Mechanical activation was used to improve the extraction of chromium in molten NaOH. It is observed that the extraction ratio reaches 97% after leaching for 200 min when chromite ore is mechanically activated for 10 min, but only 34% if not activated. Mechanical activation can decrease the particle size, increase the surface area, and enhance the …

The results showed that the carbothermal reduction temperatures of reducible oxides in the chromite spinel were decreased after mechanical activation, due to …

Effect of mechanical activation on alkali leaching of chromite ore [J] Transactions of Nonferrous Metals Society of China (2010) Shi-li ZHENG et al. ... Because the decomposition of chromite ore was carried out in high concentration alkaline liquor, agitation speed was very significant for mass transfer of materials (Zhang et al., 2010b ...

An alternative enrichment method is proposed, i.e., mechanochemical activation in the presence of chlorides (NaCl, CaCl 2 ). Mechanochemical activation …

The effects of mechanical activation on the soda roasting of chromite were investigated in this study. Structural changes in mechanically activated chromite were …

This study aimed to introduce a new cost-effective methodology for increasing the leaching efficiency of chalcopyrite concentrates at ambient temperature and pressure. Mechanical activation was employed during the leaching (mechanochemical leaching) of chalcopyrite concentrates in a sulfuric acid medium at room temperature and …

2.2 Mechanical activation of chromite samples The mechanical activation of chromite ore was performed in a planetary mill PuLuerisette 6 (FRITSH, Germany). 50 g of chromite ores were ground with 400 g

Mechanical activation was used to improve the extraction of chromium in molten NaOH. It is observed that the extraction ratio reaches 97% after leaching for 200 min when chromite ore is ...

This chapter contains sections titled: Introduction Crystal Structure of Chromite Minerals Thermal Decomposition of Chromites Alkali Roasting of Chromites Leaching of Chromite Minerals Ch...

Mechanical activation of Ca/Mg silicates by grinding is a pre-treatment of some mineral carbonization processes. In this study, the mechanical activation of lizardite ore from a chromite beneficiation plant waste by grinding in a stirred media mill was studied. For grinding studies, grinding times of 10-20-30 min and stirring speeds of 600 …

The carbothermal reduction of mechanically activated chromite with metallurgical coke under an argon atmosphere was investigated at temperatures between 1100 and 1400°C and the effects of the mechanical activation on chromite structure were analyzed by x-ray diffraction (XRD) and scanning electron microscopy (SEM).

The economic and technical values of the hydrometallurgical or leaching processing are a function of its reaction rates and these reaction rates are enhanced by mechanical activation (MA) in hydrometallurgical processing. This study presents a novel derived theoretical model for MA-assisted leaching in investigating the effects of ball mill …

The mechanical activation of chromite concentrate was performed in a Planetary Mono Mill Pulverisette 6 under the following conditions: the weight of the sample was 10 g; the …

The effects of mechanical activation on the soda roasting of chromite were investigated in this study. Structural changes in mechanically activated chromite were examined using X-ray diffraction analysis (XRD), surface area analysis (BET) and scanning electron microscopy (SEM).

The oxidation reaction of chromite by molten sodium salts was studied in the temperature range of 270N3500C. The grain size of chromite ores were kept constant …

This type of milling can also initiate phase transformations 109 or activate powders for further processing 110,111, thus reducing the length of time needed for mechanical activation to obtain ...

Abstract The carbothermal reduction of mechanically activated chromite with graphite under an argon atmosphere was investigated at temperatures between 1100 and 1400°C and the effects of the mechanical activation on chromite structure were analysed by X-ray diffraction, scanning electron microscopy and specific surface area measurement. …

The carbothermal reduction of mechanically activated chromite with metallurgical coke under an argon atmosphere was investigated at temperatures between 1100 and 1400°C and the effects of the mechanical activation on chromite structure were analyzed by x-ray diffraction (XRD) and scanning electron microscopy (SEM). An increase in specific …

The impact of mechanical activation on bioleaching of pyrite is studied. ... Traditional wet and dry Chromite Ore Processing Residue (COPR) detoxification methods consume acid for pH adjustment and produce greenhouse gasses (CO 2), yielding potential secondary pollution. It is imperative to develop an environmentally-friendly, …

This reflects the partial amorphization and structural disordering in chromite. Mechanical activation has already been reported to amorphize mineral particles[10, 11]. Tromans and Meech[13,14 ...

The carbothermal reduction of chromite with graphite under argon atmosphere was studied by differential thermal analysis up to 1350°C and the effects of mechanical activation on the chromite ...

Abstract. The carbothermal reduction of mechanically activated chromite with graphite under an argon atmosphere was investigated at temperatures between 1100 and 1400°C and the effects of the mechanical activation on chromite structure were analysed by X-ray diffraction, scanning electron microscopy and specific surface area …

It was observed by Zhang et al. (2010) that the mechanical activation significantly accelerates the extraction of chromium from chromite ore, in NaOH medium. The influence of mechanical activation of chalcopyrite on the selective leaching of copper in sulfuric acid medium was studied by Achimovicová et al. (2006).

In addition, Apaydin et al. (2011) studied the effect of mechanical activation on carbothermal reduction of chromite with graphite, and found that the activation process led to amorphisation and structural disordering in chromite, and accelerated the reduction and metallisation in the mixture of chromite and graphite. Mechanical activation can ...

Effect of mechanical activation on alkali leaching of chromite ore @inproceedings{2010EffectOM, title={Effect of mechanical activation on alkali leaching of chromite ore}, author={ and and and and }, year={2010} },, +2 authors ; Published 2010; Geology

Tests for mechanical activation were accomplished in a vibration mill type ML-30 with a capacity of 0.5–0.2 kWh and a rotation of 1500–2400 min –1. The dimension of original chromite concentrate before grinding was 0.074 mm (about 95%), and after grinding less than 10 μm. The capacity of the steel drum was 150 cm 3. The grinding …

Mechanical activation was used to improve the extraction of chromium in molten NaOH. It is observed that the extraction ratio reaches 97% after leaching for 200 …

The carbothermal reduction of chromite with graphite under argon atmosphere was studied by differential thermal analysis up to 1350°C and the effects of mechanical activation on the chromite ...

The soda-ash roasting of chromite ore processing residue for the reclamation of chromium", Metallurgical and Materials transactions B 32 (B) (2001), ... Z. Yang et al., "Effect of mechanical activation on alkali leaching of chromite ore", Transactions of Nonferrous Metals Society of China 20 (2010), 888–891.

In contrast, without CuO, the rate-determining step was external diffusion and the apparent activation energy was 38.01 kJ/mol. Key words: chromite ore; copper oxide; leaching; catalytic oxidation 1 Introduction Chromate production from the chromite ore is an important metallurgical process but it is usually associated with gross pollution [1,2].