Abstract: In structures of silicon carbide brick the leakage of molten metal or vaporous metal through breaks in joints or a crack is prevented by hot applying mortar comprising a major component of zircon and a minor component of borates or boric acid, phosphoric acid and colloidal silica to the breakages. Adhesiveness of mortar to the breakages is improved by incorporating further agalmatolite or kaolin into the mortar.

Abstract: A method of manufacturing sulfuric acid free of impurities such as mercury by the contact process, which comprises the steps: scrubbing the roasting gas coming out of a mist Cottrell with sulfuric acid having a concentration of 30 to 99% and a temperature of more than 20.degree. C within one or two mercury absorption towers (the drying tower per se may suffice) or further within an additional mercury absorption tower disposed on the outlet side of the main blower; and adding a reagent such as a sulfide, a hydrosulfide compound of alkali metal or alkaline earth metal, hydrogen sulfide, selenium compound, sulfur, etc.

Abstract: A method comprising the steps of casting molten nonferrous metal ingots, skimming scum foaming on the surface of the molten metal in each mold, cooling the molds to release ingots therefrom, stacking the ingots released from the molds to form ingot stacks each comprising a plurality of layers of ingots arranged in vertically stacked relation alternately in two different patterns, weighing the ingot stacks, and tightly binding the weighed ingot stacks with steel bands.

Abstract: A method of manufacturing sulfuric acid free of impurities such as mercury by the contact process, which comprises the steps: scrubbing the roasting gas coming out of a mist Cottrell with sulfuric acid having a concentration of 30 to 99% and a temperature of more than 20.degree.C within one or two mercury absorption towers (the drying tower per se may suffice) or further within an additional mercury absorption tower disposed on the outlet side of the main blower; and adding a reagent such as a sulfide, a hydrosulfide compound of alkali metal or alkaline earth metal, hydrogen sulfide, selenium compound, sulfur, etc.