GB/T 1819.9-2017 Methods for chemical analysis of tin concentrates—Part 9:Determination of tungsten trioxide content—The thiocyanate spectrophotometric method (English Version)
2017GB/T 1819.9-2017 Methods for chemical analysis of tin concentrates—Part 9:Determination of tungsten trioxide content—The thiocyanate spectrophotometric method
2004GB/T 1819.9-2004 Methods for chemical analysis of tin concentrates Determination of tungsten trioxide content-The thiocyanate spectrophotometric method
1979GB/T 1828-1979 Determination of tungsten trioxide content in tin concentrates--Thiocyanate photometric method