PERIPHERAL COATING PROCESS OF THE COPPER CONDUCTIVE BAR FOR THE MANUFACTURE OF ANODES, USED IN THE PROCESSES OF ELECTRO-OBTAINING OR ELECTRO-REFINING OF METALS

Abstract

The invention describes the assembly and construction method for anodes used in the electrolytic processes. It is made up of a copper bus bar (1) where the plate shall be inserted (3). It has a rough surface previously milled to form a groove (2), which is, approximately, 0.12 mm thicker than the thickness of the plate; approximately, 19 mm deep. Such copper bus bar (1) is first subject to a process mechanical/chemical or electrochemical process aimed to significantly increase its roughness, between 0.01 mm and 0.5 mm, preferably 0.15 mm, by using mechanical processes, such as sand blasting or grinding, preferably grinding with blasting material made of various metals or using glass balls/copper slag or chemical corrosion by using oxidant chemical agents or anodic electrolytic corrosion aimed to finally improve bonding between the copper bar.

Claims

1. A method for assembling lead anodes used in the electrolytic processes, which increases corrosion resistance and improves bonding between the copper bar, dip weld into a melted bath and a final peripheral coating of such copper bar comprising the following stages: a) The copper bus bar is subject to pre-coating by dip welding in a melted bath, at the right temperature (300 C.-350 C.) with an alloy mainly including lead and silver. The silver content is between 0.1% w/w and 10% w/w, preferably 3% w/w; b) After this pre-coating while the hot copper bar is at a temperature between 250 C. to 280 C., and inserted into a proper mold, the peripheral coating of the copper bar is performed by means of injection or any other similar method with a lead-antimony alloy, between 0.01 and 11% of Sb w/w, preferably 6% w/w, with a thickness between 0.01 and 10 mm, preferably 1.5 mm; c) Right after injection or pre-heating the copper bar is set onto the assembly workbench to fill the groove with a lead-bismuth alloy, between 1 to 55% w/w of bismuth, preferably 50% w/w, at such temperature to allow insertion of the lead plate, while the lead-bismuth weld remains liquid; d) Preferably with an identical alloy to that of peripheral coating to weld reinforce the joint spot, between the peripheral coating of the copper bar and the plate, on both sides when the lead-bismuth alloy poured in the groove has solidified. FEATURED, because the copper bar is previously subject to a mechanical/chemical/electrochemical process aimed to increase its roughness, before the pre-coating process of such copper bar.

2. The method, as per claim 1, FEATURED, because the roughness increasing process of the copper bar is performed by mechanical means i.e. sanding or grinding, preferably grinding, with blasting material of various metals, glass balls or copper slag.

3. The method, as per claim 2, FEATURED, because the roughness is achieved by means of chemical corrosion of the surface using oxidant chemical agents.

4. The method, as per claim 3, FEATURED, because the increased roughness process is obtained by means of anodic electrolytic corrosion of the copper bar.

5. The method, as per claims 2, FEATURED, because the final roughness of the copper bar subject to these processes is between 0.01 mm and 0.5 mm, preferably 0.15 mm.

6. A method for assembling lead anodes used in the electrolytic processes, to increase corrosion resistance and improves bonding between a copper bar and lead plate, the copper bar having a groove, comprising: a) roughening the surface of the copper bar; b) pre-coating the copper bar by dip welding in a melted bath, at a temperature in the range of 300 C.-350 C. with an alloy including lead and silver, wherein the silver content is between 0.1% w/w and 10% w/w; c) inserting the copper bar into a mold, while the copper bar is at a temperature between 250 C. to 280 C., and injecting a lead-antimony alloy, between 0.01 and 11% of Sb w/w, and having a thickness between 0.01 and 10 mm; d) filling the groove with a lead-bismuth alloy between 1 to 55% w/w of bismuth, while maintaining the temperature and inserting the lead plate in the groove while the lead-bismuth weld remains liquid, whereby a joint is formed between the copper bar and the lead plate; and d) weld reinforcing the joint when the lead-bismuth alloy poured in the groove has solidified.

7. The method of claim 6, wherein the silver content of the pre-coating step is 3% w/w.

8. The method of claim 6, wherein the lead-antimony of the inserting step is 6% w/w.

9. The method of claim 6, wherein the thickness of the inserting step is 1.5 mm.

10. The method of claim 6, wherein the bismuth of the groove filling step is preferably 50% w/w.

11. The method of claim 6, wherein the roughening step is performed prior to the precoating step by one of the group comprising: a mechanical, a chemical and an electrochemical process.

Description

DESCRIPTION OF THE FIGURES

[0014] FIG. 1 describes a full anode.

[0015] FIG. 2A describes the copper grooved bar.

[0016] FIG. 2B describes the A-A cut of FIG. 2A.

[0017] FIG. 3 describes the anode pre-assembly after the groove was filled with weld and inserted into the lead plate.

[0018] FIG. 4 describes the anode assembly completed, with its reinforcement weld.

[0019] FIG. 5 describes the peripheral coating anode assembly.

DESCRIPTION OF THE INVENTION

[0020] The invention describes the assembly and construction method for anodes used in the electrolytic processes. It is made up of a copper bus bar (1) where the plate shall be inserted (3). It has a rough surface previously milled to form a groove (2), which is, approximately, 0.12 mm thicker than the thickness of the plate; approximately, 19 mm deep. Such copper bus bar (1) is first subject to a process mechanical/chemical or electrochemical process aimed to significantly increase its roughness, between 0.01 mm and 0.5 mm, preferably 0.15 mm, by using mechanical processes, such as sand blasting or grinding, preferably grinding with blasting material made of various metals or using glass balls/copper slag or chemical corrosion by using oxidant chemical agents or anodic electrolytic corrosion aimed to finally improve bonding between the copper bar. Further dip weld, final peripheral coating, dip pre-coating by means of a welding bath (4A) made up of a lead-silver based alloy, with a silver content between 0.1% w/w and 10% w/w, but preferably lead: 97% w/w, silver: 3% w/w, at right temperature (300-350 C.), just as described in FIGS. 3 and 4. Right after, when the bar has just been coated, at 250 to 280 C. it is inserted into a proper model. The peripheral area of the bar is coated (by means of injection or any other similar mechanism) with an lead-antimony alloy, between 0.01 and 11% w/w of Sb preferably 6% w/w, and with a thickness between 0.01 and 10 mm, preferably 1.5 mm, (6), just as described in FIGS. 3 and 4. As an option, the cooper bar can be further coated with a lead-antimony alloy and when still hot it is set on a proper assembly workbench, or left to cool and further reheated in a kiln until getting a temperature between 120 C. and 170 C. and set on an assembly workbench in order to fill the groove (2) with a lead-bismuth melted alloy with having a low fusion point, between 1 to 55% w/w of bismuth (4B) just as described in FIGS. 3 and 4, preferably lead: 50% w/w, bismuth: 50% w/w. The lead-bismuth weld must have such temperature as to allow insertion of the lead plate into the assembly groove while the lead-bismuth weld remains liquid. The lead plate (3) is inserted into the groove of the copper bar, filled with weld (4B). The copper bar (1) starts to cool, while the plate (3)at the joint spotstarts to heat. After a while heat balance between both bodies is reached, at approximately 135 to 150 C. From that temperature, when both components are expanded they start to cool together. This procedure guarantees no stress generated at the welded spot, which is the cause of combed anodes.

[0021] When the assembly temperature at the joint spot has reached, approximately, 100 C., and the weld (4B) has solidified weld reinforcement (5) is made on both sides. Such weld (5) is made up of a weld bead with no filling, between the peripheral coating (6) of the copper bar (1) and the walls of the plate (3). The weld alloy may be a lead-bismuth/lead-antimony alloy, whose lead content is higher than 50% w/w.