The invention discloses a method for preparing stannous
chloride by recycling diluted
hydrochloric acid tail gas, which comprises the steps of adding
hydrochloric acid and
tin into a concentrated
hydrochloric acid reactor, heating, reacting to form stannous
chloride liquid, and gradually concentrating; generating dilute hydrochloric acid
tail gas mixed by HCl steam and
water vapor through reaction, entering a
heat exchanger, feeding cold
dilute acid salt in a cold dilute hydrochloric acid
storage tank into the
heat exchanger at the same time so as to obtain hot dilute hydrochloric acid by heating cold dilute hydrochloric acid through the hot dilute hydrochloric acid
tail gas, feeding into a hot dilute hydrochloric acid heat preservation
storage tank to be stored for standby application, and condensing the diluted hydrochloric acid tail gas and returning to a cold diluted hydrochloric acid
storage tank for later use; and pumping the hot diluted hydrochloric acid in the hot diluted hydrochloric acid heat preservation storage tank into a diluted hydrochloric acid reactor, adding
tin into the diluted hydrochloric acid reactor for reaction to prepare a stannous
chloride solution, pumping the stannous chloride solution into a concentrated hydrochloric acid reactor for concentration after the reaction is completed, and then discharging, cooling and crystallizing to obtain stannous chloride crystals. The method can directly recycle dilute hydrochloric acid tail gas to prepare stannous chloride, and is energy-saving, environment-friendly and efficient.