170135_inorganicventures_flipping

3:11 Sampling and sub-sampling

Contamina(on Issues During Sampling

Geological: Sampling of geological materials can require hundreds of kilograms of material to be processed for the determina(on of certain elements present in inclusions. For example, Mo and Nb in granite.

Figure 3.1: Genera(on of Geological Sample Geological outcrop ➡ sampling ➡ crush and mill to sand size ➡ split to 1/8 the volume ➡ grind to coarse powder ➡ split to 1/8 the volume ➡ grind to fine powder (60 microns )

When using tungsten carbide crushing and grinding appara(, the common contaminants are W, Cr, Mn, V ,Co, Fe, Cu, Zr and Zn. Sieves made of nylon are recommended to avoid contamina(on by all metals.

3:12 Sampling and sub-sampling

Contamina(on Issues During Sampling (cont.)

Soils: Soil is heterogeneous and the composi(on varies with depth. Essen(al and hazardous element distribu(ons down to 50 cm are of interest.

Figure 3.2: Genera(on of Soil Laboratory Sample Fresh soil ➡ vegeta(on and debris is removed and discarded ➡ clean glass jars or plas(c bags ➡ stored at 4̍C ➡ air-dried in clean place ➡ ground to break down soil aggregates ➡ piled and quartered ➡ ground to fine powder ➡ sieved (60 micron).

Grinding in Alundum ball mills is recommended to avoid contamina(on from most metals (Al, Si, and Fe are common contaminants from the Alundum). Sieves made of nylon are recommended to avoid contamina(on by all metals.