Clarification of Furnace Gas Cleaning Circulating Water Using Cationic Flocculant

The article presents the results of laboratory testing to select the optimal flocculant for clarification of circulating water from the shaft furnace gas cleaning of the metallization department. Laboratory testing was carried out using the standard settling (clarification) technique in sedimentation glasses. It is shown that the use of a liquid emulsion flocculant with a low cationic charge and high molecular weight allows for the successful removal of suspended and colloidal substances from the circulating water of the gas cleaning system and ensures the quality of the clarified water corresponding to the standard for the content of suspended substances ≤30 mg/dm³. It is established that the optimal dosing point for the selected liquid emulsion flocculant is a zone of high turbulence and intensive mixing, i.e., the receiving chamber of the radial-flow settling tank. The proposed reagent treatment program is recommended for industrial use for clarification of shaft furnace gas cleaning circulating water of one of the metallurgical plants in Russia. The optimal dosage range of the selected cationic flocculant (according to the commercial reagent) based on the wastewater entering the radial-flow settling tank is 0.4–0.5 g/m³.