Recovery of chemicals

Abstract From the Canadian patent

Incinerator product obtained from the incineration of black liquor and other spent liquors in the chemicals recovery circuit of a soda pulping process is treated to remove contaminants including chlorides sulphates, and potassium compounds, and to provide recovery of a high proportion of the sodium carbonate originally present in the incinerator product. The incinerator product is treated with water to form a slurry in which substantially pure sodium carbonate monohydrate is crystallised and a major proportion of the contaminants are dissolved, the sodium carbonate monohydrate is then separated and dissolved sodium carbonate is recovered as a bicarbonate or sesquicarbonate precipitate by …