Showing papers in "Minerals Engineering in 1998"

TL;DR: In this article, a model of a S m diameter ball mill is presented and the charge behaviour, torque and power draw are analyzed for a range of rotation rates from SO to 130% of the critical speed.

TL;DR: A review of the advances in the microwave treatment of minerals from the early stages of development to possibilities for future utilisation is presented in this article, where many different applications are considered, including fundamental heating rate studies, microwave assisted grinding, possible exploitation in the area of extractive metallurgy and also microwave treatments of coal.

TL;DR: In this paper, an empirical partition curve is proposed to describe the degree of entrainment within a conventional flotation cell, and two empirical parameters are defined: • • Entrainment parameter (ζ) is defined as the particle size for which the maximum entrainments are 20% and • • Drainage parameter is related to the preferential drainage of coarse particles.

TL;DR: In this paper, an ilmenite concentrate has been ball milled for up to 100 h in a laboratory mill without any evidence of a phase change, and it was found that there were two stages of dissolution, a rapid stage which was mass transport controlled (e.g., E a = ∼15 kJ mol −1 ) and a second, chemically controlled stage (e a = approximately 70 kJmol −1 ).

TL;DR: In this article, a modified flotation rate constant, K m, is introduced, defined as the product of R ∞ and k, which is the slope of the tangent of the recovery-time curve at zero flotation time.

TL;DR: In this article, a review of the work carried out on oxidative roasting of chalcopyrite and related constituents such as copper sulphide and iron sulphide is presented.

TL;DR: In this article, a 3 m3 cell fitted with four different impellers treating plant zinc cleaner feed ore was used at Scuddles concentrator in Western Australia to validate the findings at Hellyer for a different ore.

TL;DR: In this paper, the authors examined the effect of froth height to surface area flux (S b ) on the kinetics of flotation, by reevaluating and re-interpreting these results.

TL;DR: A critical analysis of available information and data, based on several case studies, flotation testing, and microscopic analysis indicates that alkyl hydroxamates can effectively recover well defined oxide minerals of copper, but not copper occurrences such as Cu-bearing goethite (often misidentified as cuprite) which report as Acid Soluble copper in chemical assays as mentioned in this paper.

TL;DR: In this paper, the effect of collectors, conditioning pH and gases on the selective flotation of sphalerite from pyrite in the presence of Cu(II) has been investigated.

TL;DR: In this paper, a review of froth recovery in steady state flotation systems is presented, where the authors identify the significance and usefulness in the modelling and scale-up of the froth phase.

TL;DR: In this article, an expert system for the supervision of flotation plants based on ACEFLOT, a real time analyzer of the characteristics of the froth that is formed on the surface of the flotation cells, is described.

TL;DR: In this article, a rehabilitation scheme is proposed for all affected areas, aiming at deactivating the pollution sources and rehabilitating the contaminated areas with remedial actions, which involves mainly removal of toxic and heavy elements from sulphidic tailings and leachates with biosorption and biosolubilisation techniques and development of a vegetative cover on phosphogypsum, cinders and sulphidics tailings.

TL;DR: In this article, the influence of several grinding parameters on the product fineness in jet mill grinding was studied experimentally with a laboratory scale spiral type jet mill, and the most significant variables in the jet mill were feed rate, volumetric flow rate of grinding air and the height of an inside classification tube for grinding at constant pressure.

TL;DR: The derived models for the selection function and the Andrews-Mika diagram can be used to simulate the effects of the processes that produce non random fracture, and thus to assess their relative importance, and also to simulations the behavior of the ore in continuous milling and concentrating circuits.

TL;DR: In this paper, an optimized flotation circuit was designed to improve the flotation rate of pulp generated in an operating plant using a locked cycle test, which indicated that substantial improvements in the plant circuit were possible.

TL;DR: In this article, the application of fuzzy logic to supervise a distributed basic control in a flotation column is discussed, and two control strategies are developed and tested to manage three basic distributed controllers: an expert supervisor, mainly based on rules following a binary logic, and a fuzzy supervisor.

TL;DR: The utility of Bacillus polymyxa, a heterotrophic bacterium indigenous to ore deposits in the degradation of several flotation collectors has been demonstrated as discussed by the authors, showing that Dodecyl amine, diamine, isopropyl xanthate and sodium oleate could be efficiently removed from alkaline solutions through bioremediation in an environmentally acceptable fashion.

TL;DR: In this article, a preg-robbing amorphous carbon and graphite were identified in two ore samples using optical microscopy to identify the mineral phases, followed by the direct analysis of gold on these phases using electron microprobe analysis.

TL;DR: In this paper, the authors measured the zeta-potential and settling rate of pyrite and galena in the presence of Ca, Pb and Fe(II) ions.

TL;DR: In this paper, an experimental study of the froth zone behavior in an industrial flotation column, is presented, which is part of the second copper cleaner circuit of the Colon concentrator at El Teniente, Codelco-Chile.

TL;DR: In this article, the authors discuss the architecture of a simulation model that permits the detailed simulation of interconnected material cycles in view of realising the ISO 14000 norm and other imposed environmental legislation.

TL;DR: In this paper, the removal of Hg, As and Se ions from processing streams of gold cyanidation circuits was studied by dissolved air flotation (DAF) at laboratory scale.

TL;DR: In this paper, the zeta potential and agglomeration of sphalerite in the presence of Ca, Pb and Fe(II) ions was studied in terms of the iso-electric point (Ip).

TL;DR: In this article, the leaching kinetics of sphalerite with pyrite, in water saturated in chlorine, have been investigated, and the mechanism of dissolution reaction for sphalite and pyrites was found to be diffusion controlled through the product layer.

TL;DR: In this paper, mixed cultures made up of pure Thiobacillus ferrooxidans, Thiooxidants and Leptospirillum ferrooxideidans strains of the DSM collection were batch tested for their ability to oxidize a cobaltiferous pyrite ore.

TL;DR: In this article, an expert and predictive multivariable control algorithm for a conventional copper flotation circuit was assessed through simulations. But the simulation was carried out with a nonlinear dynamic model, derived from mass balances and empirical relationships, that qualitatively reproduced the dynamic behaviour of real plant well.

TL;DR: In this paper, the operating practices in the beneficiation of porphyry copper ores from Chile are reviewed and the factors which affect plant metallurgical results are discussed including: ore mineralogy, reagent scheme and flowsheet.

TL;DR: In this article, a detailed experimental program was performed on a continuous Falcon Concentrator, which was found to achieve separations at mass throughput capacity values in excess of 75 tonnes/hour.

TL;DR: In this article, new collectors, oleoyl sarcosine and hydroxamate, reported for the first time in the literature, have been used to float titanium impurities in Turkish feldspar ores.