Leaching of a Mongolian chalcopyrite concentrate

A Mongolian chalcopyrite flotation concentrate was leached using sodium hypochlorite adjusted to different pH using hydrochloric acid. It was found that using a starting pH of below 5.0 resulted in more efficient leaching. The extent of chalcopyrite leaching was determined by the concentration of sodium hypochlorite with > 40% dissolution being achieved. The residue after leaching was found to consist primarily of unreacted chalcopyrite which would be suitable for further leaching or smelting

Enhancing lithium leaching by mechanical activation

The lithium (Li) bearing minerals lepidolite and spodumene were mixed with different mass ratios of Na2SO4 and mechanically activated by milling in a planetary ball mill for 5 h. The milled samples were studied using thermogravimetry under an air atmosphere up to 950 ºC. Isothermal heating of the milled samples was undertaken in a furnace at temperatures of 700 ºC and 800 ºC for 1 h. Hot water leaching of the calcines indicated that increasing the calcination temperature had a significant effect on the dissolution of lithium. The leaching of lithium from lepidolite was notably higher than that from spodumene

A comparison between structural and magnetic behavior of cobalt ferrite synthesized via solid state and chemical methods

Cobalt ferrite oxide (CoFe _2 O _4 ) was synthesized by two different methods of mechanochemical and combustion. The phase composition and the chemical bonding information of the two powders were investigated by x-ray diffraction (XRD) method and Fourier Transform Infrared Spectroscopy (FT-IR). Field emission scanning electron microscopy (FESEM) was used to study the microstructure and morphology and elemental analysis was performed with EDS. The magnetic properties were analyzed at room temperature using a vibrating sample magnetometer (VSM). According to the structural and elemental analyses, cobalt ferrite was directly synthesized in the combustion method. However, the mechanochemical route was not successful in phase formation, even after heating at high temperatures. The hysteresis loops of VSM analysis showed that the CoFe _2 O _4 powder from combustion method resulted in higher saturation magnetization and coercive field than the powder synthesized by mechanical milling. The inferior magnetic behavior of the powder from solid state method is attributed to the presence of Co ^3+ in the starting powder, which results in a non-spinel complex between cobalt and iron ions