The invention relates to the field of production of
viscose fibre in the
textile industry, in particular to a method for preparing
sodium sulfide from
hydrogen sulfide waste gas produced in the production of the
viscose fibre. The method comprises the steps as follows: A, the
waste gas is fed into an alkali
spray tower; B,
hydrogen sulfide is absorbed in an alkali liquor in the alkali
spray tower; C, impurities are removed; D, a preheated absorption liquid is delivered into a primary multi-effect
evaporator; E, a solution is subject to settlement and
desalination; F, the desalinated solution is filled into a semi-finished product
barrel, and caustic soda is added into the desalinated solution; G, the solution in the semi-finished product
barrel is delivered into a secondary single-effect
evaporator; H, after undergoing the secondary
evaporation, the solution is filled into a finished product
barrel, and then is stirred for
crystallization; and I,
crystal sodium sulfide is made into tablets. The method has the
advantage of realizing the optimal generation of
sodium sulfide through the setting of
processing parameters such as the size of main equipment, the
pore diameter of a delivery pipeline, wind volume, wind velocity, the concentration of the alkali liquor,
absorption time, circulating
evaporation time,
evaporation temperature, evaporation vacuum degree,
precipitation time, stirring velocity, the rotational speed of a tablet making
machine, and the like.