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The surface physicochemical properties of cervantite are similar to the gangue minerals, so it is difficult to achieve the flotation separation of cervantite from them. In order to improve the floatability of cervantite, the phase and floatability changes of cervantite were investigated by the sulphidization roasting with element sulfur in reducing atmosphere and flotation tests. Cervantite did not float while using isoamyl xanthate as collector. But its floatability improved greatly by the sulphidization roasting with element sulfur, and a sulfide layer of Sb2S3 is found to be the key component which causes the hydrophobic of sulphidized cervantite. The flotation recovery of sulphidized cervantite increased from 5% to 95% while the molar ratio of S:Sb changed from 0 to 1.5. In other words, the floatability of the sulphidized cervantite increased with the increase of sulfide layer thickness. However, the sulfide layer thickness depended on the additive amount of element sulfur, roasting time and t...

Coal and gas outbursts usually generate a large amount of coal fragment of various sizes. This phenomenon is assumed to be related to the exploding and shattering of coal containing high-pressure adsorbed gas when it is suddenly exposed. To verify this assumption, a laboratory device has been developed to test the shatter proneness of coal blocks at high pressure. Experiments were conducted by using coal blocks sampled from four different mines. The experiments show that if the gas pressure is high enough, all coal blocks can be shattered. The particle size of the shattered coal follows the Weibull distribution. Under specific gas pressure, the shatter proneness of coal can be represented by the scale parameter in the Weibull distribution function derived from experiments. This parameter represents the susceptibility of outburst and may be used as one of the outburst predictive indicators in the future.

A new technology, sulphidization roasting of antimony mineral cervantite with elemental sulfur followed by froth flotation is reported in this paper. The effects of roasting temperature and time, sulfur to antimony molar ratio on the properties of treated product and its flotation behavior were studied. Optimum roasting conditions are: roasting temperature 723 K; roasting time 30 min; and sulfur to antimony molar ratio of 1.5. Under these conditions, the mineral phase changed from cervantite to stibnite as expected. The flotation recovery of the sulphidized cervantite is over 90%. A flotation concentrate grading 21.04% Sb with a recovery of 77.15% is achieved by sulphidization roasting and flotation from a feed grading 1.11% Sb in which cervantite is the main antimony mineral.