Abstract: A thermal two-step process for producing ferronickel (FeNi) alloy particles from a nickel-containing sulfide material is provided. The process comprises heating a solid mixture comprising a nickel-containing sulfide material and an iron-containing material in agglomerated form, in an inert or reducing atmosphere to a heating temperature at which the solid mixture is partially molten and obtaining a hot mixture comprising a nickel-containing liquid phase, gangue, and FeNi alloy particles, and then controlled cooling of the hot mixture to increase the particle size and Ni content of said FeNi alloy particles and obtaining a processed material comprising said FeNi alloy particles having an increased particle size and an increased Ni content. Finally, the FeNi alloy particles are separated from the processed material. There is also provided FeNi alloy particles obtained from the process.

Abstract: In graphite based thermal storage units capable of operating at high temperatures, it is advantageous to have an inert nitrogen based atmosphere. Such large storage systems can be heated to temperatures in excess of 1500° C. using embedded graphite based electrical heating elements. In order to reduce possible loss of graphite, particularly from heating elements, small amounts of hydrocarbon gas is added. The preferred gas is ethylene.

Abstract: A process to the production of silicon from amorphous silica is disclosed. The amorphous silica is formed from a material rich in silica, especially rice husk ash or silica fume. The process comprises subjecting the amorphous silica to leaching with a lixiviant of aqueous mineral acid, especially hydrochloric acid. Preferably, material rich in silica is roasted at a temperature of not more than 850° C., subjected to leaching and then subjected to a second roasting at a temperature of less than 750° C. The process provides for the production of high purity silicon, especially to the production of solar grade silicon (SoG-Si).

Abstract: A process to the production of silicon from amorphous silica is disclosed. The amorphous silica is formed from a material rich in silica, especially rice husk ash or silica fume. The process comprises subjecting the amorphous silica to leaching with a lixiviant of aqueous mineral acid, especially hydrochloric acid. Preferably, material rich in silica is roasted at a temperature of not more than 850° C., subjected to leaching and then subjected to a second roasting at a temperature of less than 750° C. The process provides for the production of high purity silicon, especially to the production of solar grade silicon (SoG-Si).

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: A process to the production of silicon from amorphous silica is disclosed. The amorphous silica is formed from a material rich in silica, especially rice husk ash or silica fume. The process comprises subjecting the amorphous silica to leaching with a lixiviant of aqueous mineral acid, especially hydrochloric acid. Preferably, material rich in silica is roasted at a temperature of not more than 850° C., subjected to leaching and then subjected to a second roasting at a temperature of less than 750° C. The process provides for the production of high purity silicon, especially to the production of solar grade silicon (SoG-Si).