As part of this commitment, since 1996 we have employed a thermal sand reclamation plant.
Benefits of Thermal Reclamation of Foundry Sand
Coupled with mechanical reclamation plants, the thermal sand reclamation plant allows us to recover up to 80% of the sand used within the foundry for the production of aluminium castings which is then re-used.
Our commitment to thermal sand reclamation serves to greatly reduce the amount of new sand purchased and used within the foundry which not only reduces our waste stream but also improves cost effectiveness.
Thermal Reclamation Plant Operation
The plant runs 24 hours per day for approximately 5½ days per week. It runs automatically taking sand from bulk storage, through a cleaning system to remove small agglomerates and flash, prior to conveying to high level. A calibrated feed of 1000kg per hour is then fed into the thermal reclamation unit with a calibration screw and additive mixer. The plant operates on the Alkaline Phenolic binder systems and uses an inhibitor due to the presence of metallic salts
The plant operates at 650 deg. C. and is complete with a heat recovery system recovering heat from the processed sand and returning it to the fluidised bed to reduce the amount of gas used in the process and also increase its cost effectiveness. The fluidised bed principle is employed, where a gas and air mixture is introduced into the fluidised bed and ignited by combustion burners, with safety monitoring systems in place.
The process burns off the residual binder following mechanical reclamation and returns the sand to a suitable quality to return it to moulding production, the heat exchanger and cooler classifier cooling the sand to nominally 25 deg C and suitable for re-use.
VOC and emissions are clean and conform to the EU current regulations with the stack testing carried out annually by an independent body.
Despite its elaborate name, the thermal sand reclamation plant is actually a relatively straight forward process and onsite management together with planned and preventative maintenance result in minimal downtime and reliable use.
At Harrison Castings, we take great pride in being one of the first foundries to use thermal reclamation technology using the alkaline phenolic process and by making thermal reclamation a major part of our environmental commitment.