As the foundry industry struggles with various macro and micro economical factors, it is imperative to reflect inward at each foundry in order to stay efficient and competitive. By making small, seemingly insignificant changes to the everyday operation, the foundry has the potential to save significant costs per annum.
Whilst no two foundries are the same and all have different sand systems and requirements, there are many variations of sand reclamation plants available. Modern sand reclamation plants have evolved in such a way that even the smallest foundry can be accommodated in terms of floor space required by the plant and also in terms of investment and running costs.
However, the cooling of the sand and the removal of dust and fines is often overlooked. The sand cooler/classifier is equally as important as the attrition unit because unless you remove all of the dust and fine particles from the sand you will not see a reduction in the loss on ignition (LOI) at the mixer.
Typically a cooler/classifier would be a fluidised bed type with a copper tube heat exchanger for sand cooling. The fluidising air and the extracted air must be finely balanced so as to provide a negative pressure inside the fluidising chamber. This pressure can be adjusted according to the amount of fines in the sand.
With the ever-increasing cost of raw materials it is becoming more important to keep all of the quality and cost factors under control. One of these initiatives is one that SI Group ǀ HA is very close to – the war on fines in sand reclamation.
Laboratory studies indicate the strength gained by eliminating the fines from the reclaimed sand mix will allow the foundry to enjoy the benefits of the improved strength gained as well as save money and running costs on reduced additives.
The impact of fines on the strength deterioration over a two hour period is shown in the graphs. In this case, a strength improvement of 16.9% was achieved by removing the fines content of the sand. What could this gain or saving mean to your foundry?