NOVELTY - Preparation of potassium carbonate monohydrate and ammonium sulfate comprises performing carbonization reaction to potassium sulfate, ammonia and carbon dioxide; conveying obtained clarified filtrate into decompressing distiller (3) for distillation, cooling in cooling tower (4) to obtain potassium carbonate trihydrate and ammonium sulfate crystals; using first crusher (5) for crushing ammonium sulfate crystal and packing into ammonium sulfate product; and evaporating and concentrating potassium carbonate trihydrate crystal into potassium carbonate monohydrate in concentrator and crushing.    USE - Method is used for preparing potassium carbonate monohydrate and ammonium sulfate.    ADVANTAGE - The method converts waste material into useful product and decreases environment contamination.    DETAILED DESCRIPTION - Preparation of potassium carbonate monohydrate and ammonium sulfate comprises:    (A) dissolving industrial potassium sulfate into water to obtain aqueous potassium sulfate solution, conveying to carbonizing tower (1), filling ammonia and carbon dioxide, controlling mass ratio of potassium sulfate, ammonia and carbon dioxide at 1:0.01-0.41:0.07-0.47 and processing carbonization reaction;    (B) using filtration pump (2) for filtering obtained reacted product to obtain clarified filtrate and black impurity filter cake;    (C) conveying obtained clarified filtrate into decompressing distiller (3) to process stepped distillation according to condensing points of potassium sulfate and ammonium sulfate, cooling in cooling tower (4) to respectively obtain potassium carbonate trihydrate crystal and ammonium sulfate crystal;    (D) using first crusher (5) for crushing ammonium sulfate crystal and packing into ammonium sulfate product; and    (E) continuously evaporating and concentrating potassium carbonate trihydrate crystal into potassium carbonate monohydrate in evaporating concentrator, crushing by second crusher and packing to obtain potassium carbonate monohydrate product.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram illustrating a preparation of potassium carbonate monohydrate and ammonium sulfate. (Drawing includes non-English language text).    Carbonizing tower (1)    Filtration pump (2)    Decompressing distiller (3)    Cooling tower (4)    First crusher (5)