Abstract: This is an electrolytic apparatus and process for the production of Hypochlorous Acid (HClO) and Sodium Hydroxide (NaOH) in a closed-loop arrangement. A brine solution in an electrolyzer cell is subjected to an electric current, causing HClO and/or NaOH to be produced in water circulated through the cell. The produced solution is recirculated through the cell as its chemical properties are monitored by a sensor, connected by a controller which controls a recirculating pump and the electric current, until the sensor indicates that the concentration of the solution has reached a desired value, and the controller stops the process.

Abstract: A method for concentrating an aqueous caustic alkali produced by a membrane cell process by using a single or multiple effect evaporator system in which the vapor flows in a counter direction to the aqueous caustic alkali flow and the heat recovered from the catholyte circulation line is used as part of the concentration process. In one embodiment, a catholyte heat recovery heat exchanger and flash evaporation chamber are located after the last effect of a multiple effect evaporator system. In another embodiment, the catholyte heat recovery heat exchanger and flash evaporation chamber are located prior to the single or multiple effect evaporator system. In yet another embodiment, the catholyte heat recovery process is used in conjunction with additional heat exchanger processes to further concentrate the final product as desired.

Abstract: A device for in-situ production of caustic and increasing alkalinity of a detergent and methods for increasing alkalinity of a detergent are disclosed. In particular, in situ electrochemical conversion of bicarbonate, sesquicarbonate or carbonate sources into caustic provides a safe means for increasing alkalinity of a detergent for a variety of cleaning applications. The invention further discloses methods for cleaning using the electrochemically enhanced detergent according to the invention.

Abstract: Soluble nickel and tin contained in a coating layer are eluted into an aqueous solution by bringing a cathode coated with a nickel-tin alloy into contact with an aqueous solution of an alkali metal hydrogen carbonate such as sodium hydrogen carbonate, thereby reducing the amounts of these metals eluted during electrolysis.

Abstract: The invention relates to an evaporative crystallization process to make salt compositions that includes a step wherein a mother liquor is formed that contains an effective amount of a crystal growth inhibitor that is selected from oligopeptides, polypeptides, and polymers bearing two or more carboxylic acid groups or carboxyalkyl groups and optionally further phosphate, phosphonate, phosphino, sulfate, and/or sulfonate groups, such as carboxymethyl cellulose with phosphate groups, to form salt crystals with a (111 ) face. The salt can be washed with a reduced amount of washing water while still containing lower amounts of K, Br, SO4, and/or Ca. A wet salt can be obtained by partially drying the salt crystals that are formed.

Abstract: An electrolytic bath is divided into an anodic chamber and a cathodic chamber by a cation-exchange membrane. A base alkaline solution of high impurity concentration is supplied into the anodic chamber from a tank of a base material as well as a circulating anolyte overflowed from the anodic chamber is supplied and circulated from an anode circulating tank, and NaOH solution of low impurity concentration is supplied and circulated into the cathodic chamber through a tank of a refined solution. The concentration of the circulating anolyte is detected, and based on this detected value the supplying amount of the base NaOH solution is controlled and electrolysis is performed. Thus, the concentration of NaOH solution in the anodic chamber is kept stable, and the refined NaOH solution of low impurity concentration can be obtained in the cathodic chamber.

Abstract: An electrochemical process is provided for treatment of molten kraft smelt produced from black liquor in a kraft recovery boiler. Treated smelt can be contacted with water to produce white liquor which can be re-used or recycled in the kraft process.

Abstract: The invention relates to a process for the electrolysis of sodium chloride-containing brine with parallel operation of amalgam electrolysis units (5) and membrane electrolysis units (4) with a common brine circuit using a mercury-resistant oxygen consumable cathode in the membrane electrolysis unit (4).

Abstract: An electrochemical process for the production of a hydroxide solution and a sulfate by the electrolysis of a waste aqueous mixture of oxidizable sulfur impurities in the anode compartment of at least one electrolytic cell while producing a hydroxide solution in the cathode compartment of the cell. The process is particularly applicable to the treatment of spent caustic solutions obtained by scrubbing a hydrocarbon process stream contaminated with oxidizable sulfur impurities. The electrolytic cell used in the electrolysis process of the invention can use either a porous membrane or a cationic permselective membrane to separate the anode and cathode compartments of the electrolysis cell.

Abstract: The present invention relates to the method of treating the salt bath liquid. In the surface treatment of the steel material by the use of the high-temperature salt bath mainly comprising sodium hydroxide and sodium nitrate, the salt ingredients contained in the washings generated are separated to be recovered and the metal salts contained are separated in the form of the insoluble salts. The salts contained in the nitrate radical-containing liquid system are recovered as the free acids again, the alkalies being recovered, and the reagents contained in the overflow from the salt-washing tank being recovered. The anode chamber liquid generated in the recoverying operation of the reagents is returned to the washing tank again to increase the concentration of the salts. The anode chamber liquid is poured into the pickling tank to reduce the oxidizing soluble metal salts contained in the washings by iron within the pickling tank, whereby the oxidizing soluble metal salts are insolubilized.