(b) 1 part by weight of vegetal carbon dust produced from beech wood with a particle size of 0-100 μm, a4c0
1 part by weight of vegetal carbon dust produced from beech wood with a particle size of 0-100 μm, a3c0
1 part by weight of vegetal carbon dust (beechwood) with a particle size of 0-100 μm, a0c0