Patent ID: 8623318

Claim:
A method comprising: continuously simultaneously manufacturing both a higher-strength, lower-salt, aqueous sodium hypochlorite bleach product and a substantially dry crystalline salt product by continuously withdrawing a slurry from a first tank in which a continuous reaction is producing the slurry as a suspension of salt crystals in higher-strength aqueous sodium hypochlorite bleach by continuously introducing into the first tank 1) a lower-strength aqueous sodium hypochlorite bleach that has some sodium hydroxide and is essentially free of salt crystals, 2) an aqueous sodium hydroxide solution having a concentration by weight within a range from about 45% to about 51%, 3) chlorine in gas and/or liquid phase that may or may not include inerts, and 4) a recycle solution comprising slurry continuously withdrawn from the tank at a level below where the lower-strength bleach, the sodium hydroxide solution, the chlorine, and the recycle solution begin to mix with slurry already in the tank; continuously withdrawing from the first tank, at a level below where the lower-strength aqueous sodium hypochlorite bleach, the aqueous sodium hydroxide solution, the chlorine, and the recycle solution begin to mix with slurry already in the tank, slurry that is to be further processed to yield the higher-strength, lower-salt, aqueous sodium hypochlorite bleach product and the substantially dry crystalline salt product; wherein the further processing comprises, continuously introducing the slurry withdrawn from the first tank into a second tank, agitating the slurry in the second tank, continuously withdrawing slurry from the second tank, continuously introducing the slurry withdrawn from the second tank into a thickening device, in the thickening device, extracting a substantial portion of liquid from the slurry as the higher-strength, lower-salt, aqueous sodium hypochlorite bleach product thereby leaving thickened wet salt, continuously withdrawing the thickened wet salt from the thickening device and, continuously introducing the thickened wet salt from the thickening device into a two-stage centrifuge, and in the two-stage centrifuge, continuously centrifuging the thickened wet salt in a first stage of centrifuging to remove more liquid, then washing the salt from the first stage of centrifuging, and then centrifuging the washed salt from the first stage of centrifuging in a second stage of centrifuging to remove liquid and yield the substantially dry crystalline salt product.