Aluminium powder Drying: Equipment Selection

Aluminium powder is the material here with the strictest safety requirement. It is combustible, its dust will deflagrate at a certain concentration when it meets a spark, and it burns with a high heat value, which makes extinguishing difficult. The whole line is therefore designed around two things: producing no sparks, and leaving no dead corners where powder can accumulate. Our standard configuration is an electrically heated rotary drum: no flame, no flue gas, controllable temperature, and the drum wall held below 150°C so the material cannot ignite locally. Dust collection is the other key point.

Aluminium powder is the material here with the strictest safety requirement. It is combustible, its dust will deflagrate at a certain concentration when it meets a spark, and it burns with a high heat value, which makes extinguishing difficult. The whole line is therefore designed around two things: producing no sparks, and leaving no dead corners where powder can accumulate. Our standard configuration is an electrically heated rotary drum: no flame, no flue gas, controllable temperature, and the drum wall held below 150°C so the material cannot ignite locally. Dust collection is the other key point: aluminium powder is extremely fine and light, a plain cyclone will not capture it, so a high efficiency bag filter with explosion venting is needed, the ducting has to be statically bonded and earthed, the fan needs an explosion proof motor, and every component that could produce a spark has to be designed out. We have also run a case converting an electrically heated installation to electromagnetic heating, because electromagnetic heating has no combustion system at all and removes even the remaining possibility of a spark while giving finer temperature control. The drum also needs regular cleaning, because a layer of aluminium powder building up on the wall is itself a hazard.

Can aluminium powder be dried with a gas heat source?
It is not recommended. The powder is combustible, its dust deflagrates at a certain concentration when it meets a spark, and it burns with a high heat value that makes extinguishing difficult. Our standard is electric or electromagnetic heating, with no flame and no flue gas, and the drum temperature is easier to hold below 150°C.

Why must aluminium powder dust collection use a high efficiency bag filter?
Because the powder is extremely fine and light, and a plain cyclone will not capture it: at a high enough velocity it is simply carried out of the collector. A high efficiency bag filter with explosion venting is needed, the ducting has to be statically bonded and earthed, the fan needs an explosion proof motor, and every component that could produce a spark has to be designed out.

Why does the drum have to be cleaned regularly?
Because a layer of aluminium powder building up on the wall is itself a hazard: it increases the heated area and it reduces how much material the flights can lift. Cleaning is not a nice-to-have on the maintenance schedule, it is a safety requirement.