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By John Jiang, Brian R. Hart, Stamen S. Dimov, Aparup Chattopadhyay, Barun K. Gorain

"This paper presents a systematic approach to metallurgy diagnostics using an integrated gold deportment methodology developed for complex refractory gold and copper-gold ore bodies. Quantification of gold deportment for these ore bodies is a challenging task due to reasons such as lower grades, high variability of visible and invisible gold content in different sulphides and iron oxide phases, significant presence of disseminated and composite carbonaceous matters along with associations of various copper sulphide phases. Some case studies are presented in this paper to demonstrate the value of a high confidence gold deportment methodology in developing insights for problem diagnostics and to identify opportunities for metallurgical improvements. A holistic approach involving different fields of expertise is critical for successful development and delivery of solutions for complex ore bodies.INTRODUCTION Studies were initiated on various ore complex ore and also on samples representing various process streams. These complex copper-gold single refractory, double and triple refractory gold ores are mainly composed of silicates and/or carbonates with moderate amounts of clay and mica, along with minor amounts of sulphides and organic carbonaceous matter. Variable proportions of visible gold and “invisible gold” (sub-microscopic gold) were noted in different mineral phases for various ore types and process stream samples. Invisible gold commonly occurs as solid solution or as colloidal-sized particles in different sulphides (pyrite, arsenopyrite, pyrrhotite, chalcopyrite and galena) and other phases (including hematite, magnetite and goethite) for different refractory ores. The dominance of invisible gold and presence of highly preg-robbing along with finely disseminated carbonaceous matters adversely affects gold recovery in flotation and leach circuits for most of these double and triple refractory ores. This paper discusses applications of an integrated gold deportment technique developed for different types of gold and copper-gold ores, namely, complex copper-gold, double and triple refractory gold ores (Chattopadhyay and Gorain, 2014; Chattopadhyay et. al., 2016). Various process streams from flotation and gold leaching circuits were investigated. Different concentrates and tailings samples from flotation circuits whereas feed and discharges from pressure oxidation (POX) and carbon-in-leach (CIL) residues were used from gold processing circuits."

Jan 1, 2018

By A. G. Bulaev

Biohydrometallurgical technologies based on activity of acidophilic microorganisms oxidizing ferrous iron, sulfur, and sulfide minerals are widely used to extract base and noble metals from sulfide ores and concentrates. As sulfide minerals oxidation is exothermic, industrial processes are usually preformed at 40–50°C. Moderate thermophiles predominate under these conditions. Most of moderately thermophilic acidophilic microorganisms that oxidize metal sulfide are mixotrophic, i.e., they use both organic nutrients and CO2 as carbon sources. Carbon availability is crucial for microbial activity and affects efficiency of biohydrometallurgical processes. Aeration with CO2-enriched air is often used to increase microbial activity in biooxidation reactors. Organic nutrients can be used as alternative carbon source for moderately thermophiles performing biooxidation of sulfide concentrates. We performed several experiments with different sulfide concentrates to study effects of organic carbon sources on biooxidation efficiency and demonstrated that application of such organic nutrients as yeast extract (YE) and molasses made it possible to increase biooxidation efficiency. For example, addition of 0.02% YE in the nutrient medium increased biooxidation rate of pyrite–arsenopyrite gold bearing and chalcopyrite concentrates in batch mode at 45°C. YE addition increased oxidation rate of sulfide sulfur and gold recovery level from 65 to 87% and from 73 to 81%, respectively. Similarly, YE addition increased copper extraction from 47 to 54%. At the same time, YE addition increased efficiency of biooxidation of pyrite–arsenopyrite gold bearing concentrate in continuous mode. Without YE addition, oxidation rates of pyrite and arsenopyrite were 65.7% and 94%, while gold extraction was 71%. YE addition (0.02%) made it possible to oxidize 74% and 95 % of pyrite and arsenopyrite and extract 78% of gold. Addition of molasses (0.02%) similarly affected biooxidation efficiency. Thus, addition of organic nutrients in nutrient media is a promising strategy for improvement of biohydrometallurgical processes.

Jan 1, 2018

The characteristics of mineral resources and tailings resources in China are analyzed. Those tailings, which have double characteristics, can occupy land, pollute environment and even influence human habitat if they are not disposed in time. So pay attention to the comprehensive utilization of the tailing more and more both at home and abroad. The present situation and problems in comprehensive utilization of iron tailings in China are introduced by combine some practice experience, and have looked forward to the comprehensive utilization of iron tailing situation.

Jan 1, 2014

By M. Pelser, C Aldrich

"The presence of calcium and magnesium in the hydrometallurgical processing of base metals, results in a number of process difficulties. These problems range from the contamination of the final product (where the final product is a precipitate) to high energy consumptions and large bleed streams during electrowinning. Calcium poses an additional problem in sulphate solutions owing to the low solubility of its sulphate salts. This can easily lead to a process stream that is supersaturated with calcium sulphate, resulting in unwanted solids formation within the process equipment.Several processes are reviewed for the control of calcium and magnesium. Of these, fluoride precipitation was selected for experimental investigation. This method involves the addition of a soluble fluoride to precipitate CaF2 and MgF2. The experiments showed high selectivity for calcium and magnesium over the base metals. The experiments also showed magnesium precipitation to dominate for calcium to magnesium molar ratios greater than 1:3.To avoid the domination of magnesium precipitation, a flow sheet is proposed whereby only a portion of the base metal stream is subjected to fluoride precipitation. For the precipitation, a 10% excess of ammonium fluoride is used to remove the maximum amount of calcium and magnesium. After precipitation and solid-liquid separation the split-stream is returned to reduce the overall calcium and magnesium concentration of the base metal stream."

Jan 1, 2003

By G. Dodbiba, T. Fujita, M. Kawata, S. Yamasaki, K. Mitsuhashi, J. Ponou, Y. Iwazaki, T. Atarashi

"The grade of copper ore and concentrate is recently decreasing and it will continues decrease further in the future. The effective liberation treatment for low grade copper ore and the removal of arsenic from copper concentrate is becoming even more important. In this work, the magnetic separation of copper concentrate by heat treatment and the flotation of low grade copper ore by microwave irradiation was studied. The heat treatment of copper minerals in the air atmosphere, the magnetization of most copper minerals increases and especially the magnetization of chalcopyrite shows the largest magnetization, after being heated at 500 oC. The wet HGMS of copper concentrate has been studied and the results have then been compared with the ones when calcined concentrate was used instead. The microwave treatment before ball milling increased the degree of liberation up to 100%, especially when compared with the case when only ball mill was applied to the as-received ore. The flotation of ground copper ore after microwave irradiation showed that the grade copper minerals such as chalcosite and bornite in froth part is much larger than that of tailing part.INTRODUCTION The copper has been used many kind of technological fields and will be more important for the future technology. The global copper production from mine is predicted as shown in Figure 1 (Northey, S. 2014). The copper production peak will be appeared in 2030 and the demand peaks in 2040. In the future the recycling of stocked copper and copper alloy will be necessary to satisfy the demand (Yoshimura, A. 2018). Changes in the grade of copper in copper concentrate, exported from several countries are shown in Figure 2. The copper grade in copper concentrate after mineral processing is gradually decreases every year and it is less than 30% nowadays. On the other hand, the copper ore grade change and prediction are shown in Figure 3. The grade of copper ore is also decreasing to less than 1% in 2010 (Northey, S. 2014). In the future the copper grade gradually decreases, reaching to less than 0.5% in 2080 and the energy to produce the copper metal will increase. The effective liberation treatment for low grade copper ore and the removal of arsenic from copper minerals become more important, nowadays. The microwave irradiation of copper ore for the liberation, energy etc. has been reported by several researchers (for example, Batchelor, A.R. 2017). The magnetization change of copper ore by heating has been reported to remove the arsenic (Sawada, M 2015). In this report, the magnetic separation of copper concentrate by heat treatment and the flotation of copper concentrate by microwave irradiation are discussed after the characteristics of secondary copper minerals are investigated by these treatments."

Jan 1, 2018

By J. Botula

In the region of the North-Bohemian Coal Basin and its environment, there, in a row of places, are found the accumulations of rocks of the sedimentary and pyro clastic origin, the preliminary composition of those shows the possibility of their being utilized for the production of ecologically sparing natural Fe- and Ti- pigments and filling substances. In many places of the regions of Chomutov and Podborany and near Bilina and also in other places, there are found raw stocks perspective for the preparation of yellow up to ochre-brown, red, brown-red and green dyes. The target of project is the verification of dispensable reserves, their mineralogical composition and chemical and physical attributes, verification of treatment ways of Fe-and Ti-pigments separation (hydrocyclones, magnetic and electrostatic separation) and their stabilization and technological painting attributes for applications in colors, coating and plastic masses, mortar mixtures etc.

Jan 1, 2014

By Hamid-Reza Manouchehri

"The triboelectric charge attributes of feldspar, quartz and wollastonite minerals, after contacting different triboecharging medium made of different materials, were considered. Their charge acquisitions by different size fractions of minerals were monitored and accordingly their energetic work function values were estimated. Moreover the separation behaviours of these minerals through the electric field of a laboratory free falling separator were determined and the effects of some chemical reagents on separation their separation characteristics were studied.Finally an attempt was made to translate the findings from single mineral systems to a complex silicate ore, containing quartz, feldspars, wollastonite and some other silicates. The results show favourable prospect to apply the triboelectric separation technique for beneficiation such a complex raw material."

Jan 1, 2003

By H. R. Manouchehri

Large variations in flotation characteristics of minerals have been observed in winter and summer in plant practices as a result of changes in pulp temperature. Variations in temperature may affect the quality for pulp and related process water through changes in dissociation of different chemical species within the pulp, as well as changing in gas and metal hydroxide solubility, reagent adsorption and its stability on mineral surfaces, water/pulp viscosity, etc. All of these affect the flotation characteristics of specific mineral to some degree or another. It has been observed in Cu-Pb-Zn and/or Pb-Zn sulfides flotation that sphalerite (ZnS) flotation is strongly affected by changes in pulp temperature. Plant practices have shown that at the both low, e.g., T <10-12°C, and high, e.g., T > 60°C, the recovery for copper activated sphalerite is dramatically dropped. Within this paper the effect of pulp temperature on flotation characteristics of sphalerite is brought into considerations and laboratory flotation tests were conducted in conjunction with surface and solution chemistry analysis to understand the effect of temperature on sphalerite recovery. The effect of temperature seems to be complex since the temperature affects both the physical (hydrodynamics) and chemical phenomena in the flotation cell. In fact all sub-processes in flotation, i.e., collision, attachment and detachment, are affected by changing in temperature. Experimental results indicating that at alkaline pH values, e.g., 8.5 to 10.5, the recovery for copper-activated sphalerite is dramatically reduced when temperature is below 10-12°C, which is in agreement with plant practice at Boliden?s Garpenberg plant in Sweden. However, results from other studies indicated that the zinc recovery is also considerably decreased at high pulp temperatures, i.e., 62°C and above.

Sep 1, 2012

By Y. Q. He

The dynamic behaviors of the air bubbles in the dense gas-solid fluidized bed have a significant effect on the performance of dry coal separation. The combined method of experimental measurement and numerical simulation were conducted to conduct the research of the mean diameters and rising velocities of the bubbles in the fluidized bed. The calculation models of mean diameter and rising velocity of the single bubble were proposed. The results indicate that the models of the mean diameter raised by Rowe (1976) and the rising velocity raised in this work could be used to predict the bubble dynamic parameters in gas-solid fluidized bed. With the Geldart B type of magnetite powder as the medium solids and while the gas velocity of 1.5Umf=U=2.2Umf, the mean bubble diameter along the bed height is 36mm<Db<45mm, and the mean rising velocity of the single bubble is distributed in 40~65cm/s. The results of experimental measurement, numerical simulation and model predication provide well agreements finally. Based on the uniform fluctuations of air bubbles diameters and their rising velocities, the separation experiments of 50~6mm dry coal using the mixture of 0.3~0.15mm magnetite powder and <1mm fine coal as medium solids were carried out. The results show that the probable error, E is 0.06, which indicates a good separation performance by using the gas-solid fluidized bed. Keywords: dense gas-solid fluidized bed, bubble dynamic behaviors, numerical simulation, separation performance

Sep 1, 2012

By Jacqueline Satur, Yoshiaki Kon, Buenaventurada Calabia, Xiao Sheng Yang, Arvo Naumanen, Kenzo Sanematsu, Sayaka Morita, Tetsuichi Takagi

Granite ores are composed of silicate minerals and a variety of valuable REE (rare earth elements)-bearing minerals, however the processing technique to recover these valuable minerals is not yet developed. In this study, the recovery of REE-bearing minerals by dry magnetic separation and wet high intensity magnetic separation (WHIMS)-settling from surface sample and from drill core sample, respectively, of a granitic REE-Zr-Nb ore deposit was investigated. The two samples have different mineralogy however in both samples, light REE are commonly contained in REE carbonate minerals while Y and heavy REE are commonly contained in zirconium silicate minerals and pyrochlore. The liberation size of the REE-bearing minerals in the two samples ranges from 10-250 ?m. Previous flotation testwork conducted on the drill core sample reported high recoveries of La2O3 (88%) and Ce2O3 (88%) but low recoveries of Y2O3 (42%), ZrO2 (17%), and Nb2O5 (29%). The objective of this study was to obtain higher recoveries of Y2O3, ZrO2, and Nb2O5 by dry magnetic separation and WHIMS-settling. Both processes implemented the application of a low magnetic intensity to initially separate the ferromagnetic minerals then a high magnetic intensity to recover the REE-bearing minerals. The results showed higher recoveries of Y2O3, ZrO2, and Nb2O5 by dry magnetic separation and WHIMS-settling indicating the potential of magnetic separation and gravity separation in recovering the heavy REE-bearing minerals. WHIMS-settling is more recommendable than dry magnetic separation because of its applicability in treating a wider range of particle size. In the WHIMS-settling, the light REE, Y, and Zr minerals were recovered mainly by applying four stages at high magnetic intensity of 21,500 gauss while the weakly magnetic pyrochlore was recovered mainly by decantation of the nonmagnetic slurry after a short settling time of 0.25 to 0.50 h. (MAX.300 words)

Jan 1, 2014

By A. R. Hasankhoei

Water recycling is of prime importance in mineral processing due to consumption of large amount of water. This issue is vital in areas with a low rainfall such as Shahre-Babak (Kerman, Iran). Deep cone thickeners, unlike conventional thickeners, have a low diameter to height ratio where large amounts of flocculants are used to increase particles settling rates. The high bed heights (over 10 m) produce enough pressure to create a paste type underflow indicating maximum water recovery. Flocculent preparation, conditioning, and distribution along with the bed height are among the important factors affecting the performance. Four deep cones are used to recover water from the tailings of the plant. Plant data indicated that the thickener never reached the target underflow percent solids (63%) and the average underflow concentrations were between 49 and 57%. By modification and optimization of flocculent preparation and distribution methods the underflow percent solids increased by 3-4%. This translated to an increase of water recovery from 67 to 73%. This was equivalent of 53000 m3 saving in monthly water consumption. Keywords: deep cone thickener, water recovery, flocculant, copper tailings

Sep 1, 2012

By Z. M. Wang

A large scale a polymetallic mine in north China is a refractory ore containing many useful com-ponents: W, Mo, Cu and Fe. Mineralogical investigation shows that the deposit is a quite complex one due to fine disseminated size and unevenly distribution of valuable, intergroth of sulphide and tungsten minerals, concurrence of scheelite and calcium minerals. Based on ore characteristic, a flowsheet is used by the floatation processing of sulfide minerals superior to scheelite. Bulk sulphide flotation is used in sulphides. Mo and Cu are floated in sequence after sulphides regrinded. Tungsten mineral is floated using combined depressant that is an effective depressant to gangue, and can improve the grade of rough tungsten concentrate. Compound depressant has high effective in removal of collector in gangue and sulphide, and tungsten is activated also. High quality of tungsten concentrate is obtained at satisfactory recovery. The test production obtains Mo concentrate with grade of 48.16%, recovery of 81.43%; W concentrate with grade of 66.47%, recovery of 78.19%; Cu concentrate with grade of 23.14%, recovery of 56.6%; Fe concentrate with grade of 67.33%. The valuable metals are recovered comprehensively and well techno-economic index is obtained. The mine enterprise profit is increased greatly.

Jan 1, 2014

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 Antony Amberg, Gonzalo Saldías, Romke Kuyvenhoven, Catherine Souza, Heriban Soto, Francisco Soto

"Vizcachitas is an advanced stage copper–molybdenum porphyry deposit, fully owned by Los Andes Copper and located in Central Chile. The property contains an indicated resource of 1,038 million tonnes grading 0.37% Cu and 0.012% Mo, and an inferred resource of 318 million tonnes grading 0.345% Cu and 0.013% Mo (Coffey & Alquimia, 2014). The deposit occurs in the same geological belt as several other giant copper-molybdenum porphyry deposits including Río Blanco-Los Bronces, Los Pelambres-Pachon and El Teniente. In 2018, the original Preliminary Economic Assessment (PEA) study from 2014 was updated; this paper presents the geometallurgical testwork that was performed to support that update. The testwork focused on the metallurgical characterization of 40 DDH samples and the development of a more profound orebody knowledge by relating geological features with metallurgical performance. The scope of work included complete chemical and mineralogical QemSCAN characterization; SAG, ball mill and abrasion testing; complete rougher and cleaner kinetics including locked-cycle-test; environmental ABA and settling tests on rougher tailings. The results show that the ore can be classified as medium-hard, with a hardness that is slightly below the average for large Cu/Mo deposits in the region. A good correlation was found between lithology and breakage characteristics, implying that the specific energy consumption (kWh/t) is well correlated to rock type. The results of the flotation tests were very encouraging and did not show significant variability. An overall Cu recovery of 91% can be expected for the flotation circuit. The use of a relatively coarse primary grind size gave good final recovery and grade for both Cu and Mo, and deserves further attention in future work, as this impacts positively both energy consumption and water recovery.INTRODUCTION Los Andes Copper Ltd. is a Canadian exploration and development company focused on the acquisition, exploration and development of advanced stage copper deposits in Latin America. The company owns 100% of the Vizcachitas project in Chile, the largest copper deposit in the Americas not controlled by the majors. Vizcachitas is a copper-molybdenum porphyry deposit, located 120 km north of Santiago, in an area of very good infrastructure."

Jan 1, 2018

By S. F. Ye, L. Xiao, Y. L. Wang, P. W. Han

"Copper anode slime is a precious secondary source for the recovery of silver. However, current recovery process are constrained by either sever pollution or high cost. To cover the drawbacks of current process, this research employed a novel strategy by using the manganese dioxide as the oxidant in acid solution, which avoided the generation of sulfur dioxide while high silver extraction rate was achieved. The effects of manganese dioxide, sulfur acid concentration, stirring speed, temperature and leaching time on silver extraction rate were investigated. The silver recovery reached to 91.68% under the conditions of 1.2 g manganese, 2.0 mol/L H2SO4, 300 rpm, 80 °C and 6 h. INTRODUCTION Copper anode slime is generated from the electrolysis refining of copper and is extremely precious for its containing noble metal such as silver (Chatterjee, 1996; Amer, 2003; Yldrm et al., 2014; Syed, 2016; Wang et al., 2017). Therefore it is of great significance to extract silver from anode slime for the full utilization of resource. Pyrometallurgy is the most mature process for the extraction of silver because of its stability and adaptability (Hait et al., 2009; Zhao et al., 2010; Gao et al., 2017). However, it also suffers the drawbacks of high operating cost, low extraction rate of silver and severe pollution of smoke dust (usually containing lead and arsenic) (Ludvigsson and Larsson, 2003). To cover the drawbacks of pyrometallurgy process, more and more attentions are giving to the semi-hydrometallurgy process which usually includes a pretreatment process of sulphatising roast or low temperature oxidizing roasting (Tishchenko, 1964). After pretreatment, the refractory silver bearing phases (silver selenide, silver sulfide and silver) are converted into readily leached forms which are often extracted by ammonia, sodium sulfite in alkaline solution (Valiuniene et al., 2010; Wojciech, and Kitka, 2017). Despite its relatively high extraction rate and low investment, it still has the disadvantages of releasing harmful gases since the sulfur dioxide are generally generated in the pretreatment process. In addition, the use of ammonia can easily lead to a leaking into the atmosphere once not carefully dealt with (Aylmore and Muir, 2001). As for silver recovery by sulfite leaching, the consumption of sodium sulfite is rather high which often results in a pipe blocked (Yang et al., 2006)."

Jan 1, 2018

By J. Langwaldt

Ammonium-nitrate is a main component in blasting agents and dissolved ammonium residues may be discharged with mine water. The European Union aims to reach a good state of the water quality and recommends ammonium content below 0.5 mg/L for drinking water. Natural zeolites adsorb ammonium from water. In this work, the removal of low-concentration ammonium by commercial natural zeolites was studied in continuous tests. Natural zeolites made up between 83% and 95% of the mineral composition. The major zeolite minerals were chabazite and clinoptiolites and minor amounts of erionite and mordenite were as well present. The five natural zeolite samples, 500~710 µm, were conditioned to obtain zeolites in the Na-form. Ammonium adsorption onto natural zeolites depends mainly on the zeolite mineral type. The chabazite containing zeolite was superior over the four clinoptiolite samples for the removal of low concentrations of ammonium from water (pH of 7.5, flow 5 mL/min, room temperature). The adsorption capacity of chabazite was 48.3 mg NH4+/g zeolites, i.e. 73% of the theoretical exchange capacity 69 mg NH4+/g, during duration over 107 days and almost 6700 bed volumes exchanged. The four tested clinoptiolites had an ad-sorption capacity of 15.7mg to 25.0 mg NH4+/g zeolites. The natural zeolites were rapidly regenerated by an alkaline sodium chloride solution fed to the columns.

Jan 1, 2014

By X. Tan

In this paper, the application of the metallurgical residue produced from oceanic cobalt-rich crusts leaching process is studied in the area of wastewater treatment. The modification of the sulfuric acid leached residue and the adsorption behavior behaviour of heavy metal ions such as (Pb(II), Cu(II), Zn(II), Cd(II), Ni(II), Mn(II), Co(II), As(III)) in the waste-water on the surface of the residue are investigated. The rate of adsorption efficiency of heavy metal ions in the wastewater on the modified sulfuric acid leached residue is investigated. It is showed that when the initial pH value of wastewater containing heavy metal ions including Pb(II), Cu(II), Co(II), Ni(II), Mn(II), Zn(II), Cd(II) and As(III) range from 1.4 to 1.9, with the use of the modified leached residue, As(III) ion can be selectively separated from wastewater, and the separation efficiency can reach 90%~100%. The adsorption efficiency is affected by pH, reaction time, amount of adsorbent and the initial concentration of heavy metal ions in wastewater. The results showed that the optimum pH was natural pH value and the absorption equilibrium time was 2 hours. The adsorption efficiency of heavy metal ions increases with the addition of adsorbent and de- creases with the increase of the initial concentrations of heavy metal ions in wastewater. The heavy metal ions polluted wastewater, of which concentration is about 22.5~793.6 mg/L, can meet the national disposal standard for industrial wastewaters in China very well, after 2 hours treated by 3.75~7.50 g/L modified adsorbent at room temperature. Standard methods were used to investaged investigate the absorption behaviour between abosorbentabsorbent and metal ions in the wastewater. It is concluded that the adsorption behaviour of Co(II), Mn(II) and As(III) ion fits Freundlich iso-therm, while the adsorption behaviour of Pb(II), Cu(II), Zn(II), Cd(II) and Ni(II) ions fits Langmuir isotherm, and the saturated adsorption amount of the modified adsorbent is about 54.0~336.7mg metal/g?adsorbentabsorbent. It is suggested that the modified sulfuric acid leached residue produced from oceanic cobalt-rich crusts is environmentally attractive and meaningful as absorbent used in heavy metal ions polluted wastewater.

Jan 1, 2014

By F. Q. Cheng

Despite the successful industrial practice to recovery KCl by flotation, the adsorption state of collectors at KCl salt surfaces is still not fully understood. In this paper, the captive bubble contact angle measurements at KCl and NaCl crystal surfaces in their saturated solutions are reported. The influence of different collectors and their concentration are considered. The results show that both cationic and anionic collectors produce a hydrophobic state at the structure breaking KCl salt sur-face, with finite contact angle values of between 30o and 40o. In contrast, the contact angle at the structure making NaCl salt surface is zero at all collector concentrations, suggesting that no collec-tor adsorption occurs, a supposition that is supported by results from molecular dynamics simulation (MDS). Further, it appears that the presence of surface defects such as edges and corners promote the adsorption of collectors at the KCl surface, and that the flotation is achieved by bubble attachment at the edges/corners of KCl particles with the formation of aeroflocs.

Jan 1, 2014

By Y. F. Li

Fengning ilmenite ore is a magnetic deposit in gabbro containing high phosphorus and low titanium, the main minerals in which are ilmenite, magnetite and apatite. The dissemination size of magnetite is so fine that even the percentage of -0.010mm level is up to 36.50%. The fine and vein magnetite are distributed in gangue and ilmenite, so the majority of the magnetite is difficult to be separated from the gangue. Ilmenite is difficult to be recovered by low-intensity magnetic separation even through fine grinding. In high-intensity magnetic separation of ilmenite, the gangue inter-growth with the magnetite and the Fe-containing silicates may be enriched in the concentrate, and the ilmenite of the concentrate will be reduced. Based on the processing mineralogy research, combined gravity-flotation process is suggested to recover the ilmenite. The method is also good to reduce phosphorus in the ilmenite concentrate.

Jan 1, 2014

By Montaser S. EL Salmawy, Takahide Wakamatsu, Eishi Kusaka

"The effect of ethoxylation of long chain alcohols on the quartz and feldspar flotation behaviors was investigated for surfactants of the octylphenol polyoxyethylene family. The tests were carried out with an average of 7.5 (Triton X 114), 9.5 (Triton X 100), 30 (Triton X305), 40 (Triton X 405) and 70 (TritonX 705) oxyethylene units. Electrokinetic and flotation studies on quartz have shown that at low pH values, quartz could be floated with polyoxyethylene octytlphenols. The possible mode of adsorption of these nonionic surfactants may be suggested to be due to hydrogen bonding between the oxygen of ether and hydrogen in the free hydroxyl groups on quartz surface. It was anticipated that the selectivity between quartz and microcline would decrease as oxyethylenic chain length increases.Electrokinetic methods were used to elucidate the mechanism of surfactants adsorption and to correlate these findings with the optimum flotation conditions. The polymeric surfactants would reduce the negative values of zeta potential of quartz while the reverse is true for feldspar. After treatment of microcline with HCl, its electrokinetic behavior in the presence of Tritons X surfactants became similar to that of quartz.The obtained results would suggest that separation of quartz from feldspar using nonionic surfactants of octylphenoletoxylated alcohols having shorter oxyethylenic chain length at low pH could be achieved"

Jan 1, 2003