Brief Introduction: |
Calcination is an essential part of quality control in gypsum production. DongDa Powder has researched and developed the one-step process, two-step process, Si De calciner, Si De drier and internal and external heating fluid bed furnace, which are suitable for different heat sources, process and equipment in corresponding to materials. The selection of calcination method and its associated equipment needs to consider products usage, local heat source, power conditions, level of automation and scale of production.
Process Flows: |
One-step calcination process system
Material is fed into the calciner via feeder. Under the strength of mechanical scattering and heating air, it is scattered, drier, calcinated and homogenized at high speed, then discharged from the dumping port. The tail gas is collected and dedusted via the trap before discharged. The product gypsum is fed into the warehouse by the conveyor.
Performance Features:
Automated control, stable temperature and product quality;
Suitable for wet material; it has a combined function of drying, calcinating and scattering;
Low cost and reasonable grain size;
Adjustable drying and calcinating time, which is beneficial for setting time management;
Suitable for large-scale and continuous production; heat source has multiple choices, including direct or indirect heating calcination as well as flue gas from the power plant as the heat source.
SD Calciner System Diagram
1.Feeding Port 2.Calciner 3. Trap 4. Dumping Port 5. Warehouse
SD Drying + Fluid Bed Furnace
1. Heat Source 2. Feeding Port 3. SDDryer 4. Fluid bed Furnace 5. Dumping (semi-hydrated gypsum) 6. Warehouse
Two-step calcination process system
The drying process is performed in the SD drier. And the calcination process is carried out in the internal/external heating fluid bed furnace or SD calciner. This two-step process designed by DongDa Power is primarily choosing the steam discharged from power plants as the heat source for drying and calcinations directly or indirectly. The selection of equipment type differs from heat sources.
Type A---SD Drying + SD Calcination
1. Feeding System 2. Drying System 3. Calcination System 4. Warehouse System 5. Intermediate Warehouse 6. Heater
Type B---SD Drying + Fluid Bed Furnace
1. Heat Source 2. Feeding Port 3. Feeding 4. SD Dryer 5. Fluid bed Furnace 6. Warehouse
Suitable Material: |
Under the international promotion of energy saving and environmental protection, DongDa Powder Company has put our efforts into the research of comprehensive application of chemical gypsum. We have designed the building gypsum powder process, block panel process, retarder process, plastering gypsum process and alpha gypsum process lamp, etc, which meet the market and customer demands.
Practical Application Cases: |
Case one: Gypsum Powder, capacity of 100 000 tons per year.
Our company has provided Huaneng Wuhan Yangluo Power Plant with a production line of the capacity of producing 100,000 tons of desulfurization gypsum per year. This is the first production line that produce 100,000 tons of desulfurization gypsum in power industry in China. This project carried out a first-time-correct commissioning in later 2008. It has passed the ministry-level authentication.
The production line in Yangluo Power Plant has the capacity of producing 100,000 tons of building gypsum powder per year. It takes the steam as heat source, the temperature of the steam is 300 °C, and the pressure of it is 1.6 MPa. According to features of desulphurization gypsum,SD dryer and fluidized furnace has been selected to manufacture building gypsum powder.
Case two: Cement Retarder, capacity of 200 000 tons per year
This project takes the flue gas generating from coal burning as the heat source. By the SD calciner one-step process, the phosphogypsum is screened, purified deironed, and then calcinated. Di-hydrated gypsum will be added into the calcinated phosphogypsum. The mixture will be granulated into spherical retarder products by the pelletizer.
Case three: Gypsum Block Process
Phosphogypsum or desulphurization gypsum is treated with the one-step or two-step process, and then is fed into the block producing machine after mix and blend. The final product is high-strength gypsum building blocks.
1. Gypsum Powder 2. Burdening 3. Mixer 4. Material Preparation Machine 5. Dryer
Technical Parameters: |
Performance Indicators of the Two-step Calcination Process in Huaneng Yangluo Power Plant
Performance Parameters for Building Calcinated Gypsum Powder | ||||
Item | Unit | National Best Quality Standard | Electropositive Desulphurization Gypsum | |
Folding Strength(2h) | MPa | 2.5 | 3.85 | |
Compressive Strength(2h) | MPa | 4.9 | 8.95 | |
Setting Time | Initial Setting | Min:s | 6:00 | 10:30 |
Final Setting | Min:s | 30:00 | 16:00 | |
Water Consumption for Standard Consistency | % |
| 64 | |