Hydrochloric Acid Leaching Research Articles

폐 ITO 슬러지로부터 주석과 인듐의 분리·회수

Abstract In order to separate Indium and Tin from spent indium tin oxide (ITO) sludge, direct hydrochloric acid leaching and thermalreduction followed by HCl leaching were applied. In case of direct leaching of spent ITO, leaching rate of In and Sn was 18.5% and19.95%, respectively. Whereas, in case of thermal hydrogen treatment of ITO sludge at different temperatures such as 700 o C,800 o C, 900 o C and 1100C, followed by HCl leaching, we obtained the result of more than 97% leaching rate of Sn. Specially,thermal treatment at 800 o C showed the highest leaching rate of 98.2% of Sn. Precipitation method was used for separation andrecovery of Sn from leached mixed solution. If the solution pH were adjusted 2.0, 99.69% of Sn precipitated and 10.3% of Inwas precipitated. This confirmed the possibility of separation of Sn and In from leached solution by precipitation method. Key words : Hydrochloric acid leaching, Hydrogrn reduction, ITO sludge, Tin Recovery * Received : February 17, 2014 · Revised : March 17, 2014 · Accepted : April 1, 2014Corresponding Author : Jae woo Ahn (E-mail : jwahn@daejin.ac.kr)Advanced Materials Science & Engineering, Daejin University, Hoguk-ro 1007, Pocheon-si, Gyeonggi-do, 487-711, KoreaTel : +82-31-539-1982 / Fax : +82-31-539-1980ⓒThe Korean Institute of Resources Recycling. All rights reserved. This is an open-access article distributed under the termsof the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permitsunrestricted non-commercial use, distribution and reproduction in any medium, provided the original work is properly cited.

Mixer-settler operation for the recovery of platinum, iron and hydrochloric acid from the leaching solution of spent petroleum reforming catalysts

Bench scale mixer-settler was employed to recover Pt, Fe and HCl from the hydrochloric acid leaching solution of spent catalysts. The number of stages and flow rate ratio of the aqueous to organic was estimated from the McCabe–Thiele plots for the extraction and stripping of the elements. In mixer-settler operation, Fe was first completely extracted by TBP and then the most of Pt was extracted by Aliquat336. Finally, HCl was recovered by extraction with TEHA and by stripping with water. From mixer-settler operation, most of the Pt and Fe were recovered and the recovery percentage of HCl was 95%.

Extraction of vanadium from chloride solution with high concentration of iron by solvent extraction using D2EHPA

Vanadium (IV) bearing chloride solution with the Fe (II)/V (IV) mass ratio of 60 was prepared to simulate the acidic liquor by hydrochloric acid leaching of reduced vanadium-bearing titanomagnetite. Extractant of bis (2-ethylhexyl) phosphoric acid (D2EHPA) was used to extract vanadium from the solution. Under the optimal extraction conditions of equilibrium H+ concentration of 0.27–0.42mol/L, D2EHPA concentration (v/v, diluted in n-heptane) of 10%, extraction temperature of 20–25°C, equilibrium time of 60min, phase ratio (O/A) of 1:1, more than 99% of vanadium can be extracted. Loaded organic phase were stripped by dilute H2SO4 solution under the optimal stripping conditions of H2SO4 concentration of 20wt.%, phase ratio (O/A) of 10:1, stripping time of 120min, and 98% of vanadium can be stripped. The concentrations of V and Fe in the stripping solution were 13.0g/L and 3.9g/L, respectively. V2O5 products with purity of 99.2% were obtained after oxidation, precipitation and calcination. The overall separation coefficient of V and Fe was 200. Experimental results indicated that V (IV) can be also separated from other metal ions such as Mg (II), Ni (II), Zn (II), Ca (II), Al (III) and Cu (II) in the chloride solution. A flow sheet on the recovery of vanadium from vanadium-bearing chloride solution containing high concentration of iron was proposed.

폐촉매(廢觸媒) 염산침출액(鹽酸浸出液)에서 컬럼형 추출기(抽出器)에 의한 백금(白金) 회수(回收)

Abstract In order to recover Pt from the hydrochloric acid leaching solution of spent catalysts, bench scale Karr reciprocating columnwas employed. At an optimum flow rate and vibration frequency, iron and Pt was completely extracted by using TBP and Aliquat336. At the same vibration frequency, iron and Pt was completely stripped by HCl and HClO 4 after adjusting the flow rate. Inthe case of extraction of HCl from the raffinate with TEHA, it was difficult to maintain the stability of the column extractor.A comparison of the operation results between column extractor and mixer-settler is reported. Key words : Pt, Fe, HCl, Karr reciprocating column 1. Introduction Spent catalysts are valuable secondary resourcesfor the platinum group metals (PGMs). Much workhas been done on the recovery of PGMs from spentcatalysts by hydrometallurgical method. First, PGMsare dissolved by chloride based solution and thenare separated by employing solvent extraction or * Received : July 9, 2013·Revised : August 7, 2013·Accepted : August 21, 2013Corresponding Author : Man-Seung Lee (E-mail : mslee@mokpo.ac.kr)Department of Advanced Materials Science & Engineering, Mokpo National University, 61 Dorim-ri, Chungkye-myun, Muan-gun, Chonnam, 534-729, KoreaTel : +82-62-450-2492 / Fax : +82-62-450-2498ⓒThe Korean Institute of Resources Recycling. All rights reserved. This is an open-access article distributed under the termsof the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permitsunrestricted non-commercial use, distribution and reproduction in any medium, provided the original work is properly cited.

Production of Rutile TiO2 Pigment from Titanium Slag Obtained by Hydrochloric Acid Leaching of Vanadium-Bearing Titanomagnetite

An alternative route was proposed for preparing rutile titanium dioxide (TiO2) white pigment. The process involves the digestion of titanium slag with sulfuric acid, subsequent hydrolysis of unenriched titanyl sulfate solution with ammonia, low-temperature calcination, and unseeded crystallization, producing a high-quality rutile TiO2 white pigment. The experimental data indicated that the conversion ratio of dissolved Ti in the unenriched titanyl sulfate solution was highly dependent on the NH3/TiO2 molar ratio. Under the optimal conditions, approximately 92.0% of dissolved Ti in the solution could be converted to metatitanic acid (H2TiO3) that was then calcined at 850 °C to form rutile TiO2 pigment with purity of 98.41% and mean particle diameter of 0.1–0.3 μm. The presence of NH4+ during the hydrolysis improved the stability of the charged H2TiO3 particles and blocked further coagulation. The fast phase transformation at relatively low temperature could be attributed to the presence of self-generated rutile nuclei. In addition, the experimental validation for the unseeded precipitation of ferrous ammonia sulfate ((NH4)2Fe(SO4)2·6H2O) in the crystallization step was demonstrated.

Chloride–hypochlorite leaching and hydrochloric acid washing in multi-stages for extraction of gold from a refractory concentrate

In this research, chloride–hypochlorite leaching of gold from a highly refractory pyritic concentrate was conducted and effects of stirring speed, temperature and particle size on the leaching rate were investigated. Results showed that the particle size had a significant positive effect on the gold recovery. In this system, iron hydroxide layer formed on the pyrite particles, decreasing the gold recovery. Removing this layer by hydrochloric acid and further leaching by chloride–hypochlorite increased the gold recovery. About 96% of gold was extracted from the concentrate after three stages of chloride–hypochlorite leaching/hydrochloric acid washing.

Influence of phase and microstructure on the rate of hydrochloric acid leaching in pretreated Panzhihua ilmenite

The present study investigated the influence of high temperature oxidation and reduction pretreatments on the leaching rate of Panzhihua ilmenite. The as-pretreated ilmenite was leached with 20% HCl at 105°C. The leaching process was controlled by the phases and microstructures that evolved during the pretreatment processes. The leaching kinetics of pure hematite, ilmenite and pseudobrookite were characterized to clarify the phase effect on the iron-leaching rate; the rate of iron leaching occurs in the following order in the HCl solution: hematite (ferric iron)>ilmenite (ferrous iron)≫pseudobrookite (ferric iron). Therefore, the often-cited notion that ferrous iron dissolves faster in HCl solutions than ferric iron when explaining the pretreatment effects is inaccurate. Moreover, the oxidation pretreatment (at 600–1000°C for 4h) cannot destroy the dense structure of the Panzhihua ilmenite. Therefore, the influence exerted by the oxidation on the leaching process is primarily determined by the phase change; oxidation at 600 and 700°C slightly increased the rate of iron leaching because the ilmenite was transformed into hematite, while the oxidation at 900–1000°C significantly reduced the rate of iron leaching because a pseudobrookite phase formed. The reduction effect was subsequently investigated; the as-oxidized ilmenite was reduced under H2 at 750°C for 30min. The reduction significantly accelerated the rate of subsequent iron leaching such that nearly all of the iron had dissolved after leaching for 2h in 20% HCl at 105°C. This enhanced iron-leaching rate is mainly attributed to the cracks and holes that formed during the reduction process.

Preparation of high-value TiO2 nanowires by leaching of hydrolyzed titania residue from natural ilmenite

In this work, a simple and efficient process is developed to synthesize high-value TiO2 nanowires from natural ilmenite, combining acid and alkali leaching together. Valuable Fe and Ti were selectively divided from ilmenite by hydrochloric acid leaching, and then the obtained hydrolyzed titania residue with mainly precipitated hydrated TiO2 was leached by sodium hydroxide and hydrogen peroxide. Ti and Si were monitored by ICP and EDS during the process. The effects of NaOH to-hydrolyzed titania residue (Na+/Ti4+) molar ratio, H2O2 to-hydrolyzed titania residue (O22−/Ti4+) molar ratio, leaching temperature and leaching time on leaching of hydrolyzed titania residue were investigated. Results indicated that the recovery of Ti was 96.39% and dissolution of Si was 67.9% under the optimal conditions: Na+/Ti4+ molar ratio of 8/1, O22−/Ti4+ molar ratio of 6/1, leaching temperature of 30°C and leaching time of 30min. And then simple boiling divided the Ti and Si very efficiently resulting in high-purity of synthetic TiO2 within 0.47% of SiO2. Meanwhile, the high-value TiO2 exhibited echinus-like structure with aggregations of nanowires and well-crystallized anatase phase at 400°C.

Study of Extraction of Total Alkaloids from Caulophyllum Robustum

Objective: Optimizing the extraction of total alkaloids from Caulophyllum robustum. Methods: The taspine which is a type of alkaloids of Caulophyllum robustum is selected as the target index. First, developing the HPLC analysis protocol; second, using orthogonal design method to optimize the hydrochloric acid leaching protocol; third, using cation exchange column to isolate the alkaloids and examining the optimal conditions. Results: the optimal conditions of hydrochloric acid leaching protocol is using 7 column volume of 1% hydrochloric acid for 3 times. The materials are loaded onto the LSD001 cation exchange column with optimal pH 4 and flowrate 2ml/mL, the elution buffer is 10 column volume 5% hydrochloric acid. After desalting, the yield of alkaloids is 1.35% which includes 6.83% of taspine.

Metal Impurities Removal from Metallurgical Grade Silicon by Hydrochloric Acid Leaching

As a pre-treatment process for producing solar-grade silicon, hydrometallurgical method could remove the most of metallic impurities of metallurgical-grade silicon, which is a hopeful technology to provide solar energy material independence of the Siemens skill. Factors such as the hydrochloric mass fraction, temperature, reaction time, and particle size of silicon powders were investigated in the impurities removal experiments under the condition of mechanical stirring. The leached samples were analyzed by ICP and SEM. The optimum parameters, hydrochloric mass fraction 5%, temperature 80°C, reaction time 9h, particle size 75μm, were determined by single factor experiments and orthogonal experiments. The 86.1% of Fe, 68.1% of Al, 85.9% of Ca and 25.9% of B impurity was removed from metallurgical-grade silicon powder.

Studies of Selective Removal of Iron (III) from the Simulated Bauxite Hydrochloric Acid Leaching Liquor by Solvent Extraction

Solvent extraction technique was performed to optimize the conditions for maximum removal of iron (III) from the simulated bauxite hydrochloric acid leaching liquor of FeCl3+AlCl3+CaCl2+HCl. Some factors influencing the extraction, such as the extractant and concentration of Fe, Al, and Ca were investigated. The results indicated that the N235 is an effective extractant for selective extraction of iron (III) from chloride liquor. The concentration of Fe in raffinate is under 0.0165 gL-1 and the losing of Al is 0.50 % by N235.

Preparation of micro and nanostructured titania compounds from ilmenite concentrates

Preparation of titania compounds by double-reductive hydrochloric acid leaching of ilmenite concentrate is reported. A rod-shaped nanostructure titania compound was obtained via centrifugation of leach liquors as a by-product. The liquors of leaching experiments were subjected to zetasizer test. The suspended particles in leach liquors were investigated using SEM and TEM analysis. The results revealed that the rod-shaped particles were smaller than 100nm in width. The XRD analysis verified the formation of rutile and pseudorutile phases as main phases. Regarding to the XRF analysis, The TiO2 content of ilmenite increased from 33% in ilmenite concentrate to about 80% in the products containing some constituents such as Fe2O3, SiO2 and Al2O3.

Influence of Impurities on Crystallization Kinetics of Calcium Sulfate Dihydrate and Hemihydrate in Strong HCl-CaCl2 Solutions

The effects of inorganic impurities on the crystallization of calcium sulfates in strong HCl (6.3 mol L–1)-CaCl2 (1.8 mol L–1) solutions were investigated. The impurities considered relate to hydrochloric acid leaching of apatite-type ores for the extraction of rare earth elements. The impurities investigated were K+, Mg2+, Sr2+, Ba2+, Al3+, Fe2+, Fe3+, La3+, Y3+, F– (fluoride), and PO43– (phosphate). The investigation was done in the context of a continuous steady-state crystallization process. Therefore, temperature-controlled, semibatch crystal growth experiments with regulated reagent addition, to ensure nearly constant supersaturation, were performed. The experiments were conducted at 40 and 80 °C corresponding, respectively, to crystallization of calcium sulfate dihydrate (DH) and calcium sulfate hemihydrate (HH). Among all impurities investigated, phosphate and strontium were found to have the most significant effects, with La3+ and Y3+ having some modest effects. Phosphate (added as phosphoric aci...

Preparation of synthetic rutile from pre-treated ilmenite/Ti-rich slag with phenol and resorcinol leaching solutions

The effect of phenol and resorcinol on hydrochloric acid leaching of Ti-rich slag is investigated. The leaching rate is exponentially proportional to acid and phenol concentrations. Any metal–phenol complexes decomposed by chloride ions should considerably increase the leaching rate by playing a role of active transport. Furthermore, phenols are expected to have a synergistic effect on the hydrochloric acid leaching of metal oxides. The additives such as methyl alcohol, ethyl alcohol and ethylene glycol improve the leaching efficiency in a chloride medium. It is observed that resorcinol with ethylene glycol acts as a better additive in the leaching of Ti-rich slag. The results will have significant impact on the production of upgraded feed stock (Synthetic Rutile) from Ti-rich slag.

Electrolytic Recovery of Tin from Waste Lead Frames: Use of Aqueous HCl Leaching Solution as Electrolyte

Abstract Lead frames are generated in large quantities by modern semiconductor packaging industry and they contain significant concentrations of valuable tin, nickel, and copper. For electrowinning of tin from waste lead frames, hydrochloric acid leaching of tin is quite advantageous, but solution stability, electrolytic efficiency and deposit morphology should be optimized before commercialization. HCl electrolyte was diluted (distilled water: HCl = 350:150) for electrowinning of waste lead frames at 40 °C with 0.2 A/cm2 and Ti-Ir cathode. After 4 h electrowinning, 99% pure Sn with 99.1% recovery rate was produced. Therefore, aqueous HCl electrolyte was quite effective for electrowinning of Sn leaching solution, and a higher recovery rate of purer Sn within shorter electrowinning time was obtained.

Thermodynamics study on leaching process of gibbsitic bauxite by hydrochloric acid

For the low-grade gibbsitic bauxite, the leaching rate of alumina is very low during the Bayer process. The acid leaching method is attracting more attention, and the hydrochloric acid leaching was developed rapidly. The mineral composition and chemical composition were investigated by X-ray diffraction analysis and semi-quantitative analysis. The thermodynamics of leaching process was analyzed. The results show that the major minerals in the bauxite are gibbsite, secondly goethite and quartz, anatase and so on. The acid leaching reactions of the bauxite would be thermodynamically easy and completed. Under the conditions that ore granularity is less than −55 μm, the L/S ratio is 100:7, and the leaching temperature is 373–383 K, the leaching time is 120 min and the concentration of HCl is 10%, both the leaching rates of Al and Fe are over 95%. The main composition of leaching slag is SiO2 which is easy for comprehensive utilization.

Separation of nickel(II), cobalt(II) and lanthanides from spent Ni-MH batteries by hydrochloric acid leaching, solvent extraction and precipitation

The separation of nickel(II), cobalt(II) and lanthanides from chloride leach liquors of spent nickel-metal hydride (Ni-MH) batteries is described. After leaching in 12molL−1 HCl, the traces of iron(III) and zinc(II) were extracted in a single stage with pure TBP (25°C, A/O ratio=1v/v). Cobalt was extracted (93.6%) in two stages with Alamine 336 (10% vol. in kerosene, 25°C, A/O=1v/v, free acidity=4.3molL−1). More than 98% of the lanthanides present in the raffinate were recovered through one of the following routes: (i) extraction with PC88A (20vol.% in kerosene, 25°C, A/O=1v/v, one stage, pH 1); (ii) precipitation as oxalates at pH 0.5. Nickel(II) was precipitated (>99%) as oxalate at pH 2. Metals separation in acidic medium avoids partial or total neutralization of the leachate and reduces the amount (and salinity) of the wastewater generated in the separation processes.

Controllable Interfacial Mass Transfer Intensification for Multi-liquid Phase Extraction of Platinum, Palladium and Rhodium from Wasted Auto-Catalysts

The main purpose of present review article is to summarize our previous efforts to develop a new three-liquid-phase extraction strategy for recovery and recycling of platinum, palladium and rhodium from the hydrochloric acid leach solutions of various wasted auto-catalysts. It was found that Pt, Pd and Rh can be separated and selectively enriched into the three different liquid phases of the proposed three-liquid-phase system (TLPS), respectively. The partitioning behaviors of Pt(IV), Pd(II), Rh(III) are controllable and have a close correlation with the phase-forming behaviours of TLPS. A microphase mass transfer mechanism was proposed to explain the differences in partitioning behaviours of three platinum metal ions. The self-assembly of amphiphlic extractant molecules in aqueous solutions result in the controllable enrichment of target metal ions by those separated microphase aggregates. The differences in interfacial mass transfer of three metals are due to a controllable microscopic interaction of platinum metal ions with the microphase aggregates. The TLPS provide a unique separation medium to control the interphase mass transfer of different metal ions. The separation selectivity of the three platinum metals was improved remarkably by using the three-liquid-phase extraction technique in comparison with the traditional liquid–liquid two phase extractions. The present researches highlight a potential possibility for future industrial application of the multiphase extraction for one-step separation of different target metals from complex mixtures.

A kinetic study on hydrochloric acid leaching of nickel from Ni–Al2O3 spent catalyst

Hydrochloric acid leaching of nickel from spent Ni–Al2O3 catalyst (12.7% Ni, 39.2% Al and 0.68% Fe) has been investigated at a range of conditions by varying particle size (50–180μm), acid concentration (0.025–2M), pulp density (0.2–0.4%, w/v) and temperature (293–353K). Nickel was selectively leached from the catalyst, irrespective of the different conditions. Under the most suitable conditions (1M HCl, 323K, stirring at 500rpm, 50–71μm particle size), the extent of leaching of Ni and Al after 2h was 99.9% and 1%, respectively. The XRD pattern of the spent catalyst corresponded to crystalline α-Al2O3 along with elemental Ni. The peak due to elemental Ni was absent in the residue sample produced at the optimum leaching conditions, confirming the complete dissolution of Ni from the spent catalyst. The leaching results were well fitted with the shrinking core model with apparent activation energy of 17kJ/mol in the temperature range of 293–353K indicating a diffusion controlled reaction.

Physicochemical factors affecting leaching of laterite ore in hydrochloric acid

The effect of physicochemical factors on laterite ore leaching in hydrochloric acid was investigated in this study. The results showed that the valuable metals such as nickel and cobalt could be extracted effectively at the leaching conditions as follows: acid concentration was 8mol/L, the particle size of samples were 100% passing 0.15mm, the stirring speed was 300rpm, leaching temperature was 353K, S/L ratio was 1:4 and leaching duration was 2h. The extraction of nickel and iron presented a linear correlation, which demonstrated nickel associated in iron ore, and cobalt dissolution was not consistent with iron dissolution which indicated that the distribution of cobalt were not uniform in the iron oxide crystals and existed in other minerals, and this result had also been demonstrated by mineralogical studies. To investigate the stability of different minerals in the leaching condition listed above as well as the influence of nickel and cobalt on their dissolution in such condition, the minerals dissolution order was studied by X-ray diffraction (XRD) according to determination of the leaching residues and chemical composition of the leaching solution, and the result order was goethite>lizardite>magnetite>hematite.