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By F. J. Sotiuo

Variability of the quality of phosphate ore feed to the flotation plant has been of great concern for the industry. This variability sometimes resulted in 10% to 50% decrease of P2O5 recovery, a reduction of P2O5 concentrate grade and/or both due to depression of the system. For this investigation, samples of refractory ore and easy-to-float ore were obtained from the same mining area in Central Florida; and then submitted to bench flotation tests using fatty acids (FA). To understand the cause of difference in flotation behavior of these apparently similar ores (grade, mineralogy, and physical appearance), bulk and surface characterization studies were conducted. Based on the results of characterization studies and bench flotation tests on both refractory and easy-to-float samples, it was possible to determine FA surface coverage. It was found that the surface coverage for the refractory ore was between 6.9% and 9.8%, corresponding to 0% and 80% recovery, respectively; whereas the easy-to-float ore showed surface coverage of 17.2% (89% recovery) to 24.6% (98% recovery). Since size analysis, surface area and pore size measurements showed small differences, it was thought that the surface coverage differences could be caused by the ad-sorption of natural compounds onto the phosphate ore surfaces, depressing the system. SEM, EDS, and Leaching and Solvent Extraction (LSX) studies were performed on the phosphate ores to demonstrate the proposed mechanism. This paper summarized our characterization studies, flotation results, and findings. The study showed that the new identified compounds were responsible for the flotation behaviors of the Florida refractory phosphate ores.

Jan 1, 2014

By A. Chattopadhyay

Porphyry copper deposits are the most important source of copper and also gold within the orogenic belts. These deposits are characterized by low grade copper ore (0.2% to 1% copper) and host precious metals like gold, silver and platinum. A characterization tool has been developed for complex porphyry type copper-gold deposits with an aim to quantify copper and precious metal deportment. This quantification is a challenging task due to low grades and also due to the presence of both visible and invisible precious metal content in different sulphide and non-sulphide phases. Studies were initiated on various complex, ore deposits and also on samples representing various processing streams such as flotation and leach products. This paper presents the development of a systematic approach to diagnostic metallurgy using state-of-the-art optical and automated mineralogy, micro-probe, dynamic SIMS and TOF-SIMS analysis for quantification of invisible and visible precious metals content in various species. The relevance of this characterization to metallurgy will also be briefly discussed in this paper.

Sep 1, 2012

By G. Demi

Chromium ore exploitation has commenced in 1948 in Albania and there are produced about 24.3 million tons up to the end of 2006. Last years the prices and need were increased notably. Main export of chromium ores and concentrates was accomplished respectively 114 500 ton and 13 000 ton in People Republic of China during 2006 year. Location, status, reserves and grade of chromium deposits of Albania are presented in the paper. Chromium ore enrichment is related with their composition and Cr2O3 content, as well as with market requests. Actually, high grade chromium ores with Cr2O3 content over 38% ~ 40% are directly exported or treated in metallurgy, but last time have been exported and chromium ores with 28% ~ 30% Cr2O3 content for the reason that dressing plants can not be operated for investment lack. High grade chromium ores have been treated in heavy media separation plant before 1990. It is presented flow sheet, figures and necessity to put in operation HMS plant in the paper. Actually, low grade chromium ores with content 16% ~ 20% Cr2O3 are not enriched for the lack of investments, but before 1990 they have been concentrated in dressing plants producing chromium concentrates grade 48% ~ 50% Cr2O3. In the paper are shown technological schemes and industrial figures during more than 20 years operation and possibilities to reconstruct these mineral processing plants. Only chromium mineral processing plant of Bulqiza is in operation using as raw material its old existing tailings. The flow sheet and figures show that are possibilities to increase recovery and grade of concentrate in the plant. Separation and concentration of slimes in suitable equipment gives visible improvement of Cr2O3 recovery. Several tests have been carried out with flotation and magnetic separation methods for enrichment of low grade chromium ores. Flow sheet and figures of mineral processing ores content olivine as gangue mineral are interesting, because combination of gravimetric with magnetic methods is necessary in this case. In the paper are presented the tests and good results of low chromium ore pre concentration. Metallurgical treatment of chromium ores to produce Ferro chrome, as well as technological process, figures, consume of electrical power and materials in Elbasani and Burreli furnaces are shown and necessary investments to treat in metallurgy all produced chromium ores in Albania are considered.

Jan 1, 2014

By S. H. He

This paper focuses on the influence of pulp oxygen content on the separation of pentlandite and pyrrhotite contained in two different process streams in the Clarabelle Mill, operated by VALE INCO. The two process streams are (i) the scavenger cleaner feed, the product of regrinding the thickened, scavenged concentrate and the B cleaned tail produced from treating the non-magnetic fraction of the milled run of mine ore, and (ii) the magnetic concentrate which is the magnetic fraction of the milled run of mine ore. In the Clarabelle Mill, sulphite (SO32-) and TETA (triethylenete-tramine) are together used to selectively depress pyrrhotite from pentlandite. These depressants pre-ferentially decompose collector and/or sulphur enriched species at the pyrrhotite surface, an appar-ently essential mechanism in pyrrhotite depression from the scavenger cleaner feed stream. Selectivity in depression may originate from differences in the electrochemical rest potential of pyrrhotite and pentlandite. As both minerals are susceptible to oxidation, aeration in conditioning and flotation plays a key role in selective flotation. Important differences in the flotation behavior of pentlandite and pyrrhotite from the magnetic concentrate and the scavenger cleaner streams are highlighted in

Jan 1, 2014

By Z. Pokrajcic

The traditional comminution circuit is a major consumer of energy ? both as electrical energy and through consumption of media and wear resistant liners. Up to 40% of electrical energy con-sumed at a mine site is attributed to comminution however only a few percent of this energy is used in the generation of new surfaces from size reduction. This paper describes the evaluation of modifications using simulation models based on two operating comminution circuits. The aim of these modifications is to decrease both the amount of electrical energy consumed in the size reduction process, known as direct energy, as well as to decrease the consumption of grinding consumables such as steel grinding media and mill liners, designated as indirect energy. The approach is two-fold: ??Employ, where possible, autogenous grinding techniques to eliminate the need for grinding media and reduce mill liner wear. ??Optimise the use of the grinding energy distribution in the comminution circuit by using more energy efficient grinding devices to target typically problematic features of a comminution circuit such as critical size material from the primary mill and overgrinding in the secondary mill. The investigations show that significant total energy savings, as high as 50% in some cases, can be achieved by employing the techniques described while maintaining circuit throughput and product size. Investigations also show potential benefits in downstream flotation processes as the product size distribution generated from the eco-efficient circuit is generally ?narrower? in shape for improved flotation performance and containing less material in the coarse fraction for overall better liberation.

Jan 1, 2014

By Xianjun Lu

This paper presents gold occurrence investigations on the altered rock gold deposit from Jiaodong area of China, and comparisons of gold occurrence in the ore samples from different mining levels. According to the results, the chemical and mineral compositions of raw materials from different mining levels are quite similar. However, the relative content and grain size of gold minerals are quite different between the two mining levels of -130m~-340m and -550m~-650m. In the ore of upper mining levels of -130m~-340m, electrum is the dominant gold mineral and accounts for about 80% of the total gold minerals, while native gold is minor and accounts for about 20%. As for the ore of deep mining levels of -550m~-650m, the major gold mineral shifts to native gold which accounts for 67%, while the ratio of electrum drops to about 33%. Coarser gold grain size was observed in the upper mining level ore with a mean size of 33.05µm while the gold grain size was much finer in the ore of deep mining levels with a mean size of 22.85µm. Furthermore, the gold mineral associations also show different patterns between the upper mining level samples and the deep mining level samples. Of the three observed gold association types such as inclusion gold, fissure gold and interparticle gold, more inclusion gold was found in the ore of deep mining levels. The inclusion gold accounts for 62% in the ore of deep mining levels, while that in the ore of upper mining levels accounts for about 56%. Further study revealed that the dominant gold associated minerals are pyrite and sulphides and only a small amount of gold is associated with quartz and silicates. It was shown that the altered rock gold ore from Jiaodong area can be regarded as a free milling gold ore, but the processing parameters should be optimized for the ores in different mining levels according to the different gold occurrence. In addition, it was predicted that enhanced gold liberation is necessary for the ore in deep mining levels.

Sep 1, 2012

By S. Castro

The aim of the present paper is to review the current technologies for arsenic removal in the copper metallurgical industry, and to show the progress made with some promising emerging strategies, involving the pre-treatment of copper-arsenic concentrates by selective flotation or by alkaline leaching with Na2S-NaOH solutions. The advantages of alkaline leaching are the selective dissolution of arsenic and antimony, the high extraction yield, and the practically nil loss of copper, which remains in the clean copper concentrate as a CuS residue. Alkaline ?cured? ? a procedure similar to ?acid-cured? in conventional leaching ? improves arsenic extraction and reagent consumption, making this an interesting technology for the treatment of high As-Sb concentrates. In light of recent advances on the selective flotation of enargite and tennantite, the importance of redox conditions to control the flotation/depression of enargite-tennantite from copper sulfides has been well established. However, problems of selectivity must still be solved. Additionally, the limitation imposed in some cases by the need to recover the molybdenum by-product must be considered. The application of selective flotation to obtain a high-arsenic or ?dirty? concentrate and its sub-sequent treatment by the alkaline leaching process is suggested.

Jan 1, 2014

By M. D. Amirova

Cyanide-free technology of complex copper-lead ores flotation may be improved through enlarged range of pH values, enhanced copper recovery into copper concentrates due to additional recovery of secondary copper sulfides, as well as through enhanced efficiency of lead sulfides depression in process of new flotation modifiers-based selective separation. Study of the effects of flotation modifier (of metal nature) on minerals surface conditions proved that the xanthate is practically not adsorbed on the galenite surfaces due to minerals hydrophilization. Joint effects of sodium sulfite and modifier enhance process conditions for intensive galenite depression and at the same time for effective chalcopyrite and chalcosine flotation within a large pH values range (from pH=8 to pH=10). Identified mechanisms carry inference that proposed chemical reagent treating method is very promising for selective copper-lead concentrates separation. Potential use of carbon-containing materials as zinc flotation modifier to enhancing zinc recovery in processes of lead-zinc ores treatment has been studied. In our flotation tests we used Shalkiya (South Kazakhstan) lead-zinc ores containing such impurities as carbon shales, which presence impedes the process of saleable concentrates production and gives rise to excessive consumption of flotation agents due to the xanthate adsorption on the carbon. Lead and zinc concentrates were produced by process stages as follows: ores milled to 95% Cl. -0.074 +0; lead and zinc roughing flotation and further recleaner and testing operations. Test flotation in open process cycle resulted in enhancing zinc recovery into zinc concentrates by 21.1% and increasing zinc content in zinc concentrates by 3.96% that evidences promising potentialities for use of carbon-containing products as additional zinc flotation modifier. Works were carried out under National Program 2003~2005 of fundamental researches ?Physical and Chemical Mechanisms of Interactions in Multicomponent Solid and Liquid Systems Specific for Integrated Processing of Complex Metal-Containing Minerals and Technogenic Raw Materials? and contractual Agreement 2005 Optimization of Production and Technology of Shalkiya Lead-Zinc Ores Processing at Kentau Dressing Works.

Jan 1, 2014

By X. Xu

This paper presents the research on comprehensive recovery of copper, gold, silver and iron from tailings from high-intensity magnetic separation in Tonglushan Mine. By comparison of experimental results of three flowsheets?regrinding of tailings-conventional sulphidizing flotation, water heating enhanced sulphidizing flotation and acid leaching-sulphidizing precipitation flotation, it is concluded that regrinding of tailings-conventional sulphidizing flotation flowsheet has the best economical and technical performance and practicability. Regrinding and using the mixture of sodium hydroxamate and sodium xanthate are two of the notable technical characteristics of this best flowsheet. The system for comprehensive recovery of tailings has been put into production. It not only can recover the valuable minerals from tailings in Tonglushan Mine, but also can reduce the environmental pollution, resulting great economic and social benefit.

Jan 1, 2014

By T. Kumaresan

The Bayer process used for refining bauxite to smelting grade Alumina serves as the linchpin of the Aluminum production industry worldwide. Even though the process is well established, the presence of impurities in the liquor affects the quality of product and imposes a major economic cost on the industry. This review article focuses on the issues pertaining to Gibbsitic (Al2O3.3H2O) precipitation circuit. The comprehensive review provides a basic understanding of the aluminum trihydrate precipitation and agglomeration phenomena. Crystal growth rate and agglomeration play a significant role in determining the output PSD of agglomerates. Hence, the effect of certain thermodynamic and hydrodynamic parameters along with the impact of impurities (oxalates, aldols, acids etc.) and additives on hydrate growth has been reviewed.

Sep 1, 2012

By M. Bhartia

India is the 5th largest producer of steel in the world and is slated to produce more than 180 Mt by 2020. Expectedly about 50 % of this would be through the Blast furnace route and the rest through Sponge iron / DRI route. Considering that there will not be any major change in iron making technology by that time, the Blast operation would require lump ore (10-40mm) with around 64% Fe grade and sinter fines (<10mm) with 60% Fe (min) as its feed. DRI process would need calibrated ore of size 5-18 mm as the most suitable size of feed. It is also expected that of the total requirement of ore for the DRI route a significant part would be DRI pellets. In India, there is considerable debate going on regarding the technology to be adopted for the processing of iron ore and there is a lack of clear consensus. The above scenario indicates that the processing requirement of iron ore in the country would involve both washing technology as well as beneficiation technology. CDE Asia Ltd is in the forefront of iron ore processing in the country and the experience gained by the company over the last few years of functioning has led the company to believe that route to be adopted depends on the end product requirement and the starting grade of the feed. Keeping in mind the nature of the feed required for the Blast furnace & DRI operation; it is obvious that good washing technology would be highly beneficial to the iron ore industry. Depending on the grade of ore available the limits of washing will be decided and equipment for lump ore beneficiation such as jigs could be incorporated into the washing circuit. Scrubbing of ore either before washing or selectively scrubbing the lumps could be necessary. Very low grade ore and jig rejects would be required to be totally ground and beneficiated for the production of pellet feed in order to utilize the iron ore resources entirely. Another source of ore for pelletisation would be slimes generated from the washing process as well as the huge quantities already available in the tailings dams in the operating mines. Deslimimg and magnetic route of beneficiation could release at 30-40% of the Fe locked up in these tailings ponds/dams. The paper describes the concept with examples from operating plants and proposes how the adoption could be engineered through test work and proper plan of integration. Keywords: washing, beneficiation, iron ore, lumps, sinter fines, pellets, jigs, screens, evowash, nanowash, thickeners, log washers, drum scrubbers

Sep 1, 2012

By D. X. Chen

Comprehensive utilization of the copper associated with the complex lead and zinc sulphide ore is a recognized and difficult technical issue in ore dressing field. Qi Baoshan lead-zinc mine is a typical complex copper-lead-zinc polymetallic ore deposit and difficult to process. The application of the. traditional process is not able to make the substantive progress. According to its mineralogical characteristics, the association of copper minerals with lead minerals is very close, and their particle sizes are very fine, and the copper and lead minerals are partially oxidized. Based on the laboratory tests and comparison between different process flowsheets, preferential flotation of copper minerals, being suitable for this ore, was chosen to recover copper. The separation of copper from lead applies the following technology: regrinding middlings with cyclones to classify, which improves copper lead mineral liberation, and increases copper and lead recovery; using new high-efficient collector with good selectivity, which is able to float copper minerals; and non-toxic combined depressant which depresses lead minerals. The above technical innovation, optimizing the process flowsheet, overcoming the complex traditional process flow with high production cost, obtained good technical and economic indicator. The difficult technical problem of copper lead separation was solved smoothly. After successful performance of the bench-scale experiment, commercial-scale test was carried out. In industrial trial, a copper concentrate containing Cu18.60 %, Pb7.40 % and Zn2.50 % was obtained with copper recovery of 58.49%, lead concentrate quality improved largely. The process opened up an unique path for the comprehensive recovery of Cu from similar lead and zinc non-ferrous metals mineral to comprehensively recover copper.

Jan 1, 2014

By G. Y. Liu

The structure-activity relationships for four thionocarbamate collectors are discussed in this pa-per. These collector classes are alkyl alkyl thionocarbamates, allyl alkyl thionocarbamates, acyl al-kyl thionocarbamates and alkoxylcarbonyl alkyl thionocarbamates. The main emphasis will be to highlight the differences between collectors and their affinities for copper and iron sulfide minerals on the basis of data on electronic-structure properties obtained by vacuum and solution density functional calculations, flotation experiments and analysis measurements. The mechanism of interaction of these collectors with sulfide minerals is also discussed with perturbation theory. The theoretical study results indicate that acyl alkyl thionocarbamates and alkoxylcarbonyl alkyl thionocarbamates have best performance in these agents as flotation collectors with improved collecting power for copper sulfide minerals and excellent selectivity against iron sulfide minerals, which are consistent with the experimental data reported in the literature.

Jan 1, 2014

By I. A. Khabarova

The paper presents the results of experimental investigations of the effect by high-power nano-second electromagnetic pulses (HPEMP) on change of surface composition, physical-chemical and flotation properties of pyrrhotite, and search of optimal combination of flotation reactants providing increase of metal extraction from disseminated copper-nickel ores. Preliminary electropulse effect on products before flotation allows to create optimal conditions for flotation separation of pentlandite and pyrrhotite owing to forming the new phases and defects on the surface of sulphides. It was established, that the yield of monomineral fractions of pyrite, pyrrhotite and chalkopyrite increases by 5%~15 %, compared with flotation with one butyl xanthenes (BX), during usage of combination of thionic carbamate (isopropylmethylthionocarbamate (ITC) or isopropylethyl- thionocarbamate (Z-200) with butyl xanthate (BX). Sorption of investigated reactants and strength of their fixing on the surface of minerals are examined; it helped to reveal the cause of rise of floatability of sulphide minerals for the case of combination of reactants. Preliminary high-pulse processing and reactant conditions with usage of combination of thionic carbamate and xanthate have been tested on the sample of disseminated copper-nickel ore from Norilsk region.

Jan 1, 2014

By M. Saghaeian, R. Hejazi, R. Barreiro, M. Tavousi, M. Ahadi, O. Asghari

"Banded iron formations are the major iron source for producing high grade concentrate. BIF are generally lower grade and more difficult to extract. In order to know how best to process BIF ore, it require comprehensive knowledge on ore bodies even in the early stages of the mining process. Geometallurgy combines geological and mineral processing information and allows for higher flexibility in response to changes in the plant feed when mining different parts of the ore. This can lead to economic benefits, owing to improved plant operation, yet is time consuming and correspondingly costly. The main focus of this paper work has been to develop a comprehensive geometallurgical testing framework for developing Yogi BIF low grade magnetite deposit located at Western Australia. In order to provide successful geometallurgical mapping, was collected data from several different disciplines (geology, chemistry, mineralogy) and parameters (physical properties, metallurgical response and geotechnical measurements) during drilling activities and test work. The investigation shown magnetic separation behavior of material had high variation and is most important element in the proper design of ore beneficiation plant. This paper provides an improved and efficient magnetic separation test methods used for the investigation of separation behavior and variability of the Yogi Ore deposit and evaluates their applicability and potential in the geometallurgical context. In this paper a small-scale magnetic separation has been developed that allows estimating from single pass separation test using small amounts of sample material. Verification of the evaluation method and validation was done with different mineral systems."

Jan 1, 2018

By Longjiang Li, Mao Jiang, Zhihui Shen, Guizhou University, Yin Pan

This paper aims to study the influence and action mechanism of collector Y-89 on the flotation of auriferous pyrite. The measurement to identify adsorption quantity, IR and XPS spectrum analysis and flotation experiment made on the pure mineral were conducted. The research results show that when the dosage of MIBC is 20 mg/L, and pH of 8, the dosage of Y-89 over 60 mg/L, the pyrite recovery rate is greater than 80%.And when the dosage of Y-89is 60 mg/L, dosage of MIBC 20 mg/L, the pH in a wider range (pH=4~9), the recovery is greater than 75%. When the pH is above 10, the pyrite is depressed and its recovery rate is found to be dramatically dropping. Adsorption quantity measurement also shows that the strong alkaline conditions inhibit the adsorption of Y-89 on the surface of auriferous pyrite. IR measurement indicates that chemisorption of Y-89 occurs on the surface of auriferous pyrite. XPS spectrum analysis indicates that without adding Y-89, oxidation reaction occurs on the surface of pyrite. But when Y-89 is added, the chemical environment of Fe on the surface of pyrite has changed. Such findings indicate that with Y-89, chemisorption occurs on the surface of auriferous pyrite.

Jan 1, 2014

By Chen Dong, Yang Wenwang, Liu Zhineng, Tan Ming

"To meet the requirement of production expanding of a certain potash ore dressing plant in Xinjiang province of China, industrial test of XCF/KYF-50 flotation machine was performed to process potash ore. The tank of XCF/KYF-50 flotation cell is in U shape, 50m3 of volume. This flotation cell is able to suck slurry by itself, and can be arranged on the same base level without high difference. In this paper, two sets of XCF/KYF-50 flotation cells were adopted to replace 8 sets of 8m3 flotation cell in original flow sheet of flotation. Aeration rate, slurry suction capacity, power consumption and slurry suspension are investigated. The measuring results show the slurry suction capacity of the flotation cell is larger than 12.80m3/min and solid particles disperse evenly in the tank without deposition. Industrial test result indicates that the final grade of concentrate is 26.69% at the recovery of 90.95%, which is up to expected performance. XCF/KYF-50 flotation cell has advantages of high flotation efficiency, significant energy saving and reasonable configuration of automatic control system, this kind of flotation cell can meet the requirement of production expanding of this potash ore dressing plant well."

Jan 1, 2014

By D. Chen

The experiment adopted magnetic separation-priority flotation (first to float copper,then float lead) combined technology to deal with a complex Cu,Pb ,Zn multi-metals ore which has high sulphur content, difficult to separate Cu, Pb ,Zn minerals from sulphur and separate Cu from Pb. Floatable pyrrhotite was separated through magnetic separation which could eliminate the adverse effect on the flotation followed up. And then adopting the priority flotation process to recover the Cu, Pb ,Zn from the magnetic tailings. In priority, flotation Cu, BP(a kind of ethionine ester collector ) and ethyl xanthogenate were used as the collector, LD-1 and sodium sulphite were used as the depressant.The depressants combined with humic acid sodium and lime were used for chalcopyrite ? pyrite separation to further improve the copper concentrate grade. Considering the raw ore that contain 0.32% copper, 0.54% lead and 25.54% sulfur. The copper concentrate grade is 23.61%. The lead content of copper concentrate is only 0.85% . The recovery of copper is 75.03%,and the lead concentrate grade is 54.58%, the copper content of lead concentrate is only 0.81% and the recovery of lead concentrate is 62.24%. The mineral processing indexes were excellent, finally realizing the high effective separation of Cu, Pb , Zn and pyrite. This technique provides a new approach to highly utilize complex copper-lead-zinc ore.

Sep 1, 2012

By L. M. Wang

Chengmenshan Copper Mine Concentrator adopts the new process of preferential?bulk stage floatation and utilize reground, largely increase the mineral processing index of the copper and the sulphide concentrates. In addition, the paper describes the remarkable economic benefit of the new process through the comparison of the new and the old processes.

Jan 1, 2014

By S. K. Dutta

Enormous amount of iron ore fines is generated, due to partly soft and friable nature, during mining. Coal fines are also produced during their processing. These fines cannot be used directly in ironmaking reactors. Utilization of these fines for extracting metal is of vital concern for resource conservation and pollution control, and therefore, a novel concept of agglomeration by cold-bonding is developed. Composite briquettes/pellets of iron ore fines with coal fines were prepared in the laboratory by cold-bonding technique. Various binders such as lime, Ca(OH)2, slaked lime, dextrin, molasses, fly ash etc were employed either alone or in combination in different proportions for making composite briquettes/pellets. It was possible to obtain dry strength of composite briquettes more than 300 N/briquette in some cases and more than 200 N/briquette in many trials. The combination of fly ash with slaked lime and molasses produced the highest strength, more than 400 N/briquette. Drop strength and shatter index values of composite briquettes/pellets were also measured. In briquettes, best compressive strength (978 N/briquette) is observed by using polyvinyl alcohol (PVA) binder. In pellet, best compressive strength (362 N/pellet) is achieved by PVA; shatter index (0.1%) and dry drop strength (158 numbers) are also good. Compressive strength above 200 N/pellet is obtained by fly ash, slaked lime and molasses combination.

Sep 1, 2012