Search Documents

By Somerville M, Muray A, Bocking M

Australia has an extremely large total hot dry rock (HDR) resource above a depth of 5 km, equivalent to 7500 times its present annual energy consumption, of which 80 per cent underlies the Great Artesian Basin. The resources most likely to be exploited first are those residing in homogeneous granitic bodies beneath sedimentary basins containing insulating rocks such as shales and coal measures. In the Sydney Basin south of Muswellbrook, an area of high geothermal gradient corresponds to a gravity low thought to be a buried granite body at a temperature of possibly 250¦C. This locality is suspected to have the ideal geological characteristics for Australia's first hot rock test facility. Australia's high HDR potential is possibly unique in the world, in that the potential sites satisfy four independent, geological conditions, each considered as favourable for the creation of a resource, and for the ease of extracting that resource. They are: ò Higher crustal heat generating capacity than that of normal continental crust. ò Much of the Australian continent is covered by sedimentary basins which contain a high proportion of shales and coal measures that have low thermal conductivities, thus providing an insulating blanket for the heat being generated beneath. ò The sedimentary basins are in many places underlain by large untectonised granitic bodies that are not only a major contributor to heat generation, but also ideally suited to the establishment of HDR reservoirs. ò The crustal shortening stress field that is found in the majority of the Australian continental crust results in a vertical minimum principal stress orientation which should result in the development of favourably oriented horizontal stimulation cells necessary for maximising an HDR resource.

Jan 1, 1995

By Campain RA, Horner NJ, Limerick JM

The review covers the different concepts of automation which are appropriate to non-ferrous smelting and the degree to which the smelter, and the furnace in particular, is amenable to total automation. Due to the problems peculiar to a smelter, it is unlikely that a fully closed loop system could ever be achieved and that the smelter will continue to depend upon extended manual control supported by computer based information sorting and optimisation.Generally, loop control is performed using Taylor's Mod III process control system. For distinct plant systems involving a combination of process loops, sequencing, and data acquisition, the company has developed its own microprocessor based systems. Process optimisation using computer based analysis of operating data is well established. Utilising this data, computer modelling provides manual set point supervision for the furnace process control system.The impact of automation on the workforce and on operating costs is also examined. Predictions on future developments in the field of automation, optimisation and sequencing are propounded and related to the non-ferrous industry at large.

Jan 1, 1985

By B, J Bianchini, N Voermann, C Crowe

Operational and economic imperatives in the metallurgical industry have led to numerous advancements in furnace design. Modern furnaces provide high production rates, high percentage online time, long campaign life between rebuilds and safe operating conditions. Current trends for maximising plant efficiency include increasing the throughput of existing process vessels (often by a factor of two or more) and the use of newer, highly intense processes. In both instances, the process intensity results in the generation of higher heat fluxes to the crucible walls. High-intensity furnace operation with the objectives mentioned above has become possible with the following furnace design features: Strong sidewall cooling systems, using copper coolers, to accommodate the high heat fluxes encountered while protecting the crucible refractories; Robust, spring-loaded furnace horizontal and vertical binding systems which maintain tight brick joints through-out all stages of operation; and Well-designed, intensely cooled tapholes for metal, matte and slag. The integration of these features along with properly selected refractories, appropriate instrumentation systems and efficient water-cooling systems is also highly critical. These design features have been successfully implemented in electric smelting furnaces, flash smelting and converting furnaces (Outokumpu and INCO types) and lance injection furnaces (Mitsubishi, Ausmelt and Isasmelt types). This paper will discuss design aspects and operating results for several installations.

Jan 1, 2002

In the past few years the Rietveld method emerged as a routine tool for quantitative phase analysis (QPA) from X-ray diffraction data. Fast and reliable results became possible by combining modern computer technology and optimised mathematical algorithms with the fundamental parameters approach in the Bruker AXS TOPAS software. Here the routine analysis of bauxite raw material and of aluminium bath electrolyte is presented. The accuracy of bauxite quantification was tested by analysing the IUCr round robin sample. An agreement of better than one per cent was obtained for minor constituents and a maximum deviation of 2.5 per cent for the major phases. This is excellent agreement with expected results from weighting. Ten different phases were quantified in natural samples from Turkey with a precision better 0.5 per cent for the major phases and one per cent for the minor phases. Additionally, crystallite sizes were obtained from the peak profiles that give valuable information for the processability of the material. XRD data from solidified aluminium electrolytes were rapidly measured using silicon strip detector technology. With the LynxEyeTM detector full patterns were collected in 90 seconds and analysed with TOPAS. It is shown how to derive well-established measures such as bath ratio and excess AlF3 from the Rietveld results. These measures are widely used in aluminium production and readily available with very high precision. The excellent agreement with ALCAN reference data demonstrates the outstanding accuracy of the method. The mean deviation between here presented results and reference data is below 0.5 per cent for total CaF2, below 0.25 per cent for excess AlF3 and 0.02 for the bath ratio. The precision of the method was evaluated by repeated measurements.

Jan 1, 2008

By C Smith, D Lilly

The Lafarge Marblehead Plant in Marblehead, Ohio, USA produces 4.2 million tonnes of sized aggregate yearly. In 1997, a program was instituted to maximise primary crusher productivity through the optimisation of blasting variables and procedures. A proprietary blasting shot report database and the Lafarge production database was statistically analysed to provide guidance in the program. Blasting powder factor (kg/m3) was the main control variable utilised to increase crusher throughput. In 2005, the program was refined to increase the production of certain high margin aggregate sizes and the reduction of fines. The principal blasting component affecting the percentage of high margin size production appears to be pattern area (burden and spacing area). This can be coupled with powder factor to optimise the production rate of high margin aggregate sizes. The size optimisation program incorporates the blasting shot report database, Lafarge production database, statistical analysis and aggregate sampling. A preliminary indication is that the production of high margin sizes (12.7 mm X 4.8 mm, 24.4 mm X 12.7 mm, and 50 mm X 25.4 mm) has been increased seven to 12 per cent utilising these techniques. As an added benefit, blasting costs have been reduced linearly as burden û spacing pattern areas have increased and powder factors have decreased. The program is ongoing and will investigate other blasting procedures and variables including electronic blasting caps to further increase the production of high margin products. The statistical methods involved in the analysis are described in this article for use in other mines and situations. The methods described can be used to optimise crusher throughput, digging rates and product size.

Jan 1, 2007

Just as Australia is part of the Pacific Rim, so the Pacific Rim should be viewed as part of the whole world. That applies in particular to that scarce commodity û money. There are five main factors of production in any mining development û mineralisation, materials, manpower, management and money. LetÆs focus on the upstream input û mineralisation, and the downstream input û money, especially in the area of communications. Unknown to many, the Competent Person reporting on Mineral Resources and Mineral Reserves has a direct and unavoidable impact on the companyÆs financial statements û the profit and loss account and balance sheet. With respect to reporting of the major asset of most mining companies û the resources/reserves û investors are getting a better deal now than at any time in memory as regards flow and adequacy of information. Australia has been a world leader in this regard. The outlook is for even more informative and useful reporting. The more rigorous reporting requirements for Exploration Results and Mineral Resources/Reserves, which have become a worldwide phenomenon over the last five years, will continue. This will be positive for the mining industry as a whole and for Australia in particular. However competition for the scarce investment dollar will also increase. Put simply, mining has many competitors, unconnected with mining, for the capture of the investment dollar. It behoves all participants to recognise that there are three investment factors which influence strongly the willingness of investors to put money into mining. These are Confidence, Credibility and Consistency. AustraliaÆs investment image stands high in these three respects, but the competition will continue to grow. AustraliaÆs lead must be maintained. However, some investment decisions should not necessarily be based on fundamental, quantifiable facors. Some of these are outlined.

Jan 1, 2004

By G Munro

he Melbourne City Link project will complete a missing link between two existing major freeways in the Melbourne road network, providing a much needed bypass of the Central Business District for through traffic. The project, which is being financed under a BOOT arrangement with the Victorian State Government, involves the upgrading of significant stretches of existing freeway and the construction of new sections involving viaducts and tunnels. The tunnel sections, which are the focus of this paper, are beneath residential and business areas, the Yarra River, the Royal Botanic Gardens and significant sporting facilities where surface construction would be either impossible or unacceptable (reference Figure 1). The shorter, 1.62 km west bound Domain tunnel comprises two cut and cover sections through Olympic Park then the Yarra River, the driven section of 0.68 km length and exits through a common cut and cover section with the east bound tunnel under St Kilda Road and Sturt Street. The longer 3.76 km east bound tunnel commences at the common portal, through cut and cover under St Kilda Road then 2.86 km of driven section before exiting at a cut and cover section at Burnley. The longer Burnley tunnel has an access and ventilation shaft at approximately its mid point.

Jan 1, 1999

By P Joyce, A S. Ray, P S. Thomas, J Haggman

Climate change and global warming present a significant challenge as unsustainable levels of greenhouse gas emissions arising from human activities continue to be emitted. The cement industry is responsible for between five and ten per cent of annual world carbon dioxide emissions; most arising from the manufacture of Portland cement (PC). An effective way of reducing emissions is by incorporating supplementary cementitious materials (SCMs) as partial PC replacements. SCMs are silicate or aluminosilicate based pozzolanic materials which, in finely divided form, combine with water and calcium hydroxide (lime), liberated by cement hydration, to form compounds exhibiting cementitious properties. Pitchstone is such an aluminosilicate and has the potential to act as an effective pozzolan for partial replacement of PC. In North Queensland, Australia, a vast deposit of pitchstone is mined and processed for expandable perlite aggregate. During the classification stage of the excavated natural material, waste pitchstone fines (PF) less than 0.5 mm in size are generated. This study evaluates the waste PF as a viable, eco-friendly pozzolan for the partial replacement of PC. The reactivity of the PF is compared to fly ash (FA), using the pozzolanic compressive strength activity index (SAI) after seven, 28, and 91 days ageing at 20 per cent and 40 per cent PC substitutions. PF was found to be comparable to FA as a pozzolan at 20 per cent PC substitution at all ages tested. However, for the 40 per cent substitution blends significant strength was only achieved at 91 days ageing for the FA blend. The pozzolanic reactivity was also investigated using thermogravimetric analysis to determine the degree of free lime present after 91 days. In all cases where an SCM was added, the free lime was observed to be consumed with increasing age.

Jan 1, 2008

The paper discusses the characteristics of Be-zymianny activity during the last 2500 years. Three periods of increased activity have been identified which are the eruptive cycles lasting for 100-400 yrs. The periods of high activity fall on the fol-lowing time intervals: 2400-1700 yrs ago, 1350-1000 yrs ago and from 1955 ixp to the present time. The 1955-1956 catastrophic eruption after a long period of repose (about 900-1000 yrs) opened a new cycle of activity of the volcano which is continuing to-day. Several decades are distinguished in activity which differ in character and intensity of eruptions.

Jan 1, 1990

By J J. Cilliers, K Hadler

Froth structure and stability are known to play important roles in determining mineral flotation recovery and selectivity. However, measuring froth stability in a consistent manner remains a significant challenge, especially at an industrial scale. Following preliminary tests on a copper concentration plant, a quantitative dynamic stability measure is investigated in this study in order to extend the results over a wider range of conditions and on a different orebody. The technique is based on the Bikerman foam test and uses a non-overflowing froth column to quantify froth stability. Experiments were carried out using an automated version of the froth stability column under different operating conditions. Air flowrate was the key operating variable. Tests were reproduced on a single flotation cell of a Platinum Group Metals concentrator. The froth stability factor, , was measured for each operating condition, and compared with the air recovery in the cell, , which was measured using image analysis. The froth stability column results gave the same trends as image analysis. In particular the froth stability factor was found to be linearly related to the actual fraction of air overflowing the cell. The metallurgical results clearly indicated that changes in air flowrate result in variations in flotation performance that can be attributed to changes in froth stability. The results showed that high froth stability conditions occur at intermediate air flowrates, and result in improved flotation performance. It is found that the froth stability column is a simple, cost-effective and reliable method for quantifying froth stability, and for indicating changes in flotation performance.

Jan 1, 2005

By D E. Langberg, J S. J va, D R. Swinbourne

Specifications on the types and levels of impurities tolerable in metals are becoming increasingly stringent, and are pushing the limits achievable with conventional refining technologies. Particularly difficult is the removal of electrochemically noble elements with low volatilities, such as copper, from more active host metals such as lead, iron and aluminium. Electrochemical refining, utilising the ability of certain solid electrolytes to selectively transport copper or other impurity cations away from the molten host metal into a separate refining phase, may provide an answer to this problem. Numerous studies on solid electrolytes used in concentration sensors have been reported, as well as a limited number on metal refining. Oxygen anion conducting solid electrolytes have been applied to the deoxidation of copper and steel while cation conductors, eg ¯ -alumina and Nasicon materials, have been used to remove lithium and sodium from aluminium. However, solid electrolytes have yet to be applied to the removal of noble elements. The behaviour of solid electrolytes under the extreme conditions of molten metal refining is not well understood. This paper will examine the potential use of solid electrolytes to remove noble metals such as copper from active host metals such as iron. The suitability, and selection criteria of available solid electrolytes for implementation in the metal refining industry in the future will be discussed. In particular, the stability of Cusicon, a copper superionic conductor potentially suitable for use in metal refining, has been assessed and the results of the experiments are presented.

Jan 1, 2000

By McLennan R. G

Mr. F. Cavanaugh (E.R.S. Co. of Aust. P'ty. Ltd.) ; What is your opinion of the expendable gauze type respirator? Would you give your views on what type of training is most effective to improve the safety consciousness of "new" New Australians?Mr. Lewis: For many jobs, the expendable gauze respirators are quite satisfactory. However, where silica dust of less than 10 micron sizing is present, they Cannot be recommended. Generally, they are more acceptable to the men than the heavier but more efficient types of industrial respirator.The best avenues of approach to training appear to be:(a) Liberal use of vi~ual aids (posters, photos, slides, etc.)(b) Efficient interpreter service.(c) Constant follow-up and check by foreman and fellow workmen.Mr. W.Marsden (B.H.P. Collieries); Most colliery employees only wear masks when they can see dust which, of course, is not the hazardous dust, and they take the mask off when they can't see the dust and so expose themselves to the hazard which is often present.Mr. W. W. SoIIy (S.A. Mines Uranium Treatment Plant) ; Safety equipment as supplied by manufacturers is inefficient and short of safety and common sense requirements-operators don't wear equipment because it is uncomfortable, clumsy, or unsightly. In the case of face masks,* they are not completely, effectively sealed; hard hats should be made even lighter and yet efficiently strong; concerning gloves, it seems not too much to ask of suppliers to put up a durable glove, preferably lined for comfort, with the maximum amount of "feel". Adaptation of, say, tubeless tyre methods...

Jan 1, 1958

By P Cameron

Many products and technologies have been developed from outcomes of research projects carried out by the Julius Kruttschnitt Mineral Research Centre (JKMRC). When these products and technologies are applied to the design and optimisation of blasting, comminution and separation, improvements in profitability can be realised. In 1970 Alban Lynch promoted two practical ideas to improve plant operations: Ore and equipment properties can be separated allowing experience with one type of ore or equipment to be transferred to other types of ore and equipment. If this experience was encapsulated in a mathematical model, then these properties could be combined and used to simulate (ie to design and to optimise) complete mineral processing circuits. Many problems associated with scale-up from laboratory to industrial equipment could be eliminated by experimental work on full-scale equipment in the plant. Many JKMRC research projects have focussed on the development of models of unit operations in mineral processing and their application to process simulation. Models of comminution and classification developed at the JKMRC have been used since the early-1980s. Ore characterisation techniques developed to support these models are licensed world wide through JKTech. The application of comminution modelling techniques to blasting, which optimises the process feed size distribution is used in Mine-to-Mill? projects. The advances in the understanding and modelling of froth flotation over recent years have provided the opportunity for integrated ore characterisation and process optimisation from resource to product. JKMRC project outcomes often provide proven opportunities for the mineral industry to improve performance and productivity. JKTech was established in 1986 to commercialise and market the most promising outcomes and thus ensure their continuing availability to the mineral industry. These include: commercial software (JKSimMet, JKSimBlast and JKMetAccount); monographs (Comminution and Blasting); technologies (Mine-to-Mill? and flotation optimisation); and hardware products (JKFrothCam, JKJetLift? and the Mineral Liberation Analyser). This paper summarises these technologies and their benefits.

Jan 1, 2002

Solid Energy New Zealand (SENZ) uses a 20+ year period for integrated planning of all its business activities. It has an ongoing program of coal resource assessment to optimise future mines within this 20 year period, using a six step resource and mine planning process. Desktop review and conceptual study at preliminary Levels 1 and 2 are based on general coal resource information. Further coal resource investigations are carried out for the more detailed evaluations in secondary assessment, prefeasibility study, feasibility study and detailed engineering from Levels 3 to 6. At Levels 1 and 2, completing conceptual planning, including preliminary resource evaluation and economic appraisal to the target cost uncertainty level of ¦33 per cent, is challenging in New ZealandÆs highly variable geological and geographical conditions. Where coal deposit geometries are relatively simple, approximate methods for determining pit limits using overburden strip ratios, seam thickness, physical boundaries, and quality cut-offs may be sufficient. Many New Zealand coalfields are however complicated structurally, with multiple seams and extensive folding and faulting. Coal seams are characterised by variable dip, thickness, and quality over relatively short distances. In the North IslandÆs Waikato coalfields, coal is typically overlain by weak sediments and clay rich strata that necessitate very flat cut and fill slope angles. The proximity of these deposits to major infrastructure (including towns, highways and rail lines), significant environmental features such as the Waikato river and lakes, and valuable dairy farmland, add further complexity. Traditional preliminary mine planning techniques applied in these conditions are insufficient. Pit optimisation software, widely used in the metalliferous mining industry since the 1980s, offers the ability to analyse many more specific factors affecting pit limits, mine layouts, and economics, with more rigour and for a much larger number of scenarios, than traditional methods allow. SENZ therefore decided to adapt and use æWhittleÆ pit optimisation software for Level 2 analysis of several Waikato opencast prospects. This paper describes this work.

Jan 1, 2005

The paper deals with the taking of soundings in connection with coal mining operations under part of the Pacific Ocean adjoining John Darling Colliery.INTRODUCTIONIn the early days of mining in the Newcastle District there did not appear to be any definite law specifying the limits to which mine workings, other than certain borings, could extend under tidal waters.As time went on, a figure of 120 ft. was fixed as the minimum thickness of strata between the roof of the seam and the sea bottom; beyond this mining operations are disallowed. The laws relating to working coal under tidal waters are as follow:-The minimum width of pillars to be left shall be eight (8) yards and the maximum width of bords or other excavations shall be six (6) yards, but the lessee may at his discretion increase the minimum width of the pillars or decrease the maximum width of the bordsor other excavations so as to increase the general safety.The eight (8) yard pillars shall be left unwrought.In on-road of every pair of Winning-off or leading headings, a bore shall be kept going ten (10) feet in advance for the purpose of foretelling the presence of any fissure, wash-out, open joint, fault, dyke, or otherwise, and all winning-off headings shall be driven atleast one hundred (100) yards in advance of the working bords.The most accurate and trustworthy information shall be obtained by the lessee not only' of the depth and character of the ocean bed, river, lake, or estuary deposit, but also of the strata overlying the coal seam.When working under the ocean, strata shall be bored through and proved a minimum thickness of thirty (30) feet at the face of the leading headings or levels immediately such headings or levels are under the ocean, and...

Jan 1, 1947

By H Aral, L Malishev

The carbothermic chlorination of titaniferous materials such as rutile, synthetic rutile (SR), upgraded slag and ilmenite in a fluidised bed is an established commercial process. In this work, ilmenite sourced from the Murray Basin area of South Eastern Australia was chlorinated and an assessment of the chlorination characteristics of the ilmenite, in terms of pre-treatment, type of reductant and reaction time was made. Selective chlorination of Murray Basin ilmenite to remove Fe and Mn was achieved in this work. A synthetic rutile sample containing around 93 per cent TiO2, one per cent Fe2O3 and 0.5 per cent MgO was produced at a chlorination temperature of 1000¦C with around 25 per cent loss of Ti as TiCl4. Raising the reductant to ilmenite ratio in the chlorination reactions increased the amount of Ti chlorinated. However, complete chlorination of Murray Basin ilmenite to produce FeCl3 and TiCl4, was not achieved under the conditions used in this work. Pre-oxidation of Murray Basin ilmenite before chlorination had little affect on its reactivity, compared with æas receivedÆ ilmenite. In contrast weathered West Coast ilmenite chlorinated appreciably better than West Coast primary ilmenite, in terms of bed residues remaining and amounts of elements removed. The presence of large amounts of Mg and chrome spinel grains in the Murray Basin ilmenite used in this study are likely to make it difficult to chlorinate directly in a commercial chlorinator. However, this is not to say these ilmenites will be unsuitable for chlorination applications. Further work is needed in the separation of Mg and chrome spinel grains from Murray Basin ilmenites and the products resulting from these tests could then be assessed in terms of chlorination performance, so that further processing options can be explored.

Jan 1, 2000

By Ho-Tun E, Stewart PSB

The definition and recognition of silver minerals is very difficult. In general such minerals occur at low concentration and can be hard to identify and measure using conventional optical mineralogy. The present paper describes the use of the QEM*SEM system to tackle this problem and provide information of use to the metallurgist. Three aspects of QEM*SEM are used to special advantage in this application. Firstly the automated mode of operation is used to make a rapid search for the sparse phases. Secondly the X-ray capability is used to identify the mineral phases. Finally the image analysis programs quantify the distributions of the minerals which are found. The paper deals with the identification stage of the process and with the use of the data which can be derived. Silver minerals which covered a range of ore types and composition were collected and studied in detail. On the basis of these measurements and information received from a number of mining companies regarding the important minerals, a classification table was prepared. This table listed about 40 different silver mineral types which could be identified by QEM*SEM and which were of interest in silver recovery processes. Where the silver occurs in solid solution in concentrations greater than about one per cent, the silver content in the species was subdivided into ranges based on statistical intervals. The QEM*SEM system was programmed to recognise these as separate species. Examples are presented of the use of the system in defining the type and morphology of the silver mineralisation to assist in the assessment of batch flotation test Samples.

Jan 1, 1993

By S R. Grano, M Vera

This paper deals with two separate case studies investigating the froth phase performance and characterisation of two industrial rougher/ scavenger flotation circuits. Froth phase performance was quantified using a mass balance approach to estimate froth zone recovery. Measured characteristics of the froth phase included frother solution concentration determined by gas chromatography, and the time taken for an equilibrium froth sample to decay to one-half of its original froth height. The latter measurement is referred to as the æfroth half-lifeÆ and is strongly linked to froth stability. Special methods and techniques developed to preserve frother in solution and to measure froth half-life are briefly described. The frother type in the first case study was a mixture of straight and branched alcohols, whilst the frother type in the second case study was a mixture of alcohols, aldehydes and triethoxybutane. The first case study focussed on a flotation circuit treating a low-grade ore containing only a small fraction of floatable copper sulfide minerals, while the second case study focussed on a flotation circuit treating a higher grade complex sulfide ore containing significant quantities of chalcopyrite, galena, sphalerite and pyrite. It was found that froth zone recovery of valuable mineral generally decreased down-the-bank of the two industrial rougher/scavenger circuits. Moreover, decreases in froth zone recovery significantly limit the overall cell recovery of valuable mineral achievable from the plant scavenger cells. However, the decrease in froth zone recovery could not be linked to the removal of frother from the pulp solution to the concentrate product in the preceding rougher flotation stages. Measurements of residual frother in solution suggested that, approximately, only five to ten per cent of the added frother was removed into the rougher/scavenger concentrate, with the remainder appearing in the scavenger tailings. This finding suggested there was apparently adequate frother in solution in the scavenger stages.

Jan 1, 2005

The design and construction of a 2.5 million tonne per annum ship unloading system at the PWCS export coal terminal in Newcastle, NSW, has further increased the flexibility and sophistication of Australia's largest coal export facility. The system comprises a new unloading wharf serviced by a self unloading vessel, conveyor stream and multi compartment ground level storage shed. Coal is reclaimed from this shed by the largest portal scraper ever installed under cover. The system also provides additional flexibility by receiving coal from the existing PWCS road receival to improve scheduling. The PWCS can now simultaneously handle 11 coal types and receive from rail, road and sea at almost 15000 tonnes per hour.

Jan 1, 1987

By R Dunne, D Yan

In flotation where a bulk flotation concentrate is produced or a gangue sulfide such as pyrite contaminates a concentrate, residual collector has to be removed from the sulfide surfaces to allow selective separation in a subsequent flotation step. Depending on the sulfide mineral, the main species that needs to be removed when using a xanthate collector is either a metal xanthate or dixanthogen. For the identification of surface species, specific solvents may be used to remove each species û metal xanthates are known to be soluble in acetone whilst dixanthogens are known to be soluble in non-polar solvents such as diethyl ether. Xanthates break down with time, temperature and pH into various decomposition products. The major decomposition product is dixanthogen which can aid flotation but other products such as perxanthate and carbon disulfide can have an adverse effect on flotation. Various analytical techniques can be employed to monitor the formation of decomposition products on the surface of the mineral and in solution. The best of these is ultraviolet spectroscopy as it has diagnostic peaks for decomposition product determination. In this work two approaches were taken to understand the relationship between the flotation of a chalcopyrite and pyrite from an ore containing these two minerals. One approach was to remove the xanthate species with an organic solvent and then use ultraviolet spectroscopy to determine the concentration of dissolved species. The second method involved measuring xanthate decomposition in solution by measuring the residual xanthate concentration using ultraviolet spectroscopy. These experiments confirmed the species adsorb at the surface of the mineral and how these species affect the recovery and grade of the valuable mineral. In both cases pH and temperature were varied and two xanthate collectors (SEX and PAX) were used to study these relationships. These relationships could be applied to industrial flotation systems and allow for more accurate determination of optimal xanthate dosage and hence save on reagent costs.

Jan 1, 2005