[12] Patent
[11] Patent No.:GC0004548  
[45] Date of Publishing the Grant of the Patent: 31/Dec /2016                32/2016  
Number of the Decision to Grant the Patent:2016/89840
Date of the Decision to Grant the Patent:20/Dec/2016

[21] Application No.:GC 2012-21862

[22] Filing Date:28/7/2012

[30] Priority:

[33] State [32] Priority date [31] Priority No.
DE
29/7/2011
102011080105.7

[72] Inventors:1- Dr. Hanns WochnerĜŒ2- Thomas GailerĜŒ3- Rudolf Kellner

[73] Owner: Wacker Chemie AG , Hanns-Seidel-Platz 4, Munchen 81737, Germany

[74] Agent: Dennemeyer & Associates

  

 

  

[51]IPC:
Int. Cl.: C01B33/037; B08B3/08 (2006.01)

[56] Cited Documents:

-EP 1 894 887 A2 (WACKER CHEME AG [DE]) 05 March 2008
-DE 10 2007 039626 A1 (WACKER CHEMIE AG [DE]) 26 Fabruary 2009
-DE 43 25 543 A1 (WACKER CHEMITRONIC [DE]) 02 February 1995
-EP 1 876 13 A1 (WACKER CHEMIE AG [DE]) 09 January 2008
 
Examiner: Eng. Sattam M.AlMutairi

[54] Process for cleaning polycrystalline silicon chunks
[57] Abstract: The present invention relates to a process for cleaning polycrystalline silicon chunks in an acidic cleaning bath, wherein the cleaning comprises several cleaning cycles, wherein a particular amount of acid is consumed in each cleaning cycle, wherein an integrator of a computer-controlled dosage system is used to add up those amounts of acid consumed in each cleaning cycle to give a current total consumption of acid in the cleaning bath, wherein, on attainment of a total consumption of acid in the cleaning bath which corresponds to an optimal dosage of the dosage system, the dosage system supplies this optimal dosage of unconsumed acid withdrawn from a reservoir vessel to the cleaning bath. The invention also relates to a process for cleaning polycrystalline silicon chunks in an acidic cleaning bath comprising an acid circuit in which acid is circulated, wherein the ratio of amount of acid circulated in liters to the mass of polysilicon chunks present in the cleaning bath in kg is greater than 10.
No. of claims: 8     No. of figures: 2


 

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