A plant has recently been set up in India to produce walling blocks, ceiling tiles and binder from Phosphogypsum.
The following steps convert phosphogypsum to commercially gypsum plaster boards:
1. Grinding of calcined gypsum, and its storage.
2. Proportioning and mixing of gypsum plaster with water. Set controller and filler is-added to this slurry with a small quantity of glass fibre as reinforcement;
3. Casting of board with the board forming machine.
4. Carrying the 'green' board on a belt conveyor until the core sets and edges are stuck.
5. Cutting boards with a rotary knife into lengths of 1m to 6m before the 'green' board reaches the end of the machine belt.
6. Drying of boards by passing them through a tunnel kiln. Hot-air/steam allow recirculation of air. Natural drying is possible for small production. Drying is a very sensitive operation requiring careful attention.
7. Transferring of dry boards on to portable platform and transportation to the warehouse.
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