Abstract: An improved process is disclosed for carbothermically producing an alkaline earth metal aluminide from an aluminum-bearing material which, in one aspect comprises forming a mixture of a carbonaceous reducing agent and a slag comprising the aluminum-bearing material, the alkaline earth metal compound; forming, at a first temperature, an alloy containing impurities in the slag; removing the alloy containing the impurities from the slag; and then heating the slag to a higher temperature to form the alkaline earth metal aluminide. The alkaline earth metal compound used in the process may comprise calcium carbide. Alternatively, both the alkaline earth metal compound and the aluminum-bearing material may be obtained using a calcium aluminate slag such as a byproduct from the steel industry. The calcium aluminate slag is purified in a preliminary step to remove silicon by alloying it with iron and then removing a ferrosilicon alloy formed in this step.

Abstract: Proper cooling of fossil fuel power plant or smelter reverberatory furnace off gases for removal of sulfur dioxide by proper contacting of the same with lime or limestone, including the recycling of the scrubbing liquor.

Abstract: A process for recovering iron from preliminarily decopperized molten copper smelter slags having an initial composition which includes iron oxide, silica, and aluminum oxide as the major constituents. These constituents are initially present in the range of 40-70 percent FeO, 25-40 percent SiO.sub.2 and 5-10 percent Al.sub.2 O.sub.3. The slag is maintained in a molten state and a solid reductant is mixed into the slag using an internally cooled, metal bladed, rotating stirrer, which rotates at a rate sufficient to pump the reductant into the slag to enhance the reduction of the iron oxide. An important aspect of this invention is to reduce slag to recover iron when the slag contains the following constituents, 40-60 percent SiO.sub.2, 15-35 percent CaO, less than 20 percent FeO and 5-10 percent Al.sub.2 O.sub.3. Although the above constituents can vary within the range set forth, it is important to maintain the SiO.sub.2 to CaO ratio in the range of about 2.0 - 3.3.