Abstract:

Vermiculite ore in Pho Rang, Bao Yen, Lao Cai is one of the most valuable vermiculite deposits within the Red River structure zone. The vermiculite ore bodies in the Pho Rang area are hosted in the strongly weathered biotite-rich metamorphic rocks at the shallow levels of the Con Voi Mount complex (MP nv2). The vermiculite ore in the Pho Rang area was formed due to the weather alteration from biotite and exhibits a relatively homogeneous mineralogical composition. The vermiculite calcination experiments conducted at various particle sizes and temperatures demonstrate that the expansion of vermiculite upon heating is directly proportional to the particle size, reaching up to 9.8 times when heated at 900°C for particles >3mm, with bulk densities ranging from 0.27 to 0.41 kg/liter (based on expanded particle size).