Working of active carbon by attrition in a spouted bed

Many techniques have been developed to monitor the particle size distribution of latex and slurries, where the primary objective is to assure the uniformity and quality of the product. Unfortunately, most of the techniques which are adaptable to routine quality control, such as Beckman DU or Higher Order Tyndall Spectrum, do not have the ability to detect other important quality features such as outsize or flocculated particles in the system. Other methods such as disc centrifugation, are sensitive to outsize particles, but have other limitations.The newest method, intensity (or frequency) correlation spectroscopy, has been made commercially available in an instrument called the Coulter^® Nano-sizer. This instrument, at a cost of about $25,000.00, will give rapid (under 5 min) automatic and accurate values of the average size and polydispersity of a latex or slurry in the range from 40 to 3000 nm. It is the objective of this report to document the response of the method to various chemical types of latex, but also to latices containing outsize particles and two or more families of particles.The results of this study show that the Coulter^® Nano-sizer gives excellent particle size data correlations with other accepted methods, on lattices of narrow or broad distribution. Moreover, the method does display a sensitivity to outsize particle content, although this sensitivity varies with chemical type of latex.