Abstract: The invention relates to a method of agglomerating iron oxide-containing residual substances, in particular scale and mill scale, wherein the residual materials and the paper sludge are dried and comminuted and agglomerates are produced by means of hot briquetting from the mixture comprising the residual substances and the paper sludge. In this way, mill scale briquettes of high strength and density can be produced which in steelmaking processes can then be charged into an electric arc furnace for the purpose of recycling the iron contained in the residual substances.