The current utilization rate of steel slag is only 22% in china, far behind the developed countries. At present, the amount of slag deposited in storage yard adds up to 30Mt, leading to the occupation of farm land and serious pollution to the environment.
The pig iron contains unwanted accompanying elements such as carbon, silicon, sulphur and phosphorus. These components are removed in a so-called oxygen steel converter through the injection of oxygen, whereby the impurities are oxidised and floated on the liquid metal bath in the form of slag.
Iron and steel are key products for the global economy. Since 2000, global steel production has grown by 75%, reaching 1.49 billion tons of steel in 2011. 1 The sector is the largest industrial emitter of CO 2 (with direct emissions of 2.16 Gt in 2006) and second largest industrial user of energy (consuming 24 EJ in 2006).