Patent ID: 9023236
Filing Date: 2015-05-05
Classification: C01B

Abstract:
1. Process for preparing a concentrated solution of an alkali metal hypochlorite by reacting chlorine and a solution of the corresponding alkali metal hydroxide, in the presence of alkali metal chloride crystals in which, in an essentially vertical vessel of volume “Vr”, the bottom part of which has a cross section smaller than the cross section of its top part: a) chlorine and an alkali metal hydroxide solution are injected into the bottom part, b) in the top part, the hypochlorite solution is withdrawn at a flow rate “Qs”, (i) one portion forms the concentrated hypochlorite solution produced, (ii) the other portion is recycled to the bottom part of the vessel, c) the alkali metal chloride crystals are purged close to the lower end of the bottom part of the vessel, d) the recycling and the injection of the reactants from step a) are adjusted so that the alkali metal chloride crystals are fluidized essentially in the bottom part of the vessel, and wherein the chlorates are present in an amount between 0.01% by weight and 0.2% by weight by carrying out the process under the conditions below: where where r=k [ClO  K