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Title:
NOVEL PROCESS FOR DESCALING OR PICKLING OF STEELS AND STAINLESS STEELS
Document Type and Number:
WIPO Patent Application WO/2022/091049
Kind Code:
A1
Abstract:
This invention relates to a novel process of electrolytic or electrochemical descaling or pickling of steel, stainless steel or metal without use of any kind of acids or alkali or oxidizing agents and one or more combinations thereof and thereby to reduce the consumption of water and also reduce generation of solid waste and wastewater to a large extent which can create huge impact by reducing environmental liabilities.

Inventors:
BHOLANDA DIPAKKUMAR (IN)
RUPARELIA JAYESH (IN)
BHOLANDA JAIPRAKASH (IN)
Application Number:
PCT/IB2021/060076
Publication Date:
May 05, 2022
Filing Date:
October 31, 2021
Export Citation:
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Assignee:
BHOLANDA DIPAKKUMAR (IN)
RUPARELIA JAYESH (IN)
BHOLANDA JAIPRAKASH (IN)
International Classes:
C23G1/24; B21G1/00
Foreign References:
CN109267142A2019-01-25
GB2140037A1984-11-21
Attorney, Agent or Firm:
GAJJAR, Hardik (IN)
Download PDF:
Claims:
Claims

[Claim 1] An electrochemical process of pickling or descaling of steel, stainless steel or metals, comprising electrolyte solution, whereas a process is substantially devoid use of any acid or alkali.

[Claim 2] The electrochemical process according to claim 1, wherein the process comprising steps of: a. preparation of electrolyte solution, b. supplying the current to steel as anode or cathode at room temperature and atmospheric pressure, c. optionally, reversing the polarity of applied current, d. removal of formed scales from solution

[Claim 3] The electrochemical process according to claim 1, wherein steel, stainless steel or metal products having iron content greater than about 30%.

[Claim 4] The electrochemical process according to claim 1, wherein electrolyte solution comprises salts or compounds or ligands.

[Claim 5] The electrochemical process according to claim 1, electrolyte solution comprises salts or ligands, from concentration of at least about 1 ppm to about 1000000 ppm.

[Claim 6] The electrochemical process according to claim 4, wherein salts or ligands is selected from the group consisting of monovalent, divalent, trivalent and one or more combinations thereof.

[Claim 7] The electrochemical process according to claim 4, wherein salts or ligands is selected from the group consisting of anions, anions of organic acids or oxoanions and one or more combinations thereof.

[Claim 8] The electrochemical process according to claim 7, wherein anion salt is selected from the group consisting of hydride, oxide, fluoride, sulfide, chloride, nitride, bromide, iodide, acetate, formate, cyanide, amide, cyanate, peroxide, thiocyanate, oxalate, hydroxide, permanganate or one or more combinations thereof.

[Claim 9] The electrochemical process according to claim 7, wherein oxoanion salt is selected from the group consisting of arsenate, phosphate, arsenite, hydrogen phosphate, dihydrogen phosphate, sulfate, nitrate, hydrogen sulfate, nitrite, thiosulfate, sulfite, perchlorate, iodate, chlorate, bromate, chlorite, hypochlorite, hypobromite, carbonate, chromate, hydrogen carbonate, bicarbonate, dichromate or one or more combinations thereof.

Description:
Description

Title of Invention: NOVEL PROCESS FOR DESCALING OR PICKLING OF STEELS AND STAINLESS STEELS

Technical Field

[0001] The present invention relates to a process of electrolytic descaling or pickling of steel, stainless steel or metal without use of any kind of acids, alkalis or oxidizing agents and one or more combinations thereof.

Background Art

[0002] Steels, low alloy steels, high alloy steels, stainless steels, special steels etc. contain oxide on its surface after hot working or warm working. Such surface scales hinder further processes and promotes surface corrosion of metals and because of that smooth surfaces cannot be achieved till such oxides are present on the surface. They are porous, hard, uneven, rough and chemically complex in nature and their nature vary with type of steels, types of fuel and practices followed while hot or warm working. Such oxides are not desired for the further finishing processes. They must be removed from the surface.

[0003] In existing technologies, solutions of strong or weak acids and combinations thereof are used to descale the surface. The function of them is to loosen the scale by entering into the crevices, dissolving the metal surface layer beneath surface scale and breaking the physicochemical bond between the scale and metal, thus peeling off the scale layer uniformly over the metal object surface. Dissolved metal part and dissolved oxides make the metallic salts of simple and complex types of soluble and insoluble in solution. The solution finally reach towards equilibrium and rate of reaction slows down and virtually stops. Spent solution comprises of metallic salts and residual acids is discarded and neutralized with the help of alkali and/or base. In effluent treatment plant, neutralized spent solution yields into precipitates as well as water soluble and insoluble salts which are filtered off and thus solid waste and water are separated. Solid waste is disposed as per the statutory regulations and water is sent for further treatment.

[0004] In conventional processes, acids and/or alkalis are used as agents for removing the scale. Traces of acids are carried forward with the metal object and while water washing huge amount of water contaminate with acid. Generally, 0.15MT of spent acid and 15001itres of fresh water is utilized per 1MT of steel or stainless steel processed, these numbers varies depending on the type of product and practices. At ETP about 200 kg solid waste with 30% moisture is produced per 1MT of steel or stainless steel processed. Treated water is further adjusted for COD (Chemical Oxygen Demand) and filters with Total dissolved solid content varies from 7500 mg/L to 30,000 mg/L. Acid fumes of sulfates, nitrates, chlorates, etc. are sent to fume extraction systems and scrubbers, which are further neutralized. Acid storages, alkali storages acid protection systems, PPEs, occupational health and safety, acid proof floors, structures, statutory clearances, monitoring and control of air, water and solid waste contains huge liability on environment, safety and health. During such processes traces of metal are dissolved and loss of metals occurs by 0.6%-4.5% depending on type of processes and products involved.

[0005] Fairbourn DC, United States patent no. 6294072 discloses a system and process is provided for stripping metal oxide scale from metal products, such as stripping iron oxide scale from steel sheet and steel mill products. Steel having iron oxide scale compiling a layer of one or more iron oxide phases is associated with an electrolyte, such as by being immersed in a tank filled with the electrolyte, such as a dilute acid mixture. A counter electrode having a higher potential than steel is also associated with the electrolyte. The counter electrode is DC coupled to the steel, or to a conductive component in direct contact with the steel, such that electric current flows from the steel to the counter electrode due to the difference in the natural potentials of steel and the counter electrode. The metal oxide scale is thereby stripped from the steel.

[0006] Pedrazzini C et al., United States patent no. 5843240 discloses a process for stainless steel pickling consisting in placing the material to be treated in a bath kept at a temperature ranging from 30 °C to 70 °C. and containing a) H 2 SO 4 , b) Fe 3+ , c) HF, d) emulsifiers, wetting agents, polishing agents, acid attack inhibitors; the bath being kept under agitation with an air flow and continuously fed with a quantity of oxidizing agent adjusted to the bath redox potential to be kept at 250 mV min.

[0007] Colgan et al., United States patent no. 6428625 discloses pickling process, steel and nickel or chromium alloys are pickled with an acidic pickling solution employing an oxidant, particularly hydrogen peroxide, and in which liquor is recirculated through inlets comprising a nozzle feeding liquor into a diffuser such that liquor is withdrawn from the bath and the volume of liquor flowing through the diffuser is a multiple of flow through the nozzle. Steel or the alloys are pickled with an acidic solution containing iron and free hydrogen peroxide at a concentration of up to 0.1 gpl. The process can operate effectively at a free fluoride concentration of from 20 to 30 gpl and a sulphuric acid concentration of from 80 to 110 gpl. The process compared with using an air agitation system can lengthen the lifetime of the bath before it needs to be replaced.

[0008] Bohme O et al., DE102009038795A1 discloses a process for the surface treatment of alloys and structural shapes made of stainless steel, which comprises two process steps, the first process step having a pre-treatment or activation step and the second process step being a pickling process, a solution containing hydrofluoric acid being used in both process steps.

[0009] Therefore, there is an unmet need of a process for pickling or descaling of steels or metals without using acids, alkali or oxidizing agents.

Disclosure of Invention

[0010] The primary objective of the present invention is pickling or descaling of steel, stainless steel or any other metal products having iron more than 30% by electrochemical process.

[0011] Another objective of the present invention is pickling or descaling of steel, stainless steel or any other metal products by electrochemical process and without using any acids or alkalis or oxidizing agents and or combinations thereof.

[0012] Another objective of the present invention is descaling such surface scale by using electrolytes and direct current of different types of waveforms and polarity at different voltage, current and current densities. Surface scale is removed by applying direct current with different types of cycles in the electrolytic solution and conversion of Surface scale into metal hydroxides, oxy hydroxides and oxides.

[0013] Another object of the invention is by developing novel process of pickling or descaling of steel, stainless steel or any other metal products by electrochemical process and by avoiding use of acids, alkalis and oxidizing agents for removal of hot or warm working scale and thus reducing the consumption of water and also reducing generation of the solid waste and wastewater to a large extent and also the complexes involved in use of acids and neutralizing agents related with Safety and environment are greatly reduced.

[0014] Yet, another object of the invention is by developing novel process of pickling or descaling of steel, stainless steel or any other metal products by electrochemical process reduce the wastage of water and improvise the recycling of water.

Summary of Invention

[0015] The present invention provides a novel electrolyte composition which is devoid of acid or alkalis and one or more combinations thereof pickling or scaling of steel, stainless steel and metals by means of an electrochemical pickling method.

[0016] One aspect of the present invention includes process for pickling or descaling of steel, stainless steel and metals by use of a novel electrolyte composition which is devoid of acid or alkalis and one or more combinations thereof by means of an electrochemical pickling method.

[0017] In another aspect of the present invention, in which the steel, stainless steel and metal to be cleaned is passed through an electrolytic pickling bath and subjected therein to the action of a low voltage alternating current frequency. [0018] In another aspect of the present invention, a process for the surface cleaning of steel, stainless steel and metal by means of an electrochemical pickling method comprises steps of:

[0019] a. Preparation of electrolyte solution, b. applying the current to the products as anode and cathode (steel specimen) at suitable temperature and normal pressure, c. applying the current for different voltage, current density, time, polarity, waveform; and d. washing of the products to remove the residual scale if requires,

[0020] wherein, process is devoid of use of any acids or alkalis or oxidizing agents and one or more combinations thereof.

[0021] According to one of the embodiments, the present invention relates to process of removing surface scale by avoiding use of acids or alkalis or oxidizing agents and one or more combinations thereof by using particular type of electrolytes and direct current of different types of waveforms and polarity at different voltage, current and current densities. Additionally, surface scale is removed by applying direct current with different types of cycles in the electrolytic solution. Surface scale is converted into metal hydroxides, oxy hydroxides and oxides.

[0022] In one another aspect, this novel process of descaling without use of any acids or alkalis or oxidizing agents and one or more combinations thereof, reduce the consumption of water and also reduce generation of the solid waste and wastewater to a large extent and also the complexes involved in use of acids and neutralizing agents related with safety and environment are greatly reduced.

Brief Description of Drawings

[0023] [Fig.1]: Simple diagram of the electrochemical cell employed in present invention as (a) the undivided cell and (b) the divided cell

[0024] [Fig.2]: Image of sample piece descaled after employing the proposed invention process.

Description of Embodiments

[0025] The present teachings include descriptions that are not intended to limit the scope of any claim. The examples and methods are provided to further illustrate the present teachings. Those of skill in the art, in light of the present disclosure, will appreciate that many changes can be made in the specific embodiments that are disclosed and still obtain a like or similar result without departing from the spirit and scope of the present teachings. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context indicates otherwise.

[0026] The present invention is directed to a process for pickling or descaling of steel or metal using an electrolyte pickling solution. The process is carried out by electrochemical treatment of the steel in the absence of acids, alkalis or oxidizing agents.

[0027] As used herein, unless otherwise indicated, the term "steel" as used herein describes the steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof. Additionally, the term “steel” as used herein describes the steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof and having iron content greater than about 30% by weight.

[0028] As used herein, unless otherwise indicated, the terms “about” and “approximately” should be understood to mean within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, “about” can mean a range of up to 20%, preferably up to 10%, more preferably up to 5%, and more preferably still up to 1% of a given value.

[0029] As used herein, unless otherwise indicated, the term “pickling or descaling" as used herein describes a metal surface treatment used to remove impurities, such as stains, inorganic contaminants, rust, oxides or scale from ferrous metals, copper, precious metals and aluminium alloys using pickle liquor.

[0030] As used herein, unless otherwise indicated, the term “descaling" as used herein describes the metal cleaning process of removing oxide deposits, inorganic contaminants, rust or scale from a metal surface that removes unwanted surface deposits on metals to provide a smooth surface finish and is a part of the pre-finishing processes which include cleaning and pickling.

[0031] As used herein, unless otherwise indicated, the term “electrolyte solution or electrolytic solution” as used herein describes solution that are capable of conducting an electric current.

[0032] As used herein, unless otherwise indicated, the term “current density” as used herein describes the amount of charge per unit time that flows through a unit area of a chosen cross section.

[0033] As used herein, unless otherwise indicated, the term “metal hot or warm working” as used herein describes working, including rolling, forging, extrusion, and drawing, or any mechanical deformation to be done with metal beyond room temperature.

[0034] As used herein, unless otherwise indicated, the term “salts” as used herein describes a chemical compound comprising of an ionic assembly of cations and/or anions.

[0035] As used herein, unless otherwise indicated, the term “ligand” as used herein describes an ion or molecule, which binds to the central metal atom to form a coordination entity or complex compounds.

[0036] The present invention relates to a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more com- binations thereof having iron greater than about 30% by weight.

[0037] The present invention relates to a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof having iron greater than about 30% by weight by electrochemical process.

[0038] In one aspect of the present invention, a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof having iron greater than about 30% by weight comprises an electrochemical process which is devoid of use of acid or alkalis or oxidizing agents and one or more combinations thereof.

[0039] Further, in one aspect of the present invention, a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof having iron greater than about 30% by weight comprises an electrochemical process with use of electrolyte solution, whereas, process is devoid of use of acid or alkalis and one or more combinations thereof and it.

[0040] The present invention is directed to a process of pickling stainless steel using an electrolyte solution from an electrolytic or electrochemical process. In preferred embodiments, the neutral salt electrolytic solution is from a sodium sulfate electrolytic pickling solution. The process of the invention avoids the use of any acids or alkali or oxidizing agents.

[0041] In one another aspect of present invention, the electrochemical process of removing surface scale by avoiding use of acids or alkalis or one or more combinations thereof and by using particular type of electrolytes and direct current of different types of waveforms and polarity at different voltage, current and current densities. Surface scale is removed by applying direct current with different types of cycles in the electrolytic solution. Surface scale is converted into metal hydroxides, oxy hydroxides and oxides.

[0042] According to one of the embodiments of the present invention, a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof comprises an electrochemical process the applied current comprises direct or varying waveform.

[0043] According to one of the embodiments of the present invention, a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof comprises an electrochemical process with current voltage application from about 0.1 V to about 100 V. Preferably, an electrochemical process comprises current voltage application from about 1 V to about 75 V. More preferably, an electrochemical process comprises current voltage application from about 10 V to about 60 V. [0044] According to one of the embodiments of the present invention, a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof comprises an electrochemical process with current density application from about 0.01mA/m 2 to about lOOOA/cm 2 . Preferably, an electrochemical process comprises current density application from about O.lmA/m 2 to about lOOA/cm 2 . More preferably, an electrochemical process comprises current density application from about lOmA/m 2 to about lA/cm 2 .

[0045] According to one of the embodiments of the present invention, a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof comprises an electrochemical process with reaction time from about 1 second to about 100000 seconds. Preferably, an electrochemical process comprises reaction time from about 100 seconds to about 10000 seconds. More preferably, an electrochemical process comprises reaction time from about 1000 seconds to about 10000 seconds.

[0046] According to one of the embodiments of the present invention, a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof comprises an electrochemical process with temperature from about 0°C to about 95°C. Preferably, an electrochemical process comprises temperature from about 5°C to about 75°C. More preferably, an electrochemical process comprises temperature about 10°C to about 55°C.

[0047] According to one of the embodiments of the present invention, a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof comprises an electrochemical process with reversal of polarity change or without reversal of polarity change.

[0048] According to one of the embodiments of the present invention, a novel process descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof comprises an electrochemical process with polarity change interval from about 0.5 second to about 7200 seconds. Preferably, an electrochemical process with polarity change interval from about 2 second to about 5000 seconds. More preferably, an electrochemical process with polarity change interval about 50 second to about 2500 seconds.

[0049] In one another aspect, the present invention provides, a novel system of descaling or pickling of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof having iron greater than about 30% by weight comprises an electrochemical system as mentioned in [Fig.l].

[0050] According to one of the embodiments of the present invention, an electrochemical system comprises electrodes, electrolyte solution, and circuit as mentioned in [Fig.l]. [Fig.1] depicts the simple diagram of the electrochemical cell employed in this research with undivided cell and the divided cell, undivided cell with a bipolar electrode stack is not depicted, however it will also produce similar results. The process involves the dissolution of metal from the anode with simultaneous formation of hydroxyl ions and hydrogen gas at the cathode. This process produces the corresponding iron hydroxides and/or polyhydroxides in the electrolyte and descale the anode surface. The anode and cathode are reversed after predetermined time, even the process can be continued only on anode without this reversal. The process should be repeated and continued for specific time as described in the process.

[0051] As per one of aspect of present invention, the schematic diagram is depicted in

[Fig.1] . Electrolyte solution is made up of one type of salt or combination of salts of inorganic and organic salts, ionized or polymer type sulfates, nitrates, chlorides and other kinds in the content as per the rate of, extent of brightness of the product required. On applying electric charge at room temperature (ideally in the range from 5°C to 45°C), even above or below room temperature to the electrodes (work pieces of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof having iron greater than about 30% by weight), current flows through the electrodes and at the surface of oxide layer on anode descaling initiated.

[0052] This invention involves neutral electrolytic solution which on supply of energy in designed fashion converts the scale layers into oxy-hydroxide, hydroxide and loose oxide form and gently removes the scale uniformly over the surface at molecular level. Process is not involving any acids, alkalis and thus pollution load reduces drastically. Water used in the system is recycled, there is no loss of water except normal evaporation losses and splitting of water. Energy consumed is low enough to comprehensively compete the existing conventional processes. This process can be done at room temperatures and also above them as per the customized requirement.

[0053] In one of the embodiments, electrodes comprise of steels, low alloy steels, high alloy steels, stainless steels, special steels and one or more combinations thereof having iron greater than about 30% by weight or a like thereof material.

[0054] In another embodiment, electrochemical system may comprise undivided cell or the divided cell or undivided cell with a bipolar electrode stack.

[0055] In one of the embodiments, a novel system of descaling or pickling of steels may include:

[0056] a. preparation of electrolyte solution by use of salts or compounds or ligands and one or more combinations thereof, b. applying the current to the products as anode and cathode at temperature in between about 0°C to about 95°C and at 0.5 to 5 atmospheric pressure c. applying the current for different voltage, current density, time, polarity, waveform and d. washing of the products to remove the residual scale if required.

[0057] According to one of the embodiments of the present invention, electrolyte solution comprises salts or ligands, which includes but not limited to monovalent, divalent, trivalent and one or more combinations thereof. According to one of the embodiments of the present invention, electrolyte solution comprises salts or ligands, which includes but not limited to inorganic or organic salts and one or more combinations thereof. According to one of the embodiments of the present invention, electrolyte solution comprises salts or ligands, which includes but not limited to anions, anions of organic acids or oxoanions and one or more combinations thereof. Anions of salts of electrolyte solutions includes but not limited to hydride, oxide, fluoride, sulfide, chloride, nitride, bromide, iodide, acetate, formate, cyanide, amide, cyanate, peroxide, thiocyanate, oxalate, hydroxide, permanganate or alike thereof and combinations thereof. Oxoanions of salts of electrolyte solutions includes but not limited to arsenate, phosphate, arsenite, hydrogen phosphate, dihydrogen phosphate, sulfate, nitrate, hydrogen sulfate, nitrite, thiosulfate, sulfite, perchlorate, iodate, chlorate, bromate, chlorite, hypochlorite, hypobromite, carbonate, chromate, hydrogen carbonate, bicarbonate, dichromate or alike thereof and combinations thereof. Preferably, electrolyte solution comprises salts or ligands, which includes anions of as but not limited to sulfate, nitrate, halide, phosphate or alike thereof and combinations thereof. Preferably, electrolyte solution comprises salts or ligands, which includes cations of as but not limited to sodium, potassium, calcium or alike thereof and combinations thereof. More preferably, electrolyte solution comprises sodium sulfate or alike thereof.

[0058] According to one of the embodiments of the present invention, electrolyte solution comprises salts or ligands, from concentration of at least about 1 ppm to about maximum possible solubility of respective salts or ligands in particular solvent. According to one another embodiments of the present invention, electrolyte solution comprises salts or ligands, from concentration of at least about 1 ppm to about 1000000 ppm. Preferably, electrolyte solution comprises salts or ligands, from concentration of at least about 100 ppm to about 100000 ppm. More preferably, electrolyte solution comprises salts or ligands, from concentration of at least about 100 ppm to about 50000 ppm.

[0059] According to one of the embodiments of present invention, the electrodes area size range comprises from about 1 mm 2 to about 10000 m 2 . According to one another embodiment of the present invention, the electrodes area size range comprises from about 100 mm 2 to about 5000 m 2 . Preferably, the electrodes area size range comprises from about 1000 mm 2 to about 5000 m 2 . More preferably, the electrodes area size is about 30 m 2 .

[0060] According to one of the embodiments of present invention, the electrolyte volume range comprises from about 1 ml to about 100000 litres. According to one another embodiment of the present invention, the electrolyte volume range comprises from about 100 ml to about 10000 litres. Preferably, the electrolyte volume range comprises from about 500 ml to about 1000 litres.

[0061] According to one of the embodiments of present invention, the electrochemical stirrer speed of system comprises from about 0.1 rpm to about 1000 rpm. According to one another embodiment of the present invention, the electrochemical stirrer speed of system comprises from about 1 rpm to about 500 rpm. Preferably, the electrochemical stirrer speed of system comprises from about lOrpm to about lOOrpm.

[0062] The following examples further describe certain specific aspects and embodiments of the disclosure. However, one skilled in the art will appreciate that the specific methods and results discussed are provided only for purposes of illustration, and should not be construed as limiting the scope of the disclosure in any manner, as many variations thereof are possible without departing from the spirit and scope of the invention.

Examples

[0063] [Example 1] Descaling or pickling electrochemical process

[0064] 1. The electrochemical process was carried out using 0.5M sodium sulfate solution as electrolyte salt solution.

2. The process operated at 26°C temperature and atmospheric pressure with supply of direct current voltage of 5- 12V and at different current density in the range of 3 A/cm 2 to 9 A/cm 2 .

3. The polarity was been reversed at time interval of every 120 seconds.

4. The time taken for descaling is about 50 min to 120 min the details are provided in table 1 and 2.

5. The scale formation in electrolyte solution was been removed in continuous process. Optionally, scale formation in electrolytic solution can be removed in batch mode.

6. Optionally, in addition, based on requirement the electrode (sample piece) was been washed or cleaned with simple water for further processing.

7. The experiments were performed in triplicate and average results are as reported below.

[0065] Table 1 Common parameters for the experiments

[0066] Table 2 Variation in time for descaling the sample piece with respect to variation in current density

[0067] Results: Descaled sample piece is depicted in [Fig.2], in all the experiments almost similar visual results were obtained. From results of [Fig.2], it can be seen that the steel specimen with greater than about 75 % by weight of iron content has been successfully descaled using present invention which is completely devoid of use of any acid or alkali or one or more combinations thereof. It was been seen that, type of charge carrier may affect finish and type of descaled products generated.