Assessment of reagent and regrinding in a flotation circuit

Laboratory flotation tests using a bottom driven cell are reproduced with a high level of confidence. These types of laboratory data are used to investigate the effect of reagent and regrinding of coarse particles in an industrial flotation circuit. The addition of collector (BX) has a significant effect on the flotation response of chalcopyrite in the scavenger bank. The reconstructed recovery-time curve (combine products) is greater than that of the rougher tailings (scavenger feed) prior to reagent addition. By adding collector (BX) in the scavenger feed, the ultimate recovery of chalcopyrite increases 20% which means an increase of 1.7% of chalcopyrite recovery in the scavenger feed. Meanwhile, the reagrinding of coarse particles shows a detrimental effect on the collectorless flotation of an initially hydrophobic chalcopyrite sample. Cyclone underflow, 80% recovery at pH 7.7, was decreased to 40% after regrinding at the same range of pH. The chalcopyrite flotation response immediately after regrinding is severely retarded. It is assumed that the centrifugal action of the cyclone is another important factor restoring the chalcopyrite hydrophobic flotation due to the oxygenation of the slurry. Therefore, additional preconditioning time after a regrinding stage should have a positive change in the recovery of chalcopyrite. The overall flotation response before and after the regrinding stage showed that the cyclone underflow response is slightly slower compared with the combine feed in the first four minutes of flotation. This behavior is related to changes on surface chemistry because of the regrinding of coarse particles

Mineral liberation by high voltage pulses and conventional comminution with same specific energy levels

Comparative comminution between high voltage pulses and conventional grinding, at the same specific energy levels, shows that the electrical comminution generates a coarser product with significantly less fines than the mechanical breakage. However, minerals of interest in the electrical comminution product are better liberated than in the conventional comminution with an over 95% statistical significance. There is a potential to use less energy in the electrical comminution to generate the similar degree of mineral liberation as in the mechanical comminution. Distribution of the liberated minerals demonstrates that, in the electrical comminution product, a large percentage of the liberated minerals appear in size fractions coarser than 53 μm; while in the mechanical comminution product, the liberated minerals are accumulated in fine and very fine size fractions. Therefore there may be potential benefits in recovering the coarse liberated minerals in the electrical comminution product, prior to further grinding

Relating the mineralogical characteristics of Tampakan ore to enargite separation

The mineralogical characteristics of enargite-bearing copper ores from the Tampakan deposit have been investigated as the means to understanding the separation of enargite from other copper sulphides (chalcopyrite and bornite). It was found that a separation of these minerals was possible after grinding the ore samples to a P of 90 microns; enargite tends to be ground more readily than the other copper sulphide minerals present in ore samples tested, and consequently, it mostly reported to the fine size fractions

Pre-concentration of copper ores by high voltage pulses. Part 1: principle and major findings.

A novel ore pre-concentration technique using high voltage pulses is proposed in this study. The technique utilises metalliferous grain-induced selective breakage, under a controlled pulse energy loading, and size-based screening to separate the feed ore into body breakage and surface breakage products for splitting of ores by grade. Four copper ore samples were tested to demonstrate the viability of this technique. This study consists of two parts: Part 1 presents the principle, the validation and the major findings; Part 2 discusses the new opportunities and challenges for the mining and mineral industry to take up this technique

Methods for improving the flotation recovery of the coarse fraction of a nickel ore

Coarse particle size fractions (100 - 150 μm) generally have a poor response to flotation. This is mainly due to the low prospect of the particle-bubble aggregates withstanding the shearing forces in the flotation cell. Since particle-bubble attachment and detachment are directly related to the hydrophobicity of the particle, the most practical way to improve the fl otation of coarse fractions is to enhance their hydrophobicity. In this study, diesel oil, in addition to Potassium Amyl Xanthate (PAX), was used as an extender collector to fl oat the coarse fraction of a nickel ore in a laboratory batch flotation cell. Two different methods of oil addition were explored: oil was either emulsified with water and added to the flotation cell, or emulsified together with water and xanthate and then added to the flotation cell. It was shown that in both cases the oil addition increased the nickel recovery compared to the base case, but at the expense of concentrate grade. A high degree of entrainment, which was associated with extremely high water recoveries, was typical for flotation tests with the oil addition. The addition of collector via aerosol was also tested, as a way of introducing the collector with the air phase. This improved the quality of concentrate in terms of the nickel grade, at the expense of the lower nickel recoveries. The flotation rates of particles from flotation tests using these different methods are compared and discussed

Relating mineralogical and testural characteristics to flotation behaviour

Having knowledge of the ore mineralogy and texture can provide valuable information for effective design of a concentrator flowsheet. Specifically, these characteristics help in setting the appropriate grind size to achieve liberation and minimise overgrinding, and assist in identifying suitable flotation parameters to achieve optimum separation. This paper aims to obtain an understanding of the flotation behaviour of an ore by examining its mineralogical and textural features, particularly grain size distribution. Four samples with varying copper recoveries were obtained from different locations in a copper porphyry deposit. The samples were crushed to 4 mm and measured using a Mineral Liberation Analyser to determine the mineralogical characteristics of each. The mineralogical characteristics that were found to vary included: copper deportment and grain size and copper mineral association. This information was used to interpret batch flotation behaviour particularly copper recovery. (C) 2015 Elsevier Ltd. All rights reserved

Pre weakening of mineral ores by high voltage pulses

A new comminution method has been developed by applying high voltage pulses at specific energy 1-3 kWh/t to pre-weaken mineral particles, leading to reduction in energy consumption in the downstream grinding process. Four ore samples were tested using high voltage pulses and conventional crushing in parallel for comparison. Evidence of cracks and microcracks measured with X-ray tomography and mercury porosimetry supported the principle of high voltage pulses induced damage on rocks in the electro-comminution process, which resulted in energy saving up to 24% found in this study. Ore surface texture and mineral properties affected the efficiency of high voltage pulse breakage. The feasibility of the electro-comminution and its benefits need to be investigated case by case. © 2010 Elsevier Ltd. All rights reserved

Recent developments in high voltage electrical comminution research and its potential applications in the mineral industry

In the current energy-sensitive world, sustainable development in the mineral industry will require new, better and more efficient processes. Novel comminution methods, which offer the prospect of achieving the required outcomes of size reduction and mineral liberation at lower energy consumption, are continually being sought. In the past five years, extensive research using high voltage pulse electrical comminution technology has been carried out at the Julius Kruttschnitt Mineral Research Centre (JKMRC), in collaboration with seiFrag AG. The major outcome of this research is the development of the concept of pre-weakening ore particles by electrical comminution procedures to reduce the energy consumption in the downstream grinding circuit. The research has also verified the preferential liberation of valuable minerals by electrical comminution. Given the advantages, several potential applications of electrical comminution in the mineral industry are proposed, including AG/SAG mill feed pre-weakening, pebble treatment, ball mill feed pre-weakening, early recovery of the liberated valuable minerals, crack/micro crack generation for improved leaching, and smelter slag treatment. For the mineral industry to utilize electrical comminution, two emerging issues identified from the research need to be address. They are the energy consumption by electrical comminution in the locked cycle treatment and the facilities scale up necessary to move this technology from the laboratory to the plant

Apparatus and method for determining the breakage properties and probability of breakage of a particulate material

An apparatus for determining the breakage properties of a particulate material, the apparatus including: a support; a rotor mounted relative to the support and including at least one guide channel through which a particle of the particulate material is guided in use, the guide channel having an inlet and an outlet; a drive associated with the rotor; a feed channel for feeding particles of the particulate material to the inlet of the guide channel; a stator associated with the rotor and including an impact surface that is radially spaced from a circumferential edge of the rotor; and a collector for collecting pieces of the particulate material following impact; wherein the apparatus is provided with a control system for accurate control and adjustment of impact velocity of the particulate material with the impact surface

Effect of mineralogy on the selective flotation of enargite

Arsenic (As) is highly toxic inorganic pollutant, which causes human health and environmental problems. Enargite is a copper-arsenic bearing mineral with surface properties that bear strong similarities to common copper minerals. Recent research by CSIRO demonstrated promising results showing that it is possible to separate copper arsenic sulphides from copper sulphides using controlled potential flotation at laboratory scale with model mineral systems. However, the selective removal of copper arsenic minerals in real ore systems is less well understood, particularly, the effects of mineralogical properties such as liberation and mineralogical association. This study seeks to investigate selective separation of copper-arsenic minerals from a copper sulphide ore in a batch flotation system under controlled pulp potential. This Part I paper summarizes the current state of knowledge related to enargite separation. It then describes the results of the mineralogical characterization of the ore samples, the experimental method, and the initial results