Building materials, cements and magnesium - made in large scale plant from minerals available in the desert

Mineral building materials are made starting from unsuitable minerals which are mixed together in suitable amts. to obtain two batches (1,2), which are heated in different processes (1,2):- (1) Batch (1) is heated to a higher temp. and melted in a furnace to obtain a desired end prod. (1) which is cooled; (2) The hot exhaust gas from process (1) is used to heat batch (2) to a lower temp. than batch (1), for conversion to a prod. (2). The pref. plant includes a melting furnace for process (1), with a discharge for prod. (1) and a duct carrying exhaust gas to a furnace, esp. a sintering furnace, used for process and batch (2). Batch (2) may contain MgO and CaO, where the sintering furnace is followed by an arc furnace fed with a reducing agent for mfg. magnesium vapour fed to a cooler; the melt leaving the arc furnace travels through further processing plant from which acetylene is removed. Used e.g. in deserts where suitable stone chips, cement or gravel are not available. The invention provides usable materials from the available raw materials in processes which only demand a reasonable amt. of energy.