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CLIRIK gypsum grinding mill for gypsum powder production process

Source:nclirik Posted:2021-08-04
CLIRIK gypsum grinding mills are specialized in the production process of 30-3000 mesh gypsum powder.
The gypsum powder production process is obtained by grinding natural dihydrate gypsum ore (green gypsum) or industrial by-product gypsum (desulfurized gypsum, phosphogypsum, etc.) through a special mill and heating and calcining at a certain temperature to dehydrate and decompose the dihydrate gypsum. The product with β hemihydrate gypsum as the main component is construction gypsum (generally called plaster of paris).

What is GYPSUM?

Gypsum is a monoclinic mineral, the main chemical component is calcium sulfate (CaSO4). Natural dihydrate gypsum (CaSO4·2H2O) is also called raw gypsum.
After calcination and grinding, β-type hemihydrate gypsum (CaSO4·1/2H2O) can be obtained, that is, building gypsum, also known as plaster of paris and plaster.
If the calcination temperature is 190 °C, model gypsum can be obtained, and its fineness and whiteness are higher than building gypsum.
If the green gypsum is calcined at 400-500 °C or higher than 800 °C, floor gypsum will be obtained. Its setting and hardening are slower, but the strength, wear resistance and water resistance after hardening are better than ordinary construction gypsum.
Gypsum is usually white and colorless. The colorless and transparent crystals are called translucent gypsum.
Sometimes it is gray, light yellow, light brown and other colors due to impurities.
Streaks are white and transparent. Glass luster, cleavage surface pearl luster, fibrous aggregate silk luster.
The cleavage is very complete and medium, and the cleavage pieces are split into rhombuses with angles of 66 and 114. Brittle. Hardness 1.5~2. There are slight changes in different directions. The relative density is 2.3.

5 main production processes of gypsum powder making

1. The lump gypsum is calcined and then crushed.
In this method, the lump gypsum is first placed in an earth kiln, chamber kiln or vertical kiln for calcination, and then crushed and sieved in crushing equipment such as wheel mills or ball mills to obtain calcined gypsum powder with the required particle size. The advantage of this method is that the equipment is simple and the burning efficiency of the plaster block is high. The disadvantage is that the calcination of gypsum is uneven, which is easy to cause partial dead and raw burning, and it is also easy to mix with impurities such as coal ash.

2. Calcining the crushed gypsum powder.
In this method, the raw gypsum is crushed and crushed in a wheel mill or a squirrel-cage crusher, and then sent to a frying pan or rotary kiln for calcination, and then sieved for use after being burned. The advantage of this method is that the ground particles are burned more completely and the quality is higher. The disadvantage is that the water content of the raw gypsum is large, the crushing efficiency is low, and it is not easy to stir evenly when the gypsum is fried.

3. Grinding and calcination of green gypsum are carried out at the same time.
In this method, the coarsely crushed lump gypsum is sent to an air-swept quick-turn pulverizer for pulverization, and the suspended gypsum powder is calcined in a suspended state in a hot gas burning tube, and then the required gypsum powder is obtained by selecting the powder by wind. The advantages of this method are large output, high efficiency of frying paste, quick setting of fast-fried plaster of paris, low strength, but complex equipment.

4. The gypsum is first crushed into fine-grained sand, then fried, and then crushed and sieved.
Use general squirrel-cage grinder to crush, winnowing and sieving. The advantage of this method is that it has the advantages of the previous two methods, but the process is more complicated. This method is still widely used in the domestic ceramic industry.

5. Fried paste with pressure steaming method.
This method first preheats the raw gypsum with a lumpiness of 25-50mm after being coarsely crushed in hot air at 60°C, and then puts it in a pressure cooker with saturated superheated steam (125°C) at a pressure of 1,3 atmospheres for airtight cooking for 5-7 After hours, the hot dry air at 200℃ is introduced again until the hot dry air is discharged, and the vapor pressure semi-hydrated gypsum is obtained. This hemihydrate gypsum is in the a crystal form, and the strength of the model turned with this hemihydrate gypsum is very high, but the frying method and equipment are more complicated. Regardless of the method, the fineness of plaster of paris powder generally requires that the balance of the 80-120 mesh sieve should not exceed 0.5%.
gypsum powder

Introduction to the production process of gypsum powder

Production process Construction gypsum powder production line project (raw materials: natural gypsum ore, desulfurized gypsum, phosphogypsum) .

The production process of gypsum powder is divided into four steps: crushing, grinding(powder making), calcinationstorage and transportation.

Specific process:

After being mined, the raw stone ore is crushed by a crusher and then lifted to a silo by a hoist, and then automatically fed by an electromagnetic vibrating feeder, and the material enters the cavity of the gypsum grinding mill, the grinding roller and the grinding ring The grinding can achieve different fineness by adjusting the rotating speed of the analyzer.
Due to different heating conditions, the structure and characteristics of dehydrated gypsum are also different. Dehydrated under normal pressure and dry conditions, β-hemihydrate gypsum (building gypsum) is formed.

Gypsum powder grinding mill selection for processing gypsum powder:

YGM high-pressure medium-speed mill and Raymond mill: processing fineness between 15-425 mesh (fineness can be adjusted arbitrarily),
HGM three-ring medium-speed Ultra-fine grinding mill: The processing fineness is between 325-2500 mesh (fineness can be adjusted arbitrarily),
Coarse powder millprocessing fineness is less than 1-3mm.
gypsum grinding mills

How To Make Gypsum Powder?

The crusher crushes the large-sized gypsum ore into small particles less than 30mm, and transports them to the mill for grinding. The powdered gypsum powder that reaches the required fineness of the product after grinding is sent to the boiling furnace for calcination. The rest Part of it is returned to the mill for grinding again until it is qualified. The calcined qualified gypsum powder is sent to the clinker bin for storage or sent to the product workshop for use.

gypsum powder production process

According to the process requirements, the building gypsum production line is usually divided into five parts, which are the crushing system, the grinding system, the calcination system, the storage conveying system and the electric control system.

1. Crushing system:

The gypsum raw material enters the crusher through the feeder, and the crusher crushes the large-size gypsum ore into small particles less than 30mm for use. According to the size of gypsum raw materials and different output requirements, you can choose a crusher of corresponding specifications, usually PE jaw crusher, PC hammer crusher or PF impact crusher, etc. In order to protect the environment and clean, it can be equipped with dust removal equipment to meet environmental protection emission requirements.

2. Material transportation:

The crushed gypsum raw materials are transported to the storage bin for use by a hoist. The storage bin is designed according to the requirements of the material storage time to ensure the stable supply of materials. At the same time, all parts of the material turnover use hoists to reduce the floor space.

3. Grinding system:

The gypsum raw material in the storage bin enters the mill through the vibrating feeder for finishing.
An electromagnetic vibrating feeder is installed under the storage bin. This equipment is interlocked with the mill, and the supply of materials can be adjusted in real time according to the operation of the mill.
The materials are uniformly and continuously fed into the mill through the electromagnetic vibrating feeder for grinding.
The grinded gypsum powder is blown out by the air flow from the blower of the mill, and is classified by the analyzer above the host.
The fineness of the powder meets the specification, enters the cyclone collector with the wind flow, and is discharged through the powder outlet pipe after being collected to become the finished product.
The finished product falls into the screw conveyor and is transported to the next system for calcination.
The air flow flows into the blower from the return air duct of the large cyclone collector.
The entire air duct system is a closed loop and flows under negative pressure.
Because the raw material being ground contains water and evaporates into gas during the grinding process, the air volume in the circulating air path increases.
The increased air volume is introduced into the bag filter from the pipe between the large cyclone collector and the blower to remove dust in the air, and then discharged into the environment to ensure a clean environment.
The material passing through the grinding system changes from a particle size of 0-30mm to 80-2500 mesh, which meets the fineness requirements of gypsum powder.
The main equipment for the grinding is hoist, storage bin, vibrating feeder, mill, screw conveyor, bag filter, etc.
gypsum grinding system

CLIRIK gypsum grinding mill has a complete range, suitable for processing gypsum powder of different fineness. In addition, the CLIRIK gypsum powder grinding mill is equipped with a powder separator inside, and no external powder separator is required to simplify the grinding process.

4. Calcining system:

The raw powder transported from the grinding system is transported to the boiling furnace for calcination, and the calcined cooked powder is transported by the elevator to the finished product warehouse for standby. The system mainly includes hoist, boiling furnace, electrostatic precipitator, Roots blower and other equipment.

The boiling furnace used in this system is currently the most widely used building gypsum calcining equipment. It has small equipment, large production capacity, simple structure, not easy to damage, compact equipment, small footprint, low energy consumption, easy operation, easy automatic control, and good product quality. The seven advantages of calcined gypsum with ideal phase composition, stable physical properties, low capital investment, and low operating cost, are widely used in the calcining process of natural gypsum and chemical gypsum.

The construction gypsum powder processed by this production line equipment has good product quality. Due to the low temperature heat source, the gypsum is not easy to overburn. As long as the discharge temperature is controlled properly, the finished product does not contain dihydrate gypsum, and anhydrous gypsum is only within 5%. All are hemihydrate gypsum. This composition is ideal and the physical properties are also very stable.

5. Electrical control system:

The electrical control system adopts the current advanced centralized control, DCS control or PLC control, and each control element is selected from internationally renowned brand products.

Technical index of gypsum powder product

1. Product quality: meet or exceed the requirements of the national "Building Gypsum" standard (GB9776-2008).
2. Fineness: 80-200 mesh, sieve residue <10%.
3. Flexural strength (directly related to raw materials): ≥1.6Mpa; compressive strength: ≥3.0Mpa.
4. Main phase composition: Hemihydrate gypsum content: ≥80% adjustable
The content of dihydrate gypsum: <5% adjustable
Soluble anhydrous gypsum content: <5% adjustable
5. Initial setting time: 3-8min adjustable; final setting time: 6-15min adjustable.
6. Standard thickness: 78-85% adjustable.
Gypsum powder is one of the five major gel materials and occupies an important position in the national economy. Advanced gypsum powder production technology can boost the gypsum industry. It is used in construction, building materials, industrial molds and art models, chemical industry and agriculture, food processing and Play more important applications in many fields such as medicine and beauty.

Gypsum Application field

gypsum application
Gypsum is a widely used industrial material and building material. The microporous structure and heat dehydration properties of gypsum and its products make it have excellent sound insulation, heat insulation and fire resistance.
  • 1. Gypsum can be used as cement retarder,
  • 2. Gypsum building products,
  • 3. Model making,
  • 4. Medical food additives,
  • 5. Sulfuric acid production,
  • 6. Paper filler,
  • 7. Paint filler, etc.

Due to different heating temperatures and methods, gypsum of different properties can be produced: building gypsum, model gypsum, high-strength gypsum, etc.

Building gypsum
After hardening, the building gypsum has good heat insulation and sound absorption performance and good fire resistance and moisture absorption performance; the color is white and can be used for indoor painting construction, and is especially suitable for various productions. White, smooth and meticulous floral decoration, such as adding pigments can make the products have various colors.

Model gypsum
The calcined gypsum produced by calcining dihydrate gypsum, if it contains less impurities, the SKI is finer than the white powder and is called model gypsum. It sets faster than construction plaster and has higher strength. Mainly used for making models, sculptures, decorative flower ornaments, etc.

High-strength gypsum
High-strength gypsum puts H hydrate gypsum in an autoclave and is steamed at 1.3 atmospheres (124°C) to produce it. Type a semi-hydrated gypsum has high strength after being finely ground. After hardening, this plaster has a high degree of compactness and strength. High-strength gypsum is suitable for plastering projects, decorative products and gypsum boards with high strength requirements. After being mixed with waterproofing agent, its products can be used in environments with high humidity. It can also be added to the organic solution to be used as a binder.
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