Alternative preparation of sulphated binders from secondary raw-material resources

摘要

The insufficient occurrence of raw material resources on our territory was one of the historical reasons for marginal production of sulphated binders from secondary raw-material resources. Also the unprofitability of material production based on calcium sulphate was related to this fact. This was changed in the end of the last century when formation of waste raw materials increased with industrial development. Secondary gypsums became basic raw material for production of plaster boards, plaster mixtures and anhydrite self-levelling mixtures. Wet flue gas cleaning desulphation process during which the energogypsum is formed is nowadays realised in major part of our power stations. Annual production of the energogypsum produced in this way in particular power stations is about 250 kt. The energogypsum is generally stored in stock piles as a so called stabilisate and partially is delivered to cement works as a solidification regulator. Chemogypsum is produced in chemical works where waste waters with content of (SO_4)~(2-) occur, which must be desulphated with lime in water ambient. Further it is formed in citric acid productions where also sulphated waters occur. Last but no least it is also produced in industrial production of phosphates. Production of titanium dioxide is another example of the industry where the possibility of gypsum formation exists.