Patent ID: 6126702
Filing Date: 2000-10-03
Classification: C01D

Abstract:
A method for treating an aqueous slurry containing sodium sesquisulfate crystals to recover sodium sulfate therefrom which comprises:conducting the slurry through an elongate generally upright mixing zone in a treatment vessel and mixing the slurry in the mixing zone to promote dissolution of the crystals and formation of sodium sulfate solids;conducting the slurry from the mixing zone to a separate clarifying zone so that sodium sulfate solids are carried in the slurry from the mixing zone toward the clarifying zone and sesquisulfate crystals within the slurry descend from the mixing zone toward the clarifying zone;collecting undissolved sesquisulfate crystals descending from the mixing zone in a reservoir of a collector located beneath the mixing zone so as to intercept and collect sesquisulfate crystals descending from the mixing zone toward the clarifying zone, preventing the collected sesquisulfate crystals from entering into the clarifying zone;bubbling gas through the collected sesquisulfate crystals to promote dissolution of the crystals and to provide a flow of gas bubbles ascending through the mixing zone to promote a turbulent flow regime therein and to assist in mixing of the slurry in the mixing zone;collecting sodium sulfate solids descending from the slurry in the clarifying zone;conducting the collected sodium sulfate solids out of the vessel from the clarifying zone along with entrained liquid consisting principally of sulfuric acid and water; andconducting liquid from the clarifying zone out of the vessel along with a small amount of entrained solids consisting principally of sodium sulfate.