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By Avishan Atrafi, Marek Pawlik

"Gas dispersion properties of sodium salts of 6, 12 and 18-carbon fatty acids (hexanoic, lauric and oleic acid) were investigated as a function of pH. A strong effect of pH was observed on gas dispersion properties of fatty acids. At high pH for 12 and 18 carbon fatty acids, at which these surfactants formed a true solution, the gas dispersion properties were similar to those of MIBC. In the case of sodium hexanoate, which has a much higher solubility than the longer chain fatty acids and therefore does not form precipitates, the gas dispersion properties of this surfactant were strongly enhanced in the acidic pH range, where hexanoic acid was fully associated. This result is an indication that undissociated hexanoic acid is much more surface-active than anionic hexanoate. Only a small effect of the surfactant chain length on gas dispersion properties of the tested reagents was observed. The measured critical coalescence concentration (CCC95) values increase slightly by decreasing chain length and range from 5.8 x 10-5 mol/L (17.7 mg/L) for sodium oleate to 7.2 x 10-5 mol/L (16 mg/L) for sodium laurate at pH 10 and 1.9 x 10-4 mol/L (26 mg/L) for sodium hexanoate at pH 3.7. These are compared to CCC95 of MIBC, which is measured to be 8 x 10-5 mol/L (8 mg/L). The soluble molecular species were recognized as the most effective species in preventing bubble coalescence."

Jan 1, 2014

The ultimate goal of a mineral processing plant is to recover as much of the target mineral(s) as possible from the ore being treated to achieve the best economics. Selection of the mineral processing techniques is the most important step in achieving this goal. However, due to the complexity of the ore, the recoveries of valuable minerals may be not satisfactory even when the mineral processing technique(s) are well chosen. In other words, minerals of interest can be lost to the tailings for mineralogical reasons. For example, gold is mainly extracted from the ore by gravity, flotation, cyanidation, or a combination of these processes, and high recovery (>90%) can be achieved when gold occurs as coarse grains. However, when a refractory ore is being processed, gold extraction will be challenged by mineralogical factors, which often cause gold losses to various tailings. Mineralogical factors affecting gold recovery mainly include grain size, shape, surface coatings and rimmings, presence of cyanicides, oxygen consumers and preg-robbers, presence of slow-dissolving gold minerals and the refractory nature of submicroscopic gold. Among these factors, locking in sulphide, silicate and other minerals as fine-grained gold inclusions and/or as invisible submicroscopic gold is by far the most common factor leading to poor gold recovery encountered in gold ore processing. Processing of PGE ores faces the same challenges as gold. Small grain size and locking of PGM in sulphide and non-sulphide minerals often cause PGM losses. When silver ore contains significant amounts of pyrargyrite, proustite and stephanite, silver recovery by cyanidation can be very low because of the slow dissolving kinetics of these minerals. In the processing of base metal ores, high content of pyrite, intergrowth of chalcopyrite with sphalerite and presence of clay miner-als may cause problems in recovering Cu-, Pb- and Zn- bearing minerals. Process mineralogy helps address all issues and problems related to mineral processing with predicting and trouble-shooting being two major objectives. It provides useful information on process selection, flowsheet development, recovery improvement and reagent consumption optimization. The information acquired from a process mineralogical study can be used as a guide for a metallurgical testwork program for process design or optimization.

Jan 1, 2014

By Chandra Sekhar Gahan

The present study aimed to investigate the depyritization of coal using iron oxidizing and sulphur oxidizing acidophilic chemolithotrophic microorganisms in an iron free 9K growth medium at varying pulp densities. Three different coal samples used in the shake flask study from three different countries such as domestic anthracite (Korean), Indonesian and Chinese lignite. Experiments were carried out in batch at a controlled temperature of 35 °C and varied pulp densities of 8%, 10% and 12% (w/v) with a working volume of 100 ml containing 10 ml of microbial inoculum and 90 ml of the iron free 9K growth medium. Coal samples were crushed and ground to fine size fractions <100 microns by attrition mill wet grinding. The progress in the experiments were followed by the regular measurements of pH, redox potential, viable planktonic cell count, residual Fe2+ ion concentration, amount of acid addition and amount of slaked lime addition. The pyritic sulfur removal percentage varied between 90-95% with highest sulfur removal with China coal (95%) followed by Korean Coal (93-94%) and slightly lower level for Indonesia coal (90%). However the pyrite oxidation was highest for Korean coal ranging between 78-80% followed by a similar level of pyrite oxidation of 50-61% for the Chinese and Indonesian coal. It was found that 10-12% pulp density would be fairly feasible for all the different coals tested leading to an economical process. Another benefit from this study is the iron free 9K growth medium, which will reduce the operation cost and overall it?s an environment friendly process.

Sep 1, 2012

By W. Yao, M. L. Li, R. Cui

"The purpose of this research is providing a flotation process for recovery of lead in lead silver residues from a zinc smelting plant with a new hydroximic acid collector (HOC). The collecting ability and reaction mechanisms of HOC were investigated based on pure mineral flotation tests and analysis of zeta potential. The pure anglesite flotation tests showed that HOC has a good collecting ability for anglesite. Zeta potential measurements proved that HOC adsorbed on anglesite surface physically and chemically. The lead-silver residues in a zinc smelting plant with lead grade about 17.5% was used as raw material for flotation tests. The results showed that under the conditions of pH adjusting agent lime 500g/t, inhibitors sodium silicate 2000g/t, collector HOC 1500g/t, frother alcohol oil 75g/t, the grade of the lead concentrate can be reach 47.18% and the recovery was 76.39% by one roughing-one scavenging-three cleaning and middles back to the flow-sheet in turn after the lead-silver residues were washed by two stages of cleaning-filtration.INTRODUCTION Nowadays, with the increasing exploitation of natural mineral resources, more and more secondary resources should be researched and used for the valuable metals. Hydrometallurgical zinc leaching residues, which contain a considerable amount of zinc, lead, silver and other minor valuable constituents, is a typical and abundant secondary resources (Zhang et al., 2011). A huge quantity of zinc leaching residues (ZLR) had been produced per year (Jiang et al., 2017).This residues not only occupy precious land but also threaten the environment because of the dissolved heavy metals especially in rainy days (Han et al., 2014). Consequently, it is urgent to develop an effective and clean method to dispose this residues which can benefit not only in economical but also in environmental (Jha et al., 2001)."

Jan 1, 2018

By Liu Chun-Bao Sun, Hong-Jun, Wei Zhang, Tao Xu

SABC circuits have gained widespread attention within China, and are being gradually applied to many mines. However, the domestic knowledge of comminution process is still relatively basic, and the design and production management of the application of SABC technology lack guidance of scientific theories. This research project focuses on the Phase I SABC milling circuits of Wu Shan Porphyry copper mine. Targeting the design and operation problems of existing process and circuit, and without increased investment and alterations in equipment, the new technologies will combine ordinary crushing and grinding theories as theoretical guidance, and borrow JK Simulation Software (JKSimMet) for analysis in order to optimize the comminution process, efficiently allocate production output and energy consumption, eventually resulting in increased production and energy efficiency. Using JKSimMet Simulation Software, and combining theoretical optimizing and practical production techniques, as well as the on-site situation, the eventual SABC comminution process and circuit optimization plan is: increasing the grinding Ball charge from 8% to 10% v/v in the SAG mill; Setting the Ball charge in the Ball mill to 27% v/v and the maximum operating power draw to 5 800kW; replacing the HP Series crusher with a TRIO TC84 crusher, which is without a power controller, and adding a pebble bin. The final optimization result is: Maximum system processing capacity increased between 20%-26.7%, specific energy consumption reduced by more 2.0 kWh/t, creating an economic benefit of over 300 million RMB, thus achieving the goal of increased production, reduced energy consumption, and improved profitability.

Jan 1, 2014

By M. K. G. Vermaak

Kimberlite weathering has been a topic of ongoing research within De Beers for many years. Using kimberlite weathering as an alternative to crushing has many advantages e.g. power and reducing diamond breakage. Weathering could also possibly be used in conjunction with crushing just to weaken the material and reduce power consumption. These forces have driven current research to investigate whether kimberlite weathering could be utilised for these reasons. Weathering in this context does not refer to weathering over long period of time but rather to disintegration of the material in aqeous media in relative short time periods. Previous published work discussed that the presence of smectite renders kimberlite weatherable and that the amount of smectite determines the rate of weathering (Morkel and Vermaak, 2006). The current work investigates whether cation ex-change or the adsorption of organic species in the smectite interlayer could influence the observed weathering behaviour. The results show that cation exchange does take place in the presence of cation species and that the weathering behaviour can be drastically improved with especially Cu2+ cations. Concentration and time effects of the weathering was also investigated. Weathering tests with organic species such as ethanol, methanol, edta, pentanol, butanol, acetic acid and oxalic acid was performed. The results show that organic species does improve weathering but under these testing conditions was not as effective as cations.

Jan 1, 2014

By P. Han

The preparation technological conditions and regeneration method of two novel granulated adsorbing materials of rectorite/fly ash composite (Material 1) and rectorite/water quenched - slag composite (Material 2) and the use of them to remove heavy metals from copper smelting plant wastewater have been studied. The experimental results showed that under the preparation conditions with the ratio of rectorite to fly ash or water - quenched slag of 1:1, the amount of the additive (Industrial Starch, IS) of 15% (Material 1) or 10% (Material 2), the addition of 50% water, and the calcination temperature of 500? (Material 1) or 400? (Material 2), the efficiency of heavy metal removal with the granulated materials was the best, whereas the ratio of disintegration loss was the lowest. Under the treatment conditions of natural pH, and with the addition of the granulated materials of 0.07g/cm3 (Material 1) or 0.05g/cm3 (Material 2), a reaction time of 60 minutes (Material 1) or 40 minutes (Material 2), and the adsorption temperature of 25?, the efficiency for the granulated materials to remove Cu2+Pb2+Zn2+Cd2+ and Ni2+ from the copper smelting plant wastewater was 98.9, 97.5, 96.7, 90.2, and 79.1, (Material 1) or 98.2, 96.3, 78.6, 86.2, and 64.2, (Material 2), respectively, and the quality indexes of the wastewater after treatment conformed with the first level of integrated wastewater discharge standard (GB8978-1996). When the adsorption of heavy metal ions on the surface attained saturation the granulated materials could be regenerated by washing with 1 mol/L sodium chloride (NaCl) solution and still with quite good heavy metal removal efficiency. The granulated adsorbing materials had the advantages of high efficiency of wastewater treatment, easy method of solid-liquid separation and regeneration, and a broad prospect of applications.

Jan 1, 2014

By Arman Ehsani, Ersin Yazici, Haci Deveci

The downstream treatment of chloride leach solutions of WPCB for recovery of base and precious metals by a combination of adsorption and precipitation processes were carried out. A synthetic leach solution (1 M HCl, 116.5 g/L Cl-, 30 g/L Cu2+, 2.5 g/L Fe3+, 5 mg/L Au3+, 10 mg/L Ag+ and 20 mg/L Pd2+), which was prepared based on the composition of the pregnant leach solution obtained in the previous study was used in the tests. The leach solution was initially subjected to activated carbon (AC) adsorption (20 g/L AC, 80°C) in which gold was selectively recovered over silver and palladium i.e., 88% Au recovery at 0.5 h (92% at 3.5 h) compared with only 3-6% for Ag/Pd. Copper and iron were also observed to adsorb on AC as indicated by 1.4% and 17% decline, in their respective concentrations. Following the adsorption and filtration stage, metallic copper was added into the gold-barren solution to allow reduction of Cu2+ to Cu+, and to cement Pd on metallic copper. Over the mixing period (1 h), 93% of the Pd was recovered while only 1.4% of silver was cemented onto metallic copper. Subsequently, the leach solution was gradually neutralised by NaOH to pH 4, 7.5 and 9.5 for the precipitation of copper as cuprite (Cu2O). It was found that 41% and 46% of Cu and Ag, respectively, were precipitated at pH 4 at which iron was almost totally (99.8%) removed from solution. Precipitation of copper and silver was increased further at high pHs. At pH 9.5, cumulative recoveries for copper and silver were 91% and 85%, respectively. XRD analysis of the precipitates confirmed the presence of cupric copper oxides/hydroxides and revealed that copper losses occurred at pH 4 was due to the undesired presence of cupric copper in the solution.

Jan 1, 2014

By H. C. E. Regidor, M. G. Mena, H. D. Mendoza

Cyanidation leaching has always been the most widely used method of extraction of gold in the world. Its low cost and high selectivity has made it the prevalent choice for mining companies, and even for the small scale miners. The use of cyanidation in small scale mining has been an issue for the longest time, mainly due to the operation’s lack of safety measures, health care or environmental protection regulations. In pursuit of more environmentally friendly methods of extraction of gold, several alternative extraction processes have been explored, one of which is chlorination. The chlorination process is advantageous when recovering refractory gold locked in sulfides, as it simultaneously oxidizes the surrounding sulfides as well as dissolve any gold exposed to the lixiviant. This research was conducted to study and develop a safer alternative way of extraction of gold from small scale mining operations, without compromising the recovery of gold. In this study, a variation of the chlorination process has been employed for a refractory flotation concentrate wherein the majority of the gold is locked in sulfides. Hypochlorite-bearing reagents were used as the leaching reagents, and the method developed was a 2-stage leaching process in differing pH conditions. The solution pH and Eh was monitored all throughout the runs, and aliquot samples were taken at time intervals for analysis. SEM-EDS imaging was used to determine the mode of oxidation of the chlorination process, and the image obtained showed that the oxidized layer followed the shape of the particle, suggesting a diffusion controlled process. XRD analysis of the sample before and halfway through leaching further confirmed the oxidation of the sulfides. The amount of gold dissolved in the aqueous solution and in the solid residue were used as the basis for the determination of the recovery of gold. An average gold recovery of up to 84.38% was obtained using the developed method in just 7 hours of leaching. This method was then employed for a pilot-plant scale test and a gold recovery of 79.2% was obtained.

Jan 1, 2018

By D. Saramak

The proposal of the nip zone angle determination in HPGR crushing process is presented in the paper. Knowledge of the nip zone angle value, in turn, makes it possible to determine the real maximum pressing force in the high-pressure comminution. Two methods of determination of this maximum pressure were proposed and verified. The first method is based on the roll?s geometry, and the change of the HPGR chamber?s volume together with the roll rotation, while the second one considers the outlet gap width impact. Results of the nip zone angle calculations according to both methods are similar and show convergence with the real operating conditions. The verification was carried out in a piston-die press, and experimental results show that methodology of the nip zone angle determination presented in the paper has its practical confirmation. A proper determination of the nip zone border makes it possible to calculate the comminution probability of given type of material and is a basis for the HPGR crushing process modeling and optimization. Keywords: HPGR, comminution, nip zone, ore processing

Sep 1, 2012

By Ingvar Ymén, Alexandra Lundmark

"The depressive effect of dichromate on galena was evaluated with chemical experiments and small-scale depression experiments at a pH of around 12. The depressive effect was measured with Dynamic Vapor Sorption (DVS), which measures the water uptake of a sample as a function of the % relative humidity. The depression is due to PbCrO4PbO, which in the presence of Ca2+ and SO4 2- forms a more or less amorphous solid solution (Pb,Ca)(CrO4,SO4)PbO, which clogs to the surfaces of the ore. Free Pb2+- ions are needed for depression to occur and at high pH Pb2+ - hydroxide complexes, supply enough Pb2+ - ions to precipitate (Pb,Ca)(CrO4,SO4)PbO. In air CO2, precipitates CaCO3 which slowly lowers pH, precipitating more (Pb,Ca)(CrO4,SO4)PbO and CaCO3 on galena. Similar experiments where performed with five alternative depressors whereof phosphate, which forms an amorphous precipitate of approximate composition Pb3Ca13(PO4)10SO4, gave the best results. Phosphate was tested in laboratory scale flotation experiments giving encouraging results.INTRODUCTIONWithin Boliden Mines, concentrating of copper and lead from complex sulfide ores is performed by bulk flotation, meaning that copper and lead are concentrated in the same product. Downstream, copper and lead are separated by flotation of chalcopyrite, and depression of galena. Boliden has for many decades used sodium dichromate to depress galena (reference 1). Dichromate is both toxic and carcinogenic and Boliden has for many years investigated several alternatives. So far, however, the best results have been obtained with dichromate. Since Boliden has tried to substitute dichromate for a long time without finding a process as effective, Boliden decided to clarify the function of dichromate in the depression of galena and on the basis of the outcome find alternative depressors with similar function. This study was given to RISE Bioscience and Materials / Surface, Process and Formulation as a consultancy assignment. This paper presents the outcome of the combined efforts of Boliden and RISE."

Jan 1, 2018

By Xiaoxu Sun, Jianchao Yao, Jiancheng He, Shijie Lu, Hongxi Zhou

"With the trend of increasingly more mineral resources turning low-grade and refractory, more and more new ore bodies being developed worldwide are more finely grained, which drives the rapidly development and application of techniques related to tower mills (vertical spiral stirred mills). However, the lacking in fundamentals of fine grinding, as well as standard procedures for equipment selection and scale up, seriously restraint high efficient application of tower mills. Taking grinding media motion characteristic and grinding intensity as a breakthrough point, this paper studies mechanisms behind how critical parameters affect grinding efficiency of tower mill, including ratio of screw pitch and diameter, agitator rotation speed, grinding media size. Several sets of orthogonal test are conducted on the quartz ore using the grinding system of KLM-3 tower mill. All the tests are under the same character of feeding mineral and undergo the consistent sampling for at least 60min grinding time. The input power is measured by a torque measurement system and the grinding products are analyzed by the laser particle size analyzer. The test results show the influence of parameters on grinding efficiency. Among the three important parameters, the effect of grinding media diameter is the biggest, followed by the agitator tip speed, and finally the ratio of screw pitch and diameter. For the different particle size of grinding products, the best combination of grinding parameters is different, with the mineral size becoming finer, the ratio of screw pitch and diameter become smaller, the diameter of grinding media become smaller, while the agitator tip speed does not change too much. The conclusions of the study help us to improve the grinding efficiency of the tower mill, to assist in the selection and optimization of working parameters, establish new scale up method on the basis of grinding model and eventually provide theoretical basis of rational selections of structural and media physical parameters within tower mill."

Jan 1, 2018

By B. Orberger

The fine fraction (< 2 mm) of the high grade Mn-ore from the world class Moanda deposit, Francevillan basin, in Gabon, contains up to 30 wt. % of manganese and about 0.4 wt. % phosphorous. A pilot study at laboratory scale integrating mineralogy and geochemistry before and after ultrasonic treatment was conducted on the fine fraction (< 2 mm) of oxidized Mn ore in order to reduce the phosphorous content and enrich this fraction in manganese. The fine fraction was dried, crushed at 2 cm and sieved at 2 mm. The two fractions (< 2 mm and 2 mm ? 2 cm) were investigated by X-ray diffraction and scanning electron microprobe ? electron dispersive spectroscopy analyses. Both fractions contain lithiophorite, cryptomelane and pyrolusite as Mn carrier, and goethite, muscovite, illite and quartz as contaminants. The Mn hydroxide nsutite was only found in the fraction 2mm ? 2 cm.The < 2 mm fraction is significantly richer in goethite, muscovite/illite, and quartz. Phosphorous carriers are mainly goethite (up to 2.8 wt. % P2O5), while the Mn minerals contain up to 0.8 wt. % P2O5. The Mn minerals are partly included in an agglomerate of goethite, muscovite/illite, and quartz. The < 2 mm fraction was treated by ultrasound for 30 s in normal water. Mineralogical and chemical analyses after ultrasound treatment showed that the Mn-minerals were largely liberated from the goethite-muscovite-illite agglomerate. Mass balance calculations show that after ultrasonic treatment the < 2 mm fraction was ? 50 % enriched in Mn and ?50 % impoverished in P.

Sep 1, 2012

By B. Q. By

TiO2 is an ideal material for catalytic technology due to its unique properties. In this paper, Sm3+ doped TiO2 photo-catalyst was developed to improve the efficiency of TiO2 and to use the natural light as irradiation source, which was made from Titanium Tetrabutoxide and Samarium Oxide with the Sol-Gel process. The Sm3+-TiO2 photocatalyst was used to degrade reactive orange 4 (RO4) in Azo Dyes. The effects of solution pH, Sm3+ concentration and catalytic time on the degradation rate of RO4 were studied. The characteristics of the catalyst were analyzed with XRD and TEM. The experimental results show that the catalyst has high activity in the degradation of RO4. The Azo bonds of RO4 are active and easily broken by oxidation. The catalytic activity of the Sm3+ doped catalyst greatly depends on the pH of solution. The catalyst has high photo-catalytic activity at both neutral and alkaline conditions. The degradation mechanism of the Sm3+ doped TiO2 photo-catalyst was also discussed.

Jan 1, 2014

By G. Deschênes

In the last 4 years, the high price of silver attracted more interest for improving its extraction. Metallic silver and silver minerals require a high concentration of cyanide and show slow leaching rates and poor extraction. This investigation determined the effects of dissolved oxygen, lead nitrate and a pretreatment on silver leaching from slurry containing quartz mixed with metallic silver and high purity acanthite. Stephanite, pyrargyrite and polybasite were also used in the study. The silver minerals were characterized by chemical assay, X-ray diffraction analysis (XRD), image analysis (MP-SEM-IPS) and electron microprobe analysis (EMPA). Increased dissolved oxygen of the slurry produced the fastest silver leaching kinetics. The leaching of silver from high purity acanthite was determined under various conditions and compared to a new process called ?CANMET Enhanced Leaching Process (CELP). For a slurry containing acanthite, a 23% improvement (from 76% to 99%) in silver extraction was obtained with the CELP. In presence of pyrargyrite and polybasite, silver extraction increased from 75% to 90% and 86% to 99% respectively using the CELP. No improvement was obtained for the slurry with stephanite (99% extraction in 72 hours). However, the sliver leaching rate was much faster with the CELP. XPS analysis of individual silver mineral particles showed that CELP leached surfaces were considerably more oxidized relative to the conventional cyanidation leached surfaces. Leaching of two gold/silver ores indicated that the efficiency of the CELP increased with the refractoriness of the sample. Gold extractions were comparable for the two technologies while silver extraction improved up to 5% (70g/t) for the CELP. The final leach solutions contained lower concentrations of copper, which consequently reduces the effluent treatment costs.

Jan 1, 2014

By Gurubasayya Swamy

This paper presents the consequences of modernization and expansion of process plant by implementing SAG and Ball Mill and Carbon-in-pulp technology at the Hutti Gold Mine. From the inception of the process plant, it has undergone many changes for the improvement. In the beginning, only gravity recovery of gold was carried out by using Pebble Mills and Strake Tables. Later amalgamation, Cyanidation and Zinc precipitation and finally Carbon-in-pulp gold recovery system was implemented. Grinding plant was modernized by implementing SAG and Ball Mill and Knelson concentrator for free gold recovery as a result, the production rate, rate of recovery, reduced man power, Modernization and expansion of process plant has also yielded in safe and smooth running of the plant. Keywords: sag and ball mill, cip, modernization and expansion, productivity, gold recovery

Sep 1, 2012

By B. Hosseini

Considering the subtractive trend of the sulfide and high-grade zinc ores in worldwide and also in Iran, Nowadays special attentions have been drawn to the extraction of zinc from its other resources such as low-grade oxide ores and secondary resources. Oxide ore of the eastern part of Mehdi-abad lead and zinc mine is silicate and has an average grade of 7% (with cut off grade of 4%). Main mineral of the Mehdi-abad ore is Hemimorphite and this mineral is associated with Goethite, Hematite, Ferrous Dolomite, and Manganese oxide mineral so that oxides of Iron, manganese and silica include almost 50% of the total ore. In this paper, the results obtained from the leaching kinetic study of the low-grade zinc oxide ore using Sulfuric acid are presented. The effects of particle size, reaction temperature, acid concentration, and solid percent on the dissolution rate have been investigated. The results obtained from the Taghochi approach showed that the zinc recovery is about 78% under the following optimized conditions: particle size: 106µm, leaching time: one hour, temperature: 45°C, acid concentration: 15% and solid percent: 15%. Kinetics study was revealed that zinc minerals leaching controlled by diffusion rate through the product layer during leaching time with the activation energy of 5 KJ/mol and compliance with the 1- (2/3. x) ? (1- x) 2/3 = k. t model. Keywords: leaching kinetics, kinetics models, sulfuric acid leaching, taguchi methods, low grade zinc ore, mehdi-abad mine

Sep 1, 2012

By P. Bevilacqua

In this paper the possibility to complete the copper recovery and to enrich in PVC a mixture of plastic granules obtained by grinding electrical cables are investigated. The recovery of a large part of the copper still present among the plastic granules was possible by means of a mechanical screening, the finer polymeric fraction was collected, at the same time. In order to complete the copper polymer separation the following techniques were employed. Counter current separation in water, static dense medium separation with zinc chloride solution and copper extraction with nitric acid and subsequent electrolytic deposition. A Tri-Flo® dynamic dense medium separator was employed in order to separate the lighter polymeric fraction, from the heavier polymeric fraction, mainly PVC. Water or a salt-water solution was employed to feed the separator device.

Jan 1, 2014

By L. X. Zeng

The low-grade nickel resource is very abundant in the western China. To make the best of the low grade nickel ore, we studied the process mineralogy and beneficiation process of nickel ore in the Yangliuping of Sichuan province. The grade of nickel is 0.45% in the nickel ore and the nickel exists in the sulfide including pyrrhotite, nickel pyrite, chalcopyrite primarily. The nickel distributes in pentlandite and magnetite over 90% and the copper does in the chalcopyrite over 95%. The carri-er minerals of useful elements tend to concentrate in space for concentration. As is shown in grain-size analysis of three major minerals, there are some more fine-grained grains with the percent of from 10% to 15% (<40 µm) and from 3.5% to 5.5% (<20 µm). So there will be some smaller size disseminated sulfide minerals difficulty to liberate in the process of concentration. The liberation degree of sulfide is not high and there are much associativity in the sulfides. Therefore, we should reclaim the sulfide aggregation dominating as pentlandite when concentrating. In addition, the sulphide minerals is so brittle that we should take care of preventing from crashing when grinding. The gangue mineral is mostly metamorphic mineral including serpentine, chlorite and amphibole which is easy to be argillization and difficult to concentrate.

Jan 1, 2014

By B. H. Zhao

A low grade Pt-Pd ores, with 1g/t Pt and 0.13g/t Pd, and 8.70% Fe and 2.50% P2O5 is experimented to recover of Pt and Pd. The flowsheet is proposed which consists of Pt-Pd selective flotation, apatite flotation from tailings of Pt-Pd flotation, magnetic separation of magnetite from apatite flotation tailing. With butyl xanthate, N-ally group-O-isobuturyl-thioanimoformate and Sodium y-89 xanthate as collectors, sodium silicate as depressant, and sodium carbonate as pH regulator, a concentrate, assaying 324.52 g/t Pt and 45.62 g/t Pd, is obtained with recoveries of 87.23% Pt and 76.89% Pd from surface ore. A concentrate, assaying 1693.53 g/t Pt and 64.12 g/t Pd, is obtained with recoveries of 88.54% Pt and 83.78% Pd from primary ore. At same time, A iron concentrate assaying 64.12% Fe with a recovery of 24.94%, and a apatite concentrate assying 30.32% P2O5 with a recovery of 80.12% are obtained.

Jan 1, 2014