Process for producing potassium sulphate

A process for the production of potassium sulphate by conversion of potassium chloride and sulphuric acid using a muffle furnace, said furnace comprising a reaction chamber and a combustion chamber,

• wherein potassium chloride (KCl) and sulphuric acid (H2SO4) are reacted to form potassium hydrogen sulfate (KHSO4), and wherein in the reaction chamber potassium chloride (KCl) and potassium hydrogen sulfate (KHSO4) are reacted to form potassium sulphate while supplying heat to the reaction chamber from the combustion chamber,
• wherein the combustion chamber has at least a pair of regenerative burners and wherein the process comprises the steps of alternatingly causing one of the regenerative burners to perform a combustion operation in the combustion chamber to heat the reaction chamber and another one of the regenerative burners to perform a heat-regenerating operation in a regenerator,
• wherein heat-regenerating means that heat from the combustion chamber is intermittently stored in a storage medium of a regenerator,
• wherein the pressure in the combustion chamber is kept at a pressure of between 0.2 and 3 mbarg.