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By Liu Jin

"In order to reduce the dosage costs and increase the economic benefits of a full floating process in a low grade complex multi-metals W-Mo ore, based on the study of the magnetic characteristics of the main gangue minerals, a joint process by magnetic separation and floatation technology is adopted. The first step of the flowsheet is to recover magnetite by magnetic separation, then remove the magnetic gangues by high gradient magnetic separation (HGMS) and finally recycle the W-Mo from the magnetically separated tailings by flotation. Results of the lab experiment show that in comparison with the full flotation process, the floatation feed tonnage of the combined flowsheet are only 46%. The grade and the recovery of Mo in the rough Mo-Bi concentrate is similar with the original one while the WO3 in the tungsten rough concentrate is increased from 3.85% to 6.64%. The dosage costs are reduced by 53%. The new process can significantly improve the plant economically. INTRODUCTION With the continuous exploitation of scheelite resources, the easily obtained resource is gradually depleting. The ""lean, fine and complex"" scheelite resource has become the main research object of tungsten beneficiation (Lou et al., 2010) (Xiao et al., 2013). The passive situation of tungsten beneficiation can be reversed by enhancing technological innovation and investment in science and technology, changing the business philosophy and mode of production, optimizing the process structure and process conditions, improving various technical indexes and reducing production costs of reagents, which will maximize economic benefits (Jiang et al., 2012 ) (Zhu et al., 2016). A polymetallic deposit of tungsten molybdenum bismuth original process adopts a full flotation process. With the expansion of stope mining, the content of valuable metals in the ore continues to decrease, resulting in a high cost per ton of concentrate produced and a low output value (Li et al., 2015)."

Jan 1, 2018

By Carsten Gerold

The paper is giving an overview about successful operating Loesche Vertical ? Roller ? Mills (VRM) installations and summarises the main benefits of the dry compressive Loesche grinding technologies in Airflow- and Overflow-Mode. Some of these benefits are optimised energy efficiency of the grinding - classifying - circuits, increased mineral recoveries and decreased OPEX costs, at a parallel simplification of the process route. Within this paper the process values of the Loesche VRM are compared to existing or planned conventional grinding ? classifying circuits. Further advantages discovered in pilot trials and examples for new more efficient process route alternatives are given. The paper reports about production and pilot trial experiences obtained by crushing and grinding Iron Ore, Iron Ore Concentrates, Copper Shale, Copper Matte, Copper Slag, Titanium Slag, Tin Slag, Steel and Stainless Steel Slag with Loesche VRM.

Sep 1, 2012

Large quantities of electrical and electronic equipments are discarded at the end-of-life (EOL) in different industries and house hold applications. Their disposal is creating a challenging environmental problem due to the presence of hazardous metals and non-metallic materials such as epoxy resins and plastics including brominated flame retardants etc particularly in printed circuit boards (PCBs). The recovery valuable metals and separation of hazardous materials from discarded PCBs will not only conserve the resources but also mitigate the environmental pollution. From a recycling point of view for a sustainable society, the studies have been carried out for the recovery of metal values from EOL-PCBs of DVD video players (DVD-PCBs) and vacuum cleaners (VC-PCBs) using physical beneficiation techniques. The concentration of the metals was found to be 43 wt.% and 30 wt.% in DVD-PCBs and VC-PCBs, respectively. Both the PCBs samples were ground in a hammer mill after cutting and their size analysis was carried out. The liberation of the metallic and non-metallic fractions was investigated under the microscope for different size fractions. Subsequently, froth flotation and pneumatic air separation studied were carried out to enrich the metallic constituents. The studies showed the enrichment of metals in coarser particles (-1000 +150 µm) and non-metals in the finer particles -150 µm following mechanical recycling process. A grade of 90 % with 75% recovery was achieved by froth flotation, but lower grade and recovery of 75% and 65% respectively were obtained by pneumatic separation with -1500 µm powders for DVD-PCBs. A grade of 86% metal was obtained by froth flotation with 76% recovery in the case of VC-PCBs. The lower grade of 65% with almost same recovery was achieved during pneumatic separation studies due to lower concentration of metals in VC-PCBs. The studies also showed that the froth flotation is an efficient process for enrichment of metals from both the samples. The process is environmental friendly as no chemicals are employed during entire processing. The higher recovery and grade of metal is expected to be obtained on a large scale beneficiation process.

Sep 1, 2012

By Chris Plackowski, Bruckard. Warren J., Anh V. Nguyen

"Enargite is a significant penalty mineral in the copper industry and its separation from many copper sulfides by flotation is difficult. The separation may be crudely achieved using selective oxidation techniques or through the use of pulp potential control. This paper summarizes our latest contributions to a better understanding of enargite surface electrochemistry and hydrophobicity. Oxidation, roughness, hydrophobicity and species formation on the surface of natural enargite were examined by a novel experimental approach that combines electrochemical techniques, atomic force microscopy, X-ray photoelectron spectroscopy and droplet evaporation tensiometry. It allows for synchronized electrochemical control and examination of the oxidative surface morphology, speciation and hydrophobicity of enargite at pH 4 and pH 10. At low pH, surface layer formations consisting of metal deficient sulfide and elemental sulfur were identified associated with a limited increase in roughness and heterogeneous distribution of surface species produced by initial rapid dissolution of Cu, followed by diffusion limited surface layer deposition. At high pH, a similar diffusive mechanism associated with oxidation products consisting of copper sulfate and hydroxide and a significant increase in surface roughness were established. Receding contact angle measurements showed no significant difference in the contact angle on a surface oxidized at pH 10 and the freshly polished surface. Contact angle increased from 46° on the polished surface to 59° after oxidation at pH 4. Competing effects of hydrophilic copper oxides and hydroxides, and hydrophobic species of elemental sulfur on the mineral surfaces under oxidizing conditions at pH 4, and the change in surface roughness at pH 10, contribute to the changes in enargite hydrophobicity under electrochemically-controlled oxidation conditions. Most likely, both surface species and surface roughness produced by oxidation are critical to the changes in the wettability of enargite and other sulfide minerals."

Jan 1, 2014

By Ying Gu

Automated mineralogy methods and tools, such as the Mineral Liberation Analyzer (MLA) and the QEMSCAN, are now widely used for ore characterization, process design and optimization. Several case studies published recently demonstrate that large gains can be obtained through grinding and flotation optimization guided by automated mineralogy data. However, since automated mineralogy can only provide the information pointing to where the process gains can be made, it does not directly impact the production gain. Thus, a question is often asked: how to value the contribution of automated mineralogy to process improvement of a particular plant. This appears to be a difficult question. On close examination however, it is found that this is essentially a question of the value of information and it is reasonably well documented in various other industries. Hubbard (2010), in chapter 7 ?Measuring the Value of Information?, dealt with exactly this type of problem. The value of information is the reduced risk of an investment and opportunity loss. The methods Hubbard developed can be applied to estimate the value of automated mineralogy, as well as metallurgical test work, which also produces information that reduces the risk of investment. This paper first introduces Hubbard?s theory on the value of information and how to measure it. It then applies his methods to estimate the value of automated mineralogy, using Anglo Platinum?s fine grinding project as an example. In this case, the value of automated mineralogy includes the reduction in investment risk worth US$ 62.5million, in project rejection worth US$197 million and in opportunity loss worth US$320 million. In the end, a general model is developed to allow the simulation of the value of automated mineralogy in different mining operations constrained by different parameters.

Sep 1, 2012

There is a strong demand for nickel metal due to quick development of stainless steel and new electrical materials, most of which is extracted from sulfide resources, resulting in a serious depletion of sulfide resources. Therefore, more attentions have been paying to extracting nickel from nickel laterite, which accounts for some 50% of total nickel metal production. In this paper prereducing?magnetic separation?reduction smelting process is developed to manufacture ferronickel rom two types of nickel laterite DN and GN, assaying 1.42% 1.83% Ni and 49.09% 26.08%Fetotal, respectively. Mineralogy of two types of nickel laterite was determined and optimization of process parameters was conducted to manufacture ferronickel. Prereduction?magnetic concentration process is used to upgrade low grade nickel laterite firstly, two kinds of Ni-Fe concentrates being prepared of DN assaying 2.26% Ni and 69.45% Fetotal and GN containing 2.76% Ni and 38.00% Fetotal. Finally, two types of ferronickel were produced by reduction smelting of prereduced concentrates DN and GN, DN and GN ferronickel contains 2.97% Ni and 6.58%Ni, 89.25%Fetotal and 89.95%Fetotal, respectively. The total recoveries of Ni and Fe of the two ferronickel are beyond 90% and 80%, respectively. There is significant difference in grade of magnetic concentrates and ferronickel between DN and GN laterite due to their different mineralogy, the former belongs to limonitic laterite and the latter saponite one. There are some advantages for this process to manufacture ferronickel from nickel laterite, including effectively upgrading low grade nickel laterite by prereducing?magnetic separation technique, higher throughput and lower energy available for reduction smelting section due to some 40% gangue being rejected in pre-upgrading section, and much less metallurgical coke consumption by using non-coking coal as reductant for prereducing?magnetic separation?smelting process.

Jan 1, 2014

By Robert van Hille, Alison Lewis

The precipitation of a selection of metals from both a synthetic and an actual metal-rich effluent was investigated. The experimental aspects of this study were carried out in a two-stage process consisting of a pre-treatment clarifier and a fluidised bed (pellet) reactor. Each unit operation in the two-stage process was investigated separately. The pre-treatment clarification stage at pH ˜ 5 resulted in a 99.9% removal of iron and 97.3% removal of aluminium. The pellet reactor was used to precipitate nickel as nickel carbonate from a pure stream and a removal efficiency of 99.6% was achieved. The high local supersaturation at the reagent inlet points caused the formation of a large amount of fines, but these agglomerated onto the pellets up the length of the bed. For copper precipitated as copper sulphide from a pure stream, a maximum removal efficiency of 92% was achieved. The high local supersaturation at the reagent inlets also caused the formation of a large amount of fines, but the extremely sparingly soluble nature of copper sulphide meant that the fines were not agglomerated up the length of the bed. For removal of cobalt as cobalt carbonate from an actual stream, a stable cobalt removal of only 60% was achieved. This was found to be due to the presence of magnesium, which reduced the cobalt precipitation efficiency through the formation of the magnesium bicarbonate ion.

Jan 1, 2003

By Ronel du Plessis, John C. Davidtz, Jan D. Miller

Recent results from electrochemical measurements demonstrate that trithiocarbonate (TTC) collectors are more readily oxidized to their corresponding dithiolates than the dithiocarbonate/xanthate (DTC) collectors. Based on the traditional analysis of collector adsorption, trithiocarbonates might then be expected to be effective for bulk sulfide mineral flotation. Previous bench-scale flotation research had shown that TTC collectors are very effective for the flotation of copper sulfide minerals and PGM (platinum group metal) sulfide minerals. More recently, the TTC collectors were evaluated for auriferous pyrite recovery in benchscale plant scale flotation testing in the United States and in plant tests at Anglogold in South Africa. TTC collectors were also applied in bench-scale testing of a PGM ore. In each case an improved separation efficiency was realized. Fundamental studies at the University of Utah examining the effect of collector structure (functional group, -O-CS2 versus .S-CS2), specifically with respect to auriferous pyrite flotation, are in progress. The effect of collector structure was evaluated with air as well as nitrogen as the flotation gas medium. Experimental techniques utilized included electrochemically controlled contact angle measurements to evaluate mineral hydrophobicity and infrared spectroscopy to explain collector adsorption phenomena at the mineral surface.

Jan 1, 2003

By D. Moradkhani

Copper metal has important role in the basic industrials, as if it did not exist, modern human life would not develop! Copper leaching, as the first step, is important step in copper production processes. In this research, efficient factors on the leaching have been investigated. For this reason, four efficient factors on leaching namely pH, liquid to solid ratio (L/S), temperature and time, as independent variables, were optimized using response surface (RSM) with D-optimal. A quadratic equation was used to create response and contours. According to the results from analysis of variance (ANOVA), the value of determination coefficient (R2=96.77%) indicates that the model was good fit. Optimum experiment condition also was found: pH of 1, L/S of 8.24, temperature of 26.06 ? and time of 43.64 min. At this condition, the maximum recovery of copper was equaled to 92/38 in which good desirability achieved.

Sep 1, 2012

By S. Castro, L. Uribe

Seawater can be considered as a particular process water with a high concentration of NaCl (about 0.5- 0.6 mole/L) and high concentration of hydrolyzing metal cations (mainly, Mg2+ and Ca2+ ions). Micro-flotation tests, induction time measurements, and zeta potential measurements have been used to investigate the effect of these ions on the natural floatability of molybdenite. The results demonstrate that molybdenite is strongly depressed in the alkaline pH range over which hydrolysis products of Mg2+ and Ca2+ ions are formed. At pH 10, colloidal magnesium hydroxide seems to be responsible for molybdenite depression in seawater and in Mg2+ solutions. This is also supported by the measurements of the effect of Mg2+ ions on the zeta potential of molybdenite. The mechanism of depression of molybdenite with Ca2+ ions is different, and depression takes place in the pH range were Ca(OH)+ complexes are formed, below the pH of precipitation of calcium hydroxide. Adsorption of the cationic hydroxy species and/or hetero-coagulation of the positive charged colloidal hydroxide on the negative charged molybdenite particles seem to be the main mechanisms involved.

Jan 1, 2014

By Jing Zhou

2-hydroxy-3-naphthoy hydroxamic acid code name F203 is a good collector of cassiterite, 1-hydroxy-2-naphthoy hydroxamic acid code name ZJ-3. F203 and ZJ-3 are similar series of isomers. They have similar naphthye, and similar series of functional OH and ?CONHOH, but the seat of OH and ?CONHOH group are different, on the F203 is 2.3; on the ZJ-3 is 1.2, ortho position too. According to Isomeric principle ZJ-3 is a good collector of cassiterite slime too. Using ZJ-3 as collector flotation -10µm occupies 90%, grade 1.16% Sn cassiterite slime of Da Chang Chehe concentration plant, pass one coursing flotation, two cleaning and one scarenging flotation, and obtains grand 18.26% Sn, recovery 92.68% cassiterite concentrate. The result proves the Isomeric principle of flotation reagents is correct again. This principle may supply to synthetize new flotation reagents reference. Keywords: F2O3, ZJ-3, cassiterite flotation, Isomeric principle, Isomeric principle of flotation reagents

Sep 1, 2012

By Sumantra Bhattacharya

The per capita energy consumption in India is 510kgoe/year, the global average being nearly 1818kgoe/year. Correspondingly low is the per capita CO2 emission at 1.25t against the world average of 4.39t.65-70%, at times more, of India?s power generation from about 190,000 MW installed capacity, is however coal fired.India therefore has to secure diversified sources of energy and solar power is increasingly being looked as the real alternative to the existing over dependence on coal. To ensure sustainable solar power it is essential to secure its raw material base that is ?silica?, hitherto considered as ?minor minerals?. That calls for immediately addressing the issues of land availability, solar power cost, developing a dynamic inventory of silica containing minerals, appropriate processing technology and strong regulatory framework for sustainable mining and processing of all silica rich minerals. Keywords: silica, silicon, Thar, power generation, India, quartz, solar power

Sep 1, 2012

By E. G. Ozhogina, O. B. Kotova

"The ores of black, non-ferrous, rare, noble metals are mostly distinguished by a variety of mineral types and complexity of their material composition. This article is devoted to the promotion of the concept of mineral processing in modern realities of the deficit of high–grade ores and increase in their demand. Normative and methodical documentation for specific types analysis with the definition of the field of application are presented in this paper. . For example, the pyrochlore-monazite-goethite ores from one of the deposits from Eastern Siberia - Chuktukonskoe ore field were tested. The development of mineralogical methods and testing of specific raw materials are shown. The method of small-angle X-ray (and also synchrotron) scattering, which was developed for solving problems associated with structural high-resolution diagnostics, was tested for bauxites of Vezhay-Vorykvinskoye field.INTRODUCTION A highly intense production of many types of mineral deposits results in gradual depletion and of mining-geological and mining-technical conditions of various ore reserves ?. Relatively easily accessible and rich deposits are getting depleted in the first place, and it is necessary to involve low grade and refractory ores into production and processing. Traditional technologies can hardly be applied (Chanturia, 2017; Bazin et al., 2014; Ponaryadov, 2017). The urgency of development of the concept of technological mineralogy focuses on the confirmation of new methods and approaches to the development of mineral deposits, creation of scientific and methodological pre-requisites for solving the problem of rational development of mineral deposits, maximum extraction and integrated application of all minerals (both principal and associated), expansion and strengthening of mineral and ores.The article is aimed at updating tasks that should be addressed within the applied mineralogical research: – forecast of quality of ore at early stages of exploration and technological indicators for the redistribution of properties ore, – interactive monitoring of these indicators by mineralogical and analytical methods;"

Jan 1, 2018

By E. G. Ozhogina, O. B. Kotova

"The ores of black, non-ferrous, rare, noble metals are mostly distinguished by a variety of mineral types and complexity of their material composition.The article is devoted to the promotion of the concept of mineral processing in modern realitiesof the deficit of high-quality ores and increase their demand.Normative and methodical documentationsfor specific types of analysis with the definition of the field of application are shown. For example,the pyrochlore-monazite-goethite ores from one of the deposits from Eastern Siberia - Chuktukonskoe ore fieldare tested. The development of mineralogical methods, and testing of specific raw materials are shown.The method of small-angle X-ray (and also synchrotron) scattering, which was developed for solving problems associated with structural high-resolution diagnostics, was tested for bauxites of Vezhay-Vorykvinskoye field. KEYWORDS Technological mineralogy, rebellious ores, ore quality assessment, ?mineralogical-analytical methods INTRODUCTION A highly intense production of many types of mineral raw results in gradual depletion and deterioration of mining-geological and mining-technical conditions of development. Relatively easily accessible and rich deposits are getting exhausted in the first place, and it is necessary to involve poor and rebellious ores into production and processing. Traditional technologies can hardly be applied (Chanturia, 2017; Bazin et al., 2014; Ponaryadov, 2017). The urgency of development of the concept of technological mineralogy focuses on the confirmation of new methods and approaches to the development of mineral raw, creation of scientific and methodological prerequisites for solving the problem of rational development of mineral raw, maximal extraction and integrated application of all minerals (both principal and associated), expansion and strengthening of mineral and raw base. The article is aimed at updating tasks that should be addressed within the applied mineralogical researches: – the forecast of quality of ore at early stages of exploration and technological indicators for the redistribution of raw, – interactive monitoring of these indicators by mineralogical and analytical methods; – assessment of environmental consequences of mining and processing of minerals and measures that eliminate these consequences."

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

By M. Narasimha

The flow in a hydrocyclone classifier is highly turbulent complex nature of multi-phase structure, which has led designers to rely on empirical mathematical models for predicting the performance. A number of classifying cyclone models have been developed and successfully used in mineral comminution circuit simulators over the past four decades (Plitt, 1976 and Nageswararao, 1978). However, most of the mathematical models currently available to describe hydrocyclone classifier performance are based on single average mineral density component behavior. In industrial comminution circuits, the feed to the cyclone composed of a mixture of particles of varying degrees of liberation and sizes. The behavior of multi-component particles in a hydrocyclone is poorly understood and unaccounted for in most of the mathematical model equations available in the literature. There is evidence from a number of experimental data sets indicating the significant influence of the multi-component particles on measured cyclone performance. A concept for modeling the performance of hydrocyclones based on multi-component behavior is proposed in this paper. A set of semi-empirical model equations for cut-size, sharpness of separation are presented and the corresponding model parameters evaluated from the measured data are given.

Sep 1, 2012

By Atsushi Shibayama, Toyohisa Fujita, Wan-Tai Yen, Ke-jun Liu

"In this investigation, a sponge gold sample (99.92% pure) has been leached with ammonium thiosulfate solution. The effects of CuSO4, (NH4)2S2O3, (NH4)2SO4, NH4OH and retention time on the gold leaching % (extraction %) and thiosulfate oxidation % (consumption %) have been studied. The copper ion acts as a catalyst in gold dissolution. On the other hand, it also accelerates oxidation of thiosulfate (consumption). It was found in this study that the best gold extraction condition was obtained at 43.2 ks with 0.8 - 1.0x103 mol/m3 (NH4)2S2O3, 30 mol/m3 CuSO4, 2.0 - 3.0x103 mol/m3 NH4OH, 0.4 - 0.5x103 mol/m3 (NH4)2SO4, pH 10±0.2 and 150 rpm. The thiosulfate oxidation was about 15% of the initial concentration.For gold recovery from the pregnant solution, the trioctylmethyl ammonium chloride (TOMAC) was used in this investigation as an extractant to extract gold from thiosulfate solution without pH and other adjustments. The effects of gold concentration, pH, ammonia, thiosulfate and cupric ionic concentrations, extractant and diluent concentrations and retention time on the gold recovery were investigated. It was found that 180 mol/m3 extractant diluted with n-octant at O/A ratio of 1:1 could extracted the 100% of gold in 0.6 ks from the thiosulfate solution at the optimal leaching conditions. The 100% gold stripping could be achieved with 10% thiourea solution."

Jan 1, 2003

By Sanjay Agarwal

Polymetallic sea nodule is a good source of manganese having 22.3% Mn, 5.4% Fe, 6.14% Si, 1.1% Cu, 1.15% Ni, 0.076% Co & others. These nodules are available in plenty on the sea beds, generated over thousands of years. Nodules mainly consist of manganese dioxide and iron oxide phases and other metals are entrapped in the complex cage of these Mn-Fe oxides phases.World-wide research is going on sea nodules as an alternative future source of many metals, which has led to intensified efforts to develop practical and economical processes for recovery of these metals. Very little attempt has been made world over on manganese extraction from sea nodules. We at CSIR-NML, India have developed a direct reduction smelting process of nodules to recover manganese as Fe-Si-Mn alloy. This alloy is extensively used in the steel industry as deoxidizer and as an alloying element to make different grades of steel. Lab scale experiments were conducted to study the manganese distribution between Fe-Si-Mn alloy and FeO-SiO2-MnO-CaO-Al2O3-MgO slag at different temperatures by varying the basicity of the slag. The direct reduction smelting of nodules is carried out on 1 kg scale in 50 kVA electric arc furnaces to have Cu, Ni and Co alloy and Mn rich slag. This manganese rich slag is further treated in 50 kVA arc furnace to produce Fe-Si-Mn alloy. The composition of Fe-Si-Mn alloy obtained is in the range of Mn: 60-65%, Si: 14-17%, C: 1- 2%, S: 0.03% and the balance iron which is acceptable grade for industrial use. The equilibrium amount of MnO in the final slag is controlled by the temperature of the final melt and the silica, lime, alumina content of the final slag. Increasing the basicity of the slag plays a major role in minimizing the loss of MnO to slag, increasing the amount of SiO2 of the slag, increases the manganese loss in the slag. Increasing the CaO/ Al2O3 ratio of the slag decreases the manganese loss in the slag. Increasing the MgO/CaO ratio of the slag increases the manganese loss in the slag. Thus by adjusting

Sep 1, 2012

By V Radmehr

Ammonia and Amonium salts have been recognized as effective leaching agents in hydrometallurgical processes due to low toxicity and cost, easy recovery and high selective recovery of metals. New research findings of considerable advantages of leaching by these agents and elimination of problems associated with acid leaching has resulted in a new approach in the world to this method. The investigations in this field indicate more frequent use of this method for extracting copper from ore and concentrate relative to other basic metals. In this paper, we have attempted to describe the basis and different ammonia leaching methods and present the major research activities in this field for copper. We have also presented the latest findings and related novel processes. Comparative assessment of advantages and disadvantages of this method relative to acid leaching method, kinetic study of copper ammonia leaching and evaluation of Eh-pH diagrams in a system containing water and ammonia are other parts of our study. Finally, by describing the studies on copper extraction from the resulting pregnant solutions, the applicable extraction agents have been reviewed.

Sep 1, 2012

By Lev Filippov, Vyacheslav Severov, Inna Filippova

"Reverse cationic flotation is a very efficient method of beneficiation of oxidized iron ores when you need to separate hematite and quartz. This method can be also applied to reduce silica content in the magnetite concentrates obtained by wet low-intensity magnetic separation. However, cationic flotation in this case is less effective due to the presence of Fe-Mg-Al-bearing silicates as amphiboles in magnetite ores. These silicates are concentrated in magnetic products and determine the difficulties of their separation from iron oxides when amines and starches are used as collectors and depressants, respectively. The recalculation of the results of the electron microprobe analysis of three calcic Fe-Mg-Al-bearing amphiboles used to characterize cation distributions in structural units and to obtain structural formulas in accord with stoichiometric limits was conducted. The Mössbauer spectroscopy was used to examine the validity of the empirical estimation of cation distributions in amphiboles. The studied samples are metamorphic pargasite and ferrotschermakite and volcanic magnesiohornblende. The crystallographic analyses of the amphibole samples exhibited their heterogeneous surfaces explaining worse floatability of amphiboles with dodecylamine at pH 10. The electrokinetic measurements showed that the position of the isoelectric point of amphiboles is related to a substitution of Al3+ for Si4+ in tetrahedral sites and to an amount of Mg2+ cations in octahedral sites. Thus, the dodecylamine adsorption onto amphiboles through electrostatic interactions is mainly affected by a distribution of these cations in tetrahedral and octahedral sites of amphiboles. In addition, the effect of starch on the depression of Fe-Mg-Al-bearing amphiboles during flotation can be attributed to the presence of metal ions on the amphibole surface, which are capable of forming strong chemical complexes with starch molecules."

Jan 1, 2014