Methods and Apparatus for Producing Ferrate(VI)

Abstract

An undivided electrochemical cell. The electrochemical cell includes a housing defining an undivided chamber, the housing having one electrolyte inlet and at least two electrolyte outlets; an anode in the chamber; a cathode in the chamber; and an electrolyte in the chamber, wherein the anode and the cathode are not gas diffusion electrodes. The invention also involves a method of operating an electrochemical cell, and methods for making ferrate(VI).

1 . An undivided electrochemical cell comprising:
 a housing defining an undivided chamber, the housing having one electrolyte inlet and at least two outlets;   an anode in the chamber;   a cathode in the chamber; and   an electrolyte in the chamber,   wherein the anode and the cathode are not gas diffusion electrodes.   
     
     
         2 . The undivided electrochemical cell of  claim 1  wherein the housing has two electrolyte outlets. 
     
     
         3 . The undivided electrochemical cell of  claim 1  further comprising a fluid flow controller in fluid communication with the electrolyte outlets. 
     
     
         4 . The undivided electrochemical cell of  claim 3  wherein the fluid flow controller is selected from flow restrictions, valves, screens, fluid flow constrictions, bends or weirs. 
     
     
         5 . The undivided electrochemical cell of  claim 1  wherein the anode is made of a material containing iron. 
     
     
         6 . The undivided electrochemical cell of  claim 1  wherein the anode is selected from solid iron plate, expanded metal mesh, wire mesh, woven metal cloth, wire, rod, or combinations thereof. 
     
     
         7 . The undivided electrochemical cell of  claim 1  wherein the anode is selected from iron, steel, “dimensionally stabilized anode”(DSA), titanium, platinum, iridium, and other oxidation resistant electrolytically conductive materials. 
     
     
         8 . The undivided electrochemical cell of  claim 1  wherein a ratio of a surface area of the anode to a surface area of the cathode is in the range of 1 to at least about 10. 
     
     
         9 . The undivided electrochemical cell of  claim 1 , wherein said cathode has a physically displaced area that interfaces least 90%, and preferably about 100%, and most preferably 110% of the anode area. 
     
     
         10 . The undivided electrochemical cell of  claim 1  wherein the cathode is made of a material selected from nickel, titanium, platinum, tin, lead, stainless steel, graphite, iron or alloys thereof, or laminates or claddings thereof. 
     
     
         11 . The undivided electrochemical cell of  claim 1  wherein the cathode is selected from solid plate, expanded metal mesh, wire mesh, woven metal cloth, wire, rod, or combinations thereof. 
     
     
         12 . The undivided electrochemical cell of  claim 1  wherein the electrolyte is an alkaline solution of hydroxide. 
     
     
         13 . The undivided electrochemical cell of  claim 12  wherein the hydroxides are selected from NaOH, KOH, or combinations thereof. 
     
     
         14 . The undivided electrochemical cell of  claim 12  wherein the hydroxides are selected from >BioH, KOH, and combinations thereof. 
     
     
         15 . The undivided electrochemical cell of  claim 12  wherein the electrolyte comprises a mixture of KOH and NaOH, and wherein a molar concentration of NaOH is greater than about 5. 
     
     
         16 . The undivided electrochemical cell of  claim 15  wherein the electrolyte comprises about 40 to about 45 wt % NaOH and about 0.1 to about 8 wt % KOH. 
     
     
         17 . The undivided electrochemical cell of  claim 1  further comprising a screen between the anode and the cathode. 
     
     
         18 . The undivided electrochemical cell of  claim 17  wherein the screen is made of plastic. 
     
     
         19 . The undivided electrochemical cell of  claim 17  wherein the screen has a mesh size such to occupy at least 25%, preferably at least 50%, and most preferably at least 75% of the area between the anode and cathode surfaces, in which the open area consists of small openings, as is provided by a screen or the equivalent. 
     
     
         20 . The undivided electrochemical cell of  claim 18  wherein the plastic is selected from polyolefins, fluoropolymers, or polyvinyl chloride. 
     
     
         21 . The undivided electrochemical cell of  claim 1  wherein the housing is made of a material selected from metal, fiberglass, reinforced plastic (thermoplastic or thermoset) concrete, rubber, or combinations thereof, including constructed as a corrosion resistant liner within rigid-walled structure. 
     
     
         22 . The undivided electrochemical cell of  claim 1  further comprising a variable DC power supply operatively connected to the electrochemical cell.