Re-use of dusts from the green sand circuit in mould making

12 Re-use of dusts from the green sand circuit in mould making 

Dust is collected through the exhaust filtration from the shake-out installation and from the dosing and handling stations for dry green sand. The collected dust contains active binder compounds and may be recycled into the green sand circuit. 

Reduction in the use of binders (bentonite), and additives (carbon), through internal recirculation. 

An iron automotive foimdry, using an automated moulding line with a production of 8000 t/yr castings produces 480 t/yr of dust. This sand is collected, cooled and recycled into the sand mixer. The collected dust contains 23 % active bentonite and 10 % carbon. 50 % of the dust can be re-circulated without any risk of loss of quality due to fine dust. 

The technique may be applied in new and existing green sand installations. 

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