JPH0544067A - Production of structural material having electrolytic deposition covering layer and its equipment - Google Patents

Abstract

PURPOSE:To obtain a method and equipment for producing structural material by electrolysis where the generation of gaseous chlorine is restrained. CONSTITUTION:An electrolytic chamber is divided in three by arranging a cation exchange membrane and an anion exchange membrane in this order from the anode side. From the intermediate zone, Cl2 formed by electrolysis is recovered as hydrochloric acid. Simultaneously, an inorganic compound mainly consisting of carbonate is deposited on a porous conducting base stock by electrolysis to produce structural material which is covered with it. Thereby, Cl2 generated by electrolysis is recovered without getting scattered and lost, permitting environmental pollution and equipment corrosion to be prevented. At the same time, the deposition efficiency of CaCO3 is improved and the manufacturing efficiency of the structural material is increased.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to forming a coating layer made of an inorganic compound on the surface of a base material by electrolyzing it in an electrolytic solution using a porous conductive base material preformed in a predetermined shape as a cathode. , A cation exchange membrane between the anode and the cathode from the anode side,
The present invention relates to a method and an apparatus for manufacturing a structure, characterized in that an electrolytic chamber is divided into three parts by an anion exchange membrane, and hydrochloric acid produced from an electrolytic solution in a compartment surrounded by both ion exchange membranes is separated and recovered.

[0002]

2. Description of the Related Art Inorganic materials are applied by electrolysis on conductive materials.
Structures formed by compound coatings are already known
(Japanese Patent Publication No. 59-25038, DENKI KAGAKU 58. No. 5
(1990) P.410-415). These known techniques are
DC voltage between the insoluble anode and the cathode structure.
Ca contained in seawater by applying an electrochemical reaction²⁺,
Mg²⁺CaCO ₃, Mg (OH)₂A structure that is a cathode in the form of
By depositing and coating the surface, the structure can be protected against seawater.
It provides corrosion resistance.

The inventor of the present invention has previously proposed a structure improved from the above-mentioned known technique and a manufacturing method thereof (Japanese Patent Application No. 3-174).
No. 991 and Japanese Patent Application No. 3-189041).

[0004]

However, in the above-mentioned known technique, Cl ⁻ contained in seawater or the like which is usually used as an electrolytic solution is generated from the anode as Cl ₂ by electrolysis. When such a situation occurs, the strength of the structure itself is reduced and the surrounding environment is also contaminated.

Further, in the above-mentioned known technique, long-term electrolytic treatment of 2 to 6 months is required to form a coating on a target structure, and furthermore, the coating is uniformly formed on each part of the structure. However, the effect was not sufficient. The present invention solves the problems in the known art,
It is an object of the present invention to provide a structure which is free from environmental pollution and has high strength rapidly and a method for manufacturing the same.

[0006]

In order to achieve the above object, the present inventor has conducted extensive studies and as a result, it has been found that Cl ₂ precipitated by electrolysis can be separated and recovered from an electrolytic solution as HCl by using an ion exchange membrane. The findings led to the completion of the present invention. That is, the present invention uses a porous conductive base material preformed in a predetermined shape as a cathode and electrolyzes in an electrolytic solution to form a coating layer made of an inorganic compound on the surface of the base material. Then, from the anode side, the cation exchange membrane
The anion exchange membrane divides the electrolysis chamber into three compartments, and hydrochloric acid is generated from the electrolyte in the compartment surrounded by both ion exchange membranes.
(HCl) is a method for producing a structure characterized by separating and recovering, and in an apparatus used for producing a structure having an electrolytic deposition coating layer, an insoluble anode and a porous conductive group The electrolytic chamber between the cathode made of a material is divided into three parts from the anode side by a cation exchange membrane and an anion exchange membrane, and means for collecting HCl generated from the electrolytic solution in the compartment surrounded by both ion exchange membranes. The gist is a manufacturing apparatus for a structure, which is characterized by being provided with.

[0007]

[Operation] The configuration and operation of the present invention will be described. To obtain a coating layer forming CaCO ₃ constituting the structure, for example sea water or the like Cl ^-
When an aqueous solution containing is electrolyzed, the following reaction causes
Corrosive Cl ₂ etc. is generated. In the conventional electrolytic cell, the following reactions occur at the anode and cathode as shown in FIG.

Reaction at the anode

[0009]

[Equation 1]

The formula (2) generated as a side reaction produces Cl ₂ , which causes corrosion. In order to prevent the reaction of the equation (2), when isolating both at the cation exchange membrane between the anode and the cathode as shown in FIG. 3, Cl ^- is Cl ₂ occurs without going to the anode is prevented It On the other hand, at the cathode

[0011]

[Equation 2]

Although the reaction of (1) occurs, H ^{+ of} (1) reaches the cathode and interferes with the main reaction for the production of CaCO ₃ . That is, CO ₃ ²⁻ is obtained as a result of neutralizing OH ⁻ with carbonic acid formed from CO ₂ dissolved in water, but (OH ⁻ in formula (3) and H in formula (4) are obtained.
CO reacts with ⁺ to generate CO ₃ ^2- ), and when H ⁺ from the anode comes in here, OH ^- is consumed and the reaction of formula (4) does not occur, so CO ₃ ^2- is not obtained. That is, in order to prevent H ⁺ of the anode from approaching the cathode, an anion exchange membrane, in particular, a low H ⁺ permeable membrane may be placed and divided into A, B and C as shown in FIG. In the absence of an anion exchange membrane, Cl ⁻ increases in the cathode bath C as the electrolysis progresses, so that dissociation of CaCl ₂ is hindered, resulting in a decrease in Ca ²⁺ concentration.

[0013]

[Equation 3]

However, when an anion exchange membrane is provided, Cl ⁻ can be concentrated in the intermediate bath B and the formula (6) is not affected, and CaCO ₃
It is possible to prevent a decrease in production efficiency. In addition, the apparatus of FIG. 2 only needs to replace the bath C with seawater, and the bath A is sufficient to add the amount of water that has been consumed, so power consumption is reduced. It can also be used because hydrochloric acid can be generated in the B bath. The graph of FIG. 5 shows that the efficiency of CaCO ₃ generation improves when electrolysis is performed with the configuration of FIG.

[0015]

EXAMPLES Examples of the present invention will be described, but the present invention is not limited thereto.

[0016]

Example 1 A concrete structure, for example, an example of manufacturing a hull will be described. A conductive mat formed of a graphite fiber having a thickness of 8 mm is used as a cation exchange membrane (for example, CM-1 manufactured by Tokuyama Soda Co., Ltd.) and an anion exchange membrane (for example, ACM manufactured by Tokuyama Soda Co., Ltd.) as shown in FIG. ) Into an electrolytic cell divided into three compartments, and a 0.1% H ₂ SO ₄ aqueous solution is used as the anode bath A, and an aqueous solution containing CaCl ₂ or the like is used as the cathode bath C.
0.5mol / L electrolysis condition is voltage 40V, current density 0.1 A / cm
² applies. As a result, the cathode hull was 1.35 g / cm ²
CaCO ₃ was deposited at a rate of / day, which was 2.5 times faster than that of the conventional example using no ion exchange membrane after 300 hours.

Further, since HCl is gradually concentrated in the B bath, a predetermined amount is exchanged with a 0.1% HCl aqueous solution at regular intervals, and H
Cl was collected. After 300 hours, 13% HCl was obtained.

[0018]

[0019]

Industrial Applicability Since the present invention is constructed as described above, harmful gases such as Cl ₂ generated during electrolysis are trapped in the electrolytic solution as hydrochloric acid or the like and do not dissipate, which results in environmental pollution. Also, there is no risk of corroding peripheral equipment, and Ca
The deposition efficiency of CO ₃ etc. is improved, and it becomes possible to manufacture structures efficiently, which is extremely beneficial to the industry.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of an electrolytic cell for carrying out the present invention.

FIG. 2 is an explanatory view showing a reaction mechanism of the present invention.

FIG. 3 is an explanatory view of an electrolytic cell that uses a cation exchange membrane to prevent generation of Cl ₂ gas.

FIG. 4 is an explanatory diagram of a conventional example in which a structure is obtained by electrolysis.

FIG. 5 is a graph showing the efficiency of CaCO ₃ production.

Claims (4)

[Claims] 1. When a porous conductive substrate preformed in a predetermined shape is used as a cathode and electrolysis is performed in an electrolytic solution to form a coating layer made of an inorganic compound on the surface of the substrate, an anode-cathode is formed between the anode and the cathode. The electrolytic chamber is divided into three parts by a cation exchange membrane and an anion exchange membrane from the anode side in order, and the generated hydrochloric acid is separated and recovered from the electrolytic solution in the compartment surrounded by both ion exchange membranes. Method of manufacturing a structure. 2. The method for producing a structure according to claim 1, wherein the anion exchange membrane has low proton permeability. 3. An apparatus used for producing a structure having an electrolytic deposition coating layer, wherein an electrolytic chamber between an insoluble anode and a cathode made of a porous conductive substrate is provided with a cation exchange membrane / anion from the anode side. An apparatus for manufacturing a structure, characterized in that it is divided into three parts by an exchange membrane, and a means for collecting HCl generated from an electrolytic solution in a compartment surrounded by both ion exchange membranes is provided. 4. The structure manufacturing apparatus according to claim 4, wherein the anion exchange membrane has low proton permeability.