Raw Materials of Gypsum Board

Gypsum powder is one of the five major gel materials and occupies an important position in the national economy. The gypsum powder production line is to calcinate natural dihydrate gypsum ore (raw gypsum) or industrial by-product gypsum (desulfurized gypsum, phosphogypsum, etc.) at a certain temperature. It is ground to make the dihydrate gypsum dehydrated and decomposed. The product with β hemihydrate gypsum as the main component is the building gypsum (commonly known as plaster of gypsum).

In the past, desulfurized gypsum slag was often treated by landfill, which seriously polluted the environment and occupied cultivated land. Now, the desulfurized gypsum slag can be made into gypsum powder for construction after being processed by DSJ series drying hammer mills, turning waste into treasure. Moreover, the performance of gypsum powder made by DSJ series drying hammer mills is exceeding than natural gypsum, and it is a high-quality raw material for manufacturing gypsum board.

The gypsum ores are crushed into small granules of the size less than 30mm, conveyed to mills to complete selecting and separating, and then the qualified powder are delivered into fluidized bed boiler for calcinations while the rest return to the mill. The qualified gypsum powders are carried into the storage bin or workshop for further use.

The gypsum and FGD gypsum are fed from the inlet, effective contacting the surface of the heat exchange tube in the shell, and be burnt by the fume as a medium from the fluidized bed boiler and finally collected in the discharge outlet. Owing to the indirect heat exchange, the shell obtains higher regional vapor pressure which has positive effects on the quality of products. Moreover, there is no direct contact between the gypsum and heat carrier that keeps the maximum purity of the products. Indirect heat exchange model of rotating calcinations technique can effectively protect the gypsum against semi-hydrated gypsum by balancing the strength of the calcinations. This processing, adopting the advanced technology and taking the fluidized bed boiler as the heat source, which lowers the consumption of coal to its fullest extent and makes the full use of heat with output 100-1000t, is the ideal equipment for the calcinations of gypsum industry.

Based on the process requirements, the construction gypsum product lines include crusher, mills, calcinations, storage and conveyor and control systems.

Crushing system

The gypsum ores are fed into crusher by the vibrating feeder, and crushed into small granules of the size less than 30mm for later use. Based on size of products and capacity requirements, the appropriate models can be adopted, like jaw crusher, hammer mills and impact crusher, etc. The dust collector is optional in order to keep the environment clean and satisfy the emission requirements.

Conveying system

The crusher gypsum is conveyed into the storage bin by the lifter. The design of the storage bin is based on requirements of the storage time to ensure stable supply.

Mill system

The materials are fed evenly and continuously into the mill by the vibrating feeder for grinding, and then the ground gypsum are blowing out by the blower for the analyzer to classify. The qualified powders go with the wind to the collector and are discharged by the tube as the final products which fall on the auger conveyors for the next stages of calcinations. It is close-recycled that the whole wind system is and adopts the bag filter between the wind collector and blowers, which filter the dust in the air and release into the atmosphere so as to prevent environment from pollution. The material sizes through mill system are changed from 0-30mm to 80-120 mesh and satisfy the gypsum requirements.

The mill system includes a lifter, storage bin, vibrating feeder, mills, auger conveyor and bag-type collector. The mill is adopting our latest patented Euro-typed miller (patented number is ZL 2009 2 0088889.8，ZL 2009 2 0092361.8，ZL 2009 2 0089947.9). There is an inside classifier, no necessity of outside one, which simplify the process.

Calcinations system

It includes the lifter, fluidized bed boiler, electro-static dust remover, roots blower, etc. The fluidized bed boiler is the most widely-used calcinations equipments in our country at present, which features smart shape, great capacity and simple structure, low failure rate and compact shape, low consumption, easy operation and self-control materialization, good quality of gypsum with ideal composure and stable physical performance, low operation cost, etc. It is widely used in the calcinations process of natural gypsum and chemical gypsum.

Control system

It takes the advanced centralized-control technology, DCS control and PLC control, adopting the well-known branded controls elements.