Abstract: A method for the purification of metallurgical grade silicon is provided, which can be used to produce high purity silicon up to and including solar grade. The process relies on alloying and controlled solidification of Si with another metal, such as copper, zinc, iron, tin, nickel and aluminum, to produce purified platelets of Si, while the impurities are trapped in a getter alloy. The Si platelets are then separated from the solidified alloy by a physical separation technique such as gravity or magnetic separation. The separated grains of Si may then be further cleaned by acid leaching. Pre-refining of metallurgical grade silicon or post-refining of the product may be performed, depending on the initial impurity content of the feedstock, to obtain Si that meets solar grade requirements.

Abstract: The invention is concerned with an improved process for the desulphurization of blister copper during anode refining, wherein a mixture of an inert gas and an oxygen containing gas is blown into liquid blister copper. The improvement resides in varying the amount of oxygen containing gas in the mixture of nitrogen and oxygen during the desulphurization of blister copper. The process of the invention enables one to increase the recovery of copper, decrease the recycling of highly oxidized slag, decrease the time of desulphurization, decrease refractory wear, decrease subsequent time of reduction and decrease the amounts of reactants used.

Abstract: In a copper converting furnace, the (i) reduction of copper oxide in and the removal of copper metal from the slag, and (ii) conversion of copper sulfide in and the elimination of mineral waste from the blister copper is enhanced by introducing a gas, e.g. nitrogen, into at least one of the blister copper and slag such that the gas increases the turbulence or mixing at the blister copper/slag interface and promotes a lowering of the sulfur dioxide equilibrium pressure within the blister copper and slag phases. In one embodiment, the gas is introduced into both the molten blister copper and slag through a porous-wall injector.

Abstract: Copper matte is processed to anode copper without oxidizing blister copper in an anode furnace. Copper matte, in either molten or solid form, is fed to a continuous copper converting furnace in which it is converted to blister copper and slag. The blister copper and slag collect in the settler region of the furnace and separate into two phases, a blister copper phase and a slag phase (the latter floating upon the former). The converting furnace is equipped with means for stirring or agitating the interface of the blister copper and slag phases such that the sulfur content of the blister copper phase and the copper content of the slag phase are reduced.

Abstract: In an electrolysis cell wherein powdered material are added to a bath of molten electrolyte, the anode is provided with a duct through which the powdered material may be fed to the electrolyte. Simultaneously, a gas which is preferably inert, is also fed together with the powdered material through the duct, and both are injected beneath the surface of the electrolyte.