Case Study - Process OptimisationMajor Metal Recycling - NSW, Australia

The client operates several metal recycling facilities that separate recoverable materials into 3 streams being ferrous material, non-ferrous material and non-metallic material.

During benchmarking exercises, it was found that the level of non-ferrous metals in the non-metallic stream was several times higher than best practice.

This performance was unacceptable for two reasons:

1. 1. There was a cost to dispose of the non-metallic material. This cost was in proportion to the mass of material disposed
   2. There was a healthy market for non-metallic materials themselves.

The Six Sigma DMAIC process was used to address the problem. 

This led to a 3-stage solution:

1. 1. Assessment of the system to measure the non-ferrous material in the non-metallic stream was carried out. It was found that the methods used required improvement for any further work to be successful.  Improved methods were devised and implemented
   2. The proportion of material in each stream was controlled by a number of factors in the process. These factors could all be set at desired levels.  An initial regression analysis of the historical data was carried out to determine the most promising factors to structure further work.
   3. A statistical design of experiment (DOE) exercise was carried out using the factors identified in the earlier regression analysis. The results of this exercise enabled the tuning of the equipment to optimal settings.