Commissioned by a gold mine customers in the United States, Shandong Xinhai assumed the mineral processing of the mine. The mine is located in the northern Utah, the process scale is 3500 t/d. the gold mine is hosted in the pyrometasomatic carbonate rocks and has symbiosis with pyrite, marcasite, barite, and organics. The gold is not only exist in sulfide zone, but also exists in the oxidation zone. In sulfide ore, gold ore is wrapped in pyrite, marcasite and organics in fine-grain disseminated, the free gold has symbiosis with quartz and calcite. In the oxidized ore, the gold is exist in natural state completely. The disseminated grain-size of natural gold is 10~1μm more than half is less than 5 μm.
Autogenous ore grinding, large capacity; Hollow shaft discharge with high discharging efficiency. The grinding process is two stages a closed circuit, the first stage is adopted semi-autogenously mill, when the ore and water are fed into the from the end of the hollow shaft, and then discharge from the other end of the hollow shaft. The cylinder is rotating in specified speed, the steel balls, steel bar and ore rises to a certain height along with the cylinder under the effect of centrifugal force and friction force, and they throw down and slide down from the cylinder wall; they rising to the same height with the cylinder again, then fall again, the whole process is repeated periodically, make the ore grinded by impact and grinding effect. Crushed ore is formed the pulp (wet grinding) with water, discharge from the hollow shaft of discharge-end, finish grinding process, and then pass into the screen, the material that not meet the particle size is returned to the semi-autogenous mill, and standard material can be returned to the semi-autogenous mill or piling up.
The grinding ratio is large, greatly reduces the overgrinding, and improves the grinding efficiency. The grinding ratio is very large, which is finished grinding through the crushed material itself as the medium, simplify the crushing and grinding process greatly. The ore crushing is finished by the impact when free-falling, the grinding between ore fines and the ore instantaneous stress suddenly from pressure state into full tension, avoiding overgrinding phenomenon. Xinhai efficient autogenous mill can achieve two and three stage crushing, part or full grinding of ball mill and rod mill, which is suitable to the coarse grinding after coarse crushing process. Finally in the actual production, Xinhai efficient autogenous mill improved the production efficiency and controlled the grinding cost, the customer is satisfied with the result.