Application of Double Cone Vacuum Dryer in Concentrate Smelting

Indirect drying of the concentrate is the drying process in which the drying medium does not come into contact with the concentrate during the drying process. The equipment is a multi-layer steam coil drier, a disc dryer, a paddle dryer and a double cone vacuum dryer The Double cone vacuum dryer generally use saturated steam as heating medium, the thermal efficiency is much higher than the direct drying, and the exhaust gas is small, the dust content is low, so the process is relatively simple. Multilayer steam coil driers are the first indirect dryers used to dry the concentrate. It consists of a multi-coil structure of the rotor and a fixed shell, concentrate with the rotation of the rotor forward. Due to the strong wear of the concentrate, prone to coil damage, guard and scraper wear, maintenance work is very frequent. In general, the dryer is shut down once a week. The disc dryer was used to dry the sulfur concentrate, but there were a lot of production failures: the upper part of the drying plate on the material scar, the material easily from the outer edge of the drying tray directly to the chassis and short circuit, and rake leaves easy to wear Causing the rake bar to break. These problems directly affect the drying effect and the normal operation of the drying equipment, and finally the factory is forced to pre-drying the material and then sent to the disc dryer drying, not only the process of lengthening, and investment increased. In addition, its processing power is also small. The paddle dryer is particularly suitable for dry sticky and paste materials. According to the experimental study, the drying effect of the paddle dryer on the concentrate is very good. Due to the self-cleaning effect of the paddle, the material has no bonding condition, the flow condition is good and the moisture content and grain size of the export product can meet the industrial requirements. However, due to the characteristics of the material, the blade is easy to wear and the power consumption is large, not suitable for large installations. Double cone vacuum dryer because of its energy saving and environmental protection, a single processing capacity and low power consumption advantages, has gradually become the preferred equipment for concentrate drying.
Direct drying of the concentrate is the drying process in which the drying medium is in contact with the concentrate during drying, such as cylinder drying and air drying. Direct drying generally use hot air or hot flue gas as heating medium, according to process requirements for one or two dry. Early, the smelter generally use double cone vacuum dryer, which is dry and divided into two sections (squirrel cage diffuser + drying tube) and three sections (short cylinder dryer + squirrel cage diffuser + drying tube) The Although these two methods have large processing capacity and uniform product size, there are shortcomings of low thermal efficiency, large area and complicated process.
In addition, the double cone vacuum dryer due to the vertical transport of materials, rotary kiln power consumption is high; one of the cage hopper machine due to high-speed rotation (250-300 r / rain), the rotor easy to wear, maintenance workload, 3 weeks to pay a welding -3]. In view of the above reasons, in recent years, some manufacturers began to use rotary flash dryer to dry certain concentrates (such as molybdenum concentrate). But the rotary flash dryer generally use high temperature gas as a drying medium, easy to form SO :, the equipment caused by corrosion, and the lower part of the higher speed of the stirrer, prone to wear. In addition, the double cone vacuum dryer also has a problem that the thermal efficiency is low and the processing capacity is small. In particular, it is important to note that the direct drying method suffers from exhaust gas treatment problems. The exhaust flow, dust content is high, improper handling easily lead to environmental pollution.