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US 5,330,544 AGranted
Process and apparatus for increasing the size of ammonium sulfate crystals
AssigneeBASF SE
InventorsWalter G. Thomson, Jonathan K. Kramer
Life of this patent
Estimating the term…
Abstract
The average size of ammonium sulfate crystals is increased by passing undersized ammonium sulfate crystals through a multistage apparatus in which the crystals are contacted with an aqueous ammonium sulfate spray in a first heated chamber to increase the average size of the crystals, the enlarged crystals thereafter passing through a second heated chamber to dry the enlarged crystals.
Claims16
A process for preparing ammonium sulfate of uniform size crystals which comprises:
- a) spraying a feed of descending ammonium sulfate crystals with an aqueous ammonium sulfate solution such that individual ammonium sulfate feed crystals are contacted by the ammonium sulfate solution;
- b) providing a countercurrent flow of gas having a lifting force which retards the rate of descent of the crystals as they are sprayed, the contact time of the crystals with the solution and the temperature of such contact being sufficient to enlarge the ammonium sulfate crystals until the crystals enlarge to the point where they overcome the lifting force of the countercurrent flow of gas;
- and,
- c) heating the uniform ammonium sulfate crystals to reduce their water content.
1 more element
The process of claim 7 wherein the gas is at a pressure of from about 0.15 to about 0.20 psig.
Dependencies are inferred from the claim text.