Method of making alkali and gypsum by
proton-coupled electron transfer reaction

(22) 16.08.2019

(43) 18.02.2021

(57) The present disclosure provides a method for preparing an alkali and co-producing gypsum, and belongs to the technical field of chemical production. The method comprises the steps of placing a cation exchange membrane into an electrolytic cell, adding a solution of sodium salt of a weak acid and a compound MH to an anode region as an anode electrocatalyst, adding sodium carbonate or sodium hydroxide to a cathode region, adding a compound M as a cathode electrocatalyst, and applying a DC power supply between a cathode electrode and an anode electrode. The electrolysis oxidizes the MH into the M and releases H⁺, Na⁺ in the anolyte penetrates through the cation exchange membrane to reach a cathode region to be combined with OH- in the catholyte to generate NaOH, or further absorbs CO₂ and converts into Na₂CO₃; the anolyte containing a large amount of H⁺ is generated by the electrolysis for dissolution reaction with limestone, and the H⁺ is consumed to generate Ca²⁺, and SO₄^2- and Ca²⁺ are combined to generate high-purity CaSO₄ precipitate. According to the present disclosure, a compound capable of generating PCET reaction is used as an electrocatalyst, while M is its oxidation state and MH is its reduction state, and mirabilite and limestone are used as raw materials to realize the preparation of soda ash, caustic soda and gypsum.

(71) Yufei Wang, Chongqing (CN); Tao Liu, Chongqing (CN)