Search Documents

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 Y. S. Li

The life cycle assessment method is applied to investigate the environmental impacts of cop-per-slag and copper-ore concentration process. Some environmental load data of copper production are obtained. The result indicates that damage level of human health, ecosystem quality and re-sources respectively is 0.174, 0.0203, 0.246 in the copper-slag concentration and 0.112, 0.0136, 0.299 in the copper-ore concentration. Environmental impact of copper-slag production (0.44) is more than that of copper-ore production (0.42), but can meet the environmental protect demand. With domestic copper concentrate supply gap enlarging, recovering copper from slag will lead to a significant improving of resource utilization and development of circulation economics.

Jan 1, 2014

By Y. P. Lu

PET/kaolin nanocomposites were prepared with melt blending and the structure of the composites was characterized through IR techniques. The results showed that there is stable chemical bonding between PET and kaolin. In addition, the dispersion condition of nanokaolin was observed by means of SEM and TEM. As a result, the thickness of the dispersed nanokaolin particles in PET matrix is mainly from 20mm to 200nm, and the nanosized particles congregate to some extent in the samples. In addition, it was found the kaolin particles almost homogeneously dispersed in the PET matrix, without preferential orientation because of the shear effect due to melt blending. Furthermore, the mechanical properties of PET/kaolin nanocomposites are dependent on the modification efficiency of nanokaolin. With the poor efficiency, the nanokaolin particles tend to aggregate at a high content and have a bad interfacial compability between nanokaolin and PET matrix, which lead to stress concentration, so the mechanical property descends. Experiments of different contents of modified nanokalin indicated that the intensity of PET/kaolin nanocomposites decreased firstly, then increased, and then decreased, with the nanokaolin content of 4 to 5 percent, the rupture stress of the composites showed a maximum value, which was higher than that of pure PET. On one hand, nanokaolin decreases the function among PET macromolecules, which will decline the mechanical properties, on the other hand, the piece structure of kaolinite improves the intensity of the nanocomposite. When the nanokaolin content is low, the former has the dominant effect on mechanical property, while the latter will play a leading role with the content increasing. But if the nanokaolin content still increases, the agglomeration and stress concentration will be obvious.

Jan 1, 2014

By Evgeni Visariev

In Copper smelter Aurubis Bulgaria, the copper in slag from the Flash furnace and the Converters is recovered by flotation. The scheme of slag processing is crushing, two stage grinding (autogenous and ball) and flotation. Till 2010 the grinding cycle in the plant was in two stages ? the first stage was AG Mill 70?23 working with a classifier and the second stage was ball mill 3.6/5.5 working with a hydrocyclone. In 2010 a new AG Mill 65x78 with hydrocyclone was put in operation in order to increase throughput of the plant. The second stage of the grinding cycle is with the same ball mill. The Old AG mill processed 55-60 t/h slag with particle size -0.071 mm 75% or over 75 t/h with particle size -0.071 mm 35-40 %. The new AG Mill was designed for throughput 105 t/h with particle size -0.071 mm over 70 %. After the start up there were some problems with the equipment ? block up of AG Mill?s grate and pumps for feeding of the hydrocyclone. For optimization of the process a lot of general tests were made. One of the main problem was a wearing of the sand nozzles. Different materials (rubber, ceramic, metallic) for the sand nozzles were tested. The openings of the grate were changed. This paper presents: ? the optimal technological parameters of the old and the new working scheme; ? how the technological parameters of the new working scheme change when the hydrocyclone works with different nozzles; ? the effect of the change of the grate openings; ? the problems with the increase of the circulating load; ? a final decisions for improvement of the grinding cycle work. Keywords: spigot, wearing, classification, effectiveness, circulating load, autogenous, mill

Sep 1, 2012

By Zhang Zhonghan

A domestic tungsten-tin ore presents very complex property. How to effectively recover the scheelite, wolframite and cassiterite in the ore has long been a difficult problem to be solved urgently. On the basis of process mineralogy study, a main flow-sheet for effective recovery of tungsten-tin minerals has been developed, which including ?fine grinding of feed?bulk flotation of all sulfides followed by their selective separation?iron recovery by LIMS?tungsten-tin minerals bulk flotation using new technique developed by our institute?tungsten-tin recovery by gravity from above tungsten-tin bulk flotation tailings?. As for the treatment of tungsten-tin bulk rougher concentrate, several flow-sheets of tungsten-tin separation by direct hydrometallurgy or a flow-sheet consisting of scheelite cleaning at elevated temperature followed by the gravity separation of scheelite cleaner tailing?separation of wolframite from cassiterite by dry HIMS or by direct hydrometallurgy are developed. For a low grade head ore, all valuable sulfide, magnetite, scheelite, wolframite and cassiterite are recovered with satisfactory in lab scale test. Keywords: micro-fine cassiterite, tungsten-tin bulk flotation, gravity separation-flotation-dry HIMS combined flow-sheet, hydrometallurgy

Sep 1, 2012

By M. Bergerman

Sossego was the first Vale SAG mill operation to process copper-gold ore. It is located in Para state, south east of Amazon region in Brazil. The comminution circuit was designed to treat 41 000 metric tons per day comprising primary crushing, one 11.6 m SAG mill operating in closed configuration with cone crushers, followed by two 6.7 ball mills. In the first three years of continuous operation Vale investigated alternatives for obtained improved performance of the circuit by investigating operating conditions, mainly focusing on SAG mill. A number of actions were then implemented, which resulted in significant increase in overall production. Vale then decided to further assess the performance of the comminution circuit as a function of ore characteristics. A comprehensive ore characterization program was then conducted, together with the calibration of mathematical models on the basis of surveys carried out at the industrial circuit. The simulator was then used to predict the production level associated to each ore type, as well as to establish the optimized circuit configuration and tailored operating conditions. The ongoing validation program is planned to consolidate the selected strategy, as well as showing the benefits in adopting such indices in mine planning, as opposed to rather simplistic approaches. This paper describes in detail the main aspects of optimizing the industrial circuit performance, as well as the successful method for predicting the production as a function of ore characteristics.

Jan 1, 2014

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

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

Jan 1, 2018

By E. Isokangas

The production of minerals for economic use is a two-stage process, involving mining to extract the mineral from the ground, and processing to convert the mineral into a marketable product. Generally, mining and processing have been viewed as self-contained entities. Both have separate objectives, separate cost centres and key performance indicators (KPIs) that do not reflect the customer/supplier relationships that inherently exist. However, mining and processing operations are inter-connected and therefore intimately inter-related with the performance of one operation affecting the performance of another. Optimizing each stage separately without considering the whole system often misses potential economic benefits and energy savings. During the past fifteen years, the authors have been involved in implementing a holistic methodology ?Mine to Mill Process Integration and Optimisation (Mine to Mill PIO)? to maximize the overall profitability of the operation rather than just optimizing any individual process in a mining operation. Metso Process Technology and Innovation (PTI), along with their project partners, have conducted several projects to significantly increase their production- generating typically 5% to 20% higher throughput and improve the overall mine and concentrator performance through PIO methodology. This proven methodology has applications ranging from greenfield projects to long-standing operations with AG/SAG, HPGR or conventional grinding circuits. This paper explains the Mine to Mill PIO methodology and discusses the benefits of such an approach on the energy consumption, the overall costs and benefits of mining operations. The paper also summarizes several case studies illustrating the use of PTI methodology in a variety of applications. Keywords: integration, optimization, simulation, modeling, mine-to-mill, comminution, blast, drill, crushing, grinding

Sep 1, 2012

By Susanna G. de Jager, Francis W. Petersen

"The aim of the project was to develop a methodology applicable to different South African coal types to be able to predict with a high degree of certainty what kind of reagent will be suitable for flotation of a certain coal type.The study included 5 coal samples from different collieries and included Highveld seam 3 and 4 coal (as one sample), Waterberg coal (zone 10 -11), Highveld seam 5 upper coal and Witbank seam 2 and seam 4 coal. Seam 3 and 4 (mixture) coal, Waterberg and the seam 5 upper coal were all found to be vitrinite rich coals. The coal characterisation study included petrographic analysis, proximate analysis, float-sink analysis, oxygen-containing functional groups, surface extraction, flotation release analysis and contact angle measurements.The flotation tests showed that the best reagents to float all of the coal samples studied are iso-decanol and dodecene. These reagents produced flotation products that are near to the release curve. Statistical relationship for predicting ash content and yield that can be expected for a certain coal type and selected collector was obtained. From the relationship, the accuracy of the yield is above 95% (p-value below 0.05) with a linear regression of 0.9289. The accuracy of the ash is slightly lower with a linear regression of 0.7841 but also above 95%."

Jan 1, 2003

By Y. H. Tang, H. Y. Zhang

"Tailings from lead-zinc mine contain plenty of dolomite and low-grade fine-grained barite, which is difficult to enrich by mineral processing. Since the density of barite and dolomite has some differences due to the fine dissemination size in a complex sedimentary, the gravity separation tests were conducted with no results obtained. The magnetic separation was conducted to remove the magnetic gangues, and the results were not satisfactory because of the gangue minerals such as limonite and others were low in content. The results of floatation tests showed that the mineral separation of barite and dolomite is quite difficult because that they have similar mineral floatability. Experimental research shows that the good results can be obtained by “desulfurizationbarite floatation” processing with the new depressant TS. The barite concentrate containing BaSO4 91.27%, BaSO4recovery is 70.25% when sodium dodecyl sulfonate serves as a collector and TS as the depressant.INTRODUCTIONBarite is an important mineral material. Often associated with other minerals, it usually needs to be separated by mineral processing in order to meet the application requirements. The main barite beneficiation methods include hand sorting, gravity separation, floatation, magnetic separation, acid leaching, etc. Usually barite associated with oxide ore such as fluorite dolomite, quartz ore etc. are also associated with sulfide ore such as pyrite, sphalerite and galena. The separation between barite and sulfide ore (such as pyrite) is easy. On the other hand, the separation between barite and oxide ore (such as dolomite and fluorite) is very difficult. There are quite a lot of reports on the separation between barite with fluorite dolomite however the separation between barite and dolomite is seldom discussed.The ore properties are quite complex attributable to mineral assemblage containing a large amounts of dolomite. As the density of barite and dolomite has some differences, gravity separation between them is usually easy. The gravity separation tests were conducted with no results obtained due to the fine dissemination size in a complex sedimentary. The magnetic separation was conducted to remove the magnetic gangues, and the results are not satisfactory as the gangue minerals such as limonite and others were low in content. Due to the fine dissemination and intimate association of minerals, and barite and dolomite contain the same group ions of Ba2+, Ca2+ and Mg2+, the results of flotation tests showed that the mineral separation between barite and dolomite by flotation means problematic. Previous studies have been conducted by several institutions but none to date has come up with a satisfactory process in dealing with the deposit. This may be attributable to: high cost of reagents; unsatisfactory performance. Therefore, the key to the flotation separation of barite and dolomite is the application of selective inhibitors. Based on previous test observations and years of extensive research experience in barite processing technology, with the new depressant TS has selectivity inhibition on dolomite developed and used, good results can be obtained by “desulfurization-barite flotation”, which allows barite in the lead-zinc tailings to a comprehensive recovery."

Jan 1, 2018

By H. L. Liu

With the exploitation of mineral resources, valuable minerals are more and more finer and poorer. Priority reclaiming liberation grind particle under rough grinding, will help to pervert loss of melts, raise dewatering efficiency of concentrate, reduce consumption of reagent. And it is propitious to reduce energy consumption and raise the utilization rate of resources. With the feature of coarse particle?s desorption and deposition, CLF flotation machine has special pulp circulating way, which is not only apply to treat coarse particle but also normal size particle. The paper advanced the history, the design principle, the structure feature and the application of CLF flotation machine.

Jan 1, 2014

By Danfeng Xu

The majority of the world?s nickel (Ni) resources occur as laterite ores, which are exceptionally complex, lower grade (<1.5% Ni) and expensive to treat using conventional smelting and high temperature/pressure autoclave methods. Heap leaching is a promising, less costly, alternative technology for processing low grade nickel laterite ores. However, significant technical challenges remain with Nickel laterite heap leaching, preventing its general adoption. This paper presents some highlights of laboratory column leaching studies undertaken to characterise, evaluate and optimise sulphuric acid leaching behaviour of Nickel laterite agglomerates. They provide basic but valuable information regarding Nickel laterite agglomerate structure stability and leaching performance under industrially-relevant, continuous acid irrigation conditions. In particular, Nickel and other key metals? (e.g. Co, Fe, Al and Mn) extraction rates, free acid concentration, bed slump and structural changes were determined at a given acid percolation rate as a function of time. Potential implications of the findings, for devising strategies for improved Nickel laterite plant heap leach operations are discussed. Keywords: nickel laterite, column leaching, agglomerates, leaching kinetics, acid consumption

Sep 1, 2012

By Jianjun Tian, Changjiu Zhang, Chunmin Wang

Two lines of single stage autogenous milling circuits have been installed and commissioned as the primary grinding process for the Sino Iron project where magnetite ore is treated to produce iron concentrate via magnetic separation. Various challenges were encountered during the commissioning and ramp up stages which are discussed in the paper and include treating a highly competent ore in a closed circuit AG mill, operating the largest mills in the world and dealing with a number of engineering issues related to plant operability. Details of how these challenges were overcome are described as well as the observed operating characteristics of the mills and their optimisation through rigorous study, simulation and successful solution implementation. Further potential improvement opportunities are also discussed as part of the ongoing technical program at site.

Jan 1, 2014

By Z. D. Tan

The continuous digestion technological conditions of phosphate tailings with high magnesium content in sulfuric and phosphoric mixed acid is studied in this paper. The influences of excess coefficient of sulfuric acid, weight liquid to solid, reaction temperature and time on conversion of P2O5 and MgO are discussed. The influence of infiltration capacity of phosphogypsum by the concentration of liquid-phase SO3 is discussed too. Under the optimal technological conditions, the conversion of P2O5 is 95.56% and MgO 98.63%, the filtration rate of phosphogypsum increases with the increasing of liquid-phase concentration of SO3, the optimal apparent concentration of SO3 is 0.135~0.14g? mL-1 in liquid-phase. The filtration rate of phosphogypsum is 1473kg? m-2? h-1. N-P-Mg compound fertilizer was produced by adding magnesia powder and inflating ammonia in filtering medium.

Jan 1, 2014

Rotor speed is one of the key hydrodynamic parameters in froth-flotation and it plays an important role in bubble-particle attachment. Laboratory scale studies for optimizing the rotor speed to achieve maximum flotation rate constant (K) of quartz, ground by ball mill, are. Purity of quartz was 99.4 percent and d80 of ball mill product was 230 µm. Each size fraction was separately subjected to flotation at three different rotor speeds, namely, 1200, 1000 and 800 rpm, and the flotation rate constant was calculated. The results showed that the flotation rate constant was high at the rotor speed of 1200 rpm. The flotation rate constants achieved at 1200 rpm were 8.676, 8.232, 7.818, 7.248, 7.068 and 6.984 min-1forthesize fractions of +300, -300+250, -250+212, -180+150, -150+125 and -125+106 µm, respectively. Keywords: froth flotation, rotor speed, flotation rate constant, ball mill, quartz

Sep 1, 2012

By J. T. Liu

Packing in a flotation column is one way to increase separation efficiency and effective descending flotation-column height. In this paper, the difference between filling packing and sieve packing is described, and the flaws of filling packing in flotation columns in industrial application are pointed out. A change of flotation process and its effect on flotation results are reported. Based on sieve-plate filling, a high-efficiency mixed packing mode consisting of screen-plate packing and honeycomb-tube packing has been proposed, with the packing mode optimized in the cyclonic static microbubble flotation column in the separation zone. In the mixed packing mode, the honeycomb tubes are used to reduce the vortex effect at the base of the column and weaken the radial dispersion of jetting bubbles, and the sieve plates are used to comminute bubbles in the separation zone, to lengthen the bubble migration path, and to stabilize the foam layer. The superiority of honeycomb-tube packing is analyzed using bubble-particle collision theory, and the dynamic equations of collision probability are derived. The role of mixed packing in guaranteeing mineral recovery is analyzed by the axial dispersion method, and a dimensionless axial dispersion model is derived. When a high-turbulence flow is maintained, a static separation environment is formed in which secondary mineral processing is rendered more effective. In this way, a nonlinear separation environment is formed in the flotation column. Finally, mixed packing was applied in an industrial test. A large vortex developed at the base of the column. It was observed that the bubbles in the radial flow were homogeneously dispersed, the residence time of the pulp was prolonged, and the froth layer became thick and stable. Based on the test data, it was found that the sieve packing has the potential to yield a product of approximately 25.83% copper concentration with 91.78% recovery from a feed concentration of approximately 0.727%. If mixed packing were used, the product concentration could be further increased to 27.60% from a feed of approximately 0.739% concentration with 93.38% recovery.

Jan 1, 2014

By A. S. Choudhary

Most of the coal reserves in India are of drift origin and have very poor washability characteristics and a high level of near gravity materials. At least 30 new coal wash plants are expected to be set up in the next 5years.In such a scenario, adequate sampling followed by sink float test work for washability analysis becomes very critical for designing these new plants. For coal sampling purpose, stipulations of different standards are sometimes formidable and on the border of ?impracticality?; sometimes are self contradictory in terms of gross sample weight vis-a-vis minimum number of particles required in each size fraction and in each relative density fraction and also the minimum mass in the latter. Validation of the generated data is another important aspect of washability analysis. These issues can easily be addressed by using straight forward mathematical relationships, well known RR plots and by using simple MS Excel tool, etc.

Sep 1, 2012

By V. G. Minenko, V. A. Chanturiya, A. L. Samusev

Eudialyte is one of perspective resources of zirconium and other rare earth elements (REEs). Large reserves of eudialyte concentrated in the Murmansk region of the Russian Federation. Usually, technologies of REE treatment include the decomposition of eudialyte concentrate in different acidic, extraction and utilization of all components. The main problems in the leaching of eudialyte include are: the formation of an unfiltered silicon-containing gel; low recovery of REE; difficulty extraction of metals from the productive solution; high aggressiveness of the reagents. One of the promising trends of intensification of the processing of hard-to-degrease rare metal raw materials is the use of energy methods for affecting mineral suspensions. These methods make it possible to increase the efficiency of break up fine-dispersed mineral complexes and extracting micro- and nanoparticles of a valuable component in subsequent deep processing. The purpose of this work is to investigate the effect of energy impacts on the nitric acid leaching of eudialyte concentrate. Experimental studies were carried out in a developed laboratory facility that makes it possible to evaluate the effect of electrochemical, ultrasonic and combined effects on the leaching of zirconium and REE from eudialyte concentrate. The studies carried out on the samples of eudialyte concentrate with the size class of -0.315 + 0.063 mm showed that the use of electrochemical and acoustic effects increases the extraction of ZrO2 in the production solution in 1.6 - 2.5 times, REE in 1.3 - 2.2 times, respectively. An analysis of the microstructure and phase composition of the surface of the eudialyte concentrate showed that the intensification of the leaching process is due to surface cleaning from the silicon-containing gel, as well as the opening of capillary channels and microcracks, which accelerates mass-transfer processes. The results obtained open wide opportunities for creation of modern and effective technology of processing of eudialyte concentrate, producing high-quality zirconium products and REE.

Jan 1, 2018

By J. W. Ahn

Calcined calcium oxide from limestone is hydrated to manufacture calcium hydroxide, and then precipitated calcium carbonate is synthesized from calcium hydroxide. Precipitated calcium carbonate of various morphologies is obtained by controlled conditions of each step and characteristics of limestone, calcium oxide and calcium hydroxide. Especially characteristics of calcium hydroxide have the most influence on morphology of precipitated calcium carbonate character. In this study, therefore, it is investigated the specific surface area of calcium hydroxide and morphology of precipitated calcium carbonate according to hydration temperature. Calcium hydroxide hydrated at high initial temperature has larger particle size than that hydrated at low initial temperature. And formation yield of aragonite precipitated calcium carbonate has improved by using calcium hydroxide had larger particle size (hydrated at high initial temperature).

Jan 1, 2014

By G. Voiloshnikov, A. Bogudlova

"The deleterious effect of carbonaceous matter during cyanidation of gold ores (so called preg-robbing) has been recognized for many years. Based on this, a new method using flotation to reduce the content of carbonaceous matter was developed. Low-sulfide gold-bearing ore with carbonaceous matter of 0.14% from a Russian deposit was processed. The purpose of these tests was to compare two flow sheet options. Option I comprised removal of carbonaceous product prior to sulfide flotation. Option II comprised removal of carbonaceous matter from flotation concentrate. It was found that the content of carbonaceous material can be reduced in sulfide gold-bearing concentrate prior to leaching. High gold recovery was observed during the separation of carbonaceous material prior to sulfide flotation using Option I. Due to lower reagent consumption the costs for reagents were decreased using Option II. The results have shown the effectiveness of a new method. Patent No. 2783808 was obtained for removal of carbonaceous material prior to sulfide flotation. This information will be used to design a large processing plant flow sheet in Russia."

Jan 1, 2014