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The gypsum powder production line is made by grinding natural gypsum ore (raw gypsum) or industrial by-product gypsum (desulfurization gypsum, phosphogypsum, etc.) through a special mill and heating and calcining at a certain temperature to dehydrate and decompose the dihydrate gypsum. β-hemihydrate gypsum (CaSO4 1/2H2O) is the main component of the product, that is, building gypsum (passing for plaster).

In view of the many characteristics of gypsum, the following describes a set of high-yield gypsum powder production line. The technology used in this production line is dry process, which realizes self-grinding and self-selection. Through the frequency conversion classifier, the gypsum can be directly ground without any external screening. Or sorting. At the same time, due to the use of internal circulation wind, the gypsum powder that meets the finished product can be quickly selected, completely avoiding the phenomenon of over-grinding, greatly improving the output and production efficiency; at the same time, due to the use of the dust collector, the environmental protection effect is good.
gypsum powder processing

I. Introduction to production process

The crusher breaks the large-sized gypsum ore into small pieces of less than 30mm, and sends them to the mill for grinding. After the grinding machine, the gypsum raw powder which has reached the required fineness of the product after grinding is sent to the boiling furnace for calcination. Partially returned to the mill for re-grinding until qualified. The qualified gypsum powder after calcination is sent to the clinker silo for storage or sent to the product workshop for use.

2. Process and equipment selection
According to the process requirements, the construction gypsum production line is usually divided into five parts, namely the crushing system, the grinding system, the calcining system, the storage conveying system and the electronic control system.

1> Crushing system:
The gypsum raw material enters the crusher via a feeder, and the crusher breaks the large-sized gypsum ore into small pieces of less than 30 mm for use. According to the size of gypsum raw materials and different production requirements, you can choose the crusher of the corresponding specifications, usually choose PE jaw crusher, PC hammer crusher or PF impact crusher. In order to protect the environment, it can be equipped with dust removal equipment to meet environmental emission requirements.

2> Material transportation:
The crushed gypsum raw material is transported to a storage bin through a hoist for use. The storage bin is designed according to the requirements of material storage time to ensure a stable supply of materials. At the same time, the material turnover of each part is hoist, reducing the floor space.

3> Grinding system:
The gypsum raw material in the storage bin enters the grinding mill through the vibrating feeder for finishing. An electromagnetic vibrating feeder is arranged under the storage bin. This device is interlocked with the grinder, and the supply of the material is adjusted in time according to the running condition of the mill. The material is uniformly and continuously fed into the mill through an electromagnetic vibrating feeder for grinding. The ground gypsum powder is blown out by the air blown by the mill blower and classified by an analyzer above the main machine. The powder with fineness conforms to the specification, enters the large cyclone collector with the wind flow, and is discharged after being discharged through the powder discharge tube. The finished product falls into the screw conveyor and is transported to the next system for calcination. The wind flow flows into the blower from the return duct of the large cyclone collector. The entire air duct system is closed and flows under negative pressure. Since the material to be ground contains moisture and evaporates into gas during the grinding process, the amount of air in the circulation air path increases, and the increased air volume is introduced into the bag from the pipeline between the large cyclone collector and the blower. Remove dust from the air and drain it to the environment to ensure a clean environment. The material of the grinding system is changed from the particle size of 0-30mm to 80-120 mesh, which meets the requirements of gypsum powder fineness.

The main equipment of the grinding is hoist, storage bin, vibrating feeder, mill, screw conveyor, bag filter and so on. The mill uses the YGM series high pressure grinding mill. Since the YGM series high pressure grinding mill has a powder sorting device inside, it does not require an external classifier, which makes the process simple.
YGM high pressure grinding mill
YGM series high pressure grinding mill

4. Calcination system:
The raw powder conveyed from the grinding system is sent to a boiling furnace for calcination, and the calcined cooked powder is transported by the hoist to the finished product warehouse for use. The system mainly includes equipment such as hoist, boiling furnace, electrostatic precipitator and Roots blower.
The boiling furnace used in this system is a widely used building gypsum calcining equipment. It has small equipment, large production capacity and simple structure. It is not easy to damage the equipment. It has low energy consumption and low operation. It is easy to realize automatic control. The product quality is good. The gypsum phase composition is ideal, the physical properties are stable, the capital investment is low, and the operating cost is low. It is widely used in the calcination process of natural gypsum and chemical gypsum.
The gypsum powder processed by the production line equipment has good product quality. Because of the low temperature heat source, the gypsum is not easy to be over-fired. As long as the control discharge temperature is suitable, the finished product does not contain dihydrate gypsum, and the anhydrous gypsum is only within 5%. All are semi-hydrated gypsum. This composition is ideal and the physical properties are very stable.

5. Electrical control system:
The electrical control system uses centralized control, DCS control or PLC control.
Gypsum powder product technical indicators
1> Product quality: meet or exceed the requirements of the National Building Gypsum Standard (GB9776-2008).
2> Fineness: 80-200 mesh, screening "10%.
3> Flexural strength (directly related to raw materials): ≥1.6Mpa; compressive strength: ≥3.0Mpa.
4> Main phase composition: content of hemihydrate gypsum: ≥80% adjustable
Dihydrate gypsum content: <5% adjustable
Soluble anhydrite content: <5% adjustable
5> Initial setting time: 3~8min adjustable; final setting time: 6~15min adjustable.
6> Standard thick: 78 ~ 85% adjustable.

gypsum powder processing plant

►Production of 20 tons of building gypsum powder processing plant