Example of recovery of sulfur from gold tailings (Shandong Qibaoshan Gold Mine)

Shandong Province Qibaoshan symbiotic type gold ores of copper and sulfur is gold ore, metal sulfides mainly pyrite, and another small amount of chalcopyrite, bornite, gold-bearing minerals natural gold, a small amount of silver gold; metal mirror oxides, siderite main gangue minerals are quartz, sericite and the like. The selection process uses a period of grinding and preferential flotation process, and the gold and copper concentrate products are obtained in one time. Since 1995, the sulfur concentrate has been recovered from the gold tailings. The sulfur recovery method was used to recover sulfur. However, due to the high cost, the cyclone pretreatment process was adopted in the second half of 1996, which reduced the cost of sulfur selection. 45%, achieved very good results.

The analysis of the preferential flotation tailings found that the magnetic needle not only has a high pH value, but also contains many fine lime particles. At the same time, due to the coarse granularity of the pyrite in the ore, the density is larger than that of the gangue mineral, so the cyclone is used. The gold concentrate tailings slurry is concentrated and de-sludged, and the fine mud part is discarded. The sand-sanding water and the stirring scrub can restore the floatability of the pyrite, and the sulfur concentrate is obtained through the next flotation operation. The φ350mm cyclone is installed above the agitation tank, the grit sand enters the agitation tank, and the fresh water is added at the same time. The sulfur flotation is selected by a rough selection and a sweeping process, and the xanthate is added 60g/t and the pine oil 40g/t.

The process does not use sulfuric acid, which reduces the cost of the sulfur-selected concentrate. The obtained sulfur concentrate grade is 37.6%, the recovery rate is 82.46%, and the concentrate contains less mud, which is easy to precipitate and dehydrate, and the annual benefit is about 1.2 million yuan.