The use of the waste delisting process - case study : the management of ferrochrome slag as a construction product in South Africa
Abstract
Ferrochrome slag is a by-product from the production of ferrochrome, an essential component in stainless steel. World wide it is known that ferrochrome slags are been used mainly in the road and civil construction industries, and in producing refractories. Slag management at ferrochrome producing companies has been influenced by the limited space available and financial cost implications of the slag dumps. In South Africa, according to the Department of Water Affairs and Forestry's minimum requirements, (DWAF, 1998), ferrochrome slag due to its quantity or volume on the disposal sites has been classified as hazardous, as it leaches Manganese (Mn) (33%) above the DWAF minimum environmental requirements acceptable levels. This rating of the slag has therefore put limitations on the use of slag commercially. This paper investigates the various slag uses proposed which can impact positively on the management of the slag i.e. that would reduce its dumping loads and consequently its impact on the surrounding environment. The uses proposed for are brick and concrete making and road building. The paper provides results for the proposed slag uses leaching potential, performs a risk assessment to determine its potential effect on the environment and human health as well as discusses the method used to delist the slag through the South African delisting process. Comments on the process from the DEAT are also provided.