Alumax Mill Products
The source reduction system is for chrome conversion 6 to chrome 3 by chemical precipitation using sodium metabisulfite at a 2.0 pH. Magnesium hydroxide is added for pH adjustment along with sodium hydroxide. Polymers are added to the metal hydroxide solution to facilitate fall out and filtered through a 6 cubic foot press. This filter cake is then fed to a JWI sludge dryer at about 70% water content and dried to approximately 30% water content. This procedure has about a 4:1 ratio of reduction to the sludge being produced. As a waste being recycled and recovered the 30% water must remain to be processed. If Alumax did not have this limitation we could reduce the outgoing waste even further.
This project has only been facilitated in the last 60 days. The operation is constantly being refined by using statistical process control techniques. These developments can produce management control from the production line all the way to the recycling of the sludge.
This type of project allows for the recycling and reusing of wastes. Since the creation of another waste stream is therefore prevented, the problems associated with having to landfill are avoided.
Details of Reductions
Additional Information :
Cost savings have been justified by reducing the sludge volume. The continuing adjustments to fine tune the process will eventually impact chemical usage and sludge production. In turn, costs will be lowered. The payback period of the project is forecast at 3 years.