Alumina circulating fluidized bed roasting furnace is mainly used for roasting aluminum hydroxide. Its structure and refractory material selection are crucial to ensure the smooth progress of the roasting process and product quality. The following is a detailed analysis of the alumina circulating fluidized bed roasting furnace and its refractory material selection:
1. Structure of alumina circulating fluidized bed roasting furnace
Alumina circulating fluidized bed roasting furnace consists of multiple components, including conical cyclone, venturi dryer, fluidized bed roasting furnace body, feeding screw, fluidized bed cooler, revolving bed, discharge trough, discharge pipe, air duct and flue. The equipment is basically cylindrical in shape, with an outer diameter of 5.8m and a height of 32m. The outer shell of the equipment is welded by steel plates, and the inner lining is made of a variety of refractory materials to ensure its high temperature resistance, wear resistance and high strength.
2. Refractory material selection
The refractory material selection of alumina circulating fluidized bed roasting furnace must meet the requirements of high temperature resistance, wear resistance, high strength, integrity and strong sealing. Specifically, the selection of refractory materials should follow the following principles:
Ensure that the physical and chemical indicators meet the requirements: The physical and chemical indicators of the selected refractory materials must meet the process requirements of the alumina circulating fluidized bed roasting furnace, including high temperature resistance, wear resistance and thermal shock resistance.
Good construction performance: The construction performance of refractory materials is also one of the important factors for selection, especially refractory castables, which should have good plasticity and fluidity to facilitate construction and form a dense refractory layer.
Practical verification: The selected refractory materials must be verified in practice to ensure their reliability and stability in actual applications.
In the alumina circulating fluidized bed roasting furnace, the commonly used refractory materials mainly include the following categories:
Refractory castables: used for the first-level venturi, cooling cyclone, fluidized bed cooler, all pipelines, flues and the lower part of the fluidized bed roasting furnace and the cone part of the cyclone. These parts need to be protected by double or triple layers of refractory castables because of the high temperature and the scouring and wear of the materials.
Refractory bricks: mainly used in fluidized bed roasting furnaces, circulating cyclones, secondary cyclone separators, secondary venturi dryers, and flues. Refractory bricks have high strength and wear resistance and can withstand high temperatures and material scouring.
Insulating refractory materials: including lightweight castables, lightweight insulating bricks, calcium silicate boards, and refractory fibers. These materials are mainly used in the top of the equipment and inside the pipeline, etc., where insulation is required to reduce heat loss and improve the thermal efficiency of the equipment.
Anchors: They are the main components of the lining and are used to firmly fix the refractory materials to the furnace wall. The distribution and type of anchors should be selected according to the furnace temperature, the properties of the refractory materials, the thickness of the lining, and the use location.
The selection of refractory materials for alumina circulating fluidized bed roasting furnaces is a complex and important process that requires comprehensive consideration of multiple factors to ensure the reliability and stability of the equipment. Through reasonable selection and configuration of refractory materials, the high temperature resistance, wear resistance, integrity, and sealing of the equipment can be significantly improved, thereby ensuring the smooth progress of the roasting process and product quality.
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