Abstract: Magnesium sulphate monohydrate is a very important chemical raw material and dual-element fertilizer with more magnesium and sulfur components,added value,and market prospect than magnesium sulphate heptahydrate.Magnesium sulphate monohydrate producted by Ku-Tu method cannot meet market requirements as the lower quality.By comparing process characteristics of high-temperature crystallization and drying dehydration,a variety of equipment,as well as relevant information and pilot test data,a disc dryer was adopted to directly dry magnesium sulfate heptahydrate into magnesium sulfate monohydrate.Results showed that the dry strength of this type of disc dryer was 4.1 kg/(m²•h) at temperature of 160 ℃ and stirring speed of 15 r/min.Using this type of disc dryer can produce better magnesium sulfate monohydrate to meet the quality requirements.In addition,unit energy consumption is moderate and the net income per unit of product is in a reasonable range.

Key words: magnesium sulfate heptahydrate, magnesium sulfate monohydrate, drying and dehydration