Abstract: Disclosed is a method of thermal treatment of a carbonate suspension yielding lime and CO.sub.2 -containing gas, such suspensions may be those resulting from a filtration sediment for sugar production, comprising in general the steps of dividing the carbonate suspension into two portions, spray-drying these portions both simultaneously and independently, calcining the material produced after suspension drying, cooling the lime produced after calcination, supplying the gas from the calcination zone for spray-drying the first portion of the suspension, withdrawing carbon dioxide recovery from the spent gas after spray-drying the first portion of the suspension, the calcination being carried out by means of the heat of the heat-carrier required for calcinating the material and spray-drying only the first portion of the suspension.