At present, the drying of mineral processing products mainly uses rotary kiln, cylindrical dryer directly or indirectly heated, electric drying oven, far infrared drying equipment and the like. However, these devices have a large area, high energy consumption and low heat utilization rate. At the same time, the automation of equipment operation is low, the loss of products in the drying process is large, and the drying cost is high, which seriously affects the economic benefits of the plant. At present, the drying technology is developing rapidly, and the research and application range of spray drying, fluidized bed drying and airflow flashing dryer are very extensive. According to the characteristics of mineral processing products, combined with the new drying technology of other industries, a high-efficiency flash dryer suitable for mineral products was developed on the basis of airflow drying, also known as rotary pulverizing airflow rapid drying equipment.

1 working principle and system composition

The high-efficiency flash dryer is a type of airflow drying device, and the drying medium is hot air. The working principle is as follows: the air is heated by the air blower and enters the dryer after being heated in the heat exchanger. The rotating hot air is in contact with the wet material dropped by the feeder, so that the surface layer of the wet material is quickly dried, due to the mechanical impact of the rotating blade and the high-speed rotating heat. The blowing action of the air stream causes the material to be struck, sheared and rubbed in a floating state, and the materials bonded together are loosened and quickly dried. The material is subjected to the drying process (within a few seconds) in the dryer by the axial thrust of the blade and the tangential wind of the swirling airflow. The dried powder enters the cyclone and the bag trap with the air flow, and the finished product is discharged through the star unloader, and the exhaust gas is discharged through the induced draft fan.

2 equipment features

2.1 drying host

Using the principle of airflow drying and flash drying, the drying host is designed as an airflow flashing compound dryer. The main unit's mixing device is equipped with five mixing series, each of which has three assembly forms. The test found that the rotating device for mineral products is in the form of multi-blade and multi-layer. The volumetric heat transfer coefficient hv of the main unit is 75640kJ (h·m3·°C), and the thermal efficiency is high, which can reach more than 90%. The problem. The design speed of the stirring device is 300-1400rmin, and the transmission mechanism is simple and easy to maintain. In order to meet the drying characteristics of various mineral products, the vertical (L type) and horizontal (W type) host types are designed. The L-type mainframe has no classifier and has a small aspect ratio. It is suitable for minerals with large dry density and finer grain size. The W-type main engine's mixing blades are made of wear-resistant materials, and the spacing is increased from the inflow end to the dry density. A coarse-grained mineral product. The W-type mainframe solves the problem that the vertical structure wind needs too much.

2.2 collection system

Drawing on the technical advantages of the dry collection system of the chemical industry (including cyclone separators and bag traps), the rotary anti-drying cylinder bag trap and the long cone cyclone separator for the monolithic operation of mineral products have been developed. The collection system has the following characteristics: the product collection rate can reach 85%-95% in the cyclone; the cloth bag has a small footprint, the processing capacity per unit area is large, and the pressure loss is small, and the power of the induced draft fan of the system is reduced, achieving energy saving. The purpose of reducing consumption; the cloth bag of the bag is made of a needle-punched filter cloth, which has the characteristics of heat resistance and good gas permeability, can ensure the material loss is below 0.1%, and the exhaust gas has low dust-containing rate and meets environmental protection requirements; The combination of the device and the bagger makes the drying process of the mineral product completely closed, the product has high purity, high recovery rate, no pollution to the environment, and improved operating conditions.