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By Q. Zhang

Phosphate tailings through Flotation contains large amount of dolomite which is difficult to be separated from apatite. In this present research, phosphate tailings is recycled by Flotation i.e. re-processing. High-purity dolomite with purity as high as 91.17% is seperated, which contains 19.82% of MgO. The results of orthogonal test show that the effect of various levels of different factors on the high-purity dolomite floatated. Future utilization of purified dolomite is also discussed: magnesium fertiliser especially magnesium phosphate is expected to be an ideal product from high-purity dolomite.

Jan 1, 2014

By Z. C. Zhen

Basing on character of fine ores, and employing all the advantage of dissolved-air flotation, the study within the dissertation put forth the methods of superfine metal mineral flotation with dissolved-air flotation equipment, and constructed a full set of laboratory flotation system. Experiments both in water and in slurry were respectively carried out by means of this flotation equipment. Further study was also fulfilled on mechanism of air-dissolved released devices, and the key components of system including ejector, releaser and saturator were designed. Optimizing devices parameters were chosen by taking ideal performance of the devices into consideration, according to orthogonal experiments and tests on bubbles factors, those performance factors were called air release rate, air release efficiency. The results with some minerals are better than JJF flotation machine with 30 litres bulk. The Dissolved-air Flotation(DAF) machine shows great potentiality in treating super-fine metal mineral concentration. The research indicates the Dissolved-air Flotation(DAF) system has superiority over mechanical flotation machine in fine flotation. Air-dissolved released bubbles appear on the surface of hydrophobic minerals in priority, solving collision probability less in the tradition fine mineral separation, such that the metallurgy technology of fine metallic minerals are improved. The exploratory research is a foundation for industrial pilot, commercial test and equipment maturity in the future.

Jan 1, 2014

By Ashok Kumar, Subhadra Sen Dr. Rashmi Kumari, D. P. Chakraborty, Ajay kumar Gupta

The blast furnace coke quality depends on the characteristics of coal blend, pre-carbonization techniques adopted such as stamping, vibro-compaction etc., and coking conditions. Of the above, coal blend plays a significant role in the production of quality coke. Furthermore, the quality of the blend depends on the quality of individual coals and their interaction making up the blend. During transportation and stockpiling, coal is in contact with air for periods of time that sometimes may exceed several months. During this time, reaction with oxygen in the presence of water, sunlight and possibly elevated temperatures may take place. The resulting weathered coal suffers some alteration in its technological properties, which in turn affects coke quality for Blast Furnace operation adversely. In this work, two coals belong two prime hard coking and hard coking categories, namely Illawarra & Tahmoor, were selected and kept in a separate stock pile for a period of 120 days. These coals were characterized in terms of proximate, rheological & petrography properties at a regular frequency. This report summarizes the impact of weathering on the coking behaviour of these two coals in terms of properties as mentioned above. However, the rate of loss depends on coal rank and storage conditions. This has been seen through this study that the loss depends on coal rank and storage conditions. Deterioration of rheological and petrographic properties were seen higher for low-rank coals, like in this study Tahmoor, which is a low rank coal, compared to Illawarra showed higher degree of coking property degradation within the same time period under identical environmental conditions. Low-rank coal deteriorates at a faster rate because low-rank coal is dominated by free radicals that easily react with oxygen, resulting in the creation of various carbonyl groups and weathered vitrinite. Based on the results obtained in this study, size of stock piles for different qualities of coals to be maintained, at a specific time, can be determined and recommended, so that target coke quality is always achieved.

Jan 1, 2018

Traditional mineral processing techniques are more and more difficult to recover the increasingly low grade phosphate ores today. Although bioleaching method has been attempted to process low grade ores in hydrometallurgical field due to economical and environmental reason, it has been hardly used in leaching phosphate ore at home and abroad. Strains of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans were collected and separated from the acid drainage of a coal mine in Anhui province of China. Ultraviolet irradiation and Microwave inducement were applied to the bacterial cultivation process to produce strains of Acidithiobacillus thiooxidans and Acidithi-obacillus ferrooxidans able to tolerate extremely low pH conditions and generate sulphuric acid by oxidizing elemental sulfur or sulphide and the mutagenesis can achieve higher leaching rate. The bioleaching result will improve more by the addition of Tween series surfactants.

Jan 1, 2014

By B. McFadzean, P. E. Ngoepe, P. P. Mkhonto

"The theoretical technique of computational modeling and the experimental determination of the enthalpy of adsorption of a ligand molecule onto a mineral surface deliver the same output parameters and, therefore, complement each other in investigating the affinity of different ligand types for mineral surfaces.This study ran parallel experimental tests and computational calculations to determine the enthalpy of adsorption of a series of increasing chain length xanthates onto a pyrite surface. The outcomes showed that, while the absolute energy values were different, the trends were similar. Both computational and experimental approaches showed that the extent of the interaction of the xanthate molecule increases with increasing carbon chain length. The computational values were larger than the experimental values, which could be explained, in part, by the addition of water to the computational system, which resulted in a decrease in the heat of adsorption on the (100) surface, compared to the adsorption of the collector in a vacuum. The computational method showed that, in the case of the pyrite (100) surface, the most exothermic reaction was obtained when the two xanthate sulfur atoms bridged two pyrite 5-coordinated iron atoms. The (111) surface was found to be more reactive and different adsorption mechanisms were predicted for each of the C2, C3, C4 and C5 chain length xanthates.The experimentally determined exothermic increase in heat of adsorption for the addition of each CH2 group was found to be -8.17 kJ/mol. The contribution of the thiol head group was -34.9 kJ/mol. Previous studies on self-assembled monolayers have shown that these values are compatible with lateral interactions between CH2 groups and the exclusion of water. This study provides a rigorous experimental and computational approach which is intended to afford confidence in modelled data for the screening of new ligands for flotation processes.INTRODUCTIONComputational modelling is a fast and cost-effective method of screening collector molecules for the efficacy of their adsorption onto mineral surfaces. However, it is desirable to measure the computational outputs against experimental outputs to check for congruency. Computational modelling and experimental microcalorimetry both deliver the same output parameter: the energy of adsorption of the molecule onto the solid surface. These techniques are therefore ideally suited to complement one another in investigating the affinity of the interaction between collector molecules and mineral surfaces."

Jan 1, 2018

By M. Saghaeian, R. Hejazi, M. Farahani, M. Dehghani, A. Tohry

"Wet tailing dams of iron ore processing plants typically contain a significant amount of valuable minerals. In more recent years, due to the increase in iron’s prices and technological innovations, as well as the low energy consumption which required for processing of materials from tailings, dams can consider as potential valuable deposits. However, the production of iron concentrate from tailings is usually complicated where the high moisture content of the material, the high clay content and the presence of chemicals of processing such as flocculants, acids and flotation reagents, all make materials highly sticky which can be easily swollen. In the present paper, the optimization of operational parameters to recover ultrafine hematite iron ore from the wet tailings dams of the Chador-malu iron ore mine was investigated. The optimization of operational parameters, showed that with modification of the washing unit components for slurry making, the challenge of constraints from feeding the plant could be overcome. To decrease the magnetite content in the tail stream of the medium intensity magnetic separation (MIMS) and subsequently increase the efficiency, the orifice of the cleaner tail flow exit pipe was changed from 7 inches to 3 inch and yoke angle changed from 14 to 8 degrees. These changes increased mass yield by 3% and decreased the magnetite content in the final tailings to 1.2%. By recirculating the cleaner SLons of final tailings within the circuit, the solid percentage of the feed to rougher SLons decreased to around 15%, and as a result the matrices were not overloaded that easily, and mass yield increased to about 13% from 7%. All the above mentioned optimizations were achieved without significantly affecting the concentrate Fe grade."

Jan 1, 2018

By J. J. Cai

The status of fossil fuel and secondary resource in metallurgy industry in China were reviewed, and conversion efficiency of fossil fuel, utilization technologies of secondary energy were studied. Fossil fuel, accounting for over 90% of energy structure in metallurgy industry, took in the highest flight in China, and a great deal of which was converted to secondary energy through the equipment of blast furnace and coke oven. These secondary energy which were mostly made of blast furnace gas(BFG), coke oven gas(COG) and Lindz Donawitz gas(LDG) occupied about 30% of total secondary energy. The way enhancing fossil fuel conversion efficiency, secondary resource recovery and the secondary energy such as BFG, COG, LDG utilization promoted to save fossil fuel was discussed in this paper. And efficient use of lower caloric value fuel was studied, such as preheating combustion air and fuel, generating electricity power etc. and regeneration purposes of high-caloric fuel was also researched, for producing hydrogen, methanol or direct reduction iron etc. The using model of secondary energy at iron and steel works was presented as fuel and chemical materials. The results suggest that utilization of these energy efficiently and reasonably could help to energy saving and environment protecting.

Jan 1, 2014

By G. C. Li

Gold extraction using iodide leaching from refractory carbonaceous gold ores was studied. Thermodynamic analysis of iodide leaching chemistry had been carried out. Eh-pH diagram of Au-I2-I--H2O leaching system showed that the coordinating active forms from iodides were I3- and I-, while the major coordinate compound formed during iodide leaching was AuI-. For leaching parameters optimization, technological parameters such as I2 concentration, I2 :I- ratio, oxidation assisting agents, liquid/solid ratio, and leaching duration were studied. The leaching results showed that the average Au leaching rate reached 91% and 92% for oxidized ore and roasted primary ore respectively. Leaching process proceeded in weekly acidic or neutral slurry at ambient temperature; the leaching duration was 4 hours. After that gold was extracted from the pregnant liquor by activated carbon adsorption ? desorption ? electrowinning process. Gold recovery was over 93% in the adsorption process, while the gold recovery in electrowinning process was about 95%, provided that the initial gold concentration is 40mg/L or larger. For iodine regeneration it is enough to add hydrogen peroxide in excess into the filtrate after gold electrowinning, all the iodides existing in the solution in any forms would be precipitated in the form of elemental iodine.

Jan 1, 2014

By Q. Zhang

The flotation behavior of jamesonite was investigated with ethyl xanthate as a collector. It has been shown that jamesonite has good floatability from pH 2 to pH 12, and relatively poor floata-bility at pH>12. The flotation of jamesonite was also dependent on pulp potential at certain pH val-ues. The potential-pH range for jamesonite flotation was established. The FTIR spectroscopy analy-sis and XPS measurement showed that the major adsorption product of ethyl xanthate on jamesonite was lead ethyl xanthate and antimony ethyl xanthate. The intensity of the FTIR signals of metal ethyl xanthate adsorbed on jamesonite and the flotation response of jamesonite were correlated with pulp potentials.

Jan 1, 2014

By A. Pirson, J. Souza, A. Araujo, M. Barbosa, F. Guimarães, J. Lima

"Although a large number of processes have been developed and applied to the separation of barite from other minerals, there is a lack of information in the literature about the separation of barite from iron ores. Nowadays, there are millions of tonnes of iron ore disposed as a waste or tailings given its high content of sulphur in the form of barite. In order to effectively separate barite from iron ore and ensure that mining business is truly creating economic and sustainable values, this paper provides a greater understanding of barite properties, the origin and occurrence of this barium-bearing mineral, and the employed beneficiation processes. A test work is conducted in a barite bearing iron ore from a deposit located in the Republika Srpska (Bosnia and Herzegovina) in order to separate the barite and check if a marketable by-product can be produced by drawing upon rich barite tailings. INTRODUCTION The exploration of iron ore containing barite results in a large amount of unrecovered material. The main difficulty in processing and using barite bearing iron ores is given by their high content of sulphur, silica and barium, which are unwanted chemical compounds in the subsequent processes in iron industry. As a result, millions of tonnes of iron ore are discarded every year into tailings or as a waste, which results in production losses, higher operation costs and environmental impacts (Praes et al. 2013). Therefore, the separation of barite from iron ores not only means reducing the environmental impact, but also an opportunity to generate income and beneficiate society. The beneficiation of barite bearing iron ores is a subject which requires a deeper investigation to solve the challenges faced by the iron industry. There are only a few studies that describe flowsheets proposed for the production of barite concentrate of iron ores. The most likely reason for this gap is that barite is frequently exploited commercially as a primary product rather than a by-product. In order to effectively separate barite from iron ore and ensure that mining business is truly creating economic and sustainable values, this paper provides a greater understanding of barite properties, the origin and occurrence of this barium-bearing mineral, and the employed beneficiation processes. A test work is conducted in a barite bearing iron ore from a deposit located in the Republika Srpska (Bosnia and Herzegovina) in order to separate the barite and verify if a marketable by-product can be produced by drawing upon rich barite tailings."

Jan 1, 2018

By A. I. A. Salama

In this paper, the problem of sedimentation and consolidation of poly-disperse suspensions is considered. The solid particles are assumed to be of different densities. If the sediment solids stresses are dropped out of the system equations and using the Richardson and Zaki hindered settling model, it has been found that in the limit, i.e., as time approaches infinity, the fluid is completely displaced to the top of the sediment zone. Furthermore, the species segregate completely with the heavier and coarser particles at the bottom of the sediment and the lighter and finer particles at the top of the sediment. Practical observations do not support these behaviors and physical-ly such behaviors do not exist; consequently, results of this kind in the literature are unrealistic. Here, a mathematical structure of the poly-disperse sedimentation and consolidation problem has been proposed. In this case the compaction zone species solids stresses are introduced in the momentum balance equations of the system. The species solid stresses in the sediment are constrained so that the system equations are consistent, i.e., sedimentation and consolidation of two or more identical species should behave as a mono-disperse system. Such a condition has not been recognized and imposed in some of the studies in the literature, which has led to unreliable results. Two practical forms of species stresses that satisfy the system consistency condition are here proposed. It should be noted that the study of sedimentation and consolidation of poly-disperse suspensions could result in more realistic suspension interfaces compared to mono-disperse suspensions, and could lead to more reliable engineering designs of tailings ponds. Predictions of sedimentation and consolidation in models of poly-disperse suspensions are demonstrated using published data.

Jan 1, 2014

By E. Barsky

The composition of multi-component materials is proved to be unambiguously determined by the composition uncertainty parameter (composition entropy). At the same time, every component, depending on its content, introduces a certain value into this parameter. Quality criterion of multi-component separation is determined by the total change of this parameter for all products obtained as a result of the separation process. This parameter can unambiguously estimate both multi-product separation and complicated schemes of modern beneficiation plants. It can be used to estimate binary mixtures separation, too. During the optimization of multi-product separation, another problem arises, which is not peculiar to binary mixtures. In this case, the total efficacy depends on the order of separation boundaries, as well. In the present paper, a specific example of initial product separation into seven products by six boundaries is investigated. It is clear that with respect to a single boundary, two products only can be obtained. In this case, the separation optimum is shown to correspond to the separation of boundary-class particles equally into both products. We have also established that from the point of view of entropy, the maximal possible separation efficacy corresponds to equiprobable composition of the initial mixture, i.e., the fine product quantity in the material to be separated is equal to that of the coarse product. Three groups of experiments were carried out. In the first group, the boundaries were consecutively specified from the finest to the coarsest one. In the second group, the boundaries were set vice-versa, i.e., consecutively from the coarsest to the finest one. In the third group, no sequence was observed. At every separation stage, a boundary was specified in such a way that the separated material composition was as close as possible to equiprobable one relative to this boundary. Total efficacy was different in all the three cases. In third group of experiments, its value is the highest, which confirms the advanced supposition. The obtained results are phenomenological, ? they can be applied to any processes of solid, liquid and gaseous materials separation.

Jan 1, 2014

By Y. L. Tian

Low-grade bauxite with A/S of 4.4 from Henan province was used as raw material and the selec-tive grinding of bauxite, grinding efficiency, particle size and Al2O3 and SiO2distributions of ground products were investigated using ball and vibration mills. The results show that the selective grinding can be used to realize the separation of aluminum from silicon within a certain particle size. The optimal grinding conditions of the ball mill with bauxite are as follows: grinding material to charge ratio, 1.2, charge volume ratio, 40%, pulp con-centration, 70wt%, medium size distribution, F30mm:F20mm:F15mm=20%:50%:30%. Under the conditions, the weight rate of ground product with A/S over 7.5 is 27% and the recovery of Al 2O3is 30%. The optimal grinding condition of the vibration mill with bauxite are as follows: grinding material to charge ratio, 0.9; charge volume ratio, 70%; concentration, 70%; medium size distribution, F40mm:F30mm:F20mm=20%:30%:50%. Under the conditions, the weight ratio of ground product with A/S over 7.5 is 25% and the recovery of Al 2O3is 27%. The research is significant for the rational and economical utilization of the low-grade bauxite.

Jan 1, 2014

Cyanide is reactive to copper minerals and is not suitable to extract the gold from the copper bearing ores. Ammoniacal thiosulfate is considered an excellent alternative lixiviant for leaching copper bearing gold ores. Unfortunately the results of high reagent consumption and poor gold ex-traction were found by thiosulfate leaching of synthetic gold ores containing chalcopyrite, chalcocite or bornite and a mild refractory copper-bearing sulfidic gold ore. In this investigation, several processes have been applied to reduce the impacts of these minerals on gold leaching. The process included: the pre-oxidation of copper sulphide minerals in water or ammonia solution, the reduction of dissolved oxygen in the lixiviant (0.3 ppm DO or 0.7% oxygen), adding phosphate anion in the leach or pre-leach stage, and the addition of a strong copper ligand (e.g., EDA and DETA). The results indicated that the gold extraction could be improved to 93% with the thiosulfate consumption being reduced to less than 8 kg/t. The dissolution of copper minerals was found to be the major reason for increased consumption of thiosulfate and the highly reductive leached surfaces are responsible for the reduced gold extractions.

Jan 1, 2014

By Guanghua Ai, Xiong Huang, Huashan Yan, Ting Li, Tingsheng Qiu

"Cyanide tailings of gold and silver concentrates contain considerable quantities of copper-lead-zinc sulfide minerals that can be recovered. However, the strong inhibition effect of cyanide often makes it difficult to recover these sulfide minerals effectively. In this research, a sample of cyanide tailings was investigated based on the principles of process mineralogy; activating flotation tests were carried out for the target minerals in the tailings, and the activation mechanism of the activator and its influence on the target minerals were investigated by Fourier transform infrared spectroscopy (FTIR). Mixed flotation of copper and zinc was carried out using QJ-01, a combined agent containing sulfite, as the activator of copper and zinc minerals, and ammonium dibutyl dithiophosphate (ADD) and butyl xanthate (BX) as the combined collector. Copper concentrate was obtained from the mixed concentrate by using a combined inhibitor of sodium sulfide and zinc sulfate to inhibit the zinc mineral. Zinc concentrate was extracted from the copper tailings by using copper sulfate as the activator and BX as the collector. The flotation test yielded copper concentrate with a grade of 22.56% and recovery of 76.96%, and zinc concentrate with a grade of 42.56% and recovery of 82.29%, which shows that comprehensive recovery of the sulfide minerals – copper and zinc –from the cyanide tailings was realized. The FTIR analysis showed that CN- was chemisorbed on the surface of chalcopyrite and sphalerite following cyanide treatment, while the combined activator QJ-01 containing sulfite reduced CN- into SCN- and weakened the complexing ability of CN- with metal ions on the mineral surface, thus achieving a good activation effect on chalcopyrite and sphalerite. The results of this study can provide practical guidance in increasing the resource utilization ratio of cyanide tailings in gold mines, and thus contribute to alleviating environmental problems caused by stockpiling cyanide tailings. INTRODUCTION Cyanidation, the most widely used technology for extraction of gold, has several advantages such as high recovery, process maturity, low cost, etc. According to available data, the annual discharge of cyanide tailings from China's gold mines exceeds 20 million tons (Li et al., 2011). Lower grades of exploitable gold ore entail increased discharge of cyanide tailings. Huge quantities of cyanide tailings are regarded as waste and stored, resulting in significant wastage of land resources. Moreover, residual beneficiation reagents, cyanide ions, and heavy metal ions in cyanide tailings cause severe pollution of water and land (Laitos et al., 2013; Donato et al., 2007; Mudder and Botz, 2004). In addition, cyanide tailings often contain valuable elements such as gold, silver, copper, lead, zinc, sulfur, and iron, which, if not recycled, would result in considerable wastage of resources. Hence, it is imperative to study the reduction and safety of cyanide tailings, and the mineral resources present in them."

Jan 1, 2018

By A. Qaredaqi, M. Mohammadi

Wet High Intensity Magnetic Separators, for short, WHIMS are used for recovery of Iron ores with low magnetic susceptibility. A Jones patent WHIMS with "grooved plates" matrix is being used in Dry Tailing processing line in Hematite Recovery Plant at Golgohar mining & Industrial Co. for recovery of Hematite. In this kind of separators Matrices are used for increasing the Magnetic field intensity and providing high magnetic field gradient. The laboratory WHIMS in Golgohar Iron Ore and Steel research Institute is capable to provide a background magnetic field strength up to 0.85 Tesla and in presence of ‚expanded metal? matrix, magnetic field intensity could increase up to 0.9 Tesla. More than 50% of feed particles in this separator were finer than 36 micron and recovery of these particles needs more magnetic field intensity. Hence, ‚Grooved Plates? matrices with Js= 2 Tesla and 3.8 mm gap were constructed. Measurements indicated that magnetic field intensity around the matrix will increase to 1.25 Tesla. Graph of Magnetic field intensity around the matrix to background magnetic field intensity was plotted and a model with Rsquare= 0.9 was offered. In addition, magnetic field gradient and magnetic force were calculated. In WHIMS with feed top size of 150 micron, the main effective forces on separation process are the magnetic force and the hydrodynamic drag force. With assuming that the particles are smooth and spherical and the flow is laminar, Recovery of fine magnetic particles is problematic in this separator because of drag force. Considering these facts and mentioned model, finest particles that are recoverable in different magnetic field intensities were calculated. Computations illustrated that with magnetic field intensity more than 0.8 Tesla, particles as fine as 4 micron are theoretically separable but it should be noted that in practice a larger attractable particle size would be expected.

Jan 1, 2014

By N. Acarkan

Slags usually contain some quantity of valuable metals. They are actually a secondary resource of metals, rather than an end-waste and have been utilized as a resource material in many areas. In addition, for some applications, slags have comparable or even better properties than their competitors. Leaching is a method for extraction of metals from copper slags. The extraction of metals such as copper and cobalt from the copper slag of Küre-Turkey, was investigated in the past decades. Fayalitic type of these copper slags containing 0.934 % Cu, 0.353 % Co and 50.91% Fe were subjected to the experimental study. As a result of mineralogical analysis of the slag sample, fayalitic type of slag was found to contain hercynite, magnetite, hematite, pyrite, chalcopyrite, covellite, bornite and metallic copper. Direct acid leaching methods were applied on the sample. Effects of leaching time, temperature and acid concentration on Cu and Co leaching recoveries were investigated in the direct acid leaching. The optimum leaching conditions were found as leaching time of 2 hours, solid/liquid ratio of 1/3, H2SO4 concentration of 125 g/L and temperature of 70 °C. At these conditions, 75.5 % of Cu, 95.6 % of Co and 70.9 % Fe were extracted. In the second stage of the leaching experiments, copper in the pregnant solution was precipitated by cementation to produce a Cu concentrate assaying 95.58 % Cu; cobalt was obtained by precipitation with H2S to produce a concentrate containing 62.10 % Co. As a result of this study a process flow sheet has been developed for recovering Cu and Co from these slags to demonstrate its economic and technological benefits.

Jan 1, 2014

Low-grade ore bodies, increase in rock competency, finely disseminated valuable minerals in the ore bodies, ore variability and water scarcity are among the technical challenges faced by the mining industry. These challenges have increased the business risk, capital investment and operating cost of the mining projects. Since the last 20 years, many large-scale concentrators have been built to cope with the above-mentioned challenges. Comminution, especially the fine grinding is an energy-intensive process. For example, the ball mill has a limitation in the fine grinding regime where the energy consumption increases exponentially when the product size is below 45 µm. The industry has been seeking for solutions that have a minimum risk and total cost of ownership. The stirred milling technology such as the TowerMill is well accepted by the industry as it has demonstrated the attributes required for fine grinding. TowerMill is a matured technology that has been adopted since the 80s for regrinding duty. Recently, this technology was installed in secondary and tertiary grinding duty to prepare a finer feed to rougher flotation. Four units of TowerMills were installed in a magnetite concentrator in Western Australia in tertiary grinding duty. Recently, Nippon Eirich has conducted process performance evaluation on the TowerMill circuit. The outcome of the exercise had indicated that the circuit is consuming 3.4 kWh/t to reduce from 55 µm to 35 µm with a narrow product size distribution. The effect of operating variables such as the specific energy, grinding media size, mill content % solids and mill feed configuration on the grinding efficiency were evaluated at the plant scale. Furthermore, the scale-up methodology was validated. The scope of this paper includes the performances of TowerMill and the validation of scale-up methodology.

Jan 1, 2018

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 S. Patra, R. Venugopal

"The quality of pellets produced is affected by quality anssastd quantity of green pellets, amount of addition of binders, type of binders added, amount of moisture added along with the other variables like rotation, inclination and fineness of feed. The green pellet quality depends upon chemistry, mineralogy and granulometry of fines used for pellet making, the feed size, its moisture content and porosity. During firing of green pellets ingredients present within reacts to form different phases and microstructure. So in turn physical and metallurgical properties of pellets are influenced by amount and type of binder and flux addition, induration time and temperature. During iron making process, the metallurgical properties of fired pellets are decided by the type and amount of these phases and their chemistry. Green pelletizing and induration studies have been already carried out with hematite ore fines. Indian iron ores of high alumina content showing different pelletizing characters, these studies can’t be directly interpreted. The main objective of proposed research work is to understand the green pelletizing process and determine the water bentonite interaction at different levels. Detailed investigation on swelling behavior of bentonite and microstructure of the green pellets of iron ore fines from SAIL captive iron ore fines from the Barsua in the state of Odisha. To convert these ore fines into pellets, the key raw material, additives and process variables that influence the pellet quality needs to be identified.INTRODUCTION Pelletization is the unit operation of agglomerating iron bearing fines (generally below 150µ with 65-80% passing 40µ) by tumbling in horizontal rotating drums or inclined discs, (Sivrikaya and Arol, 2013; Bhuiyan et al., 2011; Forsmo et al., 2006; Sastry et al., 2003) and the pellets are approximately spherical lumps formed by this process in presence of water and binder, on subsequent induration at 1300°c (Sivrikaya and Arol, 2014; Sivrikaya and Arol, 2013; Sivrikaya and Arol, 2012; Sivrikaya and Arol, 2010; Sastry et al., 2003; Kawatra and Ripke, 2003; Iveson, 2001a; Iveson, 2001b)."

Jan 1, 2018