Preparation of Calcium Sulfate from Oil-refining Acid Sludge by Neutralization Method

摘要

For the purpose of recycling acid sludge of lubricant oil from refinery, on the conditions that the dilution factor is 20 and the actual addition amount of calcium carbonate and calcium hydroxide is respectively 1.15 and 1.1 times of the theoretical value, neutralization method is used to process acid sludge. By means of removing post-reaction organic phase, evaporating, drying, igniting at 650°C for 80 min, dissolving, crystallizing, calcium sulfate product is obtained. The conversion rate of (SO_4)~(2-) in acid sludge is more than 75% in the product. The purified product meets the national quality standards for similar products. The acidic sludge generated in the process of preparing sulfuric acid from petroleum products is collectively referred to as acid sludge [1]. The main components of the acid sludge are inorganic acid, organic acid and oily substances. At present, acid sludge is mainly used as auxiliary fuel for cement production at home and abroad, as a substitute for sulfuric acid to decompose ground phosphate rock for the preparation of calcium superphosphate, as the raw material to prepare asphalt of a variety of purposes by oxidation and adding blender, as an additive for the production of gypsum, as the neutralizer for soil improvement, and so on [2-6]. The experiment makes use of the acid sludge generated in sulfuric acid preparation from lubricant oil, adds calcium compounds to convert the acidic substances in the acid sludge into calcium sulfate products. The acid sludge is thereby recycled to become useful material and environmental pollution is reduced.