JPS5836677B2 - Method for recovering sulfuric acid and contained metals from iron sulfate solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a closed system to convert iron sulfate, which has conventionally been considered difficult to economically process, into H2SO and highly pure F.
The present invention provides a method that is more economical than conventional methods and can be recovered as Fe or Fe oxide.

Furthermore, the present invention provides a method for advantageously recovering these metal ions as metal bodies when Mn, Zn, Cu ions, etc. are present in the solution of iron sulfate (for example, pickling waste liquid of steel plates). be.

Therefore, the gist of the present invention is to (1) dissolve iron sulfate in water or acid, oxidize the melt, and remove Fe2 in the solution.
After converting + ions to Fe3+ ions, Fe ions are extracted by contacting with an organic solvent and H2SO4 is regenerated, while... The Fe ions extracted into the organic phase were treated with HCl.
to perform back extraction, regenerate organic solvent A, lead the back extracted group to a known electrolysis or thermal decomposition process, regenerate Fe or Fe oxide and HCl, and repeat HCl for back extraction. A method for recovering sulfuric acid and metals or metal oxides from iron sulfate consisting of
If it contains n, (2) an aqueous solution of iron sulfate containing Mn, consisting of one or more of alkyl phosphoric acid, oxime, carboxylic acid, and primary to quaternary amine, diluted with petroleum hydrocarbon; Mn in the solution is extracted by contacting with organic solvent A, and then the extracted solution is oxidized to remove the contained F.
After converting the e2+ ions into Fe''+ ions, the melt is heated by contacting it with an organic solvent B that has been extracted from one or more of alkyl phosphoric acids and phosphoric esters and diluted with petroleum hydrocarbons. The Fe3+ ions inside are extracted and sulfuric acid is recovered, the Mn ions extracted with organic solvent A are peeled off and recovered from the organic phase with water or acid, and the Fe3+ ions extracted with organic solvent B are electrolytically treated as Fe or oxides. This is a method for recovering sulfuric acid and contained metals from an iron sulfate solution.

The organic solvent A in the present invention is an alkyl phosphoric acid, an oxime,
It means one or more of carboxylic acids, primary to quaternary amines, diluted with petroleum hydrocarbon, and organic solvent B is either alkyl phosphoric acid or phosphoric ester. Or it consists of both, diluted with petroleum hydrocarbons.

The petroleum hydrocarbons (diluents) used in the present invention include aromatic hydrocarbons and aliphatic hydrocarbons, as well as miscellaneous hydrocarbon mixtures such as kerosene. The extractant concentration is in the range of 1 to 75 volumes (volume), and is diluted and adjusted depending on the purpose of use.

Next, the acid used in the present invention refers to H2SO4 or HCl.

According to the present invention, H2SO4 can be regenerated and recovered by selectively extracting Fe ions present in highly concentrated acids, which were considered difficult in the past, using a solvent extraction method, and other heavy metal ions Mn, Since Zn, Cu, etc. can also be recovered separately, the recovered Fe or Fe oxide has a high purity and can be used not only as a raw material for iron manufacturing but also as a raw material for ferrite.

In addition, according to the present invention, iron sulfate can be converted into Ca(OH)z, Ca■3
Because resources can be used effectively without having to deal with sludge treatment, acid recovery by solvent extraction reduces energy and labor costs and increases economic efficiency, making it extremely effective for this type of related industry.

Next, examples of the present invention will be described in detail based on a flow sheet, but the present invention is not limited thereto.

Example 1 (See Figure 1) When iron sulfate 1 is dissolved in water or dilute sulfuric acid 2 and Mn, Zn, Cu ions, etc. are present in addition to Fe, the Fe ions are allowed to exist as Fe2+ ions, and the organic solvent is AFor exampleD
i (2-ethyhexyl)phosphori
c acid (D2EHPA) in extraction step 3 to extract metal ions other than Fe.

After extraction of ions other than Fe such as Mn, Zn, Cu, etc., Fe2R1oH6+ and FeS
Since Fe2+ ions remain in the form of 04, they are brought into contact with a washing solution in the washing step 4 to wash and remove the Fe2+ ions in the organic phase.

In this case, a substance having a higher extraction partition coefficient than Fe2+ ions, such as a sulfate solution or a chloride solution of Mn, is used as the washing liquid.

When extracting target metal ions such as Mn, Cu, and Zn ions using an extractant such as alkyl phosphoric acid, oxime, or carboxylic acid, only Me2++2RH−+R2Me+2H+ is extracted, as with ion exchange resins. Instead, Me”++n(R2H2:)+MR.2nHn+nH+
Alternatively, Fe2+ ions are also extracted in the form of Fe2RtoHa+, as shown as an example (there are countless chemical species).

Furthermore, it physically mixes into the organic phase as FeS04.

These are collectively referred to as extraction of Fe2+ ions, and unless these are washed away, high purity metal oxides and metals cannot be obtained.

In addition, as a method for removing a specific substance from an organic phase, as disclosed by the present inventor in Japanese Patent Application No. 49-90956, it is possible to remove a specific substance by contacting it with an aqueous solution having a higher extraction and distribution ratio than that of the target substance. It is expressed as the material extraction and distribution ratio of the organic phase.

The material in the aqueous phase is then brought into contact with H2SO4 or I{C7 in the stripping step 5, with the solution in which Fe"4-on has been washed away, to remove Mn.
, Cu, and Zn are recovered as a concentrated solution (Fig. 6,
(See Figure 7).

On the other hand, the melt containing Fe2+ ions after extraction step 3 is H2
After converting Fe2+ to Fe"+ ions in the oxidation step 9 using an oxidizing agent such as 02, high pressure air, or high molybdenum oxygen, the Fe"+ ions are extracted 10 by contacting with an organic solvent A to form H2S04. is recycled, concentrated 17 and reused.

FIG. 3 shows the relationship between the Fe""f-on extraction partition coefficient and the free acid (H2SO4).

In the stripping step 11, the Fe2+ ions in the organic phase are brought into contact with a back extraction screen 12 (generally heated with 5 to 1 s% HCl dissolved) to back-extract the Fe3+ ions, and the organic solvent A is regenerated and re-extracted. Fe3+ ion extraction is repeated.

The HCI solution containing the back-extracted Fe3+ ions is led to the cathode chamber of electrolysis step 13 (the electrolytic cell is a known diaphragm type electrolytic cell used for electrolysis in the smelting of non-ferrous metals such as nickel) to remove Fe3+. Alternatively, in the next extraction step 14, alkyl phosphates and/or phosphoric esters such as TBP (tributyl pho
Fe3
+ ions are extracted as chloride complexes to regenerate HCA.

The extraction equilibrium curve is shown in FIG.

The organic phase extracted as a chloride complex (HFe (adduct formation in the form of J'4.2TBP) is brought into contact with water in the stripping step 15 to obtain concentrated FeCl3HCl,
In the next recovery step 16, Fe or Fe oxide and HCl are recovered.

In the present invention, when an alkyl phosphoric acid is used as the latter, the organic solvent A and the organic solvent B are the same as when an alkyl phosphoric acid is used as the organic solvent A, and there is no difference between the two.
When extracting Mn2+ ions, if Fe"4 on and Mn2"I' on are contained in the water solution, the extraction distribution ratio is Mn2+>Fe2+, so even if the same extractant is used, Mn2+ ions are selectively extracted. is extracted, and this is noticeable at pH 4.0 or lower.

Water dissolution after Mn extraction increases [H+] ion concentration,
The extraction and distribution ratio of Fe2+ ions further decreases.

For this purpose, the Fe2+ ions contained in the compound are oxidized to become Fe3
When Fe3+ ions are converted into Fe3+ ions and brought into contact with the same alkyl phosphoric acid as the organic solvent A at the same concentration as an extractant, Fe3+ ions are selectively extracted because the extraction and distribution ratio is large.

Therefore, even if the same organic solvent is used, the valence of the target metal ion is changed, making the separation of metals more efficient.

In the present invention, organic solvents A and B are the same when alkyl phosphoric acid is used as described above, but for convenience of explanation, organic solvent A is used to prepare Mn from an iron sulfate solution containing heavy metals other than Fe such as Mn. B was used as the organic solvent used after extracting Fe2+4 ions and converting Fe2+4 ions into Fe3+ ions by oxidation.

Example 2 (See Figure 2) Similarly to Example 1, the liquid from which heavy metal ions other than Fe have been extracted is treated with an oxidizing agent or high-moisture air,
After oxidizing Fe2+ ions in the solution to Fe3+4 ions with oxygen, adding HCl in a chemically equivalent amount to extract Fe ions as a chloride complex, organic solvent B (containing phosphoric acid esters such as TBP, etc.) was added. (organic solvent) to extract Fe, Cl ions into the organic phase and regenerate H2SO4.

The extraction equilibrium curve is shown in FIG.

On the other hand, the Fe and CA' ions extracted into the organic phase are recovered as concentrated FeCls.HCI by contacting with water, and the organic solvent B is regenerated.

Fe or Fe oxide and HCA are recovered from the thus obtained back-extracted liquid through a known electrolysis or thermal decomposition process, and the HCl is used repeatedly.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the invention. FIG. 2 shows a flow sheet showing another embodiment of the invention. Figure 3 shows the Fe3+ ion extraction partition coefficient and free acid (H2S
Graph showing the relationship between O, ). FIG. 4 is a graph showing the Fe extraction equilibrium curve in the HCl regeneration process. FIG. 5 is a graph showing the Fe extraction equilibrium curve in the H2SO4 regeneration process. FIG. 6 shows the Mn extraction equilibrium curve in the extraction process. FIG. 7 shows the Mn peeling equilibrium curve in the peeling process.

Claims (1)

[Claims] 1. After oxidizing a solution of iron sulfate and converting Fe2" ions in the solution to Fe3+ ions, alkyl phosphoric acid, oxime,
Fe''4one is extracted from one or more of carboxylic acid, primary to quaternary amines by contacting with organic solvent A diluted with petroleum hydrocarbon, and H2S04 is regenerated, while organic The Fe3+ ions extracted into the phase are back-extracted with HCl to regenerate organic solvent A, and the back-extracted liquid is led to a known electrolysis or thermal decomposition process to recover Fe or Fe oxide and regenerate HCI. A method for recovering sulfuric acid and contained metals from an iron sulfate solution, which is characterized by repeating the steps for back extraction to recover sulfuric acid and iron or iron oxides from the iron sulfate solution. 2. Sulfuric acid containing heavy metals By bringing an iron solution into contact with an organic solvent A consisting of one or more of alkyl phosphoric acid, oxime, carboxylic acid, and primary to quaternary amine and diluted with petroleum hydrocarbon, Fe in the melt can be removed. Heavy metals other than Fe2+ are extracted and recovered, and the extracted solution is oxidized to remove Fe2+ in the melting
After converting the ions to Fe3+, the Fe3+ ions are extracted by contacting with organic solvent A to regenerate H2SO4, while the Fe3+ ions extracted into the organic phase are back-extracted with HCl to regenerate the organic solvent A and reverse The extract is subjected to a known electrolysis or thermal decomposition process, Fe or Fe oxide is recovered, HCl is regenerated, and HCl is repeatedly used for back extraction to extract iron sulfate and iron or A method for recovering sulfuric acid and contained metals from an iron sulfate solution, the method comprising recovering iron oxides. When dissolving iron sulfate containing 3Mn, avoid using one or more of alkyl phosphoric acids, oximes, carboxylic acids, and primary to quaternary amines, and contact organic solvents diluted with petroleum hydrocarbons. After extracting Mn from the solution, oxidizing the extracted fukai and converting the contained Fe2+ ions into Fe''+ ions, either one of alkyl phosphoric acid and phosphoric ester
By contacting the organic solvent B diluted with petroleum-based hydrocarbons, the F during the leaching can be
E3+ ions are extracted and sulfuric acid is recovered, Mn ions extracted with organic solvent A are peeled off and recovered from the organic phase with water or acid, and Fe3+ ions extracted with organic solvent B are recovered as metallic iron or iron oxide through electrolytic treatment. A method for recovering sulfuric acid and contained metals from an iron sulfate solution.