JP3071313B2 - Method for recovering sulfuric acid from waste solution of stainless steel treated with sulfuric acid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stainless steel alloy was treated with sulfuric acid, molybdenum, niobium, a method of recovering sulfuric acid from the waste liquid containing at least one kind of vanadium.

[0002]

Use BACKGROUND ART anion exchange membrane, acid and metal ions
So-called diffusion dialysis, in which an acid is recovered from a solution containing ON by using a concentration difference as a driving force to separate metal ions, that is, so-called diffusion dialysis, has already been adopted in many fields. Numerous documents and patents have been reported for such acid diffusion dialysis membranes, but the most practical and useful are the amination of chloromethylstyrene (or vinylpyridine) -divinylbenzene copolymer (or Quaternary pyridinium) anion exchange membranes.

[0003] In the final stage of the production of stainless steel alloys, oils, dirt, and the like adhered or formed on the stainless steel alloys.
In order to remove oxides and the like, a pickling step of immersing in an acid solution for a predetermined time is essential. In such pickling,
One or more acids such as hydrochloric acid, sulfuric acid, hydrofluoric acid and nitric acid are used.

[0004]

SUMMARY OF THE INVENTION The present inventors have developed an anion-exchange membrane from a sulfuric acid treatment waste liquid such as a sulfuric acid washing waste liquid, an immersion waste liquid, or an electropolishing waste liquid of a stainless alloy containing at least one of molybdenum, niobium, and vanadium. It has been found that when recovering sulfuric acid by using diffusion dialysis, particularly when the operation is continued at a low temperature, a problem that the permeability of sulfuric acid decreases with time occurs.

An object of the present invention is to solve the above-mentioned problems and to provide a diffusion dialysis method useful for recovering sulfuric acid from a specific stainless alloy sulfuric acid treatment waste liquid.

[0006]

SUMMARY OF THE INVENTION The present invention was treated stainless alloy with sulfuric acid on one side of the anion-exchange membrane, molybdenum, niobium, contacted a liquid waste containing at least one kind of vanadium, water other-sided And recovering sulfuric acid by selectively subjecting the sulfuric acid to diffusion dialysis from the waste liquid, wherein the temperature of the waste liquid is maintained at 43 to 70 ° C. for diffusion dialysis. Here, the temperature of the waste liquid means that the temperatures of all the waste liquid in the dialysis zone are 4 points.
3 to 70 ° C.

[0007] Molybdenum, niobium, washing waste liquid of a stainless steel alloy containing at least one kind of vanadium, in the recovery of sulfuric acid from the sulfate waste solution such as a dipping waste or electropolishing waste, the cause of the permeability of sulfate decreases with time Although it is not clear yet, simply with the sulfuric acid treatment waste liquid containing iron ions, there is no decrease in performance over time,
The anion exchange membrane is contaminated by specific components such as molybdenum, niobium, and vanadium contained in the stainless alloy,
It is thought to lead to a reduction in sulfuric acid permeability.

[0008] Further, although this performance deterioration occurs in diffusion dialysis at about room temperature, the temperature of the waste liquid is 43 to 70 ° C.
Thus, it has been found that a decrease in the permeability of sulfuric acid over time can be prevented, and the present invention has been accomplished.

[0009] As the stainless alloy in the present invention,
Iron bases such as martensitic stainless steel, which is a high chromium steel containing carbon, ferritic stainless steel, which is a high chromium steel with low carbon content, austenitic stainless steel, which is a chromium / nickel steel, and their precipitation hardening stainless alloys Other than stainless steel, non-ferrous stainless alloys, for example, nickel-based stainless alloys (monel alloy, inconel alloy, hastelloy alloy) are exemplified.

[0010] These stainless alloys are used for improving corrosion resistance, heat resistance, and strength.
Manganese, molybdenum, tungsten, titanium, vanadium, niobium, silicon, phosphorus, various metals, such as boron
Has been contained, the effluent treated with acid stainless steel alloy containing these, to contain Kikin Supragenus other than iron is different from the acid treatment liquid pig iron or carbon steel.

Some metals condense their simple acid molecules to form an acid containing a large number of anhydride molecules. Just <br/> acid isopoly acid produced by a kind of metal, a heteropolyacid acid to the acid produced by the metal on the two or more kinds <br/>.
The general formula of isopolyacid is mM (I) ₂ O · nM (V) _{2
O 5 · xH 2 O, mM} (I) 2 O · nM (VI) O 3 ·
xH ₂ O, where M (I) is mainly an alkali metal,
M (V) is a well-known group V vanadium, niobium or tantalum on the periodic table, and M (VI) is a group VI chromium, molybdenum, tungsten, uranium or the like.

[0012] Polyacids that produce heteropolyacids include:
Those containing vanadium, molybdenum, and tungsten are well known . The central atom-carbon, chromium, molybdenum, manganese, iron, cobalt, nickel, tungsten, titanium, vanadium, niobium, a large number such as silicon. These polyacids have various condensates depending on the pH and concentration of the acidic solution.

In the waste liquid after sulfuric acid washing for removing rust on the surface of the stainless steel alloy, the waste liquid after immersion in sulfuric acid for producing a crystal surface without distortion on the surface of the stainless steel alloy, or the waste liquid after the electrolytic polishing, etc. Contains a metal that forms a polyacid, and is in a sulfuric acid acid solution, so it is considered that various polyacids are formed.

For example, in the case of molybdenum, Mo ₃ O _{10
^{2-, Mo 4 O 13 2-,}} Mo 8 O 25 2-, Mo 10 O 31 2-, Mo
₁₆ O ₄₉ ^2- etc. are formed, and when the anion exchange membrane comes into contact with the liquid in which they are present, they easily exchange ions and, based on the size of these ions, are fixed in the anion exchange membrane. It is considered that they adsorb to the ions and hinder the permeation of the counter ion, and as a result, the permeation rate of sulfuric acid also decreases.

[0015] In the present invention, such acid treatment effluent is held in the 4 3 to 70 ° C., diffusion dialysis is performed.

[0016] Diffusion dialysis is performed in the manner shown in FIG. The anion exchange membrane A forms a plurality of compartments arranged as shown in FIG. The various devices but is applicable, were example, if appropriate between the clamping frame body having such a configuration, a plurality of anion exchange through the chamber frame, mesh-like spacer having a supply and discharge mechanism for sulfuric acid treatment effluent A so-called filter press type (clamping type) dialysis tank in which the membranes A are arranged and clamped is preferably used.

The sulfuric acid treatment effluent X to be subjected to diffusion dialysis is supplied to every other compartment in the apparatus, preferably at a flow rate of 0.5 to 5.0 l / hr · m ² , while anion exchange In each compartment adjacent to the compartment with the membrane A interposed therebetween,
Water Y is supplied at substantially the same flow rate as the sulfuric acid treatment waste liquid X.
The water is not necessarily pure water, and a sulfuric acid aqueous solution having a lower sulfuric acid concentration than the sulfuric acid treatment waste liquid can be used. Also,
In the dialysis tank, the temperature of the water was set at 4
It may be preferable to heat to maintain the temperature at 3 to 70 ° C.

Thus, in the dialysis tank, the sulfuric acid-treated waste liquid X and the water Y are opposed to each other across the anion exchange membrane A, and the sulfuric acid in the sulfuric acid-treated waste liquid X has a concentration gradient with respect to the water Y and a negative concentration. Due to the action of the ion exchange group, the water is selectively transferred to the water Y side through the anion exchange membrane A. The sulfuric acid-treated waste liquid that has been subjected to diffusion dialysis is discharged out of the tank as a waste liquid Z from which sulfuric acid has been removed. If necessary, this is returned to the sulfuric acid-treated waste liquid X and circulated until sulfuric acid is sufficiently recovered. You may.

Thus, the waste liquid Z from which a sufficient amount of sulfuric acid has been removed is neutralized with a small amount of alkali and discarded as compared with the case where the treatment of the present invention is not performed.

On the other hand, the recovered sulfuric acid-containing liquid W is circulated by returning it to the water Y if necessary, and is taken out of the tank after the sulfuric acid concentration reaches a predetermined value. Although the recovered sulfuric acid-containing liquid W contains a small amount of iron, it contains almost no impurities such as molybdenum, nickel, and vanadium contained in the sulfuric acid treatment waste liquid X. > it can be re-used to enable.

[0021] With temperature forty-three to seventy ° C. sulfuric acid waste solution, does not decrease transmission rate of the sulfuric acid, but is is not a or bright et reason for stability performance, since polyacid is often not very stable It is presumed that the hydrolysis proceeds by increasing the temperature.

The anion exchange membrane used in the present invention includes:
Is not particularly limited, in general, styrene is commercially used - may be a divinylbenzene based anion-exchange membrane, Furthermore, for example JP-A 2-68146, the 2-7182
9, anion exchange membranes shown in 2-211257, and the like . Further, an anion exchange membrane reinforced with a porous support can be applied without any problem.

[0023]

Next, the present invention will be described with reference to examples.
The present invention is not limited by such embodiments.
The description of the symbols used in the examples is as follows.

In the diffusion dialysis, the permeation rate U of sulfuric acid and iron was determined by equation (1) . U = m / (t · A · ΔC) (1) where m is the number of moles (mol) of sulfuric acid or iron transferred to the recovery side, t is the diffusion time (hr), and A is the effective membrane. The area (m ² ) and ΔC indicate the difference (mol / liter) in the concentration of sulfuric acid or iron between the dialysate and the recovered solution.

The selectivity R _s between iron and sulfuric acid was determined by equation (2) . R _s = U _Fe / U _acid (2) where U _Fe is the permeation rate of iron, and U _acid is the permeation rate of acid.
Show.

[0026] In analogy to the synthesis method described in Example 1 Hei 1-168629 4, reacted with 4-diphenol and dichloro diphenyl sulfone, the precursor of intrinsic viscosity 0.22 consisting of units of an aromatic polysulfone synthesized and then reacted with sodium sulfide and said precursor and dichloro diphenyl sulfone, an aromatic polysulfone and polythioether sulfone equimolar to obtain a block copolymer a of the intrinsic viscosity of 0.65.

The copolymer A is dissolved in 1,1,2,2-tetrachloroethane, chloromethyl methyl ether and anhydrous tin chloride are added, and the mixture is reacted at 110 ° C. for 4 hours. After precipitation and washing, a chloromethylated copolymer B was obtained. The copolymer B was dissolved in dimethylformamide, and then trimethylamine was added to obtain an anion exchange resin solution having an ion exchange capacity of 2.0 meq / g resin. After casting the solution on a Mylar film, it was heated and dried at 110 ° C. for 30 minutes to obtain an anion exchange membrane having a thickness of 25 μm.

The resultant anion exchange one side sulfuric acid washing waste stainless alloy film (iron 27 g / liter, molybdenum 2 g / l, niobium 0.1 g / l, vanadium 1 g / l, including other), the other contacted deionized water on one side, at 45 ° C. the temperature of the effluent, to determine the permeation rate and selectivity of the sulfuric acid and iron has moved to the ion exchange water side. The results are shown in Table 1. Performance was stable for a long time .

Comparative Example 1 Table 1 shows the results of determining the permeation rate and selectivity of sulfuric acid and iron ions in the same manner as in Example 1 except that the temperature of the sulfuric acid washing waste liquid was changed to 30 ° C. The transmission performance decreased in a short period of time.

Example 2 A 5% by weight nitrile rubber was dissolved in a mixture of chloromethylstyrene-divinylbenzene and a styrene monomer, and a monomer syrup solution in which benzoyl peroxide was dissolved as a polymerization initiator was prepared.

After the monomer syrup solution was applied to a polyvinyl chloride cloth, it was sandwiched between polyester films and polymerized . The resulting polymer membrane was aminated in a trimethylamine solution to obtain a dry membrane having an ion exchange capacity of 2.0 meq / g and an anion exchange membrane having a thickness of 120 μm. Table 1 shows the results of measuring the permeation rates of sulfuric acid and iron in the same manner as in Example 1 using the ion exchange membrane. Performance was stable for a long time.

Comparative Example 2 Table 1 shows the results of determining the permeation rate and selectivity of sulfuric acid and iron ions under the same conditions as in Example 2 except that the temperature of the sulfuric acid washing waste liquid was 30 ° C. The transmission performance decreased in a short period of time.

[0033]

[Table 1]

[0034]

According to the present invention, it is possible to stabilize the permeation performance and selectivity of sulfuric acid in diffusion dialysis.
A long-term stable operation of an industrial diffusion dialysis device becomes possible.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for carrying out a diffusion dialysis method of the present invention.

[Explanation of symbols]

 A: Anion exchange membrane X: Sulfuric acid treatment waste liquid Y: Water Z: Waste liquid from which sulfuric acid has been removed W: Recovered sulfuric acid-containing liquid

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23G 1/36 B01D 61/24 C01B 17/90

Claims (1)

(57) [Claims] [Claim 1] A stainless steel alloy on one side of the anion-exchange membrane is treated with sulfuric acid, molybdenum, niobium, contacted a liquid waste containing at least one kind of vanadium, brought into contact with water other-sided, sulfate from the waste the selectively with allowed diffusion dialysis 4 in a method for recovering sulfuric acid, the temperature of the waste
A method for recovering sulfuric acid , comprising maintaining the temperature at 3 to 70 ° C and performing diffusion dialysis.