Chemical treatment of the water used in the blast furnace gas cleaning cycle in the Egyptian Iron and Steel Company: Part II

The hot gases in the blast furnace of the Egyptian Iron and Steel Company (EISCO) leave the top of the furnace carrying fine dust. Water is added to the dust as it passes through a pug mill to moisten it and prevent it from blowing into the atmosphere. Water is then pumped to the cooling tower for removal of heat from the gas washing water, through three settling tanks then recycled. The basic problem of water chemistry is to protect the cooling system from corrosion, scale formation and fouling from silt and microbiological growth. Bench-scale experiments were carried out on the collected water samples to investigate the effect of inorganic and organic coagulant agents for the suspended solids removal experiments (see Part I). The highest removal efficiency of suspended solids was achieved with anionic flocculants. Based on these results, the present paper describes a study of the effect of three commercial anionic flocculants on the properties of the blast furnace gas cleaning water, which causes blocking and corrosion of cooling tower pipes in the settling tanks. The aim was to determine the most appropriate doses of flocculant to use for the treatment.