Elkem As

Elkem Asa

Elkem Solar As

Kenneth Friestad

Ragnar Tronstad

Erik Enebakk

Cyrus Zahedi

Christian Dethloff

Bruno Ceccaroli

Torfinn Buseth

Pal Runde

The method and apparatus includes a vessel having a bottom and sidewalls arranged to house the material in a molten state. A temperature controlled horizontally oriented, cooling plate is movable into and out of the top of the molten material. When the cooling plate is lowered into the top of the melt, an ingot of solid silicon is solidified downwards.

Method and apparatus for refining a molten material

The silicon feedstock for solar cells is made from metallurgical grade silicon by the successive steps of treating the silicon with a calcium-silicate slag, solidifying the treated silicon, leaching the solid silicon with acid, remelting the leached silicon, resolidifying the remelted silicon into an ingot, removing the upper part of the ingot and then crushing and sizing.

Silicon feedstock for solar cells

The present invention relates to silicon feedstock for producing directionally solidified silicon ingots, thin sheets and ribbons for the production of silicon wafers for PV solar cells where the silicon feedstock contains between 0.2 and 10 ppma boron and between 0.1 and 10 ppma phosphorus distributed in the material. The invention further relates to directionally solidified silicon ingot or thin silicon sheet or ribbon for making wafers for solar cells containing between 0.2 ppma and 10 ppma boron and between 0.1 ppma and 10 ppma phosphorus distributed in the ingot, said silicon ingot having a type change from p-type to n-type or from n-type to p-type at a position between 40 and 99% of the ingot height or sheet or ribbon thickness and having a resistivity profile described by an exponential curve having a starting value between 0.4 and 10 ohm cm and where the resistivity value increases towards the type change point. Finally the invention relates to a method for producing silicon feedstock for producing directionally solidified silicon ingots, thin sheets and ribbons for the production of silicon wafers for PV solar cells.

The invention relates to an apparatus for continuous slag treatment of molten silicon for removal of one a more impurity elements from the silicon, the apparatus comprising a vessel () intended to contain molten silicon and liquid slag. The vessel () has an upwardly extending overflow () for slag connected to an outlet opening () for slag is the bottom () of the vessel, a open-ended pipe () arranged about and at a distance from the overflow () such than there is an annulus between the pipe () and the overflow (), which pipe () extends upwards to a level above the top of the overflow () and downwards to the bottom () of the vessel, the pipe () having at least one opening () at the bottom of the vessel () a closeable outlet opening () for treated silicon in the sidewall of the vessel, means () for supply of heat energy to the vessel, means for intermittent supply of solid or molten silicon to vessel and means for continuous of substantially continuous supply of solid or liquid slag to the top of the vessel.

Apparatus for continuous slag treatment of silicon

The invention relates to a method for purification of metallurgical grade silicon where a calcium containing compound is added to molten silicon prior to or after the silicon is tapped from the furnace. The silicon is cast and solidified at a relatively high cooling rate and the solidified silicon is crushed and subjected to a purification process consisting of two leaching steps. In the first leaching step the silicon is treated with an aqueous solution of FeClor FeCland HCl which causes disintegration of the silicon, and in the second leaching step the silicon is treated with an aqueous solution of HF or HF/HNO. Calcium-containing compound is added to the molten silicon in an amount necessary to provide between 0.3 and 0.95% by weight of calcium in the molten silicon and the weight ratio between Al and Fe in the molten silicon is regulated to between 0.5 and 2.0 by addition of aluminum to the molten silicon.

Growing community of inventors

Kristiansand, Norway

Kenneth Friestad