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By M. Pischtschan, S. Belz, M. Perrucci

In High Pressure Grinding Rolls (HPGR), the material grinding takes place between the fixed and floating rollers. In this regard, the rollers start to wear over a period of time, which is impacted by for e.g.: ore characteristics, operating pressure, feed material size and non-uniform feed presentation across the roller width. HPGR operational experiences have shown that the rollers do not wear at the same rate. This differential wear rate over time leads to differences in the tangential speeds of the rollers, causing an uneven gap between the fixed and floating rollers in relation to the material. This unwanted but extremely common situation results in a less effective grinding process due to the fact that the slip between rollers is not optimal. As the rollers wear profile increases, the roller with smaller diameter starts to wear further, deteriorating the comminution efficiency up to a point where operators have to stop the HPGR to replace the rollers. Since the wear rate of the rollers is not equal, the replacement of the same cannot be properly planned so that their life-time are fully utilized. In this paper, a dynamic load share control with the use of ABB’s variable speed drive system is proposed, which provides the possibility to the HPGR operator to impact the roller wear in such a way that it equalizes the wear rate to a certain extent and extends the roller life time. Called RollXtend™, this solution includes a load share factor which can be parameterized based on the wear measurement performed manually during maintenance procedure. Additionally, this paper describes an automated load sharing concept based on a non-invasive wear measurement method. The partial results of the technology trial in a copper/gold mine are presented, which aimed at detecting stud damage and estimating the real rollers profile throughout their life time. The final objective of the pilot project was reduce the amount of planned and unplanned downtimes of the HPGR by increasing the rollers life time and avoiding catastrophic stud damages.

Jan 1, 2018

By Lina Chica, Arturo Barrientos, O. Bustamante

Hydrocyclone is a device commonly used in mineral processing industry. Underflow control plays a fundamental role in hydrocyclone operation. This affirmation supports the fact that hydrocyclone underflow has effect in some aspects of separation performance like capacity, split ratio, cut size and bypass. Hydrocyclone operation state is associated to underflow characteristics: air core formation and discharge shape. Many studies attempt to understand size separation phenomenon and the discharge influence but none of them has taken an energy point of view. This work presents the results of a mechanical energy dissipation for hydrocyclone operation from a mechanical energy balance. The experimental results related to Newtonian suspensions show that underflow energy dissipation does not control the operation because this magnitude is small compared to interior energy dissipation. However, discharge energy dissipation provides enough information to describe underflow conditions and its influence in separation conditions. In the modelling non dimensional parameters have been considered for hydrodynamic description and for geometrical and operation hydrocyclone characteristics. Energy dissipation from the continua media approximation results into a relevant concept to understand the hydrocyclone performance and improve industrial installations.

Jan 1, 2014

By Paul W. Cleary

"Particle scale simulation of industrial particle flows using DEM (Discrete Element Method) offers the opportunity for better understanding the flow dynamics leading to improvements in equipment design and operation that can potentially lead to large increases in efficiency, throughput or product quality. DEM has been used for modelling many industrial applications, particularly milling. This includes ball and rock motions and power consumption in ball mills, AG and SAG mills, vibrational segregation, flows in rotating drums, operation of dragline excavators and hopper flows. In mineral processing, DEM has been concentrated on mills because of their critical importance. However DEM also offers the opportunity to improve many other parts of mineral processing operations. These areas often do not receive the attention that the key comminution equipment commands, but can become critical when they fail or under-perform. Importantly their assessment/improvement using DEM is often much more feasible because of smaller problem sizes and the absence of poorly understood physics such as breakage. In this paper we describe DEM simulations of four important pieces of non-comminution equipment that are commonly found in or near mineral processing plants (these are shown in Figure 1):"

Jan 1, 2003

By Mike Daniel, Eric Wang

"Several new large copper and gold concentrators have been built and commissioned around the world in the past five to eight years. The success of the ramp-up from these very large concentrators has varied. CITIC SMCC Process Technology was engaged to assist some of these mines by gaining a better understanding of the factors that influence throughput capacity. As such, site-specific throughput forecast models that are influenced by SAG mill performance were developed. The forecast models are easy to interpret and modify and can greatly assist the mine management to make predictions and informed decisions for a range of site improvements. The models investigate the influence of SAG mill performance with respect to ore competency, derived from SMC Test® via the measured DWi model parameter. In some cases the benefits of blasting and from fine tuning milling operations are already incorporated into the "site-specific" forecast models. The methodology follows rigorous plant data analysis that is analogous to a "Mine-to-Mill®" optimisation project. The CITIC-SMCC model validation includes extensive data collection, which includes drill core analysis, ore characterisation and comprehensive comminution circuit operational data to assess the limitations within the comminution circuit within the operating mine. The results and models may be used to define the operating base lines of the processing areas and identify improvement opportunities upstream and downstream of the comminution circuit. The predictive capability of the models use logged production data and has enabled the user to differentiate between alternative circuit configuration options and identify optimum operating conditions. This approach minimises the ongoing requirement for costly plant surveys. The improvement strategy for each site, included the ongoing measurement of grindability, rock strength and via the Bond and SMC Test® respectively. Some commentary as to what other practitioners do with input data and their models is also presented as this highlights some of their shortcomings relative to the CITIC-SMCC methods."

Jan 1, 2014

By J. R. Cui

The production of electric and electronic equipment (EEE) is one of the fastest growing areas. This development has resulted in an increase of waste electric and electronic equipment (WEEE). In view of the environmental problems involved in the management of WEEE, many counties and organizations have drafted national legislation to improve the reuse, recycling and other forms of recovery of such wastes so as to reduce disposal. Recycling of WEEE is an important subject not only from the point of waste treatment but also from the recovery of valuable materials. Consumer electronic equipment (brown goods), such as television sets (TV), radio sets, and video recorders, are most common. However, recent work on recycling of waste electric and electronic equipment (WEEE) primarily focused on personal computer and printed circuit boards scraps. Based on a detailed characterization study of consumer electronic scraps, recycling of TV scraps oriented to recovery of metals is highlighted by utilizing air table separation, eddy current separation, and optical (metal) sorting process. The result indicates that a high recovery of copper could be obtained by utilizing an effective gravity separation process. The separation results reveal that air table separation is an effective technology to recover metals from consumer electronic scraps. By using a DGS table, approximately 90% of non-ferrous metals were recovered in the heavy product with a purity of 40%. Printed circuit boards and cables in TV scrap cause metals loss due to the fact that metals in printed circuit boards and cables are not liberated from plastics and ceramic materials. The study shows that eddy current separation and optical (metal) sorting process provide alternatives for recovery of metals from shredded TV scraps.

Jan 1, 2014

By Liang Dianyin

In this paper, the molybdenite flotation tailing of cleaner-scavenger bank which has a mass of very fine particles has been taken as raw ore to be processed by flotation with/without ultrasonic. The effect of ultrasonic frequency, intensity, processing time and uploading location on molybdenite flotation efficiency is investigated by four-factor three-level orthogonal experiment, and the effect significances of these ultrasonic variables to molybdenite flotation efficiency have also been evaluated. Single-factor analysis of variance is conducted to investigate whether the effect of ultrasonic on molybdenum ore flotation efficiency is significant or not. The samples extracted from different ore species in different time have been mixed to analyze the particle size. The results show that the particle size of +38µm in concentrate obviously increases while the particle size of -25µmobviouslydecreaseswith ultrasonic, which means that ultrasonic is good for flotation due to sludge removing effect. Keywords: ultrasonic, flotation efficiency, sulfide ore, tailing, grade, sludge removing

Sep 1, 2012

By D. Saramak

"High-pressure grinding technology is considered as one of the most efficient techniques of ore comminution, especially in terms of energy consumption. HPGR devices has been utilized in many mining-related industrial sectors, including iron and non-ferrous metal ores processing (copper, platinum, gold), as well as cement and limestone flour production. Even though the technology well known (introduced into mineral processing circuits in 80’s), there are still examples of ineffective operation of HPGR devices. This is a result of improper application of HPGR into individual crushing circuit. The purpose of the paper was to analyze selected effects achieved in HPGR on the course and effectiveness of beneficiation operations. Investigations were carried out for copper ore, and investigative programme was run for different values of HPGR pressing force, as well as changeable ore characteristics (content of fine size fractions, material moisture). All crushing products were then treated in flotation process, in order to determine useful mineral recovery. Results of investigations show that HPGR operating pressure influences the metal recovery in proportional way, however too extensive pressure values have relatively lower impact on increasing of the metal recovery. Particle size distribution of HPGR feed and its moisture have lower influence on recovery level than HPGR pressure, but too extensive moisture content influences the higher energy consumption of the roller press, together with less effective comminution. The second aspect raised in the paper was a possibility to control and optimize the HPGR-based circuit. There were presented the proposed approach to adjustment of HPGR operating parameters that enables the higher metal recovery.INTRODUCTION The high-pressure grinding technology, invented and developed by Professor Schoenert in 70’s (Schoenert, 1979), is currently regarded as one of the most efficient methods of hard ore comminution. Since then the technology was introduced into raw materials treatment circuits in many mining and mining-related industrial sectors, including iron and non-ferrous metal ores processing (copper, platinum, gold), as well as cement and limestone flour production. Considerable number of works concerning modeling and optimization of HPGR operation were also presented (Daniel & Morell, 2004, Tavares, 2005, Saramak, 2012, Saramak & Kleiv, 2013). Nowadays high-pressure grinding rolls devices are considered as well know technology with over 500 sold machines, according to various sources."

Jan 1, 2018

By I. V. Makarskii, D. N. Nikitin, L. G. Tarasova

"The extent and nature of the damage to diamonds at processing plant is largely determined by the design features of the equipment, the characteristics of the feed ore and the parameters of the ore disintegration process (change in the rotational speed of the autogenous mills, variations of the water supply to comminution process, choice of the optimum charge, etc.). To monitor the intactness of diamonds, an instrumental method using the X-ray tomography system and colored synthetic indicator diamonds was developed for identifying the process-related damage. The X-ray tomography system consists of a CT-Portable X-ray tomographic scanner, a crystal positioning device and customized software (developed by the Fraunhofer Institute and Aliud GmbH, Germany). The developed method enables improvement of the accuracy of the results, exclusion of the subjectivity of the mineralogical assessment, acceleration of data processing and promptly planning of the activities aimed at reducing the process-related damage to diamonds. KEYWORDS Diamonds, colored indicator diamonds, process-related damage, loss of mass, instrumental method, X-ray tomography system. INTRODUCTION Industrial tests of ore processing technology at the enterprises of ALROSA PJSC are accompanied by assessment of the process-related damage to diamonds. The assessment of the process-related damage to crystals is carried out for prompt elimination of factors contributing to the increase of impact forces in the process flow sheet of ore treatment plant. For this purpose a specially selected parcel of -4.0 + 2.0 mm sized natural indicator diamonds is used. The diamonds are exposed to ionizing radiation in order to turn them green and thus to create a distinctive feature. Colored natural indicator diamonds are described, photographed in several views and introduced into the process flow sheet of the processing plant, then extracted from the process flow, described and photographed again. The comparison of diamonds before and after their passing through the process flow sheet of the plant allows to find evidence of process-related impact on the crystal and to calculate the factor of process-related damage (the number of crystals damaged during liberation and recovery), the loss of crystal weight and the degree of damage to the crystals. The method of colored indicator diamonds is used to select processing methods, equipment or regime which would be the safest for diamonds based on the analysis of the factors of process-related damage. There are limitations of the method, such as:"

Jan 1, 2018

By Lei Zhang, Xianjun Lu1, Minjie Lian, Liyang Zheng

In order to investigate rheological behaviour of fine tailings backfill pastes, the fine iron ore tailings (size fraction of -0.074mm accounts for 70%) from Fuquan Mining Co., Ltd. of Sinosteel Corporation (Shandong, China) was investigated. The rheological parameters such as slump, viscosity and yield stress of the tailings pastes under different densities were measured in detail, and the effect of paste density on the rheological property and the relationships of different rheological parameters of the pastes were also discussed. According to the results, the rheological behaviour is in accordance with the pseudoplastic fluid in a wide range of paste densities (solid content, w/w) of 65% to 80% and the pastes turn to be Bingham fluids at higher shearing rates. Along with the increase of paste density, the slump drops gradually and the viscosity and shear stress increase gradually. However, the variation extent of the rheological parameters varies at different density ranges. According to the variation pattern of the rheological parameters at different paste densities, the flow ability of the pastes can be classified into three zones. The high fluidity zone was observed at the density range of 65%-69% where the rheological parameters vary slightly along with the paste density, the moderate fluidity zone was observed at the density range of 70%-76% where the rheological parameters vary significantly along with the paste density, and the low fluidity zone was observed at the density range of more than 76% where the rheological parameters vary sharply along with the paste density and the critical density for this sudden variation is about 76%. Furthermore, linear correlations of slump/viscosity and slump/yield stress were observed. It is possible to predict the viscosity and yield stress of the pastes based on the slump measurements.

Jan 1, 2014

By Francesco Vegliò, Luigi Toro, Francesca Pagnanelli

Different hydro-metallurgical processes have been studied in order to recover manganese(II) from oxidised minerals such as MnO2. An innovative acid reductive leaching carried out in mild experimental conditions was here considered using agricultural and industrial wastes containing carbohydrates as reducing agents. The leaching process was investigated from a kinetic and equilibrium point of view in order to optimise the experimental conditions, develop a kinetic model and obtain high purity concentrated MnSO4 solutions. To study the leaching kinetic a Shrinking Core Model (SCM) was modified by a variable activation energy term to take into account both the variable reagent concentrations and the reaction rate change with respect to the manganese dioxide conversion. The influence of the particle size in the kinetic model is discussed with the support of SEM analysis before and after leaching. Manganese extraction yield was maximised (170-190 g/L) using appropriate carbohydrates and acid excesses, while impurity concentrations were kept low (Fe<10ppm and Ca<300ppm) pre-treating the ores, using hydro-alcoholic leaching medium and different combinations of down-stream processes. In particular precipitation, solvent extraction and adsorption onto active carbon were tested to eliminate Fe and Ca from MnSO4 solutions.

Jan 1, 2003

By Rasool Hejazi

The feed to Chadurmalu iron ore concentrator plant is a mixture of magnetite and haematite iron ore with a Fe/FeO ratio of about 8. The feed to plant, after grinding via wet SAG mill, is pre-separated by wet low intensity magnetic separator. Magnetic product is conducted to magnetite processing circuit for producing magnetite concentrate, and nonmagnetic product is directed to haematite processing circuit. Due to surface oxidization of magnetite particles and a decrease in magnetic attraction properties, significant amount of these particles are misled to tailing which results in decreasing the efficiency of haematite processing circuit. This problem can be remedied by using magnetic drum separator with more magnetic intensity and/or gradient. In this paper, the replacement of LIMS separators with wet medium intensity magnetic separators with a field intensity of 3800 gauss on drum surface (MIMS) have been suggested and considered as the most suitable solution to prevent the loss of magnetite particles. The results of carried out investigations with replacement of drum separators in industrial scale, showed that utilizing MIMS in magnetite processing circuit resulted in increasing final concentrate weight recovery on average by 2.59%, without any adverse effect on the concentrate quality; decreasing the magnetite content in the feed to high gradient magnetic separator (HGMS) by about 3.5%; decreasing the feed to floatation part by about 7% and consequently decreasing consumption of chemical reagents; increasing Fe/FeO ratio of the feed to plant. Keywords: iron ore, medium intensity magnetic separator, haematite, Chadurmalu

Sep 1, 2012

By Sudarshan Martins, Peter Radziszewski

"Tumbling mills are machine, operating in non-equilibrium, capable of applying forces on the ore contained within, causing the ore to break down. The action of the mill on the ore is very inefficient, producing a large quantity of heat. The inefficiencies of the mill drive the desire for improvement, spawning research and development activities. Given the non-equilibrium nature of the mill, the theory of Large Deviations is proposed as the framework that captures the state of the mill. The theory of Large Deviations allows for the determination of the rate function and the scaled cumulant generating function (SCGF), for systems in either equilibrium or non-equilibrium. Powerful connections can been made between familiar concepts of statistical physics and the concepts introduced by the theory of Large Deviations: entropy can be associated with the rate function; the scaled cumulant generating function with the free energy. It is shown that observables, compatible with Large Deviation theory, can be identified for the tumbling mill. Here, the time series of the energy associated with an element of the charge is such an observable. Furthermore, using some experimental data, it is shown that the time series of the energy can define a rate function, thereby describing the system within the Large Deviation framework. Finally, a discussion of the results is given, particularly how this theory can be further developed for tumbling mills."

Jan 1, 2014

Vanadium-titanium magnetite from Panzhihua was crushed with open and closed circuit process by high pressure grinding roller (HPGR). The particle size characteristics of the crushed product were analyzed and the micro-cracks generated by HPGR during the crushing process were studied. The results showed that, in crushed products, the reduction ratio increases and the size distribution becomes more uniform with increasing of the pressure on roller?s surfaces. The fine fraction content of crushing products from -3.2 mm classification closed-circuit by HPGR increases obviously compared with that by Jaw Crusher and particle size distribution is more uniform. Large amount of intra-crystalline cracks and cleavage cracks are generated in vanadium-titanium magnetite crushed by HPGR, which makes the specific surface area larger and Bond grinding work index (objective particle size is 0.074 mm) decreased by 14.05% than that by Jaw Crusher. And the liberation degree of monomer of the product crushed by HPGR increased compared with that by Jaw Crusher with the similar fineness of grinding. Keywords: iron ore, high pressure grinding roller, micro-crack

Sep 1, 2012

By Ayumu Tokumaru, Shuji Owada, Gangfeng Liu

"Several million spent catalytic converters are disposed annually worldwideandeach containing about 0.5-1g ofplatinum and 1-2g of all the platinum group metals (PGMs), then,it is fairly significant to recover PGMs from the spent automobile catalyst. The PGMs’ recovery is a proven technology, including pyro-and hydrometallurgicalmethods, and the highestrecovery can achieve approx. 98 wt.% by acid-leaching method, but theserecyclingtechnology seems to be too highlyenergy-consuming. SincePGMs aredistributed only in coat layer in spent catalyst, it is of great significance to enrich the coat layerwith some physical methods as a pretreatment.In this paper, according to the double-deck structureof the catalyst andthe different properties of the two main compositions, alumina-ceria phase of coat layer and cordieritephase of substrate, the concentration of the coat layer was investigated by combiningthree kinds of physical separation technologies, heating-quenching, crushing and surface grinding. In the first stage, thermal stresscouldgeneratebetween the two phasesby thermal expansion difference,to producefracturesin the thinnest part of coat layerand micro-cracksin coat layerand at the interface of coat layerand cordierite substrate. The second stage of crushing, by jaw and roll crushers, could break dominantly the coat layer and the third stage of surface grinding, carried out by attritor, promoted further separation and concentration of coat layer fromthe substrate.We also improved the attritor grinding by adding a new lift-arm to the cell for achieving better mobility of sample particles in the selective surface grinding."

Jan 1, 2014

By I. Zimbovski, T. Ivanova, E. Chanturiya

"The mechanism of selective action of new reagent-collector AMD of phenylpyrazolone class with sulphide minerals of copper-zinc ores was theoretically and experimentally investigated. The validation was carried out using spectrophotometry, Fourier-transformed spectroscopy, laser scanning microscopy, analytical scanning electronic microscopy and flotation. The reagent AMD in alkaline medium on chalcopyrite and sphalerite surfaces is chemically sorbed, forming strong hydrophobic complexes with copper and zinc. On the pyrite surface, AMD acidifies ferric iron ions with formation of hydrophilic oxidates. The selectivity of collector AMD with separation of sphalerite and pyrite in alkaline condition (??=10) is confirmed by flotation experiments. With AMD, the obtained recovery of sphalerite was 34.4 % at extraction of pyrite of 3 and 6 %. The low recovery of sphalerite is caused by weak collective ability of the reagent. The use of copper sulfate increases the flotability of sphalerite up to 82.0 % at extraction of pyrite of 5 and 2 %. It has been experimentally determined that during the flotation of sphalerite and pyrite by AMD reagent with addition of butyl potassium xanthate, and in the presence of copper sulfate and regulator of formation of ammonium thiocyanate complexes, the recovery of sphalerite is increased to 91 %, while the recovery of pyrite is decreased to 3.8 %. The chalcopyrite is floated actively (90 % recovery). The results of all theoretical research and experiments were confirmed by flotation tests on ores and products of dressing in industrial conditions."

Jan 1, 2014

By Subrata Roy

The slag produced in metallurgical smelting processes contains considerable amount of valuable metals. The present work focuses on recovery of copper value by froth flotation from the copper smelter slag. The slag samples are subjected to detailed characterization including automated quantitative mineralogy using Mineral Liberation Analyzer (MLA). The MLA results indicate that a part of copper is present in sulphide form in fayalite (iron-silicate) matrix and very poorly liberated. SEM-EDX analyses also reveal that a certain part of the copper is present within the fayalite (Fe-Ca-Si) matrix, perhaps either as lattice impurity or very fine grain. The copper smelter slag is ground in wet mode in a ball mill, to particle size distribution suitable for flotation. Subsequently, the slurry undergoes froth-flotation in lab-scale Denver-type flotation cell. Various combinations of sodium iso-propyl xanthate (SIPX) and alkyl hydroxamate collectors are used along with pine oil as frother. A multiple collector dosage is required for effective flotation of non-sulphide copper phases associated fayalite and alkyl hydroxamate is identified as one of the effective collector for non-sulphide minerals. The copper recovery can be enhanced by 7-10% with a combination of collectors as compared to conventional sulphide flotation using only xanthate type collectors. However, the grade decreases to some extent. Keywords: flotation, copper slag, hydroxamate collector

Sep 1, 2012

By Kunihiko Yamaguchi, Gjergj Dodbiba, Toyohisa Fujita

Usually magnetic separation is performed to separate ferromagnetic, paramagnetic and diamagnetic particles by controlling magnetic field strength. In this research the wet high gradient magnetic separation at various kinds of magnetization of medium has been investigated to separate different kinds of magnetization of paramagnetic mineral particles from each other. Most of week paramagnetic particles are captured at high magnetic field using superconducting magnet. If the magnetization of fluid is larger than that of paramagnetic particle, the paramagnetic particle cannot be captured in the direction of magnetic field. The paramagnetic particles of different magnetization such as hematite, chromium oxide, perovskite and rutile are separated in different magnetization of fluids. These particles are present in the incinerated bottom ash. The separation is useful to recover titanium oxide from bottom ash and the removal of chromium of bottom ash is important to reuse the bottom ash as cement. The used fluids are paramagnetic liquids dissolving paramagnetic salts and the water based magnetic fluid dispersing the stable ultrafine magnetite. The dispersion condition of particles related to zeta-potential of the suspension feed is also important to separate effectively by controlling pH

Jan 1, 2014

By J. Y. Xu

A mutant of Phanerochaete chrysosporium, which is capable of degrading lignin, was bred by ul-traviolet ray irradiation and this mutant strain shows high capability of degrading of lignite. The degradation ratio of original Yima lignite and nitric acid treated Yima lignite by this mutant are 37.6% and 51.62%respectively, whereas those by the original strain are 31.84% and 32.55% respectively. XRD and FTIR analyses of the lignite converted product show that its polymerization degree and average molecular weight are both greatly reduced. The content of the functional groups is also been altered.

Jan 1, 2014

By H. U. R. Kattentidt, W. L. Dalmijn, T. P. R. de Jong

"Research at Delft University aims to develop systems for automatic inspection and sorting of bulk solids which can be applied in the mineral processing and recycling industry. A recent development includes an automatic sorter based on airport X-ray inspection technology. It is designed for continuous inspection and sorting of 5 - 150 mm solids and has as objective a cost effective and high capacity on-line inspection and sorting.Dual energy X-ray transmission imaging provides instantaneous data about particle dimensions and the atomic number distribution. The system provides particle thickness and average atomic number on a pixel level at scanning speeds between 250 and 500 lines / second. With existing X-ray components inspection speeds between 0.5 and 2 m/s at approximately 1-meter inspection width and between 1.5*1.5 and 5*5 mm2 sensor resolution can be achieved.Imaging algorithms that were developed by Delft University for applications in recycling, waste cleaning and other applications acquire shape, size distribution and composition data. Currently on-line processing of a product at a rate of around 200 particles per second is possible using a standard PC. Experiments with a demonstration X-ray unit indicated good potential for various applications in solids processing. They include continuous inspection of organic content, sulphur, chlorine, ash, and metal distribution. It is applicable for coal cleaning, ore sorting, industrial minerals, and various applications within waste cleaning and recycling. Dual energy X-ray transmission fundamentals and recent progress in system development and applications are presented."

Jan 1, 2003

By Q. X. Li

The state discharge standard for arsenic-containing wastewater which is the first kind of pollution is less than 0.5 mg/L. In fact, in a certain company, the acidic arsenic-containing wastewater in non-ferrous smelting was as high as 860 mg/L, which is far beyond the state discharge standard. Obviously, the direct release of this wastewater without further treatment would result in great hazards to the ecological environment. To aim directly at the characteristics of acidic arsenic-containing wastewater, in this study, two steps of treatment including oxidation-flocculation and removal fluoride by mixing alkaline neutralization were suggested. Through analyzing various influencing factors in treatment effects, the optimum technical conditions were obtained. The sediments after treating were recyclable and the secondary pollutions can be avoided. Moreover, the results also show that, all indexes of the effluent after treating are lower than the First Grade Standard of Integrated Wastewater Discharge (GB 8978-1996). This novel method has advantages of short flow sheet, easy operation and low cost.

Jan 1, 2014