BE1024745B1 - METHOD AND DEVICE FOR ANODIZING ALUMINUM OBJECTS AND ANODIZED ALUMINUM OBJECT - Google Patents

Abstract

The present invention relates to a method for anodizing one or more aluminum objects 45, comprising the step of performing at least two anodizing steps sequentially, wherein during each anodizing step one or more aluminum objects 45 are arranged in different anodizing baths comprising at least a pair of cathodes and an acid solution, the articles 45 then remaining in each of the anodizing baths for a certain time, and an electric current being applied to each of the anodizing baths when the one or more aluminum articles 45 reside therein, the one or more a plurality of aluminum objects 45 can be connected as an anode, the one or more aluminum objects being flushed with water after each anodizing step. Furthermore, the present invention relates to an apparatus for anodizing one or more aluminum articles 45 and to an anodized aluminum article 45.

Description

(73) Holder (s):

MALVE NV 2321, MORE Belgium (72) Inventor (s):

SPRANGERS Bert 2321 MORE Belgium (54) METHOD AND APPARATUS FOR ANODIZING ALUMINUM ARTICLES AND ANODIZED ALUMINUM ARTICLE (57) The present invention relates to a method for anodizing one or more aluminum objects 45, comprising the step of sequentially performing of at least two anodizing steps, wherein during each anodizing step, one or more aluminum objects 45 are placed in different anodizing baths comprising at least a pair of cathodes and an acid solution, the objects 45 subsequently remaining in each of the anodizing baths, and wherein a electric current is applied to each of the anodizing baths when the one or more aluminum objects 45 reside therein, the one or more aluminum objects 45 being connected as an anode, the one or more aluminum objects being rinsed with water after each anodizing step.

The present invention further relates to a device for anodizing one or more aluminum objects 45 and to an anodized aluminum object 45. r-i

Ch i_i_

BELGIAN INVENTION PATENT

FPS Economy, K.M.O., Self-employed & Energy

Publication number: 1024745 Filing number: BE2017 / 5202

Intellectual Property Office International Classification: C25D 11/12 C25D 11/16 C25D 11/24 C25D 17/00 C25D 11/00 C25D 19/00 C25D 21/08 C25D 11/18 C25D 17/08

Date of issue: 18/06/2018

The Minister of Economy,

Having regard to the Paris Convention of 20 March 1883 for the Protection of Industrial Property;

Having regard to the Law of March 28, 1984 on inventive patents, Article 22, for patent applications filed before September 22, 2014;

Having regard to Title 1 Invention Patents of Book XI of the Economic Law Code, Article XI.24, for patent applications filed from September 22, 2014;

Having regard to the Royal Decree of 2 December 1986 on the filing, granting and maintenance of inventive patents, Article 28;

Having regard to the application for an invention patent received by the Intellectual Property Office on 27/03/2017.

Whereas for patent applications that fall within the scope of Title 1, Book XI, of the Code of Economic Law (hereinafter WER), in accordance with Article XI.19, § 4, second paragraph, of the WER, the granted patent will be limited. to the patent claims for which the novelty search report was prepared, when the patent application is the subject of a novelty search report indicating a lack of unity of invention as referred to in paragraph 1, and when the applicant does not limit his filing and does not file a divisional application in accordance with the search report.

Decision:

Article 1

MALVE NV, John Lijsenstraat 49, 2321 MORE Belgium;

represented by

BRANTS Johan Philippe Emile, Pauline Van Pottelsberghelaan 24, 9051, GHENT;

a Belgian invention patent with a term of 20 years, subject to payment of the annual taxes as referred to in Article XI.48, § 1 of the Code of Economic Law, for: METHOD AND DEVICE FOR ANODIZING ALUMINUM OBJECTS AND ANODIZED ALUMINUM OBJECTS .

INVENTOR (S):

SPRANGERS Bert, John Lijsenstraat 49, 2321, MORE;

PRIORITY:

BREAKDOWN:

Split from basic application: Filing date of the basic application:

Article 2. - This patent is granted without prior investigation into the patentability of the invention, without warranty of the Merit of the invention, nor of the accuracy of its description and at the risk of the applicant (s).

Brussels, 18/06/2018,

With special authorization:

BE2017 / 5202

METHOD AND I NO DIRECTION FOR ANODIZING ALUMINUM OBJECTS AND ANODIZED ALUMINUM OBJECTS

TECHNICAL FIELD

The invention relates to a method and device for anodizing aluminum objects and to an anodized aluminum object.

BACKGROUND

Methods and devices for anodizing aluminum, as well as anodized aluminum objects, such as, for example, anodized aluminum profiles and pipes, are well known. Anodizing aluminum objects is often carried out in several steps.

For example, US 3,650,910 describes an aluminized steel strap that is anodized during movement in a sequence of anodizing tanks, each tank housing an anodizing stage. US 3,650,910 shows the problem that insufficient measures are taken between the various anodizing stages for removing residues of solutions used for anodizing, for removing residues of formed aluminum sulphate or for removing insufficient surface-bound aluminum oxide.

The present invention aims to find a solution for at least the above-mentioned problem.

SUMMARY

For this purpose, the invention provides in a first aspect a method for anodizing one or more aluminum objects according to claim 1. More particularly, the first aspect of the invention relates to a method for anodizing one or more aluminum objects, comprising the step of sequentially performing at least two anodizing steps, wherein during each anodizing step one or more aluminum objects are placed in different anodizing baths comprising at least a pair of cathodes and an acid solution, the objects then remaining in each of the anodizing baths for a specified time, and wherein an electric current is present in each of the

BE2017 / 5202 anodizing baths is applied when the one or more aluminum objects reside in them, the one or more aluminum objects being connected as an anode, the one or more aluminum objects being rinsed with water after each anodizing step.

By rinsing the one or more aluminum objects, each comprising a surface, with water after each anodizing step, residues of an acid solution are used for anodizing, residues of formed aluminum sulphate or insufficient surface-bound aluminum oxide are removed from the objects after each step, so that the surface of each of the objects can be optimally reached by an acid solution and therefore can be optimally anodized.

Furthermore, the present invention in a second aspect relates to a device for anodising one or more aluminum objects according to claim 11. More in particular, the second aspect of the invention relates to a device for anodising one or more aluminum objects comprising at least two anodizing baths of which at least two anodizing baths in turn each comprise a pair of cathodes, the device further comprising a support device for carrying the objects, the support device comprising a frame on which a holder for managing the objects can be suspended.

The carrying device offers the advantageous possibility of being able to transport the one or more aluminum objects, and in particular a plurality of aluminum objects, smoothly between different baths and in or out of these baths.

Furthermore, the present invention in a third aspect relates to an anodized aluminum article obtained by applying a method according to the first aspect of the present invention.

FI GUREN

Fig. 1 is a schematic view of several baths of an apparatus for anodizing one or more aluminum objects, also showing incoming and outgoing fluid flows, according to embodiments of the present invention.

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Fig. 2 is a perspective view of a portion of an apparatus for anodizing one or more aluminum objects, according to embodiments of the present invention.

Fig. 3 is a front view of a detail of an apparatus for anodizing one or more aluminum objects, according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Claiming numerical intervals through the endpoints includes all integers, fractions and / or real failures between the endpoints, including these endpoints.

The term object should be broadly understood in this text in its broadest form. The term object in this text preferably refers to an equilateral L-profile, an unequal L-profile, an oval tube, a plate, a flat bar, a rectangular tube, a round tube, a bar, a T-profile, a U profile, a Square tube, a Square bar, or a Z profile.

In this text, the term aluminum object is to be understood as an object comprising an area and comprising at least 1% by weight of aluminum. Preferably, such an object comprises at least 1% by weight of aluminum at the surface of the object.

The term anodizing, as used in this text, refers to a well-known surface treatment of one or more aluminum objects. Specifically, the anodizing of one or more aluminum objects involves an electrochemical process in which the natural tendency of aluminum in an aluminum object to form a layer of aluminum oxide on the surface is enhanced. The aluminum oxide layer provides higher durability and also allows aluminum to be colored. In general it can be stated that aluminum and thus an aluminum object by anodising obtains the following improved properties: a higher hardness, up to 250 HV vickers, a better rust resistance, a higher chemical resistance, an electrical insulation and a decorative added value.

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The term anodized aluminum article, as used in this text, is to be understood as an aluminum article that has been anodized, and in particular according to a method of the present invention.

The term anodizing bath, as used in this text, refers to a bath that is used to anodize one or more aluminum objects.

In a first aspect, the invention relates to a method for anodizing one or more aluminum objects, comprising the step of sequentially performing at least two anodizing steps, wherein during each anodizing step one or more aluminum objects are placed in different anodizing baths comprising at least one pair of cathodes and an acid solution, the objects then residing in each of the anodizing baths for a period of time, and an electric current being applied in each of the anodizing baths when the one or more aluminum objects reside therein, the one or more aluminum objects as an anode, the one or more aluminum objects being rinsed with water after each anodizing step.

Said one or more aluminum objects each comprise a surface. During an anodizing step, an electric current will flow through the one or more aluminum objects, which are connected as an anode. As a result, a layer of aluminum oxide is formed on the surface of each of the one or more aluminum objects, whereby aluminum is also released. Hydrogen is formed as a counter-reaction at the cathodes. Said at least two anodizing steps may comprise any number of anodizing steps. In preferred embodiments, a method of the present invention comprises three anodizing steps, which has been found to be an approach that leads to excellent anodizing of one or more aluminum articles. Parameters such as type of acid solution, temperature of the acid solution, applied current and / or voltage of the electric current, and the time in which the objects remain in the anodizing baths for a certain time can be the same or different for the different anodizing steps. Said acid solution may include sulfuric, oxalic, chromic, and phosphoric, or any combination of the foregoing. In a preferred embodiment, said acid solution comprises sulfuric acid. When using a sulfuric acid-containing acid solution, the released aluminum will anodize the one

BE2017 / 5202 or several aluminum objects are bound with sulphate to aluminum sulphate. Said anodizing baths can be any baths known in the art which are suitable for use in anodizing. Preferably said anodizing baths are sufficiently resistant to a solution comprising one or more of the above acids. In preferred embodiments, said anodizing baths are bar-shaped, with an opening bounded by a bottom surface, four perpendicular side surfaces, but no top surface. In preferred embodiments, at least a pair of cathodes are provided along the largest dimensioned side surfaces, a first cathode located within an anodizing bath along a first largest dimensioned side face and a second cathode within the anodizing bath along an opposite second largest dimensioned side face. In preferred embodiments, when anodizing in an anodizing bath, a direct current is applied at a voltage of from 16 to 22 volts, preferably from 17 to 21 volts, and even more preferably from 18 to 20 volts, and a current of up to 24000 amps, preferably of 22000 amps at most. In preferred embodiments, an electric current is applied with a current density of 1.2 to 1.5 amperes per dm ² . In preferred embodiments, the rinsing with water is performed by placing the one or more aluminum objects in an anodizing bath comprising water.

By rinsing the one or more aluminum objects, each comprising a surface, with water after each anodizing step, residues of an acid solution are used for anodizing, residues of formed aluminum sulphate or insufficient surface-bound aluminum oxide are removed from the objects after each step, so that the surface of each of the objects can be optimally reached by an acid solution and therefore can be optimally anodized. The measure according to the present invention to rinse with water after each anodizing step is anything but obvious to a person skilled in the art. On the basis of the known state of the art, such a skilled person would indeed opt to only rinse with water after a last anodizing step, or not to rinse siphons with water and to switch directly to sealing or sealing of a final anodizing step. the one or more aluminum objects.

In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein the applied

BE2017 / 5202 electric current is identical in each of the anodizing baths and which electric current has a current strength of at most 24000 amps, preferably of at most 22000 amps, and an electric voltage of 16 to 22 volts, preferably of 17 to 21 volts and even more preferably from 18 to 20 volts. In preferred embodiments, the applied electric current is identical in each of the anodizing baths and this electric current has a current density of 1.2 to 1.5 amperes per dm ² . Applying the same electric current to each of the anodizing baths is advantageous for obtaining excellent anodized aluminum objects.

In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein one or more preliminary treatment steps are performed before the at least two anodizing steps, and one or more subsequent treatment steps are performed after the at least two anodizing steps. Anodizing usually involves one or more preliminary and subsequent treatment steps. Non-limiting examples of preliminary treatment steps are steps in which the one or more aluminum objects are degreased, rinsed with water, pickled, stripped with a stripping solution, or subjected to an acid dipping step. Non-limiting examples of subsequent treatment steps are steps in which the one or more aluminum objects are colored, rinsed with water, or compacted. Said preliminary and subsequent treatment steps contribute to the excellent anodizing of one or more aluminum objects.

In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein the one or more aluminum objects are carried continuously by means of a support device during the sequential carrying out of at least two anodizing steps, and when appropriate, during said one or several preliminary and subsequent treatment steps. The continuous carrying of the objects by means of a carrying device offers the advantage that the objects can be transported smoothly and easily in and out of a bath and from one bath to another bath.

In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein the one or more aluminum objects are carried inclined by means of the carrying device. It

BE2017 / 5202 inclined support ensures an inclined orientation of the one or more aluminum objects. This offers the advantage that solutions present on the surface, such as water used for rinsing, can be optimally drained from the one or more aluminum objects.

In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein water for rinsing the one or more aluminum objects in a cycle is used for rinsing the objects in at least two steps. In preferred embodiments, several of said cycles are employed. The use of water in a cycle ensures an ideal use of the water, whereby the water consumption is reduced.

In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein after the subsequent treatment steps, or after the at least two anodizing steps in the absence of said subsequent treatment steps, at least one of the one or more aluminum objects are comminuted. The reduction preferably takes place by sawing the objects. Shrinking the objects offers the advantage that the objects can be adjusted to a desired size, if desired.

In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein during at least one of the anodizing steps, previous treatment steps and / or subsequent treatment steps, energy for these steps is provided by cogeneration. A cogeneration can generate both electricity and heat, and is therefore very advantageous to use when anodising the one or more aluminum objects. Said electricity can be used for the anodizing steps and said heat can be used in steps that require heating.

In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein ambient air present in an outer environment is used to cool the one or more aluminum objects during at least one of the anodizing steps, preliminary treatment steps and / or subsequent

BE2017 / 5202 treatment steps. Using ambient air is a sustainable way to cool.

In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, comprising the following sequence of steps:

a sequence of preliminary treatment steps, comprising:

a) a degreasing step in which the one or more aluminum objects are applied for at least 10 minutes in a bath comprising a solution of 35 to 45 g of degreasing substance per liter, preferably of 38 to 42 g of degreasing substance per liter at a temperature of 47 up to 58 ° C, preferably from 49 to 56 ° C;

b) a first rinsing step in which the objects are placed in a bath of water;

c) a pickling step in which the objects are placed in a bath for 17 to 23 minutes, preferably 19 to 21 minutes, comprising a pickling solution comprising 46 to 54 g of sodium hydroxide per liter, preferably 48 to 52 g of sodium hydroxide per liter at a temperature of 58 up to 64 ° C, preferably from 59 to 63 ° C;

d) a second rinsing step in which the objects are placed in a bath of water;

e) a third rinsing step in which the objects are placed in a bath of water;

f) a stripping step in which the articles are applied in a bath comprising a stripping solution comprising 85 to 115 g of sodium hydroxide per liter, preferably 95 to 105 g of sodium hydroxide per liter;

g) a fourth rinsing step in which the objects are placed in a bath of water;

h) an acid dipping step in which the articles are placed in a bath comprising an acid solution comprising 40 to 60 g nitric acid per liter, preferably 45 to 55 g nitric acid per liter, at a temperature between 19 and 24 ° C;

a sequence of anodizing steps followed by rinsing steps, sequentially comprising a first anodizing step, a fifth

BE2017 / 5202 rinsing step, a second anodizing step, a sixth rinsing step, a third anodizing step and a seventh rinsing step, during each anodizing step the objects in a bath comprising an acid solution of 165 to 215 g sulfuric acid per liter, preferably from 175 to 205 g sulfuric acid per liter and at a temperature of 17 to 21.5 ° C, preferably of 18 to 20.5 ° C are subjected to a current of no more than 2400 amperes, preferably of no more than 22000 amperes and an electrical voltage of 16 to 22 volts , preferably from 17 to 21 volts, and during each rinse step the objects are placed in a bath of water; and a sequence of subsequent treatment steps, comprising:

a) a coloring step in which the articles are applied in a bath comprising a coloring solution comprising 17.5 to 22.5 g of tin sulfate per liter, preferably 19 to 21 g of tin sulfate per liter and 18.5 to 21.5 g of sulfuric acid per liter, preferably 19.5 to 20.5 g of sulfuric acid per liter at a temperature of 18.5 to 22.5 ° C, preferably from 20 to 21 ° C;

b) an eighth rinsing step in which the objects are placed in a bath of water;

c) a ninth rinsing step in which the objects are placed in a bath of water;

d) optionally, placing the objects in an empty bath; and

e) a sealing step or sealing step in which the objects are applied in a bath comprising a sealing solution comprising between 1 and 3 mg of seal product per liter, preferably between 1.8 and 2.2 mg of seal product per liter with a conductivity of less than 1200 microsiemens, at preferably less than 1100 microsiemens, even more preferably less than 1000 microsiemens, at a temperature of 94 to 100 ° C, preferably from 95 to 99 ° C, and even more preferably from 96 to 98 ° C.

A method according to the latter embodiment is very efficient for anodizing aluminum objects and provides anodized aluminum objects with a high quality.

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In a second aspect, the invention relates to a device for anodizing one or more aluminum objects comprising at least two anodizing baths, of which in turn at least two anodizing baths are each provided with a pair of cathodes, the device further comprising a carrying device for carrying the objects, which support device comprises a frame on which a holder for managing the objects can be suspended, and is preferably suspended.

The carrying device offers the advantageous possibility of being able to transport the one or more aluminum objects, and in particular a plurality of aluminum objects, smoothly between different baths and in or out of these baths.

In a preferred embodiment, the present invention provides a device according to the second aspect of the invention, wherein the frame is displaceable by means of displacement elements in rails attached to a surface, the rails being parallel to each other and oriented in accordance with the a direction that crosses at least two of the baths. This embodiment is very suitable for transporting aluminum objects between different baths. As moving elements, any elements such as, but not limited to, wheels that can be moved in rails can be used. Any suitable surface should be understood as the surface. In a preferred embodiment, the surface is a ceiling. In another preferred embodiment, the surface is a floor.

In a preferred embodiment, the present invention provides a device according to the second aspect of the invention, wherein the carrying device is provided at the height of said frame with a hoisting means for transporting one or more objects in or out of a bath. As hoisting means is meant a means that can be used to at least lift or lower the holder of the carrying device. Such a hoisting means thus simplifies the movement of aluminum objects in or out of baths. Said hoisting means may be any means known in the art which enable hoisting or lowering a device. Said hoisting means can be provided separately with said support device, or it can be a structural part of said support device.

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In a preferred embodiment, the present invention provides a device according to the second aspect of the invention, wherein the container is inclined. An inclined orientation of the holder provides for an inclined orientation of one or more aluminum objects which are covered by it. This offers the advantage that surface-based solutions, such as, for example, water used for rinsing, can be optimally drained from the one or more aluminum objects.

In a preferred embodiment, the present invention provides a device according to the second aspect of the invention, for use in a method according to the first aspect of the present invention. Accordingly, all the technical achievements and positive features of the method according to the first aspect of the present invention are combined with those of the device according to the second aspect of the present invention.

In a third aspect, the invention relates to an anodized aluminum object obtained by applying a method according to the first aspect of the present invention. In a preferred embodiment, the present invention provides an anodized aluminum article according to the third aspect of the invention, manufactured by a device according to the second aspect of the present invention. Such anodized aluminum objects exhibit a high quality, and in particular a higher hardness, up to 250 HV vickers, a better rust resistance, a higher chemical resistance, and an electrical insulation. A decorative added value can also be attributed to anodised aluminum objects obtained in this way.

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DETAILED FI GUURB DESCRIPTION JVI NG

Fig. 1 is a schematic view of several baths of an apparatus for anodizing one or more aluminum objects, also showing incoming and outgoing fluid flows, according to embodiments of the present invention. Anodizing is a surface treatment of the one or more aluminum objects. In other words, a surface of an aluminum object is treated, or surfaces of one or more aluminum objects are treated. Anodizing one or more aluminum objects involves an electrochemical process in which the natural tendency of aluminum in an aluminum object to form an oxide film on the surface is enhanced. For this, the one or more aluminum objects are connected as an anode. There are also several preliminary and subsequent treatment steps associated with anodizing. Using the schematic illustration in Fig. 1, various steps of an aluminum anodizing method according to embodiments of the present invention are also illustrated. The respective baths 1-19 are elongated and placed next to each other so that aluminum objects can be transferred from one bath to another bath simply and quickly.

In a first step, also referred to as a degreasing step, one or more aluminum objects are placed in a first bath 1, also called a degreasing bath 1, for degreasing the one or more aluminum objects. Here a solution of 35 to 45 g of degreasing substance per liter, preferably of 38 to 42 g of degreasing substance per liter, is used in the first bath 1. The temperature of said solution is 47 to 58 ° C, preferably 49 to 56 ° C. For adequate degreasing of the one or more aluminum objects, the objects are placed in said solution for at least 10 minutes.

A second step consists of a first rinsing step. After said degreasing step, the one or more aluminum objects are placed in a second bath 2 in which water is present to rinse the solution used in the first step from the aluminum objects. The second bath can also be called a first rinse bath 2. The water used can also be called flushing water. After the objects have been rinsed, the rinse water is still used to rinse objects in two other baths. This use of the rinse water for

BE2017 / 5202 rinsing the objects in several baths can also be labeled as a first rinsing cycle, with the start 21 applying a flow of rainwater 20 in the first rinsing bath 2.

In a third step, also referred to as a pickling step, the surface of each of the one or more aluminum objects is cleaned of any contaminants present and the surface is provided with a smooth, matt or semi-matt appearance. For this, the one or more aluminum objects from the first rinsing bath 2 are placed in a third bath 3, or pickling bath 3, in which a pickling solution comprising 46 to 54 g of sodium hydroxide per liter, preferably 48 to 52 g of sodium hydroxide per liter, is applied. Said pickling solution has a temperature of from 58 to 64 ° C, preferably from 59 to 63 ° C, and the objects are placed in said pickling solution from 17 to 23 minutes, preferably from 19 to 21 minutes. During the pickling step, 170 to 190 g of aluminum per liter and preferably 180 to 200 g of aluminum per liter in said pickling solution is tolerated. If these values are exceeded, said pickling solution is partially or completely replaced by a pickling solution comprising 46 to 54 g of sodium hydroxide per liter, preferably 48 to 52 g of sodium hydroxide per liter and at a temperature of 58 to 64 ° C, preferably from 59 to 63 ° C.

A fourth step corresponds to a second rinsing step. After said pickling step, the one or more aluminum objects are placed in a fourth bath 4, or second rinsing bath 4, in which rinsing water is present to rinse off residues of the pickling solution from the aluminum objects. The rinse water has previously been used to rinse the one or more aluminum objects in a later step, which will be further discussed below. At the end of the first rinsing cycle, a stream of 23 rinsing water, meanwhile very heavily polluted at the end of the first rinsing cycle, leaves the second rinsing bath 4.

A fifth step corresponds to a third rinsing step. After said second rinsing step, the one or more aluminum objects are placed in a fifth bath 5 or third rinsing bath 5 in which rinsing water is present to rinse off further impurities from the aluminum objects. The rinsing water used is received from the first rinsing bath 2 and via a conduit 29 in the third rinsing bath 5. Then the rinsing water is transferred by means of another conduit 30 to a second rinsing bath 4. This is part of

BE2017 / 5202 said first rinse cycle. The displacement of rinsing water according to the first rinsing cycle through three different rinsing baths 2, 4, 5 ensures an ideal application of the rinsing water and an optimal cleaning of the surface of each of the one or more aluminum objects. After the first rinse step, the rinse water comprises at most 15 milligrams of aluminum per liter of rinse water, preferably at most 10 milligrams of aluminum per liter of rinse water. Then, after the third rinse step, the rinse water comprises between 25 and 45 milligrams of aluminum per liter of rinse water, preferably between 32 and 38 milligrams of aluminum per liter of rinse water. Finally, after the second rinsing step, the rinsing water comprises between 1200 and 1800 milligrams of aluminum per liter of rinsing water, preferably between 1400 and 1600 milligrams of aluminum per liter of rinsing water, after which the highly polluted rinsing water as an outgoing stream 23 the second rinsing bath 4 leaves.

A sixth step corresponds to a stripping step. In this step, residual impurities are removed from the surface of each of the one or more aluminum objects by means of a stripping solution. For this purpose, the objects are applied in a stripping solution present in a sixth bath 6 or stripping bath 6. The stripping solution comprises 85 to 115 g of sodium hydroxide per liter, preferably 95 to 105 g of sodium hydroxide per liter. During the stripping step, a maximum of 60 g aluminum per liter and preferably a maximum of 50 g aluminum per liter in said stripping solution is tolerated. If these values are exceeded, said stripping solution is partially or completely replaced by a stripping solution comprising 85 to 115 g of sodium hydroxide per liter, preferably 95 to 105 g of sodium hydroxide per liter.

In a seventh step, the objects are rinsed with water, also known as rinsing water, and thus stripped of the remnants of the stripping solution. This can also be seen as a fourth rinse step. For this purpose the objects are placed in rinse water which is present in a fourth rinsing bath 7. The rinsing water in question is previously used for rinsing the objects in later steps. As a result, the rinsing water in the fourth rinsing bath 7 is very contaminated, and a flow of this rinsing water leaves the rinsing bath 7 after rinsing the objects in the seventh step. The use of the rinsing water for rinsing the objects in several bathing can also be referred to as a second rinse cycle, which is present in addition to the above first rinse cycle. The displacement of rinsing water according to the first and second rinsing cycles through different rinsing baths ensures an ideal application of the rinsing water and an optimal cleaning of the surface of each of the one or more aluminum objects.

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In an eighth step, also referred to as an acid dip step, residues of alkali or free-stained alloy components are removed from the surface of each of the one or more aluminum objects. For this purpose, the objects are placed in an acid solution contained in an eighth bath 8 or acid dip bath 8. The acid solution comprises 40 to 60 g nitric acid per liter, preferably 45 to 55 g nitric acid per liter, and has a temperature corresponding to the temperature of an environment in which the acid dip bath 8 is placed, preferably corresponding to an ambient temperature between 19 and 24 ° C.

In the following steps, the one or more aluminum objects are anodised step by step. After each of several anodizing steps, the objects are rinsed with water. In total this covers a ninth to a fourteenth step. Such a step-by-step anodization of the one or more aluminum articles offers the advantage that residues of an acid solution used for anodizing, residues of formed aluminum sulphate or insufficient surface-bound aluminum oxide are removed from the articles after each step, so that the surface of each of the objects can be optimally reached by an acid solution and can therefore be optimally anodised. In a ninth step, corresponding to a first anodizing step, the one or more aluminum objects in an acid solution contained in a ninth bath 9 or first anodizing bath 9 are applied. The acid solution comprises 165 to 215 g of sulfuric acid per liter, preferably 175 to 205 g of sulfuric acid per liter, and has a temperature of 17 to 21.5 ° C, preferably of 18 to 20.5 ° C. In the first anodizing bath 9, each aluminum object is connected as an anode, current transfer to the object taking place via contact blocks which are coupled to one side of the object. Along the one or more aluminum objects 9 cathodes are provided on and within two opposite walls of the first anodizing bath. These cathodes are parallel in a direction in which the objects, when present in the anodizing bath 9, extend the most. A direct current at 16 to 22 volts, preferably from 17 to 21 volts and even more preferably from 18 to 20 volts with a current of at most 24000 amps, preferably at most 22000 amps, is provided in the first anodizing bath 9. The first anodizing bath 9 is preferably symmetrical and preferably has a length of 16 to 17 meters, e.g.

BE2017 / 5202 preferred from 16.3 to 16.5 meters. The symmetrical design allows an even current build-up over said length, allowing anodizing of the one or more aluminum objects evenly. In addition, the design of the bath 9 optimizes the bath configuration. During the first anodizing step, 5 to 20 g of aluminum per liter and preferably 10 to 15 g of aluminum per liter in said acid solution is tolerated. If these values are exceeded, said acid solution is partially or completely replaced by an acid solution comprising 165 to 215 g sulfuric acid per liter, preferably 175 to 205 g sulfuric acid per liter and at a temperature of 17 to 21.5 ° C, preferably of 18 to 20.5 ° C. Subsequently, in a tenth step, corresponding to a fifth rinsing step, the objects are applied in rinsing water contained in a tenth bath 10 or a fifth rinsing bath 10. The rinsing water is supplied and discharged as part of said second rinsing cycle. The rinsing water is supplied via a line 32 (from another bath, see below) and discharged via a line 31 to the fourth rinsing bath 7. Then an anodizing step is followed twice by a rinsing step, on the one hand a second anodizing step in a second anodizing bath 11 followed by a sixth rinsing step in a sixth rinsing bath 12 and a third anodizing step in a third anodizing bath 13 followed by a seventh rinsing step in a seventh rinsing bath 14, the specifications being identical as described for the first anodizing step and subsequent rinsing step, with the exception of the rinsing water used. In the sixth rinse bath 12, rinse water is supplied which is supplied from the seventh rinse bath 14 via a pipe 33 and is discharged to the fifth rinse bath 10 by a pipe 32. The seventh rinse bath 14 in turn receives rinse water which is applied from another bath (see description below). In preferred embodiments, one or more aluminum recovery devices are deployed at the first 9, second 11 and third anodizing baths 13 to maintain an aluminum content of 10-15 g / liter in said acid solution during anodizing.

A fifteenth step corresponds to a color step, in which the one or more aluminum objects are colored. The coloring is intended to increase the aesthetic appreciation of the objects. For this purpose, the articles are applied in a color solution provided in a color bath 15. Said color solution comprises 17.5 to 22.5 g of tin sulfate per liter, preferably 19 to 21 g of tin sulfate per liter, and 18.5 to 21, 5 g of sulfuric acid per liter, preferably 19.5 to 20.5

BE2017 / 5202 g sulfuric acid per liter. Said color solution preferably has a temperature of 18.5 to 22.5 ° C, preferably a temperature of 20 to 21 ° C.

In a sixteenth step, or an eighth rinse step, residues of said color solution are rinsed from the one or more aluminum objects by applying them in rinse water present in an eighth rinse bath 16. Starting from the eighth rinse bath 16, rinse water used to rinse aluminum objects in different baths, as indicated above as a second rinse cycle. The rinse water for the eighth rinse bath 16 is received from a subsequent bath via line 35. In this second rinsing cycle, from the eighth rinsing bath 16, the rinsing water becomes substantially more and more polluted and more acidic, so that it can also be regarded as an acid stream, the start of the acid stream 26 corresponding to receiving rinsing water in the eighth rinsing bath 16. After the eighth rinse bath 16, the rinse water is transferred via a line 34 to the seventh rinse bath 14. For the rest of the second rinse cycle, reference is made to the above description.

In a seventeenth step, or ninth rinsing step, any final impurities or residues of said color solution are rinsed from the one or more aluminum objects by applying them in rinsing water contained in a ninth rinsing bath 17. The rinsing water is treated as an ingoing supply reverse osmosis water 27 to the ninth rinse bath 17. Said reverse osmosis water 27 has a conductivity of less than 24 microsiemens, preferably less than 22 microsiemens, and even more preferably less than 20 microsiemens. Reverse osmosis water shows a high purity. This water is therefore ideal to be used at the start of the second rinse cycle (the rinse water is transferred via a line 35 via the ninth rinse bath 17 to the eighth rinse bath 18).

In an eighteenth step, the one or more aluminum objects are placed in an empty bath 18. This is intended to build in a break.

In a nineteenth step, existing pores are closed at the surface of each of the one or more aluminum objects, which is also referred to in the prior art as sealing or compaction. This step can therefore also be described as a sealing step. For this sealing step, the one or more aluminum becomes

BE2017 / 5202 articles applied in a sealing solution provided in a sealing bath 19. Said sealing solution comprises between 1 and 3 mg of seal product per liter, preferably between 1.8 and 2.2 mg of seal product per liter and has a conductivity of less than 1200 microsiemens , preferably less than 1100 microsiemens, even more preferably less than 1000 microsiemens, and a temperature from 94 to 100 ° C, preferably from 95 to 99 ° C, and even more preferably from 96 to 98 ° C. In a preferred embodiment, said sealing bath 19 is insulated and provided with an insulated seal, preferably designed as an insulated lid. After sealing or compacting, said sealing solution is removed as an outgoing stream 28 from said sealing bath 19. The sealing bath 19 is preferably provided in large dimensions, so that a plurality of aluminum objects can be applied simultaneously in the sealing bath 19 , limiting losses in production cost and / or time.

In a preferred embodiment groundwater is pumped up to provide water that functions as rinsing water in the above first and / or second rinsing cycles. Such pumped-up groundwater is preferably iron-free. Preferably said groundwater is displaced with a pump group in order to provide the groundwater at a pressure of 2 to 4 bar, preferably of 2.5 to 3.5 bar. In one embodiment, the iron removal and the displacement are carried out in duplicate with a pump group of the groundwater.

For many of the above steps in the description of FIG. 1, cooling is required to achieve a desired temperature. Any cooling systems as known in the art can be used for cooling. In preferred embodiments, a refrigeration system is used which is split into two Systems: a first system comprising a traditional refrigeration with screw compressors and a second system with a constant control of a return temperature with respect to an ambient air temperature present in an outside environment, i.e. with regard to an outside air temperature, whereby valves are switched at a certain temperature deviation so that heated coolant goes out first to be cooled via a simple fan before returning to a cold water vessel. The latter offers the advantage that from an outside air temperature below 10 ° C such a cooling system can run completely on cooling by an ambient air present in an outside environment, i.e. outside air.

BE2017 / 5202

For many of the above steps in the description of FIG. 1, heating is required to achieve a desired temperature. Any heating systems as known in the art can be used for heating. In preferred embodiments, a heating system is used which is split into two Systems: a first system comprising a traditional heating with a thermal oil boiler installation and a second system comprising a cogeneration installation using 100% of upgraded heat in the installation. For the said second system, heat from a chimney will be used to heat return oil from a bath before it returns to a boiler; a temperature deviation of 20 ° C can be achieved at a flow rate of 20 m ³ / hour. Furthermore, in the said second system, hot water is obtained via residual heat from the chimney and heat from an engine in a central heating collector. The latter hot water can be used in several areas and includes: heating of baths that are operational at a specific temperature, heating of a warehouse or other rooms in a winter period, drying of aluminum objects in a room and preferably in an automated storage facility and heating the ninth rinsing bath 17 to obtain a better rinsing result. By using said cogeneration installation, a large amount of the consumed power consumption for anodizing aluminum objects, and even up to 1/3 of the total consumed power consumption, can be provided. In this way, purchased mains power can be limited to no less than 2/3 of the total power consumption.

In preferred embodiments, water treatment is performed to support at least one step of the above steps in the description of FIG. 1. In a preferred embodiment, water treatment comprises employing a reverse osmosis water generating device having a desired conductivity of less than 20 microsiemens. The latter embodiment is ideally suited for assurance of purity of rinse in the ninth rinse bath 17 and / or for assurance of purity of said seal solution in said seal bath 19. In a preferred embodiment, water treatment comprises employing a polymeric appliance to prepare polyelectrolyte as flocculant for water treatment, especially as flocculant for water purification. In a

BE2017 / 5202 preferred embodiment water treatment comprises using a water treatment system with one or more neutralization basins, preferably two neutralization basins, and a stirrer. In a preferred embodiment, such a water treatment system further comprises one or more CO2 injection units including valves, control, pumps and a storage facility, and preferably two such CO2 injection units, to dissolve CO2 in contaminated water or wastewater for pH control of that water. In a preferred embodiment, such a water treatment system further comprises a decanter and agitator for separating sludge from pure water. In a preferred embodiment, sludge-thickened, preferably 10-meter deep, decanter-thickened sludge is drawn in from a bottom part of a funnel-shaped, decanter-filled sludge pump and further thickened with a chamber filter press to a dry matter content of about 25%.

In preferred embodiments, air treatment is performed to assist at least one step of the above steps in the description of FIG. 1. In preferred embodiments, an air treatment system comprises one suction installation for the extraction of the baths comprising an alkaline solution and one extraction installation for the extraction of the baths comprising an acidic solution. Preferably, both extraction installations have an air flow rate between 60,000 and 70,000 m ³ / hour and preferably between 64,000 and 66,000 m ³ / hour. In preferred embodiments, said extraction installations comprise a demister, one or more counter-jets, a water reservoir with a controlled pH value by continuous change and a circulation pump.

Fig. 2 is a perspective view of a portion of an apparatus for anodizing one or more aluminum objects, according to embodiments of the present invention. The device comprises a support device 46 for carrying and transporting one or more aluminum objects in and out of baths 36, 38 and from a bath to another bath, and finally optionally to another surface, such as for instance a packing table. In particular, aluminum tubes 45 are depicted as aluminum objects in FIG. 2. The carrying device 46 comprises a frame 43 from which a holder 44 for hanging the aluminum tubes 45 is suspended by means of legs 52. The holder 44 comprises a frame 44a to which a plurality of arms 44b are attached. The arms 44b are L-shaped (with

BE2017 / 5202 supine and upward facing legs). The arms 44b are oriented transversely of aluminum objects, preferably elongated aluminum objects, such as aluminum tubes 45, which can be held by the holder 44. The arms 44b are provided in plural longitudinal direction so that aluminum tubes 45 can be properly supported, and in addition plural in longitudinal direction so that a maximum of aluminum tubes 45 can be held. In addition, said arms 44b are provided on either side of said frame 44a. The holder 44 is therefore optimized to accommodate as many aluminum tubes 45 as possible, while the whole of the holder and tubes can additionally be applied in a chemical liquid 37, 39 present in a bath 36, 38 with a length 36a, 38a, width 36b , 38b and depth gauge 36c, 38c. By means of said legs 52, the holder 44 can be brought in and out of a bath 36, 38 by means of a downward 49 and an upward movement 48, respectively. Preferably, this downward 49 and / or upward movement 48 is controlled in an automated manner. Said frame 43 of the carrying device 46 is displaceable by means of displacement elements, designed as an assembly of others 42, in rails 40 suspended from a ceiling 41, whereby movement of the container 44 along different baths 36, 38 is possible in two opposite directions 50 , 51, also known as a forward 50 and reverse 51 motion. The carrying device 46 thus has the advantageous possibility of being able to transport one or more aluminum objects, and in particular a plurality of aluminum objects, smoothly between different baths and in or out of these baths.

Fig. 3 is a front view of a detail of an apparatus for anodizing one or more aluminum objects, according to embodiments of the present invention. In FIG. 3 it is clearly shown that the holder 44 is suspended inclined from the frame 43 of the support device 46, whereby aluminum tubes 45 (with a length dimension 45a and a diameter 45b) carried by the holder 44 are oriented inclined at an angle α with respect to a fictional horizontal line 47. Such inclined orientation allows the aluminum tubes to remove liquid thereon in an improved manner, which promotes smooth anodizing of aluminum objects, such as aluminum tubes 45, according to the present invention.

After going through the different steps as discussed in the description of Fig. 1, the aluminum objects thus anodized can enter

BE2017 / 5202 embodiments are transferred to an automatic parcel wrapper with automatic wood infeed. Preferably, the anodized aluminum objects are transferred by an automatic crane. Furthermore, in preferred embodiments, one or more further improvements are employed, which improvements include: implementation of an automatic storage facility whereby production of anodized aluminum objects can be realized quickly, preferably in 24 hours, and packaging of anodized aluminum objects also quickly, preferably in 8 hours, can be realized, implementation of a barcode system and / or tablet or tablet applications at various work stations, implementation of a touch application for packaging for controlling the aluminum objects towards the packaging, and implementation of a touch application for a cash-off zone for input and / or output of baking.

BE2017 / 5202

Claims (17)

CONCLUSI ES A method for anodizing one or more aluminum objects (45), comprising the step of sequentially performing at least two anodizing steps, wherein during each anodizing step one or more aluminum objects (45) are arranged in different anodizing baths comprising at least one pair of cathodes and an acid solution, the objects (45) then residing in each of the anodizing baths for a period of time, and an electric current being applied in each of the anodizing baths when the one or more aluminum objects (45) residing therein, the one or more aluminum objects (45) are connected as an anode, characterized in that the one or more aluminum objects (45) are rinsed with water after each anodizing step. A method according to claim 1, wherein the applied electric current is identical in each of the anodizing baths and the electric current has a current strength of at most 24000 amps and an electric voltage of 16 to 22 volts. The method according to claim 1 or 2, wherein one or more preliminary treatment steps are performed before the at least two anodizing steps, and wherein one or more subsequent treatment steps are performed after the at least two anodizing steps. A method according to any one of claims 1 to 3, wherein the one or more aluminum objects (45) are carried continuously by means of a support device (46) during the sequential execution of at least two anodizing steps, and when appropriate, during said one or more preceding and subsequent treatment steps. A method according to any one of claims 1 to 4, wherein the one or more aluminum objects (45) are carried inclined by means of the carrying device (46). A method according to any one of claims 1 to 5, wherein water for rinsing the one or more aluminum objects (45) in a cycle is used for rinsing the objects (45) in at least two steps. A method according to any one of claims 1 to 6, wherein after the subsequent treatment steps, or after the at least two anodizing steps, BE2017 / 5202 absence of said subsequent treatment steps, at least one of the one or more aluminum objects (45) must be reduced. The method according to any one of claims 1 to 7, wherein during at least one of the anodizing steps, previous treatment steps and / or subsequent treatment steps, energy for these steps is provided by means of a cogeneration. The method according to any one of claims 1 to 8, wherein ambient air present in an outer environment is used for cooling the one or more aluminum objects (45) during at least one of the anodizing steps, preliminary treatment steps and / or subsequent treatment steps. The method of any one of claims 1 to 9, comprising the following sequence of steps: a sequence of preliminary treatment steps, comprising: a) a degreasing step in which the one or more aluminum objects (45) are applied for at least 10 minutes in a bath (1) comprising a solution of 35 to 45 g of degreasing substance per liter at a temperature of 47 to 58 ° C; b) a first rinsing step in which the objects (45) are placed in a bath (2) with water; c) a pickling step in which the objects (45) are placed in a bath (3) for 17 to 23 minutes comprising a pickling solution comprising 46 to 54 g of wet leach per liter at a temperature of 58 to 64 ° C; d) a second rinsing step in which the objects (45) are placed in a bath (4) with water; e) a third rinsing step in which the objects (45) are placed in a bath (5) with water; f) a stripping step in which the articles (45) are placed in a bath (6) comprising a stripping solution comprising 85 to 115 g of sodium hydroxide per liter; g) a fourth rinsing step in which the objects (45) are placed in a bath (7) with water; h) an acid dip step in which the objects (45) are placed in a bath (8) comprising an acid solution comprising 40 to 60 g nitric acid per liter at a temperature between 19 and 24 ° C; BE2017 / 5202 a sequence of anodizing steps followed by rinsing steps, successively comprising a first anodizing step, a fifth rinsing step, a second anodizing step, a sixth rinsing step, a third anodizing step and a seventh rinsing step, wherein during each anodizing step the objects (45) are placed in a bath ( 9, 11, 13) comprising an acid solution of 165 to 215 g sulfuric acid per liter and at a temperature of 17 to 21.5 ° C are subjected to a current of at most 2400 amperes and an electric voltage of 16 to 22 volts, and during which each rinsing step the objects (45) are placed in a bath (10, 12, 14) with water; and a sequence of subsequent treatment steps, comprising: a) a coloring step in which the articles (45) are placed in a bath (15) comprising a coloring solution comprising 17.5 to 22.5 g of tin sulfate per liter and 18.5 to 21.5 g of sulfuric acid per liter at a temperature of 18 .5 to 22.5 ° C; b) an eighth rinse step in which the objects (45) are placed in a bath (16) with water; c) a ninth rinsing step in which the objects (45) are placed in a bath (17) with water; d) optionally, placing the objects (45) in an empty bath (18); and e) a sealing step or sealing step in which the objects (45) are placed in a bath (19) comprising a sealing solution comprising between 1 and 3 mg of seal product per liter with a conductivity of less than 1200 microsiemens at a temperature of 94 to 100 ° C. Device for anodizing one or more aluminum objects (45), comprising at least two baths (36, 38), of which at least two baths in turn are each provided with a pair of cathodes, characterized in that the device furthermore carrying device (46) for carrying the articles (45), said carrying device (46) comprising a frame (43) from which a holder (44) for managing the articles (45) can be suspended. Device according to claim 11, wherein the frame (43) is displaceable by means of displacement elements (42) in rails (40) which are attached to a surface (41), the rails (40) being parallel to BE2017 / 5202 are located relative to each other and are oriented in a direction crossing at least two of the baths (36, 38). Device according to claim 11 or 12, wherein the carrying device (46) is provided at the height of said frame (43) with a hoisting means for 5 transporting one or more objects (45) in or out of a bath. The device according to any one of claims 11 to 13, wherein the holder (44) is inclined. An apparatus according to any one of claims 11 to 14, for use in a method according to any one of claims 1 to 10. 10 An anodized aluminum object (45) obtained by applying a method according to any one of claims 1 to 10. An anodized aluminum object (45) according to claim 16, manufactured by means of a device according to any one of claims 11 to 15. BE2017 / 5202 Fl GUREN σ> CO _Β Ε2θΠί ^52θ2 u29 TT BE2017 / 5202 «3 tri 'T« s' Τ ’ Xï UT ’Τ” • ’S T r / J3 * kT ..a * st BE2017 / 5202 METHOD AND I NO DIRECTION FOR ANODIZING ALUMI NI UM ARTICLES AND ANODIZED ALUMI NI UM ARTICLE