Lead-coated article for industrial operations in acidic medium

Abstract

Techniques described herein relate to an article, including an electrolytic tank for refining metals, and related production techniques, wherein the article defines a channel or cavity receiving a corrosive medium including sulfuric acid. The article includes a corrosion-resistant lead coating including at least one layer of lead solidified onto at least a portion of the cavity. The corrosion-resistant coating can be combined with additional layers including fiberglass-based material for further protection against corrosion.

What is claimed is: 
     
         1 . An electrolytic tank for metal recovery operations, the electrolytic tank having an inner surface defining a cavity to receive a corrosive electrolytic bath including sulfuric acid, and the electrolytic tank comprising:
 a corrosion-resistant lead coating covering at least a portion of the inner surface of the tank, the corrosion-resistant lead coating comprising at least one layer of lead being solidified onto the at least a portion of the inner surface of the tank.   
     
     
         2 . The electrolytic tank of  claim 1 , wherein a size of the at least a portion of the inner surface is selected according to at least one of the following parameters: a level of the corrosive electrolytic bath, a configuration of a capping board and contact bar assembly, and a configuration of hanging bars resting thereon. 
     
     
         3 . The electrolytic tank of  claim 1 , wherein the corrosion-resistant lead coating covers a lower portion of the inner surface of the tank to be contacted with the corrosive electrolytic bath, thereby leaving a remaining portion of the inner surface free from lead. 
     
     
         4 . (canceled) 
     
     
         5 . The electrolytic tank of  claim 1 , further comprising:
 a core having a base wall and four side walls extending upwardly from an outer edge of the base wall, thereby defining a shape of the cavity;   an inner hull bonded with an internal surface of the core, wherein the inner hull defines the inner surface of the tank and is made of a material having corrosion-resistant properties; and   an outer hull bonded with an external surface of the core, wherein the outer hull is joined to the inner hull at a top region of the side walls of the core to form an envelope.   
     
     
         6 . The electrolytic tank of  claim 5 , wherein the inner hull is made of multiple layers of a fiberglass-based material. 
     
     
         7 . The electrolytic tank of  claim 5 , wherein the outer hull is made of multiple layers of a fiberglass-based material. 
     
     
         8 . The electrolytic tank of  claim 7 , wherein each layer is fiberglass mat, knitted fiberglass, stitched, stitched-mat, knitted-mat or fiberglass woven roving. 
     
     
         9 . The electrolytic tank of  claim 5 , wherein the inner hull has a composition differing from the outer hull. 
     
     
         10 . The electrolytic tank of  claim 1 , wherein the at least one layer of lead is derived from a thermal spraying application. 
     
     
         11 . The electrolytic tank of  claim 10 , wherein the thermal spraying application is two-wire electric arc spraying, combustion flame spraying, laser cladding, plasma spraying or HVOF (High Velocity Oxygen Fuel) spraying. 
     
     
         12 . The electrolytic tank of  claim 1 , wherein the corrosion-resistant lead coating further comprises a final layer of lead electrodeposited onto the at least one layer of lead, to reduce porosity of the corrosion-resistant lead coating in comparison to that of the at least one thermally sprayed layer alone. 
     
     
         13 . The electrolytic tank of  claim 1 , further comprising:
 a core having a base wall and four side walls extending upwardly from an outer edge of the base wall, thereby defining a shape of the cavity; and   an electrically conductive coating applied to at least a portion of an internal surface of the core that defines the at least a portion of an inner surface of the tank;   wherein the corrosion-resistant lead coating is derived from electrodeposition of the at least one lead layer onto the electrically conductive coating.   
     
     
         14 . The electrolytic tank of  claim 13 , wherein the core is made of polymer concrete and the electrically conductive coating is made of a mixture of fiberglass fibers and powdered, flocs, fibers, filaments, or strings of carbon or a metallic material embedded within a cured plastic matrix. 
     
     
         15 . The electrolytic tank of  claim 13 , wherein the core is made of polymer concrete and the electrically conductive coating is made of a metallic paint applied to the polymer concrete. 
     
     
         16 . The electrolytic tank of  claim 1 , further comprising an additional corrosion-resistant coating applied onto the corrosion-resistant lead coating. 
     
     
         17 . The electrolytic tank of  claim 16 , wherein the additional corrosion-resistant coating is at least one of:
 a layer of fiberglass-based material comprising type A and/or Type C fiberglass fibers, and   a layer of synthetic fiber.   
     
     
         18 . The electrolytic tank of  claim 17 , wherein the synthetic fiber is polyester. 
     
     
         19 . The electrolytic tank of  claim 16 , wherein the additional corrosion-resistant coating is made of a thermoplastic resin including Teflon®, Bekaplast® or HDPE. 
     
     
         20 . An article defining a cavity to receive a corrosive medium, the article comprising:
 at least one layer of a fiberglass-based material defining an inner surface of the cavity, the fiberglass-based material having corrosion-resistant properties; and   a lead coating covering at least a portion of the inner surface of the cavity, the lead coating comprising at least one thermally-sprayed layer of lead being solidified onto the at least one layer of the fiberglass-based material.   
     
     
         21 . The article of  claim 20 , being an electrolytic tank for refining metals, piping, or tubing defining a cavity in contact with acid sulfuric in hydrometallurgical operation, electrowinning operation, electrorefining operation, in solvent extraction operation or in an acid plant operation. 
     
     
         22 .- 28 . (canceled)