초록 ▼

Process for producing low cost, high purity solar grade Si wherein a reduction reaction, preferably the reduction of SiF4, by an alkali metal (liquid Na preferred) is carried out essentialy continuously by injecting of reactants in substantially stoichiometric proportions into a reaction chamber hav

Process for producing low cost, high purity solar grade Si wherein a reduction reaction, preferably the reduction of SiF4, by an alkali metal (liquid Na preferred) is carried out essentialy continuously by injecting of reactants in substantially stoichiometric proportions into a reaction chamber having a controlled temperature thereby to form a mist or dispersion of reactants. The reactants being supplied at such a rate and temperature that the reaction takes place far enough away from the entry region to avoid plugging of reactants at the entry region, the reaction is completed and whereby essentially all reaction product solidifies and forms a free flowing powder before reaction product hits a reaction chamber wall. Thus, the reaction product does not adhere to the reaction chamber wall or pick up impurities therefrom. Separation of reaction products is easily carried out by either a leach or melt separation process.

대표청구항 ▼

A process for producing low cost, high purity solar grade silicon by reaction of gaseous silicon tetrafluoride with sodium in substantially stoichiometric quantities to produce a reaction product from which silicon is recovered and wherein said fluoride gas used in the reaction is obtained by therma

A process for producing low cost, high purity solar grade silicon by reaction of gaseous silicon tetrafluoride with sodium in substantially stoichiometric quantities to produce a reaction product from which silicon is recovered and wherein said fluoride gas used in the reaction is obtained by thermal decomposition of sodium fluosilicate which is precipitated from aqueous fluosilicic acid generated from phosphate rock conversion to fertilizer, said process comprising: (a) carrying out such reaction inside a reaction chamber in such a manner that a substantially free flowing powder reaction product including substantially pure silicon is produced; (b) removing the substantially free flowing powder from the said reaction chamber by free flow; and (c) separating the said substantially pure silicon from the said other reaction products.