Treatment process for recycling silicon ingot cutting waste
AssigneeRosi
InventorYun Luo
Life of this patent
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Abstract
A treatment method for purifying silicon microparticles contained in waste resulting from the cutting of ingots with a diamond wire comprises: a) providing a contaminated slurry, resulting from the waste, formed by an aqueous mixture comprising the silicon microparticles, organic species and metal contaminants; b) adding a dilute hydrogen peroxide solution to the contaminated slurry, in order to form a first mixture, and stirring the first mixture; c) solid/liquid separation of the first mixture in order to obtain, on the one hand, a first purified slurry and, on the other hand, a first liquid loaded with organic species and metal contaminants.
Claims21
A treatment method for purifying silicon microparticles contained in waste resulting from cutting ingots with diamond wires, the method comprising:
- a) providing a contaminated slurry from the waste resulting from cutting ingots with diamond wires, the contaminated slurry comprising an aqueous mixture including the silicon microparticles, organic species and metal contaminants;
- b) adding a dilute hydrogen peroxide solution to the contaminated slurry to form a first mixture consisting of the contaminated slurry, hydrogen peroxide and water, and stirring the first mixture;
- and
- c) performing solid/liquid separation of the first mixture in order to obtain a first purified slurry and a first liquid loaded with organic species and metal contaminants, the first purified slurry comprising less than 100 ppm by weight of metal contaminants,
- wherein no acid solution or solution other than hydrogen peroxide and water is used in steps a), b) and c).
A treatment method for purifying silicon microparticles contained in waste resulting from cutting ingots with diamond wires, the method comprising:
- a) providing a contaminated slurry, resulting from the waste, comprising an aqueous mixture including the silicon microparticles, organic species and metal contaminants;
- b) adding a dilute hydrogen peroxide solution to the contaminated slurry to form a first mixture comprising the contaminated slurry, hydrogen peroxide and water, and stirring the first mixture;
- c) performing solid/liquid separation of the first mixture in order to obtain a first purified slurry and a first liquid loaded with organic species and metal contaminants;
- and
- after step c, a step c″) comprising:
- providing the first purified slurry, kept in a form of a filter cake,
- circulating a dilute hydrofluoric acid solution between 0.10% and 1%, in weight percentage, through the filter cake;
- circulating pure water through the filter cake, allowing rinsing of the filter cake and elimination of the dilute hydrofluoric acid solution;
- and
- obtaining a third purified slurry.
Dependencies are inferred from the claim text.