Enhanced copper recovery from low grade copper sulfide ores through bioleaching using residues produced by fermentation of agricultural wastes

Effects of residues produced by agricultural wastes fermentation(AWF)on low grade copper sulfide ores bioleaching,copper recovery,and microbial community were investigated.The results indicated that adding appropriate bulk of AWF made contributions to low grade copper sulfide ores bioleaching,which may be mainly realized through reducing the passivation layer formed by Fe3+hydrolysis.Improved copper recovery(78.35%)and bacteria concentration(9.56×10^(7)cells·mL^(−1))were yielded in the presence of 5 g·L^(−1)AWF.The result of 16S rDNA analysis demonstrated that microbial community was differentiated by adding AWF.Bacteria proportion,such as Acidithiobacillus ferrooxidans,Moraxella osloensis,and Lactobacillus acetotolerans changed distinctly.Great difference between samples was showed according to beta diversity index,and the maximum value reached 0.375.Acidithiobacillus ferrooxidans accounted for the highest proportion throughout the bioleaching process,and that of sample in the presence of 5 g·L^(−) AWF reached 28.63%.The results should show reference to application of agricultural wastes and low grade copper sulfide ores.

Heap-Leaching of Low-Grade Uranium Ore at SOMAIR： From Laboratory Tests to Production of 700 Tonnes U Per Year

In 2006, SOMAIR decided to increase the uranium production by 50% using heap leaching for the treatment of low grade ores. These ores, which come from different lodes with various properties, have been studied in four steps： （ 1 ） Lab tests： to compare the ores （characterization, acid consumptions, recovery...）; （2） Column tests on an average sample： to define significant parameters for a feasibility study; （3） Column tests on specific samples： to optimize recovery for each ore and identify problems of percolation due to the clays; （4） Pilot tests in large boxes （stalls）： to validate process parameters. Uranium production by heap leaching started in July 2009.

Dissolution kinetics of low grade complex copper ore in ammonia-ammonium chloride solution

The leaching kinetics of Tang-dan refractory low grade complex copper ore was investigated in ammonia-ammonium chloride solution.The concentration of ammonia and ammonium chloride,the ore particle size,the solid-to-liquid ratio and the temperature were chosen as parameters in the experiments.The results show that temperature,concentration of ammonia and ammonium chloride have favorable influence on the leaching rate of copper oxide ores.But,leaching rate decreases with increasing particle size and solid-to-liquid ratio.The leaching process is controlled by the diffusion of the lixiviant and the activation energy is determined to be 23.279 kJ/mol.An equation was also proposed to describe the leaching kinetics.

Effect of technological factors on bacterial leaching of low-grade Ni-Cu sulfide ore

The bioleaching of a low grade Ni Cu sulfide ore from Jinchuan Mine with Thiobacillus ferrooxidans (TF5) and Thiobacillus thiooxidans (TT) was investigated. The effect of pH, the initial cell numbers of bacteria, the pulp density and the ratio of TF5 and TT on leaching was described, and the favorable bioleaching conditions for the ore were experimentally confirmed. The aeration leaching, agitation leaching with air bubbling, and column leaching were respectively tested. The highest recovery was achieved in the aeration leaching. After leaching for 20?d with pulp density of 15%, the extractions of Ni, Cu and Co were respectively 95.4%, 48.6% and 82.6%.

Flotation technology of refractory low-grade molybdenum ore

Because of the low grade, high oxidation rate and the accumulation of little associated metal sulfide ore in the molybdenum concentrate during flotation, the Qingyang molybdenum ore is difficult to beneficiate. The experimental studies of grinding fineness, the amount of roughing modifier, depressant and collector were completed. In the cleaning process, the contrast experiments of one regrinding, the regrinding and scrubbing, two-stage regrinding was carried. The result shows that the grade of molybdenum ore concentrate is 45.31%, the recovery is 65.98% and the rich ore ratio reaches 20.59% by the regrinding and scrubbing seven cleaning, the regrinding of concentrations from middling of molybdenum-sulfur separation. The regularly-concentrated material from the apparatus was as the middling products. Hence, ideal beneficiation index can be obtained with a rational mineral processing, which offers new beneficiating technology for the refractory low-grade molybdenum ore in China.

Making Ferronickel from Laterite Nickel Ore by Coal-Based Self-Reduction and High Temperature Melting Process

Based on the process of coal-based self-reduction and melting separation at high temperature, it was investigated that the effect of process factors on the reduction of iron and nickel oxide, the metal yield and the nickel content in ferronickel about the laterite nickel ore, was from Philippines and contented low nickel, high iron and aluminum. The results showed that if the C/O mole ratio was not higher than 0.5 and the reduction temperature was kept as 1200°C and then increased up to 1500°C, the metal could not separate from molten slag for the A series of experiments, which were only added CaF2. However, when the C/O ratio was added up to 0.6 - 0.8, the metal could separate well from the slag, and the yields of Fe and Ni increased gradually. But the nickel content in the metal declined from 1.79% to 1.34%. When the C/O ratio increased to 1.2, and the temperature of melting products obtained at 1200°C and rose to 1550°C, the separation of metal from slag could not be realized in B group of tests, which were only added hydrated lime. However, when both of CaF2 and hydrated lime were added, the metal could separate from slag in C group. In order to increase the content of nickel in the metal, it is necessary to restrain the reduction of iron oxide. When the C/O mole ratio is 0.6, the nickel content of metal could be 1.79%, which was higher than the theoretical ratio 1.65% of Ni/(Ni + Fe) of the latcritic nickel ore, but the yield of nickle was only 71.3%.