A model to determine the physical dynamics of the process, an estimate of the maximum thickness of the paste before it falls off the belt, and the optimal vacuum box pressures will help control the process and increase the productivity of the machine. This project fills in the intermediate stage between the MISG 95 and 96 projects and involves the first stage of the emulsification process. The products are cast in metal moulds, made up of a separate top and bottom, which sits on a pallet car. The mould consists of mild steel with vertical walls and a lip of width 3 cm on top and bottom which surrounds the whole mould region. The moulds are filled with damp sand, coal dust and a binder impacted into the mould under high pressure air.
Moisture is forced out of the damp sand mixture.
Significant pitting damage occurs to the lips of the bottom mould, which creates problems to the quality of the casts. At the bottom of the heap an acidic solution rich in copper is collected and processed to remove the copper, and the aqueous solution is returned to the heap to leach more copper. As there is a net consumption of acid, sulphuric acid is intermittently injected into the solution that irrigates the heap. Prior to heap leaching, column leaching experiments are performed and the column leach data is used to predict the performance of the heap leach process. The predictions are usually wrong, due to the difference in the physical and chemical processes that occur in column and heap leaching.