CS218616B1

CS218616B1 - A method of controlling the pH of a sodium nitrate electrolyte solution for electrochemical! and the equipment to move it

Info

Publication number: CS218616B1
Application number: CS27280A
Authority: CS
Inventors: Jan Zubak
Original assignee: Jan Zubak
Priority date: 1980-01-14
Filing date: 1980-01-14
Publication date: 1983-02-25

Abstract

Vynález rieši plynulú reguláciu hodnoty pH roztoku elektrolytu dusičnanusodného pri elektrochemickom obrábaní. Podstata vynálezu spopíva v elektrolytickom vylučovaní přebytku iónov Na4- na katodě před vstupom do medzielektródového priestoru, ktoré sú odvádzané častou elektrolytu mimo medzielektródový priestor do regeneračnej nádrže. Zariadenie k prevádzaniu spósobu pozostáva z telesa, ktoré je umiestnené v prívodnom potrubí elektrolytu. Na vnútomej ploché telesa je uložená anoda rozdělená na dve časti rámom, v ktorom sú upevněné oproti sebe katody tvoriace uzavretú dutinu. Hodnota pH roztoku elektrolytuNaNO3 sa reguluje změnou intenzity prúdu na elektrodách elektrolyzéra v závislosti na množstve elektrolytu přetékaného prívodným potrubím. Výnález móže byť účelne využitý pri elektrochemickom obrábaní, pri ktorom sa používá ako elektrolyt roztok dusičnanu sodného.The invention solves the problem of continuous regulation of the pH value of a sodium nitrate electrolyte solution during electrochemical machining. The essence of the invention lies in the electrolytic elimination of excess Na4- ions on the cathode before entering the interelectrode space, which are discharged by part of the electrolyte outside the interelectrode space into the regeneration tank. The device for performing the method consists of a body that is placed in the electrolyte supply pipe. On the inner flat body is placed an anode divided into two parts by a frame in which cathodes are fixed opposite each other, forming a closed cavity. The pH value of the NaNO3 electrolyte solution is regulated by changing the current intensity on the electrodes of the electrolyzer depending on the amount of electrolyte flowing through the supply pipe. The invention can be effectively used in electrochemical machining, in which a sodium nitrate solution is used as an electrolyte.

Description

(54) Sposob regulácie hodnoty pH roztoku elektrolytu dusičnanu sodného pri elektrochemickou! ohráhaní a zariadenie k jeho prevádzaniu(54) How to control the pH value of a sodium nitrate electrolyte solution at electrochemical! and the equipment for its operation

Vynález rieši plynulú reguláciu hodnoty pH roztoku elektrolytu dusičnanu sodného pri elektrochemickom obrábaní.The invention provides a continuous control of the pH value of a sodium nitrate electrolyte solution in electrochemical machining.

Podstata vynálezu spopíva v elektrolytickom vylučovaní přebytku iónov Na^4- na katodě před vstupom do medzielektródového priestoru, ktoré sú odvádzané častou elektrolytu mimo medzielektródový priestor do regeneračnej nádrže. Zariadenie k prevádzaniu spósobu pozostáva z telesa, ktoré je umiestnené v prívodnom potrubí elektrolytu. Na vnútomej ploché telesa je uložená anoda rozdělená na dve časti rámom, v ktorom sú upevněné oproti sebe katody tvoriace uzavretú dutinu. Hodnota pH roztoku elektrolytu NaNO₃ sa reguluje změnou intenzity prúdu na elektrodách elektrolyzéra v závislosti na množstve elektrolytu přetékaného prívodným potrubím.SUMMARY OF THE INVENTION The invention is based on the electrodeposition of excess Na ⁴ ions on the cathode before entering the inter-electrode compartment, which are discharged by a portion of the electrolyte outside the inter-electrode compartment into the recovery tank. The method of transferring the method comprises a body which is located in the electrolyte supply line. On the inside of the flat body is an anode divided into two parts by a frame in which the cathodes forming a closed cavity are fixed against each other. The pH value of the NaNO ₃ electrolyte solution is controlled by varying the current intensity at the electrodes of the electrolyzer as a function of the amount of electrolyte flowing through the supply line.

Výnález móže byť účelne využitý pri elektrochemickom obrábaní, pri ktorom sa používá ako elektrolyt roztok dusičnanu sodného.The invention can be conveniently used in electrochemical machining, in which sodium nitrate solution is used as the electrolyte.

Vynález sa týká spósobu regulácie hodnoty pH roztoku elektrolytu dusičnanu sodného pri elektrochemickou! obrábaní a zariadenia k prevádzaniu tohoto spósobu.The invention relates to a method for controlling the pH of a sodium nitrate electrolyte solution at an electrochemical process. machining and equipment for carrying out the process.

Pri elektrochemickom obrábaní v roztoku dusičnanu, sodného dochádza k trvalej zmene hodnoty pH vplyvom úbytku NO₃ iónov, čo má za následok ovplyvňovanie procesu obrábania a to najma změnu Specifického úberu materiálu. To sa prejavuje hlavně v sériovej výrobě, kde sa preto nedosahuje opakovatelnost zhotoveného tvaru. Z týchto dóvodov je potřebné udržiavať hodnotu pH roztoku elektrolytu v určitom stanovenom rozsahu.In electrochemical machining in a sodium nitrate solution, the pH value is permanently changed due to the loss of NO ₃ ions, which results in the machining process being affected, in particular the change in specific material removal. This is manifested mainly in mass production, where the repeatability of the produced shape is therefore not achieved. For these reasons, it is necessary to maintain the pH of the electrolyte solution within a certain range.

V súčasnosti sa u stroj ov pre elektrochemické obrábanie regulácia hodnoty pH u roztokov dusičnanu sodného prevádza přidáváním kyseliny dusičnej v priebehu procesu obrábania v určitých dávkách podfa vefkosti zaznamenanej změny hodnoty pH.At present, for electrochemical machining machines, pH control of sodium nitrate solutions is accomplished by adding nitric acid during the machining process at certain batches, depending on the observed pH change.

Nevýhody uvedeného spósobu udržiavania hodnoty pH v požadovanom rozsahu spočívajú najma v nebezpečnej manipulácii so žieravinami pre obsluhu zariadenia. Okrem toho eliminovanie změny pH nie je plynulé, pretože kyselina sa přidává v určitých dávkách a pri nedokonálom premiešavaní sa často do medzielektródového priestoru dostává elektrolyt so značnou změnou hodnoty pH.The disadvantages of this method of maintaining the pH in the desired range are, in particular, the hazardous handling of the caustics for the operator of the device. In addition, the elimination of the pH change is not continuous, since the acid is added at certain doses, and when incomplete mixing often leads to an electrolyte with a significant change in pH value in the inter-electrode space.

Změna hodnoty pH nie je pri obrábaní plynulá, mění sa v závislosti od intenzity prúdu prechádzajúceho medzielektródovým priestorom a závisí tiež od druhu obrábaného materiálu. Uvedené skutočnosti za súčasného stavu nedávajú teda předpoklad k udržiavaniu hodnoty pH v presne vymedzenom rozsahu.The pH change is not continuous during machining, it varies depending on the intensity of the current passing through the inter-electrode space and also depends on the type of material to be machined. Thus, the present state of the art does not provide a precondition for maintaining the pH within a well-defined range.

Vyššie uvedené nevýhody zmierňuje spósob regulácie hodnoty pH roztoku elektrolytu dusičnanu sodného pri elektrochemickom obrábaní podfa tohoto vynálezu, ktorého podstatou je, že z roztoku elektrolytu NaNO₃ sa před vstupom do medzielektródového priestoru vylučuje elektrolýzou na katodě prebytok iónov Na⁺, ktoré sú odvádzané časťou elektrolytu mimo medzielektródový priestor do regeneračnej nádrže.The above disadvantages relieves method of regulating the pH of the electrolyte solution of sodium nitrite for the electrochemical machining according to the invention, which is characterized in that the electrolyte solution of NaNO _3, prior to entry into the inter-electrolysed the cathode, excess Na ^+, which is discharged a part of the electrolyte past the the inter-electrode space into the recovery tank.

Do podstaty patří tiež zariadenie k prevádzaniu spósobu pozostávajúce z telesa, ktoré je umiestnené v prívodnom potrubí elektrolytu. Na vnútornej ploché telesa je uložená anoda rozdělená na dve časti rámom, v ktorom sú upevněné oproti sebe najmenej dve sieťové katody opatřené na vonkajšej straně diafragmami a tvoriace uzavretú dutinu. Dutina vyúsťuje v hornej časti do výpustného otvoru elektrolytu telesa 1 opatřeného uzavieracím kohútom. V dolnej časti diafragiem sú vytvořené vstupné otvory elektrolytu.The invention also relates to a method for carrying out a method comprising a body which is arranged in an electrolyte supply line. On the inner flat body there is an anode divided into two parts by a frame in which at least two net cathodes fitted with diaphragms on the outside and forming a closed cavity are opposed. The cavity opens at the top into the electrolyte outlet of the body 1 provided with a stopcock. Electrolyte inlet openings are formed at the bottom of the diaphragms.

Podstatou vynálezu je tiež to, že hodnota pH roztoku elektrolytu NaNO₃ sa reguluje změnouIt is also an object of the invention that the pH of the NaNO ₃ electrolyte solution is controlled by change

Claims

SUBJECT

1, the anode 3 is interchangeably disposed of an electrochemical corrosion-resistant material, for example a nickel sheet, which is divided into two parts by an electrical insulating material frame 5. At least two net cathodes 6 are mounted opposite to each other on the frame 5. The cathodes 6 are provided on the outside with diaphragms 7 and form a closed cavity 4 with the frame 5. The cavity 4 opens at the top into the electrolyte discharge opening 9 in the body 1 Inlet 10 of the electrolyte is formed in the lower part of the diaphragms 7.

The electrolyte is supplied through a supply line

1. A method for controlling the pH value of a sodium nitrate electrolyte solution at an electrochemical current intensity at the electrodes of an electrolyzer as a function of the amount of electrolyte flowing through the supply line.

The advantage of the method of controlling the pH value of the electrolyte solution and the device for carrying out the method is the possibility of continuously changing the pH value or keeping it within a precisely determined range. Since the pH value of the electrolyte solution varies depending on the intensity of the current passing between the electrodes of the electrolyzer and the type of material being machined, it is possible to control the pH value of the electrolyte solution depending on the current intensity during machining or according to a predetermined program.

An apparatus for performing a method of controlling the pH value of an electrolyte solution is shown by way of example in the accompanying drawing. 1 is a longitudinal section through the device; and FIG. 2 is a cross-sectional view of the apparatus A-A.

The device for controlling the pH value of the electrolyte solution is arranged such that a body 1 is provided in the electrolyte supply line 2.

2. The control method according to claim 1, characterized in that the pH of the electrolyte solution of NaNO ₃ is controlled by changing the intensity of the current at the electrodes of the electrolytic cell depending on the amount of flow of the electrolyte supply line.

In the cathode compartment, an excess of Na ⁺ ions are deposited on the cathode and with a portion of the electrolyte solution of about 1-2 liters / min are discharged into a recovery tank where the alkaline NaNO solution is collected. ₃ neutralizes with concentrated nitric acid HNO ₃ to the determined pH of the solution. After regeneration, it returns to the working tank. The bulk of the electrolyte passes through the anode compartment in which there is an excess of NO ₃ ions. Since the electrolyte is fed to the electrolyzer under relatively high pressure, electrolyte inlet openings 8 are formed in the lower part of the diaphragms 7, which serve to eliminate the overpressure in the electrolyzer, especially with a strong contaminated solution. The outlet 9 of the electrolyte in the body 1 into which the cavity 4 constituting the enclosed cathode space opens, serves to drain a portion of the electrolyte containing an excess of Na ⁺ ions. The amount of electrolyte discharged into the recovery tank is controlled by the shut-off valve 10.

Machining characterized in that an excess of Na ⁺ ions are discharged from the NaNO ₃ electrolyte solution prior to entering the inter-electrode compartment by electrolysis at the cathode, which are discharged by a portion of the electrolyte outside the inter-electrode compartment into the f-recovery tank.

Device according to Claims 1 and 2, characterized in that a body (1) is placed in the electrolyte conduit (2) on the inner flat surface of which the anode (3) is arranged, divided into two parts by a frame (5), in which at least two mesh cathodes (6) are mounted opposite one another, provided with diaphragms (7) on the outside and forming a closed cavity (4) leading to a top opening in the electrolyte discharge opening (9) of the body (1) provided with a stopcock 10), wherein electrolyte inlet openings (8) are formed in the lower part of the diaphragms (7).