Electrochemical treatment to condition contaminated EAFD as addition to immobilisation mortar in low level waste concrete containers

The steel industry generates a substantial quantity of waste, the so called electric arc furnace dust (EAFD). The chemical composition of this dust varies even for the same factory from one batch to another, but in all cases, this dust contains hazardous metals, and in some cases, it contains other species such as chloride ions. In addition to the intrinsic hazardous characteristics of this waste, it may accidentally happen that the scrap contaminated by radioactive elements be melted during the process; in this case, the resulting EAFD has to be managed as a radioactive waste, and therefore, it has to be disposed in a repository, where reinforced concrete barriers play an important role. In some cases, if there are potentially damaging species for the engineering barriers in the EAFD, they have to be removed before immobilising it in the cementitious matrix. In this paper, a case study is presented where EAFD is treated electrochemically, after a leaching treatment, to remove chloride ions before using it as an addition in the immobilisation mortar. This mortar is used to fill voids among waste drums inside concrete containers before putting them in the disposal area (concrete vaults) of the El Cabril low level waste repository (Spain).