The problem: India currently accounts for 10% of world production in the casting and forging industry, of which carbon dust and residue from recycled waste forms nearly 4.3 million metric tons of dumped waste each year, a huge environmental hazard. Added to this is mixed plastic dumping taken across the country by hospitals, industry and society at large. The result is landfills cropping up every few kilometers across major cities.
India based company, Rhino Machines has launched the Silica Plastic Blocks - a sustainable building brick that is made from recycling foundry dust/sand waste (80%) and mixed plastic waste (20%). The project comes in collaboration with r+d labs, which is the research wing of the architectural firm R+D Studio.
The ‘Silica-Plastic Block’ Project seeks to find a solution within the problem and thus started with a clear mandate achieving zero waste from the sand reclamation portion of the Rhino Machines Foundry Plant. In the initial stages, experiments were conducted by using foundry dust in cement-bonded fly ash bricks (7-10% waste recycled) and clay bricks (15% waste recycled). The above experiments additionally required the use of natural resources such as cement, fertile soil and water. The amount of natural resources consumed in the process was not justified by the waste it was able to recycle.
These trials led to more research by the inhouse R&D team, resulting in a possibility of bonding the sand/foundry dust with plastic. By using plastic as a bonding agent, the need for water during mixing and thereafter curing is completely eliminated. The ‘Silica-Plastic Blocks’ can be directly used after cooling down from molding process. These plastic blocks were found to be 2.5 times the strength of normal red clay bricks and consumed around 70 to 80% of the foundry dust with 80% lesser use of natural resources.
With further testing and development, newer molds were prepared to test these blocks as paver blocks. Over a period of 4 months, various industries such as hospitals, societies, individuals, social organizations and the local municipal corporations were approached to provide clean plastic. In total, six tonnes of plastic waste and sixteen tonnes of dust and sand from the foundry industry was collected for recycling. Since the SPB is a result of a waste product, the cost of production is competitive and can easily compete with the commonly available red clay brick or the CMU ( Concrete Masonry Unit).
Rhino Machines is now preparing to come up with an ecosystem solution so that the foundries across the country can develop and distribute these SPBs within their impact zones through CSR. (Corporate Social Responsibility - a Government of India initiative for businesses to undertake philanthropic causes and give back to the community). These SPBs could be used to build walls, toilets, school campuses, health clinics, pavers, driveways and more.