20.59.56.66 Catalyst in the form of grains of which 90 % or more by weight have a particle-size not exceeding 10 micrometres, consisting of a mixture of oxides on a magnesium silicate support, containing by weight: 20% or more but not more than 35% of copper and 2% or more but not more than 3% of bismuth, and of an apparent specific gravity of 0,2 or more but not exceeding 1,0 - EU Vocabularies
