commercial collector. This new and feasible end-use of biosolids and humic acids should be new environment-friendly organic froth flotation agents for greening the concentration of copper sulphide ore. Now, further research is needed in order to scale current laboratory assays to operational mining scales to determine efficiencies to industrial scale.     

Case studies on the performance and characterisation of the froth phase in industrial flotation circuits

This paper deals with two separate case studies investigating the froth phase performance and characterisation of two industrial rougher/scavenger flotation circuits. Froth phase performance was quantified using a mass balance approach to estimate froth zone recovery. Measured characteristics of the froth phase included frother solution concentration determined by gas chromatography, and the time taken for an equilibrium froth sample to decay to one-half of its original froth height. The latter measurement is referred to as the ‘froth half-life’ and is strongly linked to froth stability. Special methods and techniques developed to preserve frother in solution and to measure froth half-life are briefly described. The frother type in the first case study was a mixture of straight and branched alcohols, whilst the frother type in the second case study was a mixture of alcohols, aldehydes and triethoxybutane. The first case study focussed on a flotation circuit treating a low grade ore containing only a small fraction of floatable copper sulphide minerals, while the second case study focussed on a flotation circuit treating a higher grade complex sulphide ore containing significant quantities of chalcopyrite, galena, sphalerite and pyrite.It was found that froth zone recovery of valuable mineral generally decreased down-the-bank of the two industrial rougher/scavenger circuits. Moreover, decreases in froth zone recovery significantly limit the overall cell recovery of valuable mineral achievable from the plant scavenger cells. However, the decrease in froth zone recovery could not be linked to the removal of frother from the pulp solution to the concentrate product in the preceding rougher flotation stages. Measurements of residual frother in solution suggested that, approximately, only 5–10% of the added frother was removed into the rougher/scavenger concentrate, with the remainder appearing in the scavenger tailings. This finding suggested there was apparently adequate frother in solution in the scavenger stages.There was, however, a correlation to the froth half-life, with the froth half-life also generally decreasing down-the-bank. A simple, empirical model, based on the froth half-life and froth residence time of gas, is proposed here to predict froth zone recovery. Further, it is proposed that the froth stability, as measured by the froth half-life, is strongly linked to the presence of particles in the froth, with poorly mineralised scavenger froth characterised by a short half-life and, potentially, a low froth zone recovery. The importance of particles on froth stability was confirmed in separately conducted laboratory experiments. These experiments also demonstrated the wide variation in froth stability behaviour between different frother types.     

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.     

The effect of galvanic interaction on the behaviour of the froth phase during the flotation of a complex sulphide ore

A literature review has shown that the chemical effects of grinding media on the flotation of real ores, especially those containing pyrite, are still not understood adequately. Many studies have been conducted on isolated minerals or in solutions only, and transport phenomena in the froth phase have generally been ignored in studies on galvanic interactions. A complex ore containing galena, sphalerite, chalcopyrite and significant quantities of magnetite, pyrrhotite and pyrite was used in batch flotation tests to study this problem. Metallic iron powder was added in different quantities to a ceramic ball mill in order to simulate the use of mild steel grinding media in flotation tests aimed at selectively floating chalcopyrite.An oxygen-saturated pulp milled in the presence of iron yielded the best recovery of chalcopyrite and copper-lead selectivity. Milling under a nitrogen atmosphere in the absence of metallic iron resulted in poor copper-lead selectivity. The galvanic interaction caused by the presence of iron yielded a stable, well-drained froth with low ratios of solids/water recovery and larger bubbles in the froth. However, milling in the absence of iron caused an extremely brittle froth with very fine bu bubbles, high recoveries of low grades of sulphur. In contrast with the improvement in the copper recovery and copper-lead selectivity obtained when the pulp was pre-aerated after milling in the presence of iron, no significant increase in the copper grade was observed after extensive pre-aeration when milling occurred in the absence of iron. The unsatisfactory flotation results in the absence of iron could be explained by the enhanced floatability of iron-bearing gangue minerals, which rupture films and suppress froth stability owing to bubble-overloading.     

Froth recovery measurements in an industrial flotation cell

The froth phase serves an important role in upgrading the final concentrate in flotation. At present, the techniques that are used in the mineral industry to determine the effect of froth phase on the metallurgical performance of plant scale flotation cells have limitations.The aim of this paper is to investigate the performance of the froth in an industrial flotation cell. A unique device has been developed which is able to decouple the froth zone from the pulp zone. The device consists of two concentric tubes. The inner tube acts as a dropback collection chamber or catcher. The particles that return from the froth phase fall directly into the catcher and are collected as froth dropback. This technique is capable of measuring plant scale flotation cell froth recovery as well as providing valuable information on froth dropback particles.The froth recovery measurements were carried out in a rougher bank of a copper concentrator treating sulphide minerals. The dropback device is designed so that it can be immersed into an industrial size flotation cell and plant froth recovery measurements can be taken at any given location. During the experiments, the bubbles laden with valuable mineral particles entered the device from the flotation cell, subsequently rising to form a froth layer at the top of the device. The particles that detached or drained from the froth zone were collected in the dropback collection chamber whereas the concentrate sample was collected through a launder. By sizing and chemical analysis of the concentrate and dropback samples, the froth recovery was estimated on the basis of the valuable component. The effect of air rate on the froth recovery was also investigated. Metallurgical grades of the froth dropback device samples for different particle size ranges were compared to those of the concentrator to better understand the froth dropback mechanism.     

The influence of pyrite content on the flotation of chalcopyrite/pyrite mixtures

In the flotation of copper ores, several processing plants report that copper recovery is affected by the proportion and reactivity of pyrite in the ore, with the effect becoming more intense when the feed particles are finer as a result of regrinding. In this work, a mixed model mineral system consisting of chalcopyrite (CuFeS₂) and pyrite (FeS₂) with varying pyrite content (20–80 wt.%) was used to investigate the effect of pyrite on the pulp chemistry and chalcopyrite recovery. Flotation tests showed that chalcopyrite flotation rate, recovery and grade, as well as the pulp oxidation potential, decreased with increasing pyrite content whilst pyrite recovery increased. Surface analysis (XPS, ToF-SIMS and EDTA) indicated that copper activation of pyrite increased with increasing pyrite content, facilitating pyrite recovery. The decrease in chalcopyrite recovery can be attributed to increased surface oxidation.     

Effect of grinding media and NaHS on copper recovery at Northparkes Mines

The flotation behaviour of copper minerals in the Northparkes Mines copper-gold ore is dependent on grinding media (and hence grinding Eh) and aeration during conditioning. Laboratory grinding and flotation tests were conducted using mild steel and stainless steel rods with and without the addition of sodium hydrosulphide (NaHS) in the conditioning stage. In the absence of NaHS, grinding using stainless steel media increased the kinetics of subsequent copper mineral flotation compared to the use of mild steel media. Flotation kinetics after grinding using mild steel media were increased by aeration prior to reagent addition. The addition of NaHS after grinding using mild steel rods increased the froth stability by increasing froth mineralisation, thus increasing the flotation kinetics of the copper minerals. When stainless steel grinding media was used, the copper flotation recovery was very high (>90 % in the rougher stage) without the addition of NaHS, so its use was not warranted. The flotation of the bornite was not reduced by oxidation, in fact copper mineral recovery was the highest under the most oxidising grinding conditions.     

某高硅铜硫矿石分选试验

广西某高硫铜矿石中滑石等易浮硅质矿物含量高,现场采用弱磁选-浮铜-浮硫工艺流程进行分选,除弱磁选能较好地回收磁黄铁矿外,黄铜矿浮选和黄铁矿浮选均因易浮硅质矿物的干扰而难以获得合格精矿。为此,在大量探索试验的基础上,采用弱磁选-黄铜矿和硅质矿物混合浮选-混浮精矿铜硅摇床分离-混浮尾矿浮黄铁矿的工艺流程处理该矿石,获得了磁选硫精矿硫品位和回收率分别为38.69%和64.48%,浮选硫精矿硫品位和回收率分别为44.57%和30.99%,铜精矿铜品位和回收率分别为13.87%和63.89%的良好试验指标,有效地综合回收了铜、硫矿物。     

从某硫精矿中回收铜的试验研究

某硫精矿含铜0.41%,铜矿物主要为黄铜矿和辉铜矿,硫矿物主要是磁黄铁矿,其次是黄铁矿,脉石矿物为少量蛇纹石、滑石、绿泥石等易泥化矿物,经镜下鉴定铜矿物与黄铁矿关系密切,基本以较粗的连生体形式存在,而磁黄铁矿基本不含铜。综合考虑矿石性质,确定采用"磁选脱硫—脱泥—浮铜"流程回收铜,全流程获得铜精矿铜品位20.26%,铜回收率73.41%。     

某难选铜镍硫化矿选矿试验研究

某铜镍矿含铜0.23%、镍0.42%,属低品位硫化矿石。矿石中铜矿物大部分为黄铜矿,镍矿物主要为镍黄铁矿,其他金属矿物主要为黄铁矿、磁黄铁矿、磁铁矿。脉石矿物主要有橄榄石、辉石、斜长石、透闪石等。矿物学研究表明,该铜镍矿呈典型的浸染状构造,影响铜镍回收的主要矿物学因素是矿石中黄铜矿、镍黄铁矿的产出形式较为复杂、嵌布粒度较细、形态不甚规则。根据该矿石性质,采用BK303新型高效捕收剂,CMC作脉石矿物抑制剂,通过“两粗两扫三精-粗精矿再磨-中矿顺序返回”的工艺流程,成功实现了铜镍的高效浮选回收,闭路试验获得了铜品位3.29%、镍品位5.32%,铜回收率81.78%、镍回收率71.53%的铜镍混合精矿,取得了良好的浮选指标。     

以羟乙基纤维素为抑制剂浮选分离铜硫

为检验铜硫分离新型抑制剂HEC的有效性,并了解HEC作用效果的影响因素,以丁基黄药为捕收剂,对黄铜矿、黄铁矿纯矿物进行了浮选试验,并以HEC为抑制剂进行了实际矿物浮选试验。结果表明：①丁基黄药对黄铜矿的捕收能力强于黄铁矿,且几乎不受矿浆pH值的影响,在无抑制剂的情况下,高碱环境可抑制黄铁矿的上浮。②HEC可用于铜硫分离,用量为200 mg/L时可显著抑制黄铁矿,但对黄铜矿的抑制能力很弱。③抑制剂HEC适宜在pH=7的环境下浮选分离黄铜矿与黄铁矿的人工混合矿。④在分选内蒙古某铜硫矿石时,以HEC为铜硫分离黄铁矿的抑制剂,可获得铜品位为23.21%、铜回收率为81.75%的铜精矿,以及硫品位为13.20%、硫回收率80.83%的硫精矿,较好地实现了铜硫分离。     

陕西某复杂含砷铜矿石选矿试验研究*

陕西某铜矿石属于含砷难选铜矿石，铜、砷、硫含量分别为0.74%、0.43%和1.54%，主要有用矿物是黄铜矿、辉铜矿，杂质矿物为毒砂和黄铁矿，矿石中铜砷矿物结合紧密，粒度较细，且矿物种类较多，嵌布关系复杂，普遍相互包裹，有用矿物单体解离较困难。为确定该矿石的选矿工艺进行了选矿试验研究。结果表明，矿石采用抑砷浮铜的优先浮选工艺流程处理，以石灰为含砷矿物抑制剂，获得了铜品位为25.27%、含砷0.085%、含金0.23 g/t、含银40.52 g/t、铜回收率为92.72%的铜精矿，尾矿铜品位为0.053%。铜精矿产品质量达到国家六级品标准，试验指标较理想。     

Dynamic characterization of column flotation process laboratory case study

The objective of metallurgical column control is to achieve the economic optimum combination of concentrate grade and mineral recovery for any given feed. Metal prices and the cost of consumables will dictate the metallurgical concentrate and mineral recovery targets. Furthermore, experience has shown that collection zone height, air holdup and bias water flow rate are key parameters (controlled variables) that affect metallurgical performance. The collection zone height is related, mainly, with the residence time of the particles inside the collection zone, air holdup is correlated to the available surface area of air bubbles and bias water flow rate is an indirect measure of the cleaning action of the froth zone. However, these variables cannot be directly manipulated. Instead, wash water, air and underflow flowrates are the directly manipulated variables [1]. Therefore, if dynamic relationships could be established between the three manipulated variables and the three controlled variables, column metallurgical control may be improved. This study was an attempt to model these relationships using a tool known as System Identification, that includes Transient Analysis.The study consists in experimental tests, transient response analysis and identification of black box type models with cross validation.The experimental work was performed in a pilot scale laboratory flotation column of 3.2 m high by 80 mm of diameter. This flotation column operates in a plant with all the required instrumentation installed. The study considers the operation of the two phase air-water system.     

Combinations of different-class collectors in selective sulphide-ore flotation

The paper discusses laboratory test data on well-known sulphydryl collectors and new modified dithiophosphates Beraflot used to float monomineral fractions of pyrite, chalcopyrite, galena, and sphalerite. Frothless flotation is employed in flotation tests, IR-spectroscopy is used to identify surface compounds, and technological investigations are based on froth flotation. It is shown that dimethyl dithiocarbamate, isobutyl dithiophosphate and modified collector Beraflot-3035 give the poorest results of pyrite flotation, while Beraflot-3035 provides the highest galena and chalcopyrite recovery. It is found that Beraflot-3035 is capable to form different surface compounds on pyrite, chalcopyrite, galena, and sphalerite. Unclosed ore tests verify selectivity of Beraflot-3035.     

蒙古某铜矿伴生金银浮选回收工艺技术研究

蒙古某铜矿含铜0.61%,含硫2.57%,含金0.80g/t,含银15.12g/t,矿石中铜矿物主要为黄铜矿、斑铜矿及辉铜矿,脉石矿物有石英、长石、云母等。矿石中金、银等有价元素与黄铜矿、黄铁矿等金属矿物之间嵌布关系密切。本文研究针对该矿石特征,采用铜优先-铜和脉石浮选分离工艺流程,粗选采用选择性捕收剂BKH优先选铜,精选采用新型抑制剂BKL抑制脉石矿物,最终获得实验室闭路试验结果为：铜精矿含铜24.85%,铜回收率81.88%;含金21.87g/t,金回收率55.00%;含银515.80g/t,银回收率68.89%。     

西藏某含金浸染状次生硫化铜矿石浮选回收铜金试验

西藏某浸染状次生硫化铜矿石铜品位为1.86%，原生硫化铜占总铜的15.05%，次生硫化铜占总铜的76.88%，主要铜矿物为斑铜矿、黄铜矿，其他金属矿物有黄铁矿、磁黄铁矿等；脉石矿物以石榴石、辉石、石英等为主。为了确定该矿石中铜、金的适宜回收工艺，进行了选矿试验。结果表明，矿石在磨矿细度为-0.074 mm占70%的情况下进行1粗2精快速浮选，1粗2扫常规浮选，快速精选1尾矿与常规粗选精矿合并再磨至-0.038 mm占80%的情况下进行1粗2精2扫铜硫分离，获得的快速浮选精矿铜品位为27.05%、金品位为8.28 g/t，铜、金回收率分别为60.79%、50.90%；常规浮选铜精矿铜品位为17.06%、金品位为5.02 g/t，铜、金回收率分别为29.81%、23.99%。快速浮选+常规浮选、快速精选1尾矿与常规浮选粗精矿再磨再选工艺流程既能避免铜矿物的过磨，保证铜的回收率，又可得到较高品位的铜精矿，获得较好的铜、金回收指标。     

Flotation of mixed copper oxide and sulphide minerals with xanthate and hydroxamate collectors

Sherwood Copper’s Minto Mine processes a high grade copper–gold deposit in Yukon, Canada. The ore mined is from a primary copper sulphide deposit with separate additional deposits of copper oxides. In conjunction with Ausmelt Chemicals, Minto is currently investigating options to recover copper oxide and sulphide minerals using flotation by blending their primary sulphide ore with oxide ores. The blend used in this laboratory scale investigation was 70% sulphide ore and 30% oxide ore on a weight basis. The copper sulphides present in the blend were bornite and chalcopyrite, while the oxides were malachite and minor azurite.From previous flotation investigations of mixed copper oxide and sulphide minerals using xanthate and hydroxamate collectors it was hard to distinguish the impact of the alkyl hydroxamate collector on sulphide recovery as the sulphide and oxide minerals occurred naturally together. In the case of the Minto operation the copper oxide and sulphide minerals occur in separate ore deposits and can be treated separately or blended together. This investigation has shown that using n-octyl hydroxamates (AM28 made by Ausmelt Limited) in conjunction with traditional sulphide collectors can successfully simultaneously recover copper sulphides and oxides by flotation from blended ore minerals. The copper sulphide recovery did not decrease when processing the blended ore compared to treating the sulphide ore independently. At a blend of 70% sulphide ore and 30% oxide ore, the rougher scavenger copper recovery was as high as 95.5%. The copper recovery from the blended ore using a mixture of collectors was shown to be superior to the recovery obtained using only xanthate after controlled potential sulphidisation.     

提高德兴铜矿泗洲选矿厂铜回收率的途径

针对德兴铜矿低品位矿石(铜品位0.31%)难磨难选的特点,在矿石性质分析的基础上开展了浮选试验研究。矿石黄铜矿主要呈浸染状分布,部分呈细小粒状分布于脉石中或被脉石包裹,少量黄铜矿与黄铁矿毗邻嵌布。全流程闭路浮选结果表明,在磨矿细度为-0.074 mm占61.60%,粗选石灰调矿浆pH值为8.0时,以Mac-12+丁黄药为捕收剂,经1粗2扫铜硫混合浮选,粗精矿再磨至-0.037 mm占68%,经1粗2精2扫铜硫分离浮选,获得的铜精矿铜回收率和品位分别为85.56%、27.27%,较现场当班铜精矿铜品位提高了1.68个百分点,铜回收率提高了3.95个百分点。提高矿浆pH值或优化捕收剂配比可改善粗选泡沫结构,提高浮选指标。     

起泡剂对硫化矿浮选的影响

研究了起泡剂MIBC、BK201、松醇油及2-乙基己醇对石英及黄铁矿单矿物浮选行为的影响, 并进行了实际矿石浮选试验。单矿物试验结果表明: 石英通过泡沫夹带进入浮选精矿, 而黄铁矿通过疏水上浮和泡沫夹带的双重作用进入浮选精矿。不同起泡剂作用下, 精矿中泡沫水回收率越高, 石英和黄铁矿的浮选回收率越高, 不同起泡剂对石英和黄铁矿具有不同的夹带效果, 使石英和黄铁矿浮选回收率最高的起泡剂分别为BK201和MIBC。实际矿石浮选试验表明: 浮选产率、精矿品位及回收率与泡沫水回收率密切相关, 泡沫水回收率增大, 精矿产率增大, 而品位降低。选择合适的起泡剂能够增加硫化矿物的回收率并降低石英的回收率, 获得较好的浮选分离效果。     

捕收剂Mac-10浮选铜硫矿石的试验研究

通过纯矿物和实际矿石试验, 采用丁黄药、680和Mac-10作为捕收剂, 在不同条件下进行了黄铜矿和黄铁矿的浮选对比试验。研究结果表明, Mac-10在铜硫浮选分离中具有良好的应用潜力, 其捕收能力较丁黄药、680好, 并且选择性好, 能在较少的药剂用量下, 在中性或者弱碱性条件下有效实现黄铜矿与黄铁矿分离。实际矿石浮选试验表明: 碱性条件下(pH值8～9范围内), 将捕收剂Mac-10与680 (2∶1)混合使用, 相对于单独采用Mac-10, 铜精矿品位低0.25个百分点, 但回收率高3.59个百分点; 相对于单独采用680, 铜的回收率低0.22个百分点, 但铜精矿品位高2.70个百分点。