Process for manufacture of hydroxide slurry

Abstract

A method of manufacture of high-solids hydroxide slurries from caustic calcined carbonate powder is described, whereby the properties of the slurry are its low resistance to shear thinning to facilitate transport, a high stability for transport and storage, ease of reconstitution after long periods of storage, and, as required, a high concentration of chemically reactive species at the particle surface. The method achieves these specifications by mixing caustic calcined carbonate or hydroxide powder with water in an insulated reactor vessel, and agitating the slurry sufficiently such that the hydration reaction causes the water to spontaneously boil, such that the remaining hydration proceeds spontaneously under the fixed conditions of boiling through the water loss. The mixing process is preferably carried out by a shear pump. A viscosity modifier, such as acetic acid, is used to thin the slurry to enable the mixing system to maintain uniform mixing. The reaction is terminated when the boiling has spontaneously ceased and the temperature has spontaneously dropped to a set point though the reactor heat losses, where the processing time is sufficiently long that the slurry meets the desired specifications.

What is claimed is: 
     
         1 . A reactor vessel adapted to produce a hydroxide slurry, wherein the reactor vessel comprises:
 providing the caustic calcined hydroxide powder through a first inlet of the reactor vessel and providing the water through a second inlet of the reactor vessel, the reactor vessel comprising a controller that is adapted to electronically control the process within the reactor vessel, a viscosity sensor positioned therein and adapted to supply viscosity information about the reaction mixture to the controller, and a temperature sensor positioned therein and adapted to supply temperature information about the reaction mixture to the controller;   applying a shearing force to the reaction mixture comprises applying a shearing force to the reaction mixture with a shearing apparatus positioned external to the reactor vessel, wherein the rate of shearing is controlled by the controller; and   allowing steam to evaporate from the reaction mixture comprises evaporating steam through a steam outlet of the reactor vessel, such that, in use, the reaction is controlled by the controller so that the heat of hydration may raise the temperature of the reaction mixture, allowing water to boil off from the reaction mixture as hydration proceeds, and removing steam via the steam outlet to remove excess heat and control reaction temperature at boiling point.   
     
     
         2 . The reactor vessel of  claim 1 , wherein further comprising mixing the powder with water in the reactor vessel comprises mixing particles of the caustic calcined hydroxide powder with the water, wherein the particles have particle size distribution in the range of 0.1 to 150 microns; and wherein the reaction mixture has an apparent viscosity in the range of 60-300 cP.