마이크로웨이브 가열에 의한 금광석내 페널티원소 제거특성

Abstract

Chapter 1.

Removal of penalty elements in sulfide minerals of selective transform using microwave heating

Arsenic is usually contained in the concentrate as arsenopyrite. The concentrate containing a large quantity of arsenic is delivered to the smelter and it is smelted to obtain the valuable metals. During the smelting processes, arsenic is released to the environment as As2O3 and the As2O3 has serious harm to the environment and health of workers. Therefore, if more than 2,000 ppm of arsenic is contained in the concentrate, the smelter imposes penalty on the miner who supplied the concentrate. The penalty is the cost required to remove the arsenic. The content of arsenic in the concentrate must be controlled under 2,000 ppm. Accordingly, the aim of this study is to remove the content of arsenic in the concentrate using microwave heating. For the purpose, this study examined the time effect of microwave heating and the power effect of microwave heating in an industrial microwave. The samples were ore minerals selected from the Samjo mine, the Manjang mine and the Moisan mine. As a result of the reflected microscopy and the XRD analysis, it was discovered that a large quantity of arsenopyrite was contained in the Samjo mine and the Manjang mine. As the results of the microwave heating experiments, arsenic was removed up to 90% only in 10 mins of heating. Through a microscopy, a SEM & EDS and a XRD analysis of the roasted solid-product sample from microwave heating, it was confirmed that the phase was transformed in an order of arsenopyrite(FeAsS), pyrrhotite(FeS) and hematite(Fe2O3). As the results of the microwave power experiments, the arsenic was removed up to 90% at 5kW. It was suggested that arsenic is effectively removed in the ore mineral due to a phenomenon of shrinking core model. In conclusion, it is certain that arsenic will be effectively removed if the microwave pre-treatment is applied to the concentrate or mine wastes.