JPS5870879A - Recovery of valuable component from liquid used for treating iron with acid - Google Patents

Abstract

PURPOSE:To efficiently separate and recover hydrochloric acid and high-purity iron, by adsorbing and removing metal ion impurities in a liquid used for treating iron with hydrochloric acid by using anion-exchange resin, oxidizing dissolved iron ion, and then treating the liquid by solvent extraction. CONSTITUTION:The liquid used for treating iron with hydrochloric acid is brought into contact with anion-exchange resin at the concentration of hydrochloric acid of 2-8N, to adsorb and remove trace metal ions as impurities, e.g. lead and zinc, contained in the treating liquid. The liquid purified by said adsorption is subjected to oxidation such as electrolytic oxidation to convert Fe<2+> ion contained as a main component into Fe<3+> ion, and then the oxidized treating liquid is treated by an extracting method using a solvent such as phosphates to separate and recover hydrochloric acid and iron. The iron extracted by the solvent is stripped in the form of its chloride, hydroxide or the like in accordance with required uses.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention of this application is a method for recovering valuable components from an iron pickling solution in KIIL, 411, in which iron pickling waste is subjected to adsorption treatment, oxidation treatment, and solvent extraction treatment to recover valuable components from the waste solution. This invention relates to a method for recovering hydrochloric acid and iron with high purity.

Iron pickling waste liquid is produced in large quantities, for example, during the surface cleaning process using hydrochloric acid in the manufacture of steel products, and it is desirable to recover the large amounts of hydrochloric acid and iron contained in the acid treatment liquid from the viewpoint of pollution prevention and resource conservation. .

However, small amounts of lead, zinc, etc. are dissolved as impurity metal ions in the formic acid treatment solution, and it is difficult to efficiently separate and recover high-purity iron along with hydrochloric acid from such acid treatment solutions using conventional methods. was difficult.

Namely, the evaporation concentration method in which the acid-treated waste liquid is distilled and concentrated under reduced pressure at low temperature, and the pyrolysis furnace method in which the liquid is made into a spray and decomposed at high temperature in a pyrolysis furnace are known as methods for recovering hydrochloric acid. However, these methods require expensive equipment materials that can withstand severe corrosion, require a large amount of energy for evaporation and heating, and are methods that recover hydrochloric acid, making it difficult to recover iron at high purity at the same time. cannot be done easily.

In addition, a method for separating and recovering hydrochloric acid and heavy metals in waste liquid by combining solvent extraction method and electrolytic method was published in 1982-5827.
However, the process is very complicated, requires a large number of equipment tanks, and is inefficient at separating minute amounts of impurity metal ions, so this method is applied to iron acid treatment solutions. There are many problems with that.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for efficiently recovering hydrochloric acid and iron with high purity from a hydrochloric acid treatment solution for iron.

In the present invention, impurity metal ions are adsorbed and removed by contacting an iron hydrochloric acid treatment solution with an anion exchange resin, and the # adsorption removal solution is oxidized to remove Fe''+ ions contained as the main component.
0 ions, and then the oxidized solution is treated by a solvent extraction method to separate and recover hydrochloric acid and iron.

The present invention adsorbs and removes trace impurity metal ions such as lead and zinc contained in the acid treatment solution using an anion exchange resin.
Then, after oxidizing the dissolved F ions to Fe 1+ ions, the main components, hydrochloric acid and iron, are separated and recovered by a solvent extraction method. This has been fully achieved, and with a small device, extremely pure iron can be efficiently and easily separated and recovered together with hydrochloric acid, and stone effects can be obtained.

The solvent extraction method for recovering waste hydrochloric acid is an effective method in which impurity metal ions are usually extracted and removed in the first step, main component metal ions are extracted in the second step, and hydrochloric acid is recovered at the same time. However, although the solvent extraction method is extremely effective in separating components that exist in large amounts, it is inefficient in extracting and removing trace components at a few hundred to several tens of ppm. This requires a large number of stages, making the device extremely large and practically impossible.

Therefore, the present invention proposes that by adsorbing and removing the trace impurity components using a 7-ion exchange resin and further performing solvent extraction, the main component iron can be recovered with high efficiency and high purity together with hydrochloric acid. As a result of our studies, we found that in the hydrochloric acid treatment solution for iron, Fe'' contained in the treatment solution is adsorbed by the anion exchange resin, and K<<, while Pb'', zn''+, etc. can be easily adsorbed and removed. Based on the fact that F@″+ is difficult to extract with a solvent especially in a low pH range, whereas pe s+ can be easily extracted, the acid-treated solution is first brought into contact with an anion exchange resin to extract Pb*. Only impurities such as Zn are adsorbed and removed, and then the treated solution is oxidized to convert dissolved Fe to Fe, and then the hydrochloric acid treated solution is extracted with a solvent.
We have discovered that high-purity iron and hydrochloric acid can be efficiently and easily separated and recovered using a small-scale device.

More specifically, when an ion exchange resin is used to adsorb and remove ions, the number of stages is nearly infinite when the resin column is used, and even trace components can be completely adsorbed and removed. In hydrochloric acid solution, many metals form complex anions, and by using a 7 anion exchange resin, υ-complex anions can be formed.
The metal that forms ions is efficiently removed by an exchange reaction as shown in the following equation.

R-CL +HMC4H+1-+R-MCLn+1+H
CL, (1) (R is an anion exchange resin, M is an n-valent metal) The metal forming the skeleton complex anion is pbl+
, zn1+, Fe", Ru", Ir", pt number+
+ P d" + Cd"+Ag" + Hg" +
These metals can be removed as impurities by anion exchange resin.However, the iron content in the hydrochloric acid treatment solution for iron is treated as Fe!+ ions. Since it is dissolved, it is not adsorbed by the anion exchange resin, and only impurity metals such as pbl+ and znl+ are adsorbed and removed.

In the present invention, adsorption by an anion exchange resin can be carried out by applying known means, and anion exchange resin is attached to a three-dimensionally polycondensed polymer base as an exchange group.
A suitable method is to fill a column with a variety of commercially available anion exchange resins to which a grade ammonium group or a primary to 5 grade amine is bonded. In this adsorption treatment, the hydrochloric acid concentration is 2
If it is less than N, the removal of impurity metal ions will be insufficient, and if it is more than 8N, Fe! Since some adsorption of + ions occurs,
The concentration of hydrochloric acid during the adsorption step of the present invention is preferably in the range of 2N to 8N. Further, the anion exchange resin after adsorption can be easily desorbed with water or dilute hydrochloric acid as shown in the following equation, and can be recycled and used repeatedly.

RMCtn-N +Hz O→RCL 1 Mczn+H
mO-(2) In this way, the acid treatment solution from which impurities have been removed is obtained as a solution of pure iron and hydrochloric acid, but as mentioned above, the iron in this solution exists as Fel + ions, which are difficult to extract with solvents. Therefore, it is necessary to oxidize the p61+ ions to extractable e1+ ions before solvent extraction.

In the present invention, various known chemical or electrochemical oxidation methods can be applied to the oxidation treatment.

For example, injection of oxidizing agent, blowing of oxidizing gas, electrolytic oxidation, etc. are not possible, but in order to perform oxidation quantitatively without contaminating the processing solution, oxidation using hydrogen peroxide, ozone, air, oxygen gas, chlorine gas, etc. method, electrolytic oxidation method, and combinations thereof are preferred. Electrolytic oxidation can be easily carried out by introducing the treatment liquid into the anode chamber of a known diaphragm electrolytic cell and energizing it. Next, the oxidized solution is treated by a solvent extraction method to separate and recover hydrochloric acid and iron. Conventionally known methods can be applied to the solvent extraction process, and in the present invention, phosphoric acid esters, such as DEHP (di-2-ethylhexyl phosphate), which can extract Fel+ ions from the hydrochloric acid solution, are used.
, DBP (diptyl phosphate), TBP (tributyl phosphate) and primary to quaternary amines, such as TOA ()! Jisooctylamine) etc. are preferably used as the solvent.

The solvent and the treatment liquid are sufficiently contacted and mixed by stirring, etc., and then separated into a solvent layer in which iron ions have been transferred and extracted and a hydrochloric acid liquid layer. Iron extracted into a solvent can be exfoliated in the form of sulfuride, hydroxide, etc. depending on the application. Water, hydrochloric acid, etc. are suitable as the stripping agent, and the solvent after stripping can be recycled and reused. Furthermore, if the liquid stripped off as F e CLm by water is used as a catholyte in an oxidation process by electrolysis, the electrolytic voltage can be lowered, resulting in a power saving effect.

The present invention will now be described with reference to Attachment 70-Jito.
The present invention is not limited to this.

Example Pickling Iron with Hydrochloric Acid The acid treatment solution having the following composition produced in step 1 was passed through a column packed with a strongly basic anion exchange resin (trade name Diaion 5A10A) at 5V10 in adsorption step 20.

The composition of the resulting discharged liquid was as follows, and impurity metals were sufficiently removed.

The adsorbed impurities 8 are removed using water as the desorbent 9, P b
It was removed as CLx + Z n C1. The discharged liquid 5R is led to the anode chamber of the diaphragm electrolytic cell in the oxidation step 3,
Fe1+ was oxidized to Fe"0. The electrolytic cell was made of rubber-lined iron, the cathode was a Ti plate, and the anode was titanium coated with a noble metal oxide. The cathode chamber and anode chamber were equipped with a cation exchange membrane ( The 9-FeCtm acidic aqueous solution 15 recovered from the stripping process 5 described later is passed through the cathode chamber to reduce the electrolytic voltage by the reduction reaction of pe''+→Fe''+. The electrolytic voltage was 2.4 V at 40° C., 5 KA, current reading IKA/m”, and electrolysis was carried out for about 12 hours to perform sufficient oxidation treatment.

Next, the obtained oxidation treatment liquid was extracted with 1
Two-stage extraction was performed using OXTOA (kerosene dilution) as a solvent, and as shown in the following formula (p, l+ were extracted and separated into the solvent layer, and hydrochloric acid was separated and recovered in the other layer).

H"(FeCt,)-10RsN-+RsNH"(
: FeC44, l-... (a) F in recovered hydrochloric acid 7
e3+ is Q, 1 g/l, and can be reused as hydrochloric acid 11 for the Mayuki pickling process.

The Fe + extracted into the solvent is processed as shown in the following formula in the peeling step 5.
High purity F is added to the aqueous phase by contacting with water as a release agent 14.
e CLs was peeled off as an acidic solution.

Rm NH”CF'eCL6 ) −+ Is O→
RsN + FeCLs + HCL + Hm O The solvent 15 after stripping was reused in a small amount in the solvent extraction step 4.

[Brief explanation of drawings]

The drawing is a detailed illustrative flow sheet of the invention. 1: Iron pickling process 2: # & wearing process 5 Dioxidation process 4: Solvent extraction step 5; Peeling process % permission: 11 people, Toshihiro Suzuki and 1 other person servant

Claims (6)

[Claims] (1) The iron hydrochloric acid treatment solution is brought into contact with an anion exchange resin to adsorb and remove impurity metal ions, and the hydrochloric acid treatment solution is treated by a solvent extraction method to separate and recover hydrochloric acid and iron. Features: A method for recovering valuable components from acid treatment solutions for iron. (2) The method according to claim (1), wherein the concentration of hydrochloric acid during adsorption by the anion exchange resin is 2N to 8N. (3) The method according to claim (1), wherein the oxidation treatment is performed by electrolytic oxidation. (4) The method according to claim (1), in which the oxidation treatment is performed using hydrogen peroxide. (5) The method according to claim (1), wherein the oxidation treatment is performed using air, oxygen gas, or chlorine gas. (6) The method according to claim 1, in which primary to quaternary amines or phosphoric acid esters are used as the solvent in solvent extraction. (η The method according to claim (1) for separating and recovering iron as high-purity iron chloride.