silicon for the chemical and solar industry XIII

Silicon for the Chemical and Solar Industry XIII

Kristiansand, Norway, June 13 – 16, 2016

Tapping Si furnaces using advanced oxygen lances

Peter Sylvén

Envicom AB, Sweden,

Abstract

Tapping a large Submerged Arc Furnace efficiently, safe and causing a minimum of

damages to the taphole refractories is an art. When mechanically tapping a large

Silicon furnace producing high purity grade Silicon, the challenges are even greater.

When you survey the methods used around the world today, you will find operators

using either drills, shotguns, graphite stinger rods, oxygen steel pipes, aluminium

pipes, oxygen pipes with ceramic coating, pieces of wood or all of the above.

Good taphole management is crucial for a safe and profitable furnace operation. In

addition, the capability to keep the taphole in as good condition as possible will

reduce the gas blowing from the furnace through the taphole. This in turn will

improve the environmental impact and more importantly, the working conditions for

the operators.

This paper will show the proven advantages using the new carbon steel oxygen

thermal lances from Trefimet, with a computed design of the inserted steel profiles,

for this operation. Once developed for the copper smelters, this patented invention is

now successfully used by leading Silicon producers, both for refreshing a taphole

where the flow of silicon has dropped due to the precipitation of SiC or the opening

up of a new taphole.

Keywords

: Taphole, Oxygen lance, Thermal lance, Silicon Metal.