JPH0121098B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides HCl containing a large proportion of Ti ions,
This invention relates to a method for extracting and removing Ti ions from H ₂ SO ₄ , HNO ₃ or HNO ₃ +HF to recover these acids. Conventionally, Ti ions or Ti ions and Co, Cd,
Contains one or more heavy metal ions of Sn, Pb, Zn, Cu, Hg, Fe, Mo, W, and Cr.
HCl, H ₂ SO ₄ , HNO ₃ , and HF + HNO ₃ Waste acids are treated by neutralization, which involves adding alkali, generally caustic soda or lime, but this method not only cannot recover the acid, but also Containing metal ions are formed in a form that cannot be recycled as sludge-like hydroxide. Therefore, there is a disadvantage that a large amount of cost is required to dispose of the sludge. As the waste acid recovery method, these acids (HCl,
There is a method in which H ₂ SO ₄ is added to HNO ₃ +HF), heated and evaporated, and then condensed or absorbed with water. This method uses a large amount of energy for heating, and the heating capacity is severely corroded, resulting in many troubles that often force the equipment to shut down. In addition, since a neutralization step in which caustic alkali is added with lime is required to treat the evaporation residue, there is a drawback that the sludge produced by the neutralization has problems in disposal. The purpose of the present _invention is _to overcome the _drawbacks of these conventional methods.
+HNO ₃ ) with an organic solvent prepared by diluting one or more selected from the group of alkyl phosphoric acids and the group of alkyl dithiophosphoric acids with petroleum-based hydrocarbons, the Ti ions in the waste acid are removed from the organic solvent. The acid is recovered by extraction into the
NH ₄ HCO ₃ , (NH ₄ ) ₂ CO ₃ , NH ₄ F, NH ₄ H ₂ F,
By contacting with an aqueous solution containing one or more selected from the group of HF and _NH3 ,
A method for recovering an acid characterized by stripping off Ti ions and regenerating an organic solvent;
One or more types selected from the group of primary amines to quaternary amines and the group of neutral phosphoric acid esters are added to the HCl solution containing one or more types of heavy metal ions of W, Cr, and Cu. By contacting the solution with an organic solvent diluted with petroleum hydrocarbon,
A first step of extracting heavy metal ions other than Ti ions, and adding one or more selected from the group of alkyl phosphoric acids and the group of alkyl dithiophosphoric acids to the solution after the first step using petroleum-based hydrocarbons. A method for recovering acid is characterized by extracting and removing Ti ions into an organic solvent by contacting it with a diluted organic solvent. Embodiments of the present invention will be described below with reference to the drawings. The flow sheet of FIG. Embodiments corresponding to methods are described. HCl, H ₂ SO ₄ , HNO ₅ or HNO ₃ + containing Ti ions as shown in the flow sheet of Figure 1.
In extraction process B, waste acid A selected from the HF aqueous solution is
One or more extractants selected from the group of alkyl phosphoric acids and the group of alkyl dithiophosphoric acids are brought into contact with an organic solvent C diluted with a petroleum hydrocarbon (hereinafter, the above organic solvent is simply referred to as organic solvent C). As a result, the Ti ions in the aqueous solution are extracted into the organic solvent C to recover the acid. The recovered acid is recycled to treatment step D again. The Ti ions transferred to the organic phase are converted into (NH ₄ ) ₂ CO ₃ , NH ₄ HCO ₃ , NH ₄ OH, NH ₄ F,
Ti ions in the organic phase are removed by contacting with a stripping aqueous solution F (hereinafter simply referred to as aqueous solution F) containing one or more selected from the group of NH ₄ HF ₂ , HF and NH ₅ . After stripping, organic solvent C is regenerated, and Ti extraction step B is repeated again. The group of alkyl phosphoric acids used in the present invention refers to any of the following.

【formula】

【formula】

【formula】

[Formula] or

[Formula] (In the formula, R represents an alkyl group, generally an alkyl group having 4 to 14 carbon atoms.)Alkyldithiophosphoric acid refers to any of the following.

[Formula] (In the formula, R is an alkyl group, generally an alkyl group having 4 to 14 carbon atoms.) Petroleum-based hydrocarbons used as diluents include aliphatic hydrocarbons, aromatic hydrocarbons, and their A mixture is used, and a typical example of the aliphatic hydrocarbon is kerosene, and a typical example of the aromatic hydrocarbon is Sorbetso 100 or Sorbetso 150 (trade name). These are merely representative examples; other aliphatic or aromatic hydrocarbons can also be used. FIG. 2 shows another embodiment of the first method in the flow sheet of FIG. The embodiment of FIG. 2 contains HCl, H ₂ SO ₄ , HNO ₃ or
Ti ions and other heavy metal ions are co-extracted into the organic solvent by contacting an aqueous solution A, such as an aqueous HNO ₃ +HF solution, with an organic solvent C in an extraction step B, thereby extracting these acids (HCl,
H ₂ SO ₄ , HNO ₃ or HNO ₃ +HF). Next, the difference from the embodiment of the flow sheet shown in FIG.
HCl, H ₂ SO ₄ , HNO ₃ and HNO ₃ + HF contained in the organic phase by contacting with an aqueous solution H containing HF.
Heavy metal ions other than Ti ions are removed, leaving only Ti ions in the organic phase, and then in a stripping step E, the Ti ions are stripped by contacting with an aqueous solution F. Organic solvent C is regenerated similarly to the embodiment of FIG. Figure 3 shows a flow sheet for recovering Ti and titanate. That is, a waste acid aqueous solution A containing Ti is brought into contact with an organic solvent C in an extraction step B to extract Ti in the waste acid aqueous solution A into the organic solvent C,
At the same time, the acid is regenerated and recycled to process step D.
The organic solvent C containing Ti is stripped with an aqueous solution F in the stripping step E to regenerate the organic solvent C, and is recycled to the extraction step B, which is the same as the method shown in the flow sheet of FIG. The peeled titanium is collected in HTi recovery process T.
Ti is recovered as a titanate by adding a water-soluble alkali or alkaline earth metal carbonate such _as K ₂ CO 3 , Na ₂ CO ₃ , SrCO ₃ , BaCO ₃ as a solid or an aqueous solution. Next, FIG. 4 shows a second embodiment of the method in which heavy metals are first selectively extracted from a waste HCl aqueous solution containing heavy metals as well as Ti, and then Ti is extracted.
In other words, in the method shown in FIG. 4, together with Ti ions,
Hg, Cd, Pb, Sn, Zn, Fe, Co, Mo, W,
This shows a case where an aqueous HCl solution A containing one or more heavy metal ions such as Cr ⁶⁺ and Cu is treated. The aqueous solution (A) is led to a heavy metal extraction step BN, and a group of neutral phosphoric acid esters, By bringing one or more extractants selected from the group of primary amines to quaternary amines into contact with an organic solvent CM diluted with petroleum hydrocarbon, it is possible to remove Ti ions other than Ti ions in the solution A. The first step is to extract heavy metal ions as chloride complexes. Since the aqueous solution that has undergone the first step substantially contains only Ti ions, it is led to the next Ti extraction step B and brought into contact with an organic solvent (C) to remove the Ti in the aqueous solution. The ions are extracted and the hydrochloric acid is regenerated and recycled to the treatment step (D). On the other hand, the Ti ions transferred to the organic solvent C are brought into contact with the aqueous solution F in the stripping process E.
It consists of a second step of stripping off Ti ions. Organic solvents containing amines in heavy metal extraction process BN
Heavy metals selectively extracted in CM are removed during the cleaning process.
By washing GM with water or an aqueous solution such as Na-containing liquid, NaHS, Na ₂ S, etc., the heavy metal ions are removed, and the organic CM is regenerated and recycled to the heavy metal extraction step BN. The amines used as extractants in the organic solvent CM are selected from the following: Primary amines: RNH ₂ (wherein R represents an alkyl group, generally an alkyl group having 4 to 18 carbon atoms) Secondary Amine: Represented by R ₂ N or R ₂ NH, where R is an alkyl group, generally an alkyl group having 4 to 18 carbon atoms) Tertiary amine: Represented by R ₃ N or R ₃ NH, (R in the formula represents an alkyl group, generally an alkyl group having 4 to 18 carbon atoms) Quaternary amine:

[Formula] (where × ^- is Cl ^- or another anion; R is an alkyl group, generally preferably an alkyl group having 4 to 18 carbon atoms) Also, the diluent used in the organic solvent CM Petroleum hydrocarbons are the same as those described for organic solvent C. Petroleum hydrocarbons are used as diluents in the process of the invention. Therefore, in addition to aliphatic hydrocarbons and aromatic hydrocarbons selected from Group A, mixtures thereof are naturally used, and mixtures of miscellaneous hydrocarbons such as kerosene are also used. The target mineral acid aqueous solution containing Ti ions is
In an aqueous solution containing HCl, H ₂ SO ₄ , HNO ₃ or HNO ₃ + HF, the valence of Ti ions is tetravalent, trivalent,
Both divalent ions are extraction target ions. The method of this invention will be explained below with reference to Examples. Extraction step B: Extract by bringing HCl, H ₂ SO ₄ , HNO ₃ and HNO ₃ + HF aqueous solution into contact with aqueous solution A containing Ti ions and organic solvent C containing 30% of alkyl phosphoric acid and alkyl dithiophosphoric acid extractants. I did a test.
The Ti concentration in the acid aqueous solution after extraction is shown below:

[Table] In the table: In organic solvent C: D ₂ EHPA...di-2-ethylhexyl phosphoric acid, DDPA...dodecyl phosphoric acid,
TBP...tributyl phosphate,
D ₂ EHPDTA... Di-2-ethylhexyldithiophosphoric acid diluent: Ti ion concentration of aqueous solution using 100% isoparaffin: 12.8 g / Extraction conditions: shaking time 10 minutes Organic layer / aqueous phase (O /A) = 1.0/1.0 volume ratio Temperature: 20 to 18℃ As can be seen from the extraction test results above, there is not much difference in the extraction ability of titanium for each type of alkyl phosphate, so below it will simply be referred to as alkyl phosphate. 30%
The alkyl phosphate residue is Ti by isoparaffin.
FIG. 5 shows the relationship between the contact time during extraction and the titanium extraction distribution ratio. In the figure -Γ- is an HCl aqueous solution, -Γ
- is H ₂ SO ₄ aqueous solution, -△- is HNO ₃ aqueous solution, -×
- is data when using HNO ₃ + HF aqueous solution. Figure 6 also shows HCl 180-200g/, organic solvent C
The figure shows an extraction equilibrium curve for Ti ³⁺ and Ti ⁴⁺ when a Ti-HCl aqueous solution and organic solvent C are brought into contact with each other for a contact time of 5 minutes using 30% alkyl phosphoric acid (the remainder is isoparaffin). Further, FIG. 7 shows the extractant (alkyl phosphoric acid) concentration and the extraction distribution ratio of Ti (Ti ⁴⁺ ). Peeling Step E A peeling experiment was conducted by bringing stripping solution F into contact with organic solvent C containing Ti ions in the organic phase. The peeling rate (%) of Ti peeled off in the stripping solution is shown in the table below. Experimental conditions: Volume ratio of organic phase/aqueous phase (O/A) = 1.0/1.0 Shaking time 10 minutes Temperature 20 to 18°C The extractant concentration in the organic solvent and the type of diluent are the same as extraction step B. It is. The peeling rate (%) is shown below:

[Table] Washing process G 30% D ₂ Organic solvent C, which extracted Fe ( ), Cu, Zn, and Cd ions in addition to Ti ions, was washed with the following stripping aqueous solution H into the organic phase of EHPA + 70% isoparaffin. The cleaning rate (%) in aqueous solution H after cleaning is shown in the table below.

[Table] The cleaning rate was calculated by subtracting the analytical value of the aqueous phase from that of the organic phase.
Extraction process Hg and Ti ions are added to BN 200g/HCl aqueous solution,
The following aqueous solution A (initial aqueous phase concentration solution) to which heavy metal ions such as Cd and Zz ions were added was synthesized, and a test was conducted to extract these metal ions as a chloride complex with an organic solvent CM. The concentration of Ti and other heavy metal ions remaining in the aqueous phase after extraction is shown in the table below.

【table】

[Table] Extraction conditions: T・HCl of aqueous solution A (total Hu) 240
g/O/A=1.0 Shaking time 5 minutes Temperature 18-20℃ Extractant used: Primary amine CH ₃ C (CH ₃ ) ₂ CH ₂ C (CH ₃ ) ₂ CH ₂ C
( _{CH3 ) 2CH2C ( CH3} ) _2CH2C ( _CH3 ) _{2NH2Secondary amine} Tertiary amine Quaternary amine Diluent using an alkyl group of R=C ₁₀ to _{C 18} : More than 99% aromatic hydrocarbon, Etsuo Oil Co., Ltd. trade name "Solbetsuso 150" Extractant concentration is 10% (volume) for each amine (residual diluent) was used. In addition, the following table shows the results of contacting an organic solvent containing a neutral phosphoric acid ester diluted with kerosene to an aqueous solution of 210 g of HCl containing Ti ions as well as Fe, Cd, Zn, Mo, and W ions:

[Table] The extraction equilibrium curves for each metal are shown in Tables 8 to 1.
Shown in Figure 0. FIG. 8 shows an extraction equilibrium curve when an aqueous HCl solution (HCl concentration 200 to 250 g/) containing Fe, Cd and Hg was extracted with 5% alkylamine (the remainder being "Solbetsuso 150"). In the figure -□- is Fe,
-△- indicates the extraction equilibrium curve of Cd and -Γ- indicates the extraction equilibrium curve of Hg. Figure 9 shows an aqueous HCl solution containing Pb, Sn and Zn ions (HCl concentration 200-250 g/
) to 10% alkylamine (the remainder is ``Sorbetso''
150" is shown, and in the figure -△
- indicates the extraction equilibrium curve of Zn, -□- indicates Sn, and -Γ- indicates the extraction equilibrium curve of Pb ion. Figure 10 shows an HCl aqueous solution containing Mo, Co, and Cu (HCl concentration 200 to 250).
The extraction equilibrium curve is shown when 10% alkylamine (remainder: Solbetuso 150) is extracted with 10% alkylamine. In the figure, -Γ- indicates the equilibrium curve of Mo, -△- indicates Co, and -□- indicates the equilibrium curve of Cu. Titanium recovery process T To stripping aqueous solution F (HF or NH ₄ HF ₂ containing liquid)
After transferring 38.4g/Ti ion, NH ₃ ,
After adding K ₂ CO ₃ and Na ₂ CO ₃ and cooling, Ti in the stripping aqueous solution F was analyzed to determine its residual amount.

[Table] The values in the table above indicate that after the reaction is complete, the stripping aqueous solution F is
This is the Ti concentration in the aqueous phase after cooling to ℃ and standing for 24 hours.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing a preferred embodiment of the first method of the present invention, FIG. 2 is a modified flow sheet of FIG. 1, and FIG. 3 is a flow sheet of a modified version of FIG. A flow sheet explaining the process is shown. FIG. 4 is a flow sheet showing the second method of the present invention. Figure 5 shows the relationship between contact time and extraction distribution ratio during titanium extraction, Figure 6 shows the extraction equilibrium curve for two types of titanium valences, and Figure 7 shows the relationship between alkyl phosphate concentration and titanium extraction distribution ratio. show. 8th
Figures 1 to 10 show extraction equilibrium curves for various metal ions.

Claims (1)

[Scope of Claims] 1. Ti ion-containing waste acid containing a small proportion of heavy metals or substantially no heavy metals is a group of alkyl phosphoric acids,
Ti ions in the waste acid aqueous solution are extracted into an organic solvent by contacting one or more extractants selected from the group of alkyl dithiophosphoric acids with an organic solvent obtained by diluting with petroleum hydrocarbon. The acid was recovered, and the resulting organic solvent was mixed with water, HCl, H ₂ SO ₄ ,
NH ₄ HCO ₃ , (NH ₄ ) 2 CO ₃ after selectively cleaning heavy metal ions by contacting with a cleaning solution selected from HNO ₃ and HNO ₃ +HF aqueous solution, or directly without contacting with said cleaning _solution . ，
(NH ₄ ) ₂ By contacting with a stripping aqueous solution containing one or more selected from the group of HF ₂ , NH ₄ F, HF and NH ₃ , Ti ions are stripped and the organic solvent is regenerated. A method for recovering acid characterized by the following. 2 Together with Ti ions, Hg, Cd, Pb, Sn, Zn,
A HCl solution containing one or more heavy metal ions selected from Fe, Co, Mo, W, Cr, and Cu is added to a group of primary amines to quaternary amines and a group of neutral phosphate esters. A first step of extracting heavy metal ions other than Ti ions in the solution as a chloride complex by bringing one or more selected extractants into contact with an organic solvent diluted with petroleum hydrocarbon; , 1 selected from the group of alkyl phosphoric acids and the group of alkyl dithiophosphoric acids to the solution after the first step.
A second step of extracting and removing Ti ions by bringing the seed or two or more extractants into contact with an organic solvent diluted with a petroleum-based hydrocarbon.