Briquettes for the liquefaction of metallurgical slag are formed from a mixture containing, by weight, 85-98% slag from secondary aluminium processing, 1 to 8% polyvinyl acetate dispersion as the polymeric bonding agent and the remainder water, the briquettes containing water in the form of residue humidity at a quantity of maximally 1. Reacquisition techniques may include identifying and decoding only select portions of header information in the broadcast signal. An overhead track suspends animal carcasses in alignment with the channel. The light source is adapted to illuminate at least a portion of the columns.