CN101362601A - Purification processing method of casting ingot cleaved bark slat and head material - Google Patents

Abstract

A method for purifying and pretreating flaw-piece and head materials generated during ingot casting relates to the technical field of solar monocrystalline silicon production. The selected materials are ground by a carborundum grinding wheel to remove impurity spots and adherent quartz; the flaw-piece and head materials generated during the ingot casting are separated according to resistivity into materials with the resistivity of 0.1-0.2, 0.2-0.5, 0.5-3 and more than 3; the separated materials are dipped and washed by an acid to remove the impurities and quartz on the surface, and rinsed by deionized water to wash the acid on the surface of the materials; the materials are packaged in a stainless steel box to be dried in an oven, and packaged in bags respectively after cooling; the raw materials are drawn, purified and washed by the acid to remove the flaw-piece and head material impurities generated during the ingot casting, thus the quality of the drawn monocrystalline silicon is ensured.

Description

The purification method for pretreating of ingot casting flaw-piece and head material

Technical field

The present invention relates to solar monocrystalline silicon production technical field.

Background technology

The method that draws solar monocrystalline silicon is by radiant heat polycrystalline silicon raw material to be melted, and in quartz crucible, forms column silicon single crystal by rotating, and takes out cylindrical silicon single crystal then.Because produce flaw-piece and head material impurity in ingot casting, the inferior quality of these products can not be directly used in the drawing of drawing of silicon single crystal.In order to draw qualified silicon single crystal, must purify earlier.

Summary of the invention

The object of the invention is to invent a kind of to producing the pretreatment process that flaw-piece and head material are purified in the ingot casting.

The present invention includes following steps:

1) well-graded material is ground off impure point and adherent quartz with grinding wheel;

2) ingot casting is produced flaw-piece and carry out sorting,, be divided into more than 0.1～0.2,0.2～0.5,0.5～3 and 3 by the resistivity classification with the head material;

3) well-graded material is carried out pickling with acid and soak, remove the impurity and the quartz on surface;

4) use deionized water rinsing, the acid of material surface is rinsed well;

5) material is loaded on puts into oven for drying in the stainless steel box, pack packing respectively to be cooled.

After above technology, again raw material is drawn purification, pickling, could remove and produce flaw-piece and head material impurity in the ingot casting, thus the quality of guarantee pulled crystal silicon.

Embodiment

One, material pre-treatment:

1, well-graded material is ground off impure point and adherent quartz with grinding wheel.

2, ingot casting is produced flaw-piece and head material and carry out sorting,, be divided into more than 0.1～0.2,0.2～0.5,0.5～3 and 3 by the resistivity classification.

3, well-graded material is carried out pickling with acid and soak, remove the impurity and the quartz on surface.

4, use deionized water rinsing, the acid of material surface is rinsed well.

5, material is loaded on puts into oven for drying in the stainless steel box, pack packing respectively to be cooled.

Two, draw purification:

1, material that pre-treatment is good carries out proportioning by resistivity.

2, advance shove charge by normal pull-rod program, find time heating and melting.

3, keep 1420 ℃～1460 ℃ high temperature evaporation 2～3 hours.

4, carry out seeding and draw, earlier the impurity that swims in liquid level is proposed during drawing, draw out polycrystalline silicon rod again.

Three, pickling impurity removal:

1, the polycrystalline silicon rod that draws is carried out the classification of model resistance, the silicon rod epidermis be ground off detection; Purify again less than 0.5 cut-out if any resistivity.

2, will detect qualified silicon rod is undertaken by top process: the removal of impurity, fragmentation, pickling, oven dry, packing.

The concrete grammar of impurity is: the quartz that adheres on supracutaneous hard point and the flaw-piece is ground off with grinding wheel.

The concrete grammar of pickling is: with nitric acid and hydrofluoric acid with the volume ratio mixed liquid dipping of 3:1 2 ± 0.2 hours, until no quartzy impurity.

The concrete grammar of oven dry is: with the material that acid soaks, rinse well with deionized water; Put into the water extracter of heating, keep 150～200 ℃ and dewater, material surface does not have to put into baking oven after water stain, keeps 1～2 hour under 200 ℃ of conditions, then cooling.

Claims (1)

1, the purification method for pretreating of ingot casting flaw-piece and head material is characterized in that may further comprise the steps:

1) well-graded material is ground off impure point and adherent quartz with grinding wheel;

2) ingot casting is produced flaw-piece and carry out sorting,, be divided into more than 0.1～0.2,0.2～0.5,0.5～3 and 3 by the resistivity classification with the head material;

3) well-graded material is carried out pickling with acid and soak, remove the impurity and the quartz on surface;

4) use deionized water rinsing, the acid of material surface is rinsed well;

5) material is loaded on puts into oven for drying in the stainless steel box, pack packing respectively to be cooled.