|Monthly Tech-Tip |
Used for ball clays. Gives indication of the presence of coarse silica or lignite. Visual observation of this residue is more valuable than the printed value. Analyzing this amount relative to carbon content and LOI can be enlightening also.
To measure particle size in a slurry or powder you need sieves. This is the most popular type used in labs. They are made from brass by a company named Tyler. The range of screen sizes for testing particle size is very wide (obvious here: the top screen has an opening of 56 mm, the bottom one 0.1 mm - the wires are almost too small to see). You can often buy these used on Ebay for a lot less than new ones, search for "tyler sieve". The finer sieves (especially 200) are fragile and more easily ripped. It is good to have a 50, 100 and 150.
% Passing 325 Mesh Wet
LDW LOI, density and water content test procedure for plastic clay bodies and porcelains
Tests conducted to determine particle populations, sizes, shapes, densities, surface areas, etc.
Sieves are important in ceramics for removing particulates and agglomerates from glaze, engobe and body slurries.
|By Tony Hansen|
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