As a result of an increasing volume and variety of waste products, Japan is facing issues such as pressure on landfill sites and a growing percentage of difficult-to-treat materials. Recovering and recycling waste without producing secondary waste has therefore become a top priority.
As one of very few companies in the world that has both nonferrous smelting and cement plants, we run a combined smelting and cement recycling system as part of our environmental recycling operations here at the Mitsubishi Materials Group, in an effort to help establish a recycling-oriented society. Our smelting plants use byproducts generated by our cement plants as raw materials, and vice versa, enabling us to recycle waste without any need for landfill sites. One of the byproducts we generate at our smelting plants is copper slag, which is increasingly being used as an aggregate for concrete, as part of our own contribution to recovery and reconstruction work following the Great East Japan Earthquake.
Making the most of this system, which enables us to process E-scrap, used home appliances, scrap vehicles, batteries and various other types of waste, we have also started to recycle difficult-to-treat waste such as rubble from disaster areas and waste plasterboard. We use unique technologies at our cement plants in particular to recycle waste plasterboard into raw materials for cement, and are working to reinforce our processing capabilities even further.
Our unique Mitsubishi Continuous Copper Smelting and Converting Process (Mitsubishi Process) is a highly efficient copper manufacturing process that has exceptionally low environmental impact. We put copper concentrate through a series of three connected furnaces connected by pipes to produce blister copper (98.5% purity). The required facilities are compact and also help to save energy and cut costs.
Raw materials (including wastes and byproducts) are prepared during the raw material grinding process and then sintered at high temperatures to produce a hydraulic mineral during the burning process.
Once the raw mixture has reached the maximum temperature (1,450°C) and a series of chemical reactions are completed, it is quickly cooled into an intermediate product called clinker.