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Status : Active
Standard Type : Main
Document No : ISO 3431:1976
Document Year : 1976
Pages : 3
Edition : 1
Section Volume : Materials for the production of primary aluminium (ISO/TC 226.)
Applicable to products having SO4 contents of more than 0.05 % (m/m). Covers the dissolution of the test portion in hydrochloric acid and evaporation in hydrochloric acid solution for drying. Dissolution of the residue in a hydrochloric acid solution. Measurement of the turbidity obtained by precipitation, under specified conditions, of barium sulphate using a spectrophotometer at a wavelength of about 470 nm or a photoelectric absorptiometer.