Abstract: The hydrothermal decomposition process of nesquehonite and the effects of decomposition conditions on the composition of products have been studied. The nesquehonite decomposes quickly in water. It first decomposes into protohydromagnesite, then dypingite appears in a mixture with protohydromagnesite, and finally the hydromagnesite is produced;i. e. via a two-intermediate path. It is a result different from those observed in other studies and may have some guiding significance for the actual production.

Key words: nesquehonite, protohydromagnesite, dypingite, hydrothermal decomposition, intermediate