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Manufacture, use & exposure

Manufacture

Documentsopen allclose all

Manufacture

Contributing activity / technique for the environment
Environmental release category (ERC):
ERC1: Manufacture of the substance
Contributing activity / technique for workersopen allclose all
Process category (PROC):
PROC 3: Manufacture or formulation in the chemical industry in closed batch processes with occasional controlled exposure or processes with equivalent containment conditions
Process category (PROC):
PROC 4: Chemical production where opportunity for exposure arises
Process category (PROC):
PROC 5: Mixing or blending in batch processes
Process category (PROC):
PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities
Process category (PROC):
PROC 9: Transfer of substance or mixture into small containers (dedicated filling line, including weighing)
Process category (PROC):
PROC 15: Use as laboratory reagent
Process category (PROC):
PROC 22: Potentially closed processing operations with minerals/metals at elevated temperature. Industrial setting
Related assessment:
use assessed in a joint CSR

Manufacture

Contributing activity / technique for the environment
Name of activity / technique:
Manufacture of fused tungsten carbide powder
Environmental release category (ERC):
ERC1: Manufacture of the substance
Contributing activity / technique for workersopen allclose all
Name of activity / technique:
Step 1: Preparation - Raw material handling: tungsten (W) metal powder is received in closed steel containers and carbon black powder in paper bags. W metal and carbon black powders are weighed and transferred to another steel container; this involves manual operation. Not applicable to fused tungsten carbide powder. Exposure to W metal and carbon dust is possible. (Note that the flammability classification is for W powder with a particle size less than 9.0 µm only).
Process category (PROC):
PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities
Name of activity / technique:
Step 2: Mixing - Tungsten metal and carbon black powders are mixed in an intensive mixer. Loading and unloading are made through powder tight systems. Mixer cleaning involves manual operation. Not applicable to fused tungsten carbide powder. Exposure to W metal and carbon dust is possible.
Process category (PROC):
PROC 3: Manufacture or formulation in the chemical industry in closed batch processes with occasional controlled exposure or processes with equivalent containment conditions
PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities
Name of activity / technique:
Step 3: Melting operation - Approximately 20 kg of W and C powder mix is loaded into the crucible of an induction furnace and heated until it melts. Fused tungsten carbide is cast on a water cooled copper plate for quenching. After complete cooling, it is stored in steel containers. The transfer of fused tungsten carbide and recovery of flashings is manual. There is limited exposure to fused tungsten carbide as it is in bulk form.
Process category (PROC):
PROC 4: Chemical production where opportunity for exposure arises
PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities
PROC 9: Transfer of substance or mixture into small containers (dedicated filling line, including weighing)
PROC 22: Potentially closed processing operations with minerals/metals at elevated temperature. Industrial setting
Name of activity / technique:
Step 4: Crushing - The as-quenched fused tungsten carbide is transferred to the hopper of a jaw crusher. It is continuously sieved, and the coarse particles recycled until the desired size is achieved. This is done in powder tight equipment. Possible short-term exposure to fused tungsten carbide fine powders.
Process category (PROC):
PROC 3: Manufacture or formulation in the chemical industry in closed batch processes with occasional controlled exposure or processes with equivalent containment conditions
Name of activity / technique:
Step 5: Final sieving / Blending - The crushed fused tungsten carbide is sieved and, if needed, blended until the desired size distribution is achieved. This is done in powder tight equipment. This step involves repeated sampling and testing of the material. Possible short-term exposure to fused tungsten carbide fine powders.
Process category (PROC):
PROC 3: Manufacture or formulation in the chemical industry in closed batch processes with occasional controlled exposure or processes with equivalent containment conditions
PROC 5: Mixing or blending in batch processes
PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities
PROC 15: Use as laboratory reagent
Name of activity / technique:
Step 6: Packaging - The product is weighed and packed in steel drums with inner polythene bags. Possible short-term exposure to fused tungsten carbide fine powders
Process category (PROC):
PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities
PROC 9: Transfer of substance or mixture into small containers (dedicated filling line, including weighing)
Name of activity / technique:
Step 7: Maintenance and cleaning - Various maintenance and cleaning operations inside and outside the equipment. Exposure to tungsten and fused tungsten carbide powders is possible. (Note that the flammability classification is for tungsten powder with a particle size less than 9.0 µm only).
Process category (PROC):
PROC28: Manual maintenance (cleaning and repair) of machinery
Related assessment:
use assessed in a joint CSR