Pre-selection preparation of molybdenum ore (3)

(B) the application of high chromium cast iron ball in gold molybdenum concentrator beneficiation plant genus ball high consumption, especially iron ore concentrator ball unit consumption is higher than abroad more than doubled, so the ball great consumption According to the statistics of relevant departments in China, in 1979, the domestic concentrating plant used about 240,000 tons of grinding balls in the whole year. Therefore, researching the material of grinding balls, improving and improving the performance of grinding balls and reducing the single consumption of grinding balls will start the national economy. Great energy saving effect.
The Department of Mechanical Engineering of Xi'an Jiaotong University and Jinduicheng Molybdenum Co., Ltd. jointly carried out tests on the application of high- chromium cast iron balls in molybdenum beneficiation plants, and achieved remarkable results.
High chromium cast iron is characterized by its metallographic structure: high yield strength martensitic metal matrix with discontinuous high hardness (Fe, Cr) 7C3 carbide phase, so it is especially suitable for abrasive wear. High chromium cast iron flat plate in a coal grinding mill liner as the roll sleeve and has been quite successful, its life was 3 to 4 times the original high-manganese steel and 9 to 10 times. Used as a lining in cement mills, the wear is also greatly reduced. It shows that high cast iron has a broad prospect in the case of abrasive wear, but what is the effect of high chromium cast iron under wet grinding conditions? No domestic data reported in Japan recently reported high-chrome cast iron wet grinding of copper ore wear rate of 0.4997 g / hour, we can see, although wet grinding to reduce abrasion resistance, but the high chromium cast iron wear rate is still much lower.
1. Chemical composition casting process of high chromium cast iron balls The chemical composition of high cast iron balls is shown in the table.

The casting process of the grinding ball is made by wet sand casting, and the atmospheric pressure side feeder is fed. The temperature of the tapping is 1450～1470°C, and 0.8% of the rare earth is added to the bag, and the pouring temperature is 1350～1360°C. Grinding ball heat treatment is kept at 980 ° C for two hours after the furnace temperature. Immediately after the furnace is released, the grinding ball is spread on the ground, air-cooled, and the surface hardness of the grinding ball is checked, generally Rc ≥ 60.
Jinduicheng Molybdenum Co., Ltd. originally used medium carbon steel balls produced by Handan Iron and Steel Co., Ltd. The surface hardness of steel balls is Rc52～56, and the hardness of core is Rc34～36.
2. The molybdenum ore mineral composition andesite type metal ore, granite porphyry see small object molybdenite minerals, mineral and non-current quartz, potassium feldspar, plagioclase were interspersed with other symbiotic relationship, and its hardness In terms of minerals, the highest hardness quartz is 30.5%, and the composition of molybdenum ore is shown in the table below.