Electrolysis tank used for aluminum electrolysis and electrolysis process using the electrolyzer

Abstract

An electrolytic cell for aluminum electrolysis includes a cell body, in which an anode and a cathode are arranged inside the cell body, the cell body is filled with an electrolyte, and at least a part of the anode is immersed in the electrolyte; the anode is arranged above the cell body, the cathode is arranged at the bottom of the electrolytic cell and is covered by aluminum liquid, the electrolyte is located between the anode and the cathode and covers the aluminum liquid; and an insulating layer is arranged on the inner sidewall of the cell body for isolating oxygen or the electrolyte from a carbon block. The anode contains Fe and Cu as primary components; and the electrolyte is composed of 30-38 wt % of NaF, 49-60 wt % of AlF 3 , 1-5 wt % of LiF, 1-6 wt % of KF and 3-6 wt % of Al 2 O 3 , and the molar ratio of NaF to AlF 3 is 1.0-1.52.

1 . An electrolytic cell for aluminum electrolysis, comprising:
 a cell body, an anode and a cathode being arranged inside the cell body, the cell body being further filled with an electrolyte;   the anode being arranged above the cell body, and at least a part of the anode being immersed in the electrolyte;   the cathode being arranged at the bottom of the electrolytic cell and covered by a certain amount of aluminum liquid;   the electrolyte being located between the anode and the cathode;   wherein the anode contains the components including Fe, Cu, Ni and Sn, wherein Fe and Cu serve as primary components; and   the electrolyte is composed of 30-38 wt % of NaF, 49-60 wt % of AlF 3 , 1-5 wt % of LiF, 1-6 wt % of KF and 3-6 wt % of Al 2 O 3 , wherein the molar ratio of NaF to AlF 3  is 1.0-1.52.   
     
     
         2 . The electrolytic cell according to  claim 1 , wherein the bottom surface of the anode is kept parallel to the cell body, and an insulating layer is arranged on the inner sidewall of the cell body and is used for isolating oxygen or the electrolyte from a carbon block. 
     
     
         3 . The electrolytic cell according to  claim 1 , wherein a cell cover is arranged at the upper end of the cell body and is provided with a vent and a feeding hole; a cathode bar is arranged inside the cathode, one end of the anode penetrates through the cell cover and is connected and provided with a binding post for connection with a power supply. 
     
     
         4 . The electrolytic cell according to  claim 1 , wherein the mass ratio of Fe to Cu to Sn is (23-40):36-60):(0.2-5). 
     
     
         5 . The electrolytic cell according to  claim 1 , wherein the components of the anode further include Ni. 
     
     
         6 . The electrolytic cell according to  claim 5 , wherein the anode is composed of Fe, Cu, Ni and Sn, wherein the content of Fe is 23-40 wt %, the content of Cu is 36-60 wt %, the content of Ni is 14-28 wt % and the content of Sn is 0.2-5 wt %. 
     
     
         7 . The electrolytic cell according to  claim 5 , wherein the components of the anode further include Al and Y. 
     
     
         8 . The electrolytic cell according to  claim 7 , wherein the anode is composed of Fe, Cu, Ni, Sn, Al and Y, wherein the content of Fe is 23-40 wt %, the content of Cu is 36-60 wt %, the content of Ni is 14-28 wt %, the content of Al is more than zero and less than or equal to 4 wt %, the content of Y is more than zero and less than or equal to 2 wt %, and the content of Sn is 0.2-5 wt %. 
     
     
         9 . The electrolytic cell according to  claim 1 , wherein the molar ratio of NaF to AlF 3  is 1.12-1.52. 
     
     
         10 . The electrolytic cell according to  claim 1 , wherein the liquidus temperature of the electrolyte is 620-670° C. 
     
     
         11 . An electrolysis process using the electrolytic cell according to  claim 1 , comprising the steps of:
 (1) adding specified amounts of NaF, AlF 3 , LiF, KF and Al 2 O 3  to a melting furnace for mixing and melting to form a melt; or adding specified amounts of NaF, AlF 3 , LiF and KF to a melting furnace for mixing and melting, and then adding Al 2 O 3  to obtain a melt; and   (2) raising the temperature of the melt prepared in step (1) to above 720-760° C., and then, pouring the melt into the electrolytic cell and carrying out electrolysis while the temperature is maintained at 720-760° C.   
     
     
         12 . The electrolysis process according to  claim 11 , wherein the electrolysis temperature is 730-750° C. 
     
     
         13 . The electrolysis process according to  claim 11 , wherein Al 2 O 3  is quantitatively supplied in the electrolysis process. 
     
     
         14 . The electrolytic cell according to  claim 2 , wherein a cell cover is arranged at the upper end of the cell body and is provided with a vent and a feeding hole; a cathode bar is arranged inside the cathode, one end of the anode penetrates through the cell cover and is connected and provided with a binding post for connection with a power supply. 
     
     
         15 . The electrolytic cell according to  claim 2 , wherein the mass ratio of Fe to Cu to Sn is (23-40):(36-60):(0.2-5). 
     
     
         16 . The electrolytic cell according to  claim 3 , wherein the mass ratio of Fe to Cu to Sn is (23-40):(36-60):(0.2-5). 
     
     
         17 . The electrolytic cell according to  claim 2 , wherein the components of the anode further include Ni. 
     
     
         18 . The electrolytic cell according to  claim 3 , wherein the components of the anode further include Ni. 
     
     
         19 . The electrolytic cell according to  claim 4 , wherein the components of the anode further include Ni. 
     
     
         20 . The electrolytic cell according to  claim 1 , wherein the components of the anode further include Al and Y.