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By F. Q. Dong

According to the principle that should be originated from nature, compatible with nature, used in nature and back to nature and based on conception of designing of eco-material, the author combined the ideas of material, environment, zoology and healthy. Properties of natural mineral materials were used to produce micro-aggregate elements by bionic method, so its components and function could accord with living environment. Eco-mineral functional materials which can adjust, purify and optimize the microclimate were reviewed. The authors pointed out the multifunction, com-pounding, the compound characteristics and integration regularities of micro-aggregates. It was the first time in the world to put forward the ?gene? technique or ?material chip? technique of manufacturing function micro-aggregates and eco-function elementary materials. The results of this re-search supported by the national ?863? Hi-tech Project, mainly including the high-efficient air purifying mineral compound material indoor, the clay elementary antibacterial materials, the masonry cement/coating/putty/compound with preventing radon radiation, environmental friendly composite functional coatings, mosquito repellent and healthcare material and zeolite-based energy-saving composite materials, were introduced. Finally, the foreground of mineral materials in the field of future advanced eco-friendly materials was also discussed.

Jan 1, 2014

Poor floatability of fine particles is known to be the main cause of the low recovery of ilmenite in Panzhihua, which is the largest titanium mine of China. To get an optimum ilmenite recovery, selective flocculation, and flotation of fine ilmenite was investigated through flotation tests, particle size analysis, zeta potential tests and scanning electron microscopy. The results indicate that carboxymethyl cellulose (CMC) shows flocculation effect for both ilmenite and titanaugite without selectivity, while selective flocculation could be realized by the combination of water glass and CMC. It is because that competitive adsorption would take place on these two kinds of mineral when water glass and CMC are used together. On the surface of ilmenite, the adsorption ability of CMC is stronger than that of water glass, so that CMC can absorb to the same extent irrespective of the presence of a pre-adsorbed layer of water glass and ilmenite particles is flocculated by CMC. The same cannot be said of the titanaugite phase as water glass strongly adsorbs onto the titanaugite, and the adsorption of CMC is hindered. Therefore, the titanaugite particles keep dispersion. Furthermore, the flotation of fine ilmenite particles is feasible as the ilmenite floccules could react with sodium oleate. In the flotation separation of Panzhihua ilmenite ore, the recovery of TiO2 increased from 52.63% to 68.28% by selective flotation. Keywords: ilmenite, flotation, selective flocculation, adsorption

Sep 1, 2012

By Jorge Misle, Daniel Silva

"This paper addresses the need for advanced control technologies and strategies in the mining industry, its potential and actual impact on mining processes and the best practices for their implementation, operation, and long term sustainability. It is well known that advanced process control (APC) can be a very good source for incremental process improvement for the mining industry, yielding to higher production rates or helping maintain consistent production rates despite ore changes. The application and integration of new technology, process knowledge and innovation are key elements in building such a supporting structure. More specifically, and this cannot be emphasized enough, the correct application and assembly of control tools, the in-time presentation of key data to decision makers and the development of relevant statistics and KPI’s (key performance indicators) can and will make a difference not only in terms of production, but also in plant stability, availability and production costs. In deploying such ideas and aiming at the long-term goal of "Operational Excellence", Minera Los Pelambres (MLP) has developed a number of successful control strategies, best practices and technologies, which are not only the application of state-of-the-art automation and computing tools, but rather the assembly of the above presented structuring factors. This work discusses some of the key tools and ideas implemented for SAG & Ball milling and Flotation areas, their performance results and the roadmap taken for the integration of process knowledge and control tools. Also, cases studies are presented and discussed further to not only show the main areas of improvement, but also to highlight the benefits of such strategy that for the most part, deviate from the traditional mining industry control approach. Also, a word is given on the need for innovating in the design of control strategies and leveraging best practices and process knowledge that ultimately, will contribute to long-term reliable operations, improved mineral processing and, although unmeasured, lead to a superior overall performance and productivity of all mining personnel involved."

Jan 1, 2014

By Peter Riccio

Oxiana Sepon?s mineral processing facility in south central Laos produces copper cathode using leach-autoclave-SX/EW flotation technology. Pyrite recovery in the flotation circuit is critical to the operation, as it is used to generate acid for the leach circuit. However, low pyrite recovery has been an ongoing challenge in the flotation circuit. Tailings characterization work done by Ian Wark Research Institute showed that the pyrite losses to the tail are made up of a combination of coarse liberated particles and finer particles that have been coated by clay fines. In December of 2005, a joint Cytec-Oxiana technical program was initiated to address the pyrite recovery issue. A series of diagnostic tests were performed in the Cytec Stamford Research Facility using synthetic plant water showing that the collector was precipitating as a metal salt, and was un-available for mineral attachment. The tests also identified several collector chemistries that would likely be robust in the Sepon low pH, high dissolved metal ion environment, and will not complex with ferric, ferrous, or copper in solution. With the support of the Sepon on-site engineers, an extensive, successful laboratory program was completed, which then was followed by on plant testing that showed a step wise improvement in pyrite recovery.

Jan 1, 2014

By Sergey Ulianov, Arkady Senchenko, Alexey Shvets, Arkady Bakotin

"This paper contains description of research results of technology development for copper recovery from weathered tails of iron processing plant. The predominant host mineral that contains valuable component is chalcopyrite occurring in its free form and in associations with ore and rock-forming minerals. Copper grade is 0.26-0.30%. Emulsion inclusions of chalcopyrite in pyrite and sphalerite were noted. Major problem is low copper recovery (30-35%) by flotation. When studying chalcopyrite in primary concentrate it was determined that the surfaces of many chalcopyrite grains are covered with oxide films which prevented collector attachment onto them. Second issue was deep association of chalcopyrite with pyrite and sphalerite. Sulfidizing reagent addition did not help to reach the required level of copper recovery to concentrate. In the result of research performed the technological flowsheet was developed including preliminary treatment of head material in a special unit aiming at oxide films removal, followed by copper rougher flotation on head size tails, crude concentrate regrinding and a number of cleaner flotation operations. After the treatment of weathered tails according to the flowsheet developed, copper recovery to flotation concentrate became 71.53%, at 23.46% copper grade. The suggested technology allows one to solve the issue with treatment of technology-related copper-containing stockpile material, as well as to include the ores where copper is represented by sulfide minerals covered with oxide films into processing."

Jan 1, 2014

By M. Saghaeian, R. Hejazi, A. Dehghani Ahmadabadi, M. Zare

"In the most iron ore beneficiation plants, reverse flotation is the best method for removing silicate gangues from final iron ore concentrate. Many previous studies show, if the major portion of impurities include quartz minerals, the flotation process is simple, but if iron silicates are dominant, reverse flotation is so complicated and mostly not very effective. In this study which was performed on the Sangan iron ore concentrate, the performance using of reverse flotation and magnetic flotation separator for elimination of silicate gangues from the magnetic iron concentrate was investigated. The operational parameters for reverse flotation are considered as: collector and frother types and dosages and also modifiers. But for magnetic flotation separator parameters were magnetic field intensity as well as overflow and underflow water rates. Results showed that reverse flotation has not a significant effect on the elimination of impurities. Because of the silicate gangues of Sangan concentrate including a mixture of quartz and iron silicates (amphibole, pyroxene and feldspar), so downgrading of the SiO2 content for the flotation concentrate was rather low and only average reduces of 20.60% were possible. But the findings of using magnetic separator was more satisfactory. Results of the weight recovery, iron grade and also SiO2 and S grades of final concentrate were better with magnetic flotation device. So at the best and optimum condition, we could reduce 51.01% of the total silicate (SiO2~ 2.19%) along with 74.66% of sulfur content (S~ 0.076%) and concentrate weight and Fe recoveries of 92.04% and 94.51% respectively, final Fe grade of 68.73%.INTRODUCTION Chemical/traditional flotation is one of the most effective methods for separating valuable particles from waste minerals, which is used in most mineral processing industries. In the iron ore processing industry, the major impurities present in iron ore concentrate include sulfur, silica and phosphorus (Bruckard et al, 2015), which are often carried out by reverse flotation methods for the removal of sulfide and oxide impurities (Donald, 1967: Araujo et al., 2005: Ma, 2012)"

Jan 1, 2018

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

The ore studied occurred in the Three Rivers area in China and was a silver-lead-zinc complex ore containing 400.52 g/t silver, 4.77 % lead and 3.47 % zinc. Silver, lead and zinc were the major valuable elements in the ore and copper, cadmium and tin were the associated elements to be comprehensively recovered, whereas arsenic was the harmful element. The element silver occurred mainly in freibergite with small proportion in dyscrasite and other silver minerals. The carrier minerals for silver were mainly galena and oxidized lead minerals and then sphalerite, arsenopyrite and pyrite. The ore contained numerous minerals with complex mosaic texture and the lead and zinc minerals enclosed each other multiply, which made the separation of the minerals in the ore very difficult. Experimental investigation on the beneficiation of the ore indicated that with flotation separation process it was very hard to obtain single lead concentrate or single zinc concentrate that would meet the requirement of market. In the meantime, during the separation process of lead and zinc, silver tended to be dispersed, resulting in a low recovery of silver. Therefore, a rational utilization technique for the ore should be a combined process of bulk flotation to reduce arsenic? sulphating roasting of silver-lead-zinc bulk concentrate-leaching with diluted sulphuric acid to separate silver, lead and zinc. With this process quality lead concentrate containing silver and high grade zinc product and silver product could be obtained. The recovery of silver, lead and zinc in flotation was 85.10%, 84.48% and 82.48%, respectively. The total recovery of silver, lead and zinc in chemical processing was 97.07%(sum of recovery of silver ingot and lead concentrate), 99.61% and 90.93%, respectively.

Jan 1, 2014

By I. Baltov

The Chelopech Mine, located in Central Bulgaria, is one of Europe?s largest underground copper- gold mines, currently mines and processes approximately one million tonnes of ore per year. Copper concentrates containing gold and silver with significant arsenic content are produced and sold on the world markets. The operation was acquired by Dundee Precious Metals in 2003. A modernization program for the Mine and Plant has since been in progress to increase both production and mechanical reliability, and also to optimize metallurgical recoveries. Since then, mine output and plant throughput have doubled, plant availabilities and utilization have increased significantly, and overall metallurgical performance for copper and gold improved. The paper presents the systematic approach for obtaining and analyzing data, communicating it, and making suggestions for changes to the technological parameters and flowsheet in order to maximize metal recoveries. These studies have correlated the ore characteristics (particle size distributions, metal assays, and Cu and Au mineralogical and phase analyses) with the actual plant performance (kinetics, recoveries, and throughput). Cu recovery by size has been calculated from the mineralogical analyses of feed, concentrate and tails, with the most significant losses being identified in terms of fraction and phase recoveries. This has provided the recommendations (some of them tested in plant) for changes in the grinding and flotation circuits.

Jan 1, 2014

By V. I. Lakshmanan

The growing concerns on process efficiency, escalating operating and capital costs along with environmental and social concerns of using conventional technology for extracting gold and titanium dioxide demand an in-depth understanding of the fundamentals and a broader understanding of the various process steps involved. This will allow development of efficient process flowsheet for product recovery and compliance with regulatory guidelines. This paper will discuss our recent developments in mineral processing and hydrometallurgical technologies to recover gold and titanium dioxide from a wide range of feed materials including ores, concentrates and tailings.

Sep 1, 2012

By J. Masinja

The mining industry is known to be a potential major contributor to the industrial development of any economy. Large-scale mining has been going on in Zambia for the last 100 years. The impact of mining in Zambia has been to create a development corridor along the line of rail to the Copperbelt Province, where hitherto, mining was concentrated, and then to develop a large consolidated high-density economic zone covering an area of about 72 km by 60km. This area is home to a number of very large integrated copper/cobalt mining complexes. The mining zone has expanded to the Northwestern Province in the last 10 years, where the largest copper mine in Africa now exists, having produced about 300 000 tonnes of copper in 2011. The total output of the Zambian mining industry is now about 820 000 tonnes per annum with projections of reaching 1.5 million by 2015, due to new Greenfield investments expected to come online by then. These new mining industry developments have come on the back of strong and sustained high base metal prices, in the last 10 years or so, due to demand mainly from China and India. This new lease of life has increased the contribution of the sector to the national treasury. The mining industry in Zambia has undergone a very important ownership restructuring with the sale of the previously Government owned parastatal, Zambia Consolidated Copper Mines (ZCCM) which dominated the sector, to allow for private sector participation. The privatization process lasted from about 1995 to about 2002. The recent growth of the mining sector has unfortunately not been matched by an adequate supply of skilled manpower for various reasons. These include: (i) A lack of strong in-house training strategies by the new mine owners (ii) Decrease in industry support to the training institutions (iii) The demise of and restructuring of ZCCM which has consequently limited the Government human resources planning tools for the mining sector (iv) The cyclic nature for the fortunes of the sector has lead to fluctuating interest of student recruitment into training institutions (v) Limitations, both staff and equipment, in the training institutions (vi) A re-structuring of the training institutions This paper examines the current status, and student output from tertiary training institutions for the mining sector in Zambia. This is then compared to the skilled labour demands of the sector. The various cause and effect issues are considered and a proposal on how this skills gap could be addressed sustainably is proposed. Keywords: skills gap, graduate training, quality of graduates

Sep 1, 2012

By D. Moradkhani

The objective of this research was, to evaluate the hazard of heavy metals in the soil around the National Iranian Lead & Zinc (NILZ) Company. In this study, 38 samples of soil around the NILZ factory were collected using standard sampling method, so that, the heavy metals Pb, Zn, Cd and Cr have been evaluated. The concentration of heavy metals were measured and compared with standard limits. The results show that the hazard of heavy metals in soil is not so serious and the content of Pb in just 5 percent of samples, and the content of Zn in just 3 percent of samples were above standard limits and the concentration of Cd and Cr were under the standard limits. Average, variance and standard deviation of the elements are calculated and with due attention to the standard deviation, Pb and Zn are seen to be more distributed than Cd and Cr. Also the isograde curve of heavy metals was drawn using software called Surfer. These curves showed that the heavy metals are concentrated at particular distances from the factory. Keywords: heavy metals, remote sensing, sampling method, isograde curve, Surfer software

Sep 1, 2012

By S. Leroy

Grinding is the most energy consuming step in mineral processing, however, it is still poorly understood and its efficiency is difficult to monitor. Mill performances are traditionally measured at the mill discharge, on the basis of a mass percentage passing a certain sieve. This approach does not reflect what happens to the fines through milling. On another hand, if many macroscopic parameters, such as the percent solids of the pulp, its viscosity, or its mean residence time in the mill are known to be related to grinding efficiency, the link between these parameters and particle size distribution (PSD) is still unclear. Here, a methodology is established to understand the effect of ball mill operating conditions on particle size and shape distribution in the grinding process. The study focuses on the particular case of an Upper Group 2 (UG-2) platinum ore concentrator. Due to the very low grade of sulphide and PGM (Platinum group metals) in UG-2, grinding mechanisms are entirely control by gangue minerals. These two minerals have contrasted properties and PGM content and these properties immediately affect the entire recovery process. So, the grinding of both gangue minerals is studied on a size by size basis. At particle scale, three parameters are addressed: particle size, particle composition and particle shape. The specific behavior of chromite and silicate grains is demonstrated. As a conclusion, this study gives some clues to operate ball mills in a more efficient manner regarding chromite issue in the processing of UG-2. Keywords: ball milling control, UG-2, chromite, fine particle, particle shape, segregation

Sep 1, 2012

By Carina Ulsen

The existing construction and demolition (C and D) waste recycling technologies and standards have been essentially focused on the production and use of coarse recycled aggregates. Very few papers focus on the production of recycled sand, although some previous results show that fine aggregates fraction represents around 40 to 60% (in mass) of the Brazilian waste and it is usually used as road sub-base or disposed in landfills. The quality of the recycled aggregate is strictly related to the content of porous and low strength phases, mainly the patches of cement remaining on recycled aggregate surface. Some technologies have already been described in the literature, even though, to the moment none of these technologies has clearly succeeded in reaching the large market available. This paper presents a summary of the main properties of the sand produced from C and D waste by tertiary crushing at vertical shaft impact crusher (VSI). Additionally mineral processing technologies were applied on the attained product, such as gravity concentration by shaking table and spirals and removal of cement paste by attrition. The main properties of recycled sand are discussed and compared to the previous C and D waste, respectively: particle size distribution, particle shape, chemical composition, cement paste content and porosity. The results demonstrates that the crushing allowed producing a VSI-sand with low porosity and water absorption due to the increasing on the content of silicates from natural rock phases and increasing liberation between these phases and porous cement paste; the particles from the attained product presented also a better shape (sphericity and aspect ratio). The attrition tests assayed on VSI recycled fine aggregates accomplished a further selective disaggregation of cement paste and other porous materials - the porosity was reduced from 10% to 7%. The concentration by shaking table at narrow sieve fractions led to a product with low porosity and reduced content of cement paste, however, concentration on spirals did not succeed since separation was performed essentially by the size of the particles. The heavy product from shaking table represented almost 75% in weight and has less than 60% recovery of CaO+LOI, and expressive reduction on porosity. The aim of producing sand from construction and demolition waste through mineral processing unit operations changes the recycling approach and contributes for up cycling the recycled sand. The exhaustion of sand deposits on Brazilian large centers, the increasing price and the construction boom encourages the development of alternative materials as construction raw material. Keywords: recycled sand, construction and demolition waste, technological characterization

Sep 1, 2012

By Ali Dehghani Ahmadabadi

Gravity separation technique is widely used in mineral beneficiation practices for its low cost, ease of operation, and eco-friendly nature. The most commonly used gravity methods for beneficiation of iron ores are shaking table, jig and spiral methods which aren&apos;t very effective for iron mineral fines. Multi-Gravity Separator (MGS) is suitable for the treatment of fines with a maximum particle size of approximately 500 µm. This study was performed on a low-grade haematite iron ore from Chadormalutailing dams. Detailed mineralogical, physical and chemical characteristics of a goethiticlateritic iron ore showed that the sample contained porous and friable oxides and hydroxides of iron. The ore sample had a feed grade of 35% Fe, 1.1% FeO, 15.5% SiO2 and 8.5% Al2O3. Haematite and goethite are the main iron-bearing minerals while quartzite and kaolinite are the major gangue mineral constituents. In this paper, the statistical evaluation and optimization of grade and recovery using a factorial design of experiment (DOE) method has been carried out for Chadormalulow grade ultra-fine haematite tailings with MGS. The input process parameters considered are drum speed, tilt angle, wash water flow rate and pulp density. The results show considerable improvements in both the quality characteristics such as grade and recovery with statistical evaluation and optimization, compared to the initial value of grade and recovery. Keywords: multi-gravity separator, mgs, statistical evaluation, optimization, haematite

Sep 1, 2012

By M. R. Hosseini

Among all gravity concentration methods, Shaking-table is the most effective one from the metallurgical point of view. In this study, Shaking-table was used for concentrating a manganese ore sample from Ghasem Abad area in Kerman, Iran. Experiments were designed by using L8Taguchi design with five variables and each variable in two levels. The influence of each variable and their interactions on the operation of the device was studied. The variables under investigation were: table slope, table frequency, water flowrate, feed rate, and particle size. The manganese concentrate grade and recovery were used as response variables. It was shown that water flowrate, table slope, feed rate, and particle size are the significant variable on concentrate grade; while, all the variables influence manganese recovery.

Jan 1, 2014

By Sunil K. Tripathy

Particle characteristics such as size, density, liberation and magnetic susceptibility play vital role in magnetic separation technique. To understand the performance of magnetic separation process for chromite beneficiation industry, particle characteristics need to be analysed. However, to date, this has been an expensive and time consuming task, thus only minimal amounts of this type of data are available in the literature. Several new methods are being developed, that will produce the required mineralogical and liberation data to provide processing information rapidly and inexpensively. Among these, QEMSCAN is a unique and advanced characterisation equipment used for liberation analysis for different ore whereas S.G. Franz Isodynamic Separator for determining the magnetic susceptibility. In Indian chromite deposits, the content of iron bearing minerals in the ore is typical which controls the Cr:Fe ratio in the product while treating in gravity based beneficiation plant. In the present investigation, detailed characterisation of two distinct chromite ore samples from Sukinda chromite deposit, India, was investigated which includes advanced mineral characterisation using QEMSCANand magnetic susceptibility measurement by using Frantz Isodynamic separator, etc.. Presence of haematite and gibbsite along with chromite mineral were identified as major gangue minerals in the high grade ore from XRD pattern whereas Goethite, Quartz, Haematite, Kaolinite, Ringwoodite identified in the low grade ore. The mass magnetic susceptibility of low grade ore is very high 5.2 cm3/g compared to 2.7 cm3/g for high grade ore, due to the presence of abundant quantity of iron bearing minerals. Subsequently, these two types of ore were subjected for magnetic separation for improving Cr:Fe ratio by using different magnetic separators viz. induced roll magnetic separator, wet high intensity magnetic separator, rare earth roll magnetic separator, rare earth drum magnetic separator. The results of magnetic separation studies indicated that, Cr: Fe ratio of the chromite ores can be improved to 3.99 and 1.97 from the feed assaying 3.09 and 1.29 respectively. Studies on rare earth roll magnetic separator indicated that both the ores were upgraded to a maximum Cr:Fe ratio level at optimised condition. Keywords: characterization, QEMSCAN, magnetic separation, rare earth roll magnetic separator, industrial mineral, chromite

Sep 1, 2012

By P. Altinkaya, O. Celep, H. Deveci, E. Y. Yazici

"Copper-bearing gold ores have proved difficult to treat in conventional cyanide leaching process owing to prohibitively high consumption of cyanide by readily soluble copper minerals interfering with gold extraction. Cyanide leaching of gold from copper-rich ores can be improved by intensive cyanidation or application of physical and chemical pre-treatment methods (e.g., ultra-fine grinding, roasting and leaching). In this study, nitric acid leaching of a copper-bearing pyritic concentrate (0.3% Cu, 62 g/t Au and 110 g/t Ag) as pre-treatment prior to cyanidation was investigated. The mineralogical analysis of the concentrate has revealed that it is composed of mainly quartz (25%), pyrite (32.7%), sphalerite (5.37 %), galena (2.12 wt %) and anglesite (1.13 %). Arsenopyrite, chalcopyrite, covellite and bournonite were also detected as minor phases present. Previous studies carried out by the authors showed that direct cyanidation (1.5 g/L NaCN) of the as-received concentrate (d80: 80 µm) produced low gold (45% Au) and silver (46% Ag) extractions. Nitric acid pretreatment of the as-received concentrate was performed for 5 hours at 1-5 M HNO3 and 80oC. In these tests, 65% Cu/Pb and 94% Zn were leached. The nitric acid pre-treatment improved the extraction of gold and silver in subsequent cyanide leaching (1.5 g/L NaCN) to 82% Au and 87.5% Ag with a concomitant decrease (up to 54%) in cyanide consumption. It can be inferred from these findings that the removal of copper from the concentrate and the liberation of the occluded gold by nitric acid leaching as pretreatments can be appropriately employed for the treatment of the copper-bearing pyritic concentrate with high gold/silver content. INTRODUCTION Refractory ores are often characterized by their low amenability to cyanide leaching resulting low (often <80%) Au/Ag extractions (Bhappu, 1990; Celep et al., 2009; Marsden and House, 2006). One of the most common causes of refractoriness is the physical or chemical encapsulation of submicroscopic or fine-grained gold in sulphide minerals such as arsenopyrite and pyrite (La Brooy et al., 1994; Vaughan, 2004). To render refractory gold ores/concentrates amenable to cyanide leaching, the decomposition of sulphide minerals within a pre-treatment process to expose the encapsulated gold grains to the action of cyanide is required. In this regard, roasting, pressure oxidation and biooxidation are commercially used processes for pretreatment of arsenopyrite/pyrite gold ores/concentrates ahead of cyanide leaching (La Brooy et al., 1994). Presence of cyanide-soluble copper minerals in the ore leads to low gold recoveries and high cyanide consumptions under conventional cyanide leaching conditions. High cyanide concentrations (CN:Cu>4) should be employed to achieve high gold recoveries from copper-rich gold ores/concentrates. This may require recovery of cyanide from effluents. In this regard, SART Process (sulphidisation-acidification-recycling-thickening) employed industrially for recovery of cyanide and copper as a by-product. This process simply relies on the addition of sulphide (as Na2S, NaSH or H2S) to the leach solution prior to the acidification to pH 4-5. This results in the precipitation of copper as Cu2S and occurrence of free cyanide which is recycled to the leaching circuit after S/L separation (Dai et al., 2012)."

Jan 1, 2018

By Jing Zhou

In view of the state of the long time use of sodium cyanide in lead-zinc-sulfur-silver multimetallic ore production, we propose alternative reagents system through experimental research. The experiment first used TJ, sodium sulfide to adjust the flotation pulp, after that, zinc sulfate, sodium sulfite was added to low alkaline pulp to inhibiting zinc sulfur mineral and adapted MB, 25# aerofloat and diethyl dithiocarbamate combination collectors to float lead minerals. The obtained test index is as follows: lead concentrate recovery rate of small scale test was increased by 5 to 10%, the recovery rates of gold and silver in lead concentrate were increased by 7% and 11% respectively; the industrial test is conducted under the condition that the total grade of lead and zinc content in raw ore decreased by 4.81%, the total recovery rate of lead and zinc increased by 7%, recovery rates of gold and silver in lead concentrate were increased by 7.62% and 9.65% respectively. So it successfully realizes the target to replace the sodium cyanide, using low-alkaline non-toxic reagents system in mineral processing practice of three kinds of complex lead-zinc-sulfur ore of this mine. Keywords: refractory lead-zinc-sulfur ore, depressant, non-cyanide flotation

Sep 1, 2012

Ca-containing gangue minerals such as Fluorite, Calcite have same surface activity point--calcium ions and approximate floatability with scheelite, it is difficult to achieve good dressing index of rough concentrate of scheelite. Mono-mineral experiments and ore tests indicate that, according to mineral composition, gangue minerals can be inhibited selectively by adopting suitable regulators, then the separation of scheelite from gangue minerals can be realized effectively. Mechanism analysis was taken by zeta potentials measurements and FTIR tests. Good dressing indexes are also obtained in practical ore tests and industrial tests. Keywords: scheelite, fluorite, calcite, regulator, flotation separation

Sep 1, 2012