탄소열환원반응에 의한 동 제련 슬래그로부터 주철용 선철 제조 연구

Abstract

The copper smelting slag is an industrial by-product obtained by cooling molten slag, which is a by-product generated in the process of smelting copper in a flash furnace or a continuous furnace, in water and crushing it. It is known that about 2 tons of slag is generated from the manufacture of 1 ton of cooper, and about 1,5million tons of copper slag are generated from copper smelters in Korea. The copper slag contains not only ceramic components such as SiO2, Al2O3 and CaO but also a large iron content (35-45%), which can be used as raw material of iron. However, even though it contains a large amount of Fe component, it is difficult to utilize it as scrap because it acts as an impurity which deteriorates the quality during steelmaking due to the copper contained in 1-5% in the slag.

Various processes for recovering iron from copper have been proposed up to date and the proposed processes can be divided into physical separation process and dry smelting process. However, it has been reported that the physical separation is not effective in separating and recovering the iron, and the dry smelting process is difficult to use because it requires a high temperature of 1673K and increases the cost of process.

Therefore this study was conducted to manufacture the foundry pig iron (Fe-Cu) from copper smelting slag, and to analyze the effect of reaction time on Fe content in the process of manufacturing pig iron. In order to reduce the S content in the produced pig iron, a study was carried out according to the partial pressure of oxygen and the amount of additive.

As a result, it was confirmed that the whole of the slag should smelted to recover the Fe-Cu alloy, and that slag smelting behavior became active with increasing reaction temperature. The whole of Fe in the slag was recovered at the reaction temperature of 1600℃ and the recovery rate of Fe and Cu was increased with increasing reaction temperature. Also, No residual Fe was observed in the slug after 30 minutes of smelting. Experimental results with oxygen composition were insufficient. In the experiment according to the amount of additive, the content of s component was less than 0.001 when added more than 15wt.%.