Eltech Systems Corporation

Anthony R Sacco

Jean M Hinden

Jeries I Bishara

Roland J Horvath

James R Brannan

Kenneth L Hardee

Richard C Carlson

Richard J Coin

Donald L DeRespiris

Eric J Rudd

Donald J Groszek

Joseph E Elliott

Bonnie M Ivancic

Methods, and various apparatus therefor, are disclosed for the electrolytic treatment of an acidic solution. Generally the method comprises: (a) providing an electrolytic cell, the cell comprising: (i) an anode chamber and an anode therein; (ii) a cathode chamber and a cathode therein; and (iii) a diaphragm. Usually the diaphragm is of a non-isotropic fibrous mat comprising 5-70 weight percent organic halocarbon polymer fiber in adherent combination with about 30-95 weight percent of finely divided inorganic particulate impacted into said fiber during fiber formation, the diaphragm having a weight per unit of surface area of about 3-12 kilograms per square meter. The method can continue by (b) introducing the acidic solution into the cell; (c) impressing a current on the anode and the cathode causing the migration of ions through the diaphragm; and (d) recovering a product of the electrolytic treatment from the anode chamber, or the cathode chamber, or from both chambers. In one method, the acidic solution is a cell bath circulated to the anode chamber, while rinse solution downstream of the cell bath is circulated to the cathode chamber. The method, and apparatus therefor, are particularly applicable to the recovery of hexavalent chromium from a dilute chromium electroplating rinse solution.

Apparatus for electrolytic treatment of an electrolytic solution

Electrolytic treatment of an electrolytic solution

The present invention resides in a process and apparatus for the electrolytic production of strong solutions of halogen oxyacids, more specifically for the production of such acids having a normality of about 0.1 to about 3.6 from the corresponding alkali metal salts of such acids. The present invention comprises establishing a solution of the corresponding alkali metal salt having a molar concentration less than that at which precipitation of said salt occurs. An electrolytic cell is provided comprising an anode compartment containing an anode, a cathode compartment containing a cathode, and a middle feed compartment intermediate the anode compartment and cathode compartment. The feed compartment is separated from the anode compartment by a diaphragm and from the cathode compartment by a cation-selective membrane. Means are provided for introducing said alkali metal salt solution into said middle feed compartment and for applying a voltage between the anode and cathode. Under the influence of the applied voltage, the alkali metal ions migrate through the cation-selective membrane to the cathode, reacting with hydroxyl ions to form alkali metal hydroxide, and the oxyhalogen ions migrate through the diaphragm to the anode reacting with protons to form halogen oxyacid. Means are provided for maintaining the cell at a temperature in the range of about 10.degree. C. to about 40.degree. C.

System for electrolytically generating strong solutions by halogen

Chlorine dioxide is generated from chlorate salt and introduced into a treatment stream. Initially following dissolution of the salt in aqueous medium, the solution is subjected to ion exchange for producing intermediate chloric acid. The acid is next converted to chlorine dioxide by electrolysis. The chlorine dioxide produced can then be extracted for use with a treatment stream. The chlorine dioxide generated can be free from unwanted by-products. The total generation system lends itself to recycling of unused product for obtaining virtually complete conversion of chlorate salt to useful chlorine dioxide.

Producing chlorine dioxide from chlorate salt

A plate heat exchanger assembly is provided having an anodic protection system comprising a plate heat exchanger frame, a plurality of heat exchanger plates mounted to the frame and means for selectively applying a voltage across the plates whereby during operation of the plate heat exchanger assembly biofouling and scaling is inhibited. The plurality of heat exchanger plates are mounted to the frame to define a plurality of heat exchange chambers for heat communication between a first and second process fluid being transmitted through the assembly. An insulating contact coating at points of electrically conductive contact between adjacent plates of the heat exchange chambers is provided such that the chambers comprise electrolytic chambers means are provided for selectively applying a voltage across said adjacent plates. A method of applying the insulating contact coating to a heat exchanger plate is also disclosed. The method comprises identifying points of electrically conductive contact between said adjacent heat exchanger plates and applying an insulating material to the points of contact.

Plate and frame heat exchanger assembly with anodic protection

Growing community of inventors

Mentor, OH, United States of America

Anthony R Sacco