DRY CONVERSION OF HIGH PURITY ULTRAFINE SILICON POWDER TO DENSIFIED PELLET FORM FOR SILICON MELTING APPLICATIONS

摘要

A bulk silicon material for making silicon ingots, consisting of silicon pellets, and a method for making the pellets from an agglomerate-free source of high purity, ultra fine silicon powder by feeding a controlled amount of silicon powder into a pellet die, and dry compacting the powder at ambient temperature with pressure to produce a pellet that has a density of about 50-85% of the theoretical density of elemental silicon, a weight within a range of about 1.0 gram to about 3.0 grams, a diameter in the range of 10 mm to 20 mm and preferably of about 14 mm, and a height in the range of 5 mm to 15 mm and preferably of about 10 mm.