Pickle Liquor Research Articles

Effective degradation of tetracycline by magnetic palygorskite synthesized with different dosages of NaOH.

In the process of preparing magnetic palygorskite from waste pickling liquor of the steel industry, the dosage of NaOH will affect the properties of the magnetic palygorskite. The experimental results showed that magnetic palygorskite can be effectively prepared when NaOH dosage is between 255 and 330 g/L. Vibration sample magnetometry proved that different NaOH dosages can affect the saturation magnetization of magnetic palygorskite. The catalytic performance of five catalysts synthesized with different NaOH dosages hardly changed after five cycles of Fenton-like catalytic degradation of tetracycline (TC). The magnetic palygorskite prepared by this method had good catalytic performance even when the catalyst preparation conditions were magnified ten times, which can provide a reference for large-scale preparation of magnetic palygorskite.

An investigation on optimum grinding system and conditions for steel plant ARP by-product α-Fe2O3 for pigment industry

After some other processes, α-Fe2O3 red powder particles -by-product of regeneration of spent pickling liquor in ARP in iron and steel industry- should be ground up to pigment grade to convert it to a value added product, red iron oxide pigment. In this study, grinding tests on α-Fe2O3 red powder were performed using four different types of laboratory-scale mills, namely the vibrating cup mill, vertical ball mill, planetary ball mill, and fluidized bed jet mill. The particle structure of the α-Fe2O3 was investigated by SEM, while its chemical composition was determined by ICP-OES, density, LOI, humidity, Cl content etc. were determined by laboratory tests. Particle size distribution and surface area value of each ground sample was determined using the laser diffraction method. Targeted particle size distribution ranges could only be achieved with the jet mill. Other mills encountered caking and adhesion problem with α- Fe2O3. It was assessed that the adhesion to the inner walls of the grinding chamber and the caking effect were both caused by the humidity content of the material. The grinding yield of the material was found to increase with increased jet mill grinding air pressure (0.8, 3.2 and 7 bars).

Experimental and theoretical study on the behaviour of a pickling solution: The role of ferrous ions

Abstract The existence of ferrous ions plays an important role in the performance of pickling liquor as well as the recovery of hydrochloric acid from waste pickling liquor. The promotion mechanism and the interaction between ferrous ions and hydrogen chloride molecules have remained largely unsolved. In this research, the fundamental aspects of a simulated hydrochloric acid pickling solution with different concentrations of ferrous ions were experimentally and theoretically studied. The experimental results showed that the existence of ferrous ions in the pickling liquor effectively inhibited the volatilisation of hydrogen chloride from solution and that the inhibition of volatilisation enhanced with an increase in concentration of ferrous ions. To understand the interaction between ferrous ions and hydrogen chloride molecules, the structure and thermodynamic properties of possible hydration structures were obtained by using molecular simulation. The results showed that a new type of cluster, hydrogen chloride-ferrous ion-water, was formed in the presence of ferrous ions, which made the hydrogen chloride molecules in the pickling liquor more stable compared to the same condition without ferrous ions. The existence of ferrous ions in pickling liquor benefits the pickling process from an economic and environmental aspect.

Pyrometallurgical recycling of stainless steel pickling sludge: a review

Stainless steel pickling sludge (SSPS), generated from the lime neutralization process of spent pickling liquor, is classified as a hazardous waste consisting of abundant metals like Fe, Cr and Ni, and other elements like F, S and Na, etc. Rather than a common disposal in landfill, recovering these metals and other valuable components from SSPS can not only create economic benefits, but also eliminate its adverse impacts on human health and the environment. A review of the formation mechanism and basic properties of SSPS was made, and the technical features, advantages and limitations of a series of pyrometallurgical treatment processes were summarized. Based on these, the main challenges for recycling of SSPS through the existing techniques are demonstrated. The traditional pelletizing/sintering-blast furnace process can only be used as a partial solution. Direct use of SSPS as flux in an argon–oxygen decarburization converter or electric arc furnace is a promising way, but low S sludges are preferred. The STAR process shows excellent recovery for metals, but it also has a low tolerance to the S and F contents in SSPS. And the INMETCO process is highly flexible in treatment of various wastes, whereas it exhibits relatively low Cr recovery and produces poor-quality pig iron. In addition, the feasibility of the rotary kiln-electric furnace, solid-state reduction of chromite and reduction-magnetic separation processes requires further studies. An urgent task at present is to develop a system for scientific classification and separate collection of SSPS in terms of chemical composition, notably S and F contents.

Recycling of Electroplating Wastes without Formation of Galvanic Sludges

The reasons and eco-economic consequences of galvanic sludge accumulation in environment have been considered. The economic futility of recycling of galvanic sludges has been shown. It has been established that recycling of chrome-containing wastes together with waste pickle liquors of steel-rolling mills enables to fully regenerate all components of the above wastes without sludge formation. The chemical processes for regenerative recycling of spent alkaline copper solutions of all kinds have been described. Deacidification of some acid electroplating wastes permits to extract oxides of nonferrous and heavy metals. Employment of the developed technologies in common will allow recycling all kinds of electroplating wastes and electrolytes without formation of sludges. Such a complex approach has some undisputable ecologic and economic advantages.

SYNTHESIS OF MAGNETIC NANOPARTICLES FROM SPENT PICKING LIQUORS IN AQUEOUS SATURATED SOLUTION OF CALCIUM HYDROXIDE

Spent pickling liquor is a considered hazardous waste because of its very high level of acidity and high metal concentration, and the conventional neutralization method regenerates an excessive quantity of sludge that poses a serious problem concerning to the landfill disposal and risk of ground water contamination. Therefore, recovery of spent pickling liquor is necessary. Several approaches have been investigated for spent pickling liquor recovery, but they are generally costly and lead to produce various iron salts or oxides which have a limited value. In the present study, we explore the potential of using spent pickling liquor as iron precursor for the synthesis of magnetic nanoparticles. Here, Fe3O4 nanoparticles were prepared easily by oxidation-precipitation from spent hydrochloride acid pickling liquors in aqueous saturated solution of calcium hydroxide at room temperature, in the air, and under suitable speed of rotation. The FT-IR, XRD and TEM results shown that monodisperse Fe3O4 nanoparticles in the size range of 10-25 nm were obtained, with a high level of crystallinity. The BET surface area was about 46 m2 g-1. The synthesized Fe3O4 nanoparticles exhibited the superparamagnetic behavior with relatively high saturation magnetization, Ms = 73 emu/g. The synthesis procedure of magnetic nanoparticles revealed here will provide a new possibility for spent pickling liquors recovery more effectively.
 For citation:
 Vu Minh X., Le Ha T. T., Pham Lan T., Pham Nam H., Le Huong T. M., Le Lu T. Nguyen Dung T. Synthesis of magnetic nanoparticles from spent picking liquors in aqueous saturated solution of calcium hydroxide. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 9-10. P. 59-63

Fabrication of magnetic activated carbons from corn cobs using the pickle liquor from the surface treatment of iron and steel

Corn cobs were impregnated with the pickle liquor from the surface treatment of iron and steel at ambient temperature for 24 h, dried at 393 K for 12 h and carbonized at 573, 773 and 973 K for 1 h to obtain magnetic activated carbons (MACs). The adsorption of methyl orange (MO) onto the MACs was investigated under different conditions. Results show that the surface area of the MACs increases with carbonization temperature from 423.5 to 784.8 m2 g−1. The MACs consist of hematite (Fe2O3) and magnetite (Fe3O4). The MAC obtained at 973 K has the highest MO monolayer adsorption capacity of 555.56 mg g−1 at 298 K in a water sample containing MO dye. The adsorption is endothermic and obeys pseudo-first-order kinetics. The MACs can be easily separated from the dye water by an external magnet.

Treatment of paper mill wastewater using a composite inorganic coagulant prepared from steel mill waste pickling liquor

In this study, a waste pickling liquor from a steel mill, which is rich in iron and acid, was used as the main raw material to prepare a composite coagulant: polymeric ferric aluminum sulfate chloride (PFASC). The as-prepared PFASC was used, together with PAM, for the tertiary treatment of papermaking wastewater to decrease its COD and Chroma. The Results from FT-IR and XRD of PFASC, supported the conclusion that polymeric ferric aluminum hydroxide hydrates compounds/ complexes are formed in the synthesized PFASC. When applied to a waste water sample from a paper mill, PFASC, together PAM, leads to decreases in COD and Chroma by 65.3% and 71.2%, respectively (initial pH 7.5, 1 ml/L PFASC, 1.0 ppm PAM). The technology has been implemented at a paper mill, and the obtained results are consistent with those from the laboratory.

Electroplating wastes

AbstractElectroplating and other metal finishing industries, like every metal and metallurgical industry, are associated with the generation of waste. Spent electroplating baths, waste pickle liquors, etching solutions and rinse waters from electroplating units and steel finishing operations are complex solutions containing acids and several hazardous metals. It is compulsory, for environmental and economic reasons, to treat these solutions for recovering acid, metals and/or reusing these solutions/waters. This article is a review on the characterization of the wastes that are generated in electroplating industry, steel processing and copper etching in printed circuit boards manufacture, as well as on the treatment and regeneration methods of such streams. Various techniques, such as neutralization, crystallization, evaporation, pyrohydrolysis, electrodialysis, ion exchange, classical solvent extraction and membrane-based solvent extraction are presented, their advantages and disadvantages being scrutinized.

Electrochemical Removal of Copper from Regenerated Pickling Solutions of Steel Plants

The spent pickle liquor contains the dissolved metal salts of iron, chrome, copper, nickel and zinc [1]. The acid can be cleaned from its impurities, except for its copper ion, by the regeneration process. When the copper concentration of the pickling solution exceeds the level of about 100 ppm, the copper inside the solution replaces the iron in the steel and copper starts plating randomly on the metal surface in the following pickling processes. Because of the plating problem, the acid needs to be discard from the acid line. By adding fresh acid to the line the discarding can be delayed [2]. An electrochemical procedure was conducted to overcome the cementation problem experimentally in an environmental and economical way. Electrowinning of dilute copper from strong acid solution is a challenge in this case so the optimum current density, electrolysis duration and the electrode materials were determined in this study. It was found that increase in the current density and electrolysis duration increases the copper removal, but changes the morphology of deposits. A slower compact deposition procedure was selected to achieve continuous removal of copper instead of faster discontinuous powder deposition from the regenerated pickling solutions of steel plants.

Raw materials recovery from spent hydrochloric acid-based galvanizing wastewater

The composition of spent hydrochloric acid-based pickling liquors, deriving from the galvanizing industry, greatly depends on how long the bath has been used for pickling. We considered solutions containing 40–50 g L−1 of iron and zinc (as FeCl2 and ZnCl2) and 130–220 g L−1 of chloride, and used tri-butyl phosphate (TBP) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) in kerosene as extraction solutions. From the spent liquors, zinc was selectively extracted and then recovered from the organic phase by using water or dilute hydrochloric acid. By using the kinetic results obtained for TBP and D2EHPA, recovery selectivity of zinc over iron (αZn/Fe) was estimated to be of 16.7 and 0.5, respectively. According to the McCabe & Thiele diagram for an organic to aqueous ratio of 2, three stages of extraction are sufficient to remove about 98% of the zinc from a real solution. The remaining solution of FeCl2 can be used to recover HCl and FeSO4 through the so-called “sulphuric acid distillation”. Finally, the recovered HCl can be used as a raw material, together with limestone, to produce CaCl2. Overall, an integrated process to recover the above-mentioned raw materials (Zn salts, FeSO4·7H2O and CaCl2) is presented: all products have been obtained in a ready-to-sell form, minimizing the waste according to the strategies of the “circular economy” and the “near-zero discharge” of hazardous chemicals.

Evaluation of time-gated Raman spectroscopy for the determination of nitric, sulfuric and hydrofluoric acid concentrations in pickle liquor

The focus of this study was to assess the feasibility of time-gated Raman spectroscopy for stainless steel pickle liquor acid quantification. Pickle liquor is used for dissolving metal surface impurities during the pickling process. The pickle liquor samples consisted mainly of 11–89g/L HNO3, 20–160g/L H2SO4, 5–57g/L HF and stainless steel residue. Raman peaks correlating with the different acids were identified in both aqueous and pickle liquor solutions. The linearity between Raman scattering intensity and acid concentration was studied. Multivariate PLSR calibration for pickle liquor HNO3, H2SO4 and HF quantification was also investigated. Time-gated Raman spectroscopy was found to be a promising technique for pickle liquor HNO3 and H2SO4 quantification.

Processing of spent pickling liquor formed during treatment of titanium products

The article presents the research findings on processing of spent acid pickling liquor (SAPL) formed during etching of titanium products. The processing includes neutralizing the SAPL with alkali, filtering, drying and calcining the titanium hydroxide precipitate as well as electrochemical processing of the filtrate in an ion-exchange membrane cell. The proposed SAPL processing procedure allows obtaining titanium dioxide, sodium hydroxide and a mixture of acids. Titanium dioxide can be used in paint-and-varnish industry. The alkali can be used in neutralizing the SAPL. A mixture of acids is suitable for use in etching process of titanium products.

Selective separation of copper and zinc from spent chloride brass pickle liquors using solvent extraction and metal recovery by precipitation-stripping

Copper and zinc were recovered from spent chloride brass pickle liquor using solvent extraction and precipitation-stripping. Speciation diagrams reveal that bivalent copper and zinc and their monovalent chlorocomplexes were present in the liquor. Copper was extracted by hydroxyoxime LIX84IC in kerosene while zinc was extracted using D2EHPA. 98.8% copper was extracted at an equilibrium pH of 2.5 using 30% v/v LIX 84IC whereas 98.3% zinc was extracted at an equilibrium pH of 2 using 15% v/v D2EHPA. Precipitation-stripping of loaded organic phase using oxalic acid resulted in recovery of copper and zinc as water insoluble oxalates. Solubility plots developed on theoretical considerations for copper-oxalic acid and zinc-oxalic acid system predicted the yield of precipitates in close agreement with experimental values. 97.3% of both copper and zinc present in the pickle liquor were recovered as their oxalates. The organic phase could be used for multiple cycles. Calcinations of the oxalates to their oxides did not induce any change in the ordered structure observed in oxalates. Morphology of the precipitates revealed highly agglomerated particles. Copper oxide 100% pure and zinc oxide with 99.1% purity were obtained as value added products. A process flow diagram of the proposed scheme is presented that could be implemented to generate wealth from waste.

Toxicity assessment of pickling liquors containing TiF₃, HF and HCl before and after neutralization using a phytotesting method

The paper evaluates the toxicity of spent acid pickling liquor (SAPL) formed in the production of titanium products during its etching with a mixture of hydrofluoric and hydrochloric acids. The SAPL contained TiF₃, HF and HCl in the amounts of 21,9 g/l, 1,7 g/l and 6,2 g/l, respectively. To determine the toxicity of SAPL, a phytotesting method was used. As a phytoecological indicator, cress of Zabava variety was used. The experiment was carried out according to the procedure for determining the toxicity of drinking, ground, surface and sewage water; the toxicity of chemical solutions by measuring the germination index, average length and average dry weight of seed germs of cress (Lepidium sativum). The toxicity of the SAPL was determined before and after neutralizing with alkali. It has been shown that SAPL has an acute toxic effect both before and after its neutralization by alkali. To determine a safe dilution rate, the influence of SAPL dilution on seed germination, average length and average dry weight of the seedlings was studied. It was found that the seedlings average length-dilution rate equations most reliably describe the experimental findings. The safe dilution rate calculated from these relations is 669,2 for non-neutralized SAPL and 382,5 for alkaline neutralized SAPL.

산세수와 게껍질을 이용한 신기능성 철분 비료의 상추 생육 촉진 효과

작물 재배에서 빈번히 발생되는 철분 부족 현상은 식물의 생육 저하와 생산성 감소를 야기한다. 철분의 흡수는 철분 킬레이트제를 이용해서 높일 수 있다. 본 연구에서는 제철산업의 부산물인 산세수 유래의 2가 철 이온을 게껍질(CSP)에 킬레이트시킨 신기능성 철분 비료(FCSP)를 제작하고, 상추 재배에 적용하여 생육 촉진 효과를 분석하였다. 제조한 철 비료의 효과를 검증하기 위해, 연구실 내 소규모 시험에서 무처리구, 게껍질 처리구, 그리고 여러 농도의 Fe-게껍질 킬레이트 처리구에서 상추의 생장을 분석한 결과, 50 ppm Fe-게껍질 킬레이트 처리구에서 엽수, 엽중, 엽장 및 엽폭이 무처리구와 게껍질 처리구에 비해 증가하였으며, 상추 잎의 엽록소의 함량 또한 증가하였다. 포장 시험 역시 50 ppm Fe-게껍질 킬레이트 처리구에서 엽수, 엽중, 엽장 및 엽폭에서 화학비료와 퇴비를 혼합한 기존 재배 방식 처리구에 비해 최대 2배 이상의 증가를 보였고, 식물체내 Fe의 함량 또한 가장 높게 나타났다. 또한 철 이온을 게껍질에 킬레이트한 비료의 처리가 토양 내의 Fe와 Ca의 함량을 증가시켰으며 유효인산과 유기물의 함량 또한 증가시켜 토질을 개선시키는 효과를 보였다. 이러한 결과들을 종합할 때, Fe-게껍질 킬레이트 복합체는 기존의 비료 처리 방식인 화학비료와 퇴비 사용 보다 뛰어난 생육 증대 효과와 토질 개선 효과를 나타냄으로써 작물 재배에 있어서 효과적인 신기능성 철분 소재로서 활용 가치가 있을 것으로 사료된다. Iron (Fe) is an important micronutrient for the health and growth of plants. Iron is usually provided by fertilizers, and iron-chelate fertilizers are well absorbed by plants. This study presents the plant growth-promoting effects of a new functional iron fertilizer, Fe-chelating crab shell powder (FCSP), which is generated from the chelation of Fe ions with crab shell powder. Iron chelate was derived from spent pickling liquor, which is rich in reductive iron, iron(II) oxide. To analyze the effects of FCSP on plant growth, we treated lettuce with several concentrations of FCSP in both lab- and field-scale experiments. In the lab-scale test, the treatment of 50 ppm of FCSP highly promoted growth and resulted in increases in the size, weight, number and chlorophylls content of leaves of plants compared to the treatment of crab shell powder. Fifty ppm of FCSP also increased the size and weight of leaves up to 2 times compared to the application of chemical fertilizer and/or compost in field conditions. In addition, the FCSP treatment resulted in the highest ion uptake of Fe in lettuce leaves. Moreover, FCSP led to increases in the amounts of Fe, Ca, available phosphorus and organic matter in treated soil, indicating that soil quality was improved. Taken together, our results demonstrate that FCSP promotes lettuce growth via enhancement of Fe availability and improves soil quality. Therefore, FCSP can be utilized as a new functional iron fertilizer.

Novel coprecipitation–oxidation method for recovering iron from steel waste pickling liquor

Waste pickling liquors (WPLs) containing high concentrations of iron and acid are hazardous waste products from the steel pickling processes. A novel combined coprecipitation–oxidation method for iron recovery by Fe3O4 nanoparticle production from the WPLs was developed in this study. An oxidation–reduction potential monitoring method was developed for real-time control of the Fe2+/Fe3+ molar ratio. The key coprecipitation–oxidation parameters were determined using the orthogonal experimental design method. The use of promoters greatly improved the Fe3O4 nanoparticle crystallinity, size, magnetization, and dispersion. X-ray diffraction patterns showed that the produced Fe3O4 nanoparticles were single phase. The Fe3O4 nanoparticles were approximately spherical and slightly agglomerated. Vibrating sample magnetometry showed that the Fe3O4 nanoparticles produced from the WPLs had good magnetic properties, with a saturation magnetization of 80.206 emu·g–1 and a remanence of 10.500 emu·g–1. The results show that this novel coprecipitation–oxidation method has great potential for recycling iron in WPLs.

Two-step process of regeneration of acid(s) from ZrF4 containing spent pickle liquor and recovery of zirconium metal

In this paper we describe a progressive two-step process that allows zirconium fluoride (ZrF4) contained in spent baths for etched zirconium alloys to be effectively recycled on a pilot scale and produce a high purity regenerated pickling acid. In the first step, a spent pickling liquor is treated by a BaF2 suspension to produce water insoluble Ba2ZrF8. After filtration of Ba2ZrF8 more than 99.9 wt % purity pickling acid is regenerated. The precipitation mechanism of Ba2ZrF8 is discussed and the role of BaF2 particles size on the precipitation process is demonstrated. In the second step the as-precipitated Ba2ZrF8 is mixed with Mg and Cu metal powders and heat-treated at 1200 °C (or above) to produce CuZr alloy ingot. The characteristics of the ingot are discussed in regard to Cu concentration and the heating temperature.

Crystalline-selected synthesis of ferrous oxalate dihydrate from spent pickle liquor

Ferrous oxalate dihydrate with different crystalline structures, polymorphs and sizes have been synthesized through a facile precipitation reaction from spent pickling liquors (SPL) by controlling synthesis conditions. The β-FeC2 O4 · 2H2 O in orthorhombic phase can be formed at room temperature, whereas α-FeC2 O4 · 2H2 O with a monoclinic unit cell can be obtained after aging at 80 °C. With the increasing aging temperature, the morphology of samples can be tailored from flower-like to prismatic-like and the particle-sizes are decreased. Innovatively, thermal decomposition behaviors of products have been investigated in details by X-ray diffraction pattern (XRD) and thermal gravimetric-differential scanning calorimetry (TG-DSC). The results show that both FeC2 O4 · 2H2 O samples can be transformed to α-Fe2 O3 in air atmosphere and Fe3 O4 in argon atmosphere at T ≧ 400 °C. In air atmosphere, there are two sharp exothermic peaks for β-FeC2 O4 · 2H2 O (250 °C) and α-FeC2 O4 · 2H2 O (239.5 °C) correspond to the decomposition reactions. In argon atmosphere, the decomposition end temperatures are 500 °C and 430 °C for β-FeC2O4 · 2H2O and α-FeC2O4 · 2H2O, respectively. This indicates that β-FeC2O4 · 2H2O has higher thermal stability in comparison with α-FeC2O4 · 2H2O.

Synergistic extraction and separation of Fe(III) and Zn(II) using TBP and D2EHPA

ABSTRACTWaste chloride pickle liquors from hot-dip galvanizing plants, steel plants and flue dust contain reasonable amounts of heavy metals such as Zn, Cr, Ni, etc. Iron is invariably associated with most of these materials and comes into solution during leaching. Thus, the synergistic extraction of zinc(II) and iron(III) from leach solutions in tri-n-butyl phosphate (TBP)–di(2-ethylhexyl) phosphoric acid (D2EHPA) system diluted in kerosene was investigated. The Zn and Fe concentrations in the leach liquor used in the present study were 2 g/L. Experiments were carried out in the pH range of 0.5–4.0, temperature of 25°C, using sole D2EHPA, sole TBP and D2EHPA–TBP mixtures at different ratios. Results showed that the co-extraction of zinc(II) and iron(III) increased with increasing equilibrium pH using D2EHPA. It is demonstrated that the mixtures of TBP and D2EHPA are more efficient and selective than D2EHPA alone. At low pH values, the separation factor is low when pure D2EHPA is used as an extractant; however, using TBP as a synergist, the separation factor increases and results in a better separation of zinc from iron. Increasing TBP to D2EHPA ratios in the organic phase caused a slight shift to the right in the extraction isotherm of iron and a marked shift to the right in the extraction isotherm of zinc, and the maximum separation factor of 13.3 × 103 was achieved at a TBP to D2EHPA volume ratio of 4:1 (0.58 M TBP: 0.12 M D2EHPA). Furthermore, the effect of equilibrium pH, organic to aqueous phase ratio and Cl− concentration on the selective extraction was investigated. Using two extraction stages at the O/A ratio of 2:1 and pHe (equilibrium pH) of 3 and 1 for zinc and iron, respectively, 99% of zinc(II) and 96.25% of iron(III) were extracted.