ISO 12830 pdf download Paper, board and pulps — Determination of acid-soluble magnesium, calcium, manganese, iron, copper, sodium and potassium 5.2Filter paper, ash free,particle retention 20 um to 25 um. 5.3Crucibles, platinum or fused silica, of minimum capacity 50 ml. 5.4 Muffle furnace, capable of maintaining a temperature of 525°C±25°C. 5.5 Balance, of capacity 100 g, accurate to 0,1 mg....