Pickle Liquor Research Articles

A symmetric aqueous rechargeable battery based on NiFe2O4 derived from industrial effluents

Two different industrial effluents, spent pickle liquor and Ni-containing wastewater, were simultaneously treated via chemical precipitation and hydrothermal reaction to generate valuable NiFe2O4. Subsequently, the NiFe2O4 was used to construct a NiFe2O4//NiFe2O4 symmetric battery. The assembling process of NiFe2O4//NiFe2O4 symmetric battery is very simple since both the cathode and anode are the same material and the manufacturing cost for practical application is low. The NiFe2O4//NiFe2O4 symmetric battery was able to deliver specific capacity 23.1mAh/g based on the total mass of the active materials at discharging current densities 0.5A/g. After 500 charge-discharges cycles, the crystalline structure of NiFe2O4 still exhibit good stability and can pass the TCLP limits to be regarded as a general industrial waste. This research not only removes the heavy metal from two wastewaters to avoid the environmental risks but also provides an effective method to turn “waste” into useful materials.

Recovery of zinc from industrial waste pickling liquor

The constantly increasing global demand of zinc metal along with the decreasing zinc ore reserves has led to an upward trend of zinc production from secondary sources. Galvanizing industry generates byproducts and wastes containing zinc in the form of intermetallic compounds or oxides (zinc dust). One such byproduct, waste pickling liquor (WPL) is generated in galvanizing industry during the pickling of defective galvanized material. WPL contains Zn and Fe in ionic form and is discarded after neutralization. In the present work, chemical precipitation method is used to recover zinc from WPL; with an objective to retain maximum possible iron within the WPL solution. The effect of precipitating agent concentration, number of reactions steps, temperature and stirring speed were considered to determine process parameters for maximum zinc recovery. The iron rich WPL solution with negligible quantities of zinc is a valuable ingredient for production of red oxide pigment. Thereby, two products are obtained by adopting this technique: (i) Zinc rich precipitates and (ii) iron rich pickling liquor. X-ray diffraction (XRD) analysis of precipitates (heated at elevated temperature), shows that zinc oxide and zinc ferrite phases were formed from the zinc rich precipitates.

Simulation of a regeneration plant for spent pickling solutions via spray roasting

Nowadays, pyrohydrolysis techniques are widely applied for regeneration of spent pickling liquors providing an excellent environmental and economical strategy to the problem of waste disposal/recovery, also thanks to the high acid recovery efficiencies (>99%) achieved. In fact, in these processes, iron chlorides are converted into iron oxides and hydrogen chloride at high temperature in spray roasting or fluidized bed reactors. Though the state-of-the-art technologies have been successfully applied only to large-scale plants, the development of small-scale units, able to perform a delocalized regeneration of spent solutions where these latter are actually produced, would be strongly needed in order to minimize the transportation of hazardous spent pickling and fresh HCl solutions to/from pickling factories from/to large centralized regeneration plants. In the present work, a steady-state simulation model for regeneration of spent pickling liquor via spray roasting has been developed, aiming at the analysis of performance of a small-scale unit. The simulation and optimization of the process has been carried out using Aspen Plus simulator. A simplified model of the spray roaster, based on the data collected from studies reported in the literature, has been implemented and exported from Aspen Custom Modeler. Solid recovery from roaster off-gases has been obtained by a cyclone and a Venturi scrubber, where the spent pickling liquor is concentrated prior to be sprayed into the reactor. Hydrogen chloride is absorbed in an adiabatic absorber, where a sub-azeotropic (18–20 wt%) hydrochloric solution is obtained. Prior to the stack, a scrubber is required to wash off the exhaust gases. Several parametric studies have been performed. Different designs of solid separators have been compared in order to investigate the particulate separation efficiency of the process, while absorption column’s packing types and rinse water flow rates have been varied in order to investigate their effects on HCl recovery and acid gas emissions.

Low temperature hydrothermal synthesis and characterization of iron oxide powders of diverse morphologies from spent pickle liquor

Iron oxide nanoparticles (goethite and hematite) of various shapes have been synthesized through a simple hydrothermal reaction from the stripped solution of Fe(III) obtained after extraction and separation of Zn and Fe from spent pickle liquor. The influence of pH and synthesis time on the structure and morphology of the as-prepared α-Fe2O3 are investigated. It was possible to control the particle size and shape by adjusting the pH (2–12) of the starting solutions and time of synthesis (1–6h). Under the appropriate conditions, rod-like α-FeOOH (goethite) and hexagonal α-Fe2O3 (hematite) materials of the uniform nano-crystalline structure were selectively synthesized in large quantities. The morphology and structure of the final products were investigated in detail by X-ray powder diffraction pattern (XRD), transmission electron microscopy (TEM), Raman spectroscopy and vibrational sample magnetometer (VSM). The probable mechanism of formation of uniform α-FeOOH and α-Fe2O3 nano-particles is discussed on the basis of the experimental results and characterization studies. The evaluation of the magnetic property has established the weak ferromagnetism characteristics of both goethite and hematite at room temperature.

铟富集工艺优化试验研究及生产实践

对铟富集进行工艺优化试验，并进行了生产改造，通过降低中浸、酸浸、高浸液固比，提高始酸，达到了提高铟浸出率，提高酸浸液铟离子浓度的目的；用硫化锌精矿对酸浸液除杂，实现了中和沉铟，从源头上治理了砷污染，降低了铟锭生产成本，改善了职工操作环境，并为铟回收工序打下了良好的原料基础。经济效益，环境效益显著。 Optimizing experiment of indium enrichment process was done and the production was remoulded. The indium leaching rate and indium ion concentration of pickle liquor were improved by reducing neutral leaching, acid leaching, as well as high leaching liquid-solid ratio and enhancing the acid in the beginning. Edulcoration of pickle liquor using zinc sulfide concentrate realizes neutralization of indium, controls arsenic pollution from the source, reduces the cost of indium ingot production, improves workers’ operating environment, and lays a good material base for indium recovery process. Economic benefit and environmental benefit are remarkable.

Utilization of neutralized spent sulfuric acid pickle liquor from metal treatment in cement production

The research addresses the issue of utilization of neutralized spent sulfuric acid pickling liquor, deposited in 1.62 ha lagoons, derived from steel industry, in cement production. Physical–chemical characteristics of the investigated waste revealed low levels of contaminants with the exception of sulfate anions. However, the presence of CaSO4·2H2O revealed a new utilization option for the investigated waste. A key part of the research involved studying the usability of stored waste as a substitute of natural gypsum, acting as a set retarder in cement production. Cement was prepared by grinding Portland clinker with the addition of waste gypsum and then was subjected to the examinations of initial setting time, specific surface, water demand and compressive strength. The analysis of mechanical and physical properties revealed that the tested cement with the addition of waste meets standard requirements for Portland cement. Furthermore, the study of natural radioactivity of the waste did not reveal a rise in the level of radionuclides, thus confirming that the investigated waste can be used for the production of construction materials used in buildings intended for human residence. Utilization of the deposited wastes can help eliminate the environmental hazards regarding sulfuric acid pickle liquor waste and can also provide a low-cost resource of waste gypsum, which can be widely used in the production of construction materials.

Solvent extraction and separation of zinc and iron from spent pickle liquor

The present study reports liquid-liquid extraction and separation of zinc and iron values from a spent pickle solution. Tertiary amine viz. tri-iso-octyl amine (TiOA) or tris(2-ethylhexyl) amine (TEHA), in the absence and presence of di-(2-ethylhexyl)phosphoric acid (HDEHP), has been used for the separation of zinc and iron. Three aqueous solutions were investigated: i) HCl–Fe(II)–Fe(III), ii) Zn(II)–HCl, and iii) HCl–Fe(II)–Fe(III)–Zn(II) with the composition similar to that of pickle liquor (g/L) [117 Zn(II), 90 HCl, 30 Fe(II) and 1 Fe(III)]. Co-extraction of Zn(II), HCl and Fe(III) was noticed with the extractants (amine/amine+HDEHP) without any appreciable selectivity except for Fe(II) which was not extracted by the solvent. Zn(II) was extracted selectively leaving Fe(II) in the raffinate provided that Fe(III) was removed from the solution at a low O/A phase ratio or reduced to Fe(II) state. Stripping of HCl, Zn(II) and Fe(III) was also not selective with distilled water. The Zn(II) free raffinate containing Fe(II) was microbially oxidized to Fe(III) and was then quantitatively extracted in 3-stages with 30% Versatic 10 acid at the O/A phase ratio of 3.5:1. Loaded Fe(III) was easily stripped from the organic phase with dilute sulfuric acid. A flowsheet is proposed to produce high purity Zn(II) and Fe(III) solutions by solvent extraction.

Comparisons of the reactivity, reusability and stability of four different zero-valent iron-based nanoparticles

Our previous reports showed that nano zero-valent iron (nZVI), steel pickle liquor for the synthesis of nZVI (S-nZVI), nZVI immobilised in mesoporous silica microspheres (SiO2@FeOOH@Fe) and nano Ni/Fe bimetallic particles (Ni/Fe) have been proved to show good property for elimination of polybrominated diphenyl ethers (PBDEs). However, it is necessary to compare their reactivity, reusability and stability when applied to in situ remediation. In this study, the performances of different iron-based nanoparticles were compared through reusability, sedimentation and iron dissolution experiments. The SiO2@FeOOH@Fe and Ni/Fe nanoparticles were shown to have higher reusability and stability, as they could be reused more than seven times, and that the SiO2@FeOOH@Fe can effectively avoid leaching iron ions into the solution and causing secondary pollution in the reaction. This study may serve as a reference for PBDE remediation in the future.

A study on treatment methods of spent pickling liquor generated by pickling process of steel

Metals to be coated require pre-treatment to remove rust or scale, impurities and inorganic contaminants. In steel industries, pickling process generates a considerable quantity of Spent Pickle Liquor (SPL) containing the dissolved metal salts of iron, chromium, copper, nickel and zinc as well as residual free acid. The waste generated by metal pickling and electroplating industries is identified as hazardous solid waste as per Indian Standards and United State Environmental Protection Agency (US EPA). This paper discusses the advantages and disadvantages of treatment methods of spent pickling liquor generated by pickling line of steel. The discussion shows that treatment method depends upon the quantity, quality and composition of SPL. Experimental modelling helps in better understanding of treatment process and also craft process more technically and economically feasible.

Investigation of stainless steel pickling liquor as a precursor for high Capacity battery electrode materials

Stainless steel and battery manufacturing industries can be united for mutual economic and environmental benefits by utilizing stainless steel pickling liquor waste as a precursor for high energy iron fluoride based positive electrode materials in batteries.

Development of a process for the recovery of zinc sulphate from hot-dip galvanizing spent pickling liquor via two solvent extraction steps

A process for zinc sulphate recovery from the spent pickling liquor of a hot-dip galvanizing plant is developed. Two solvent extraction steps are used, the first with tributyl phosphate to selectively extract zinc chloride from the spent liquor and the second with di-2-ethylhexyl phosphoric acid (D2EHPA) to transfer zinc from a chloride to sulphate media. The final product of the process is found to meet the specification of low chloride concentration required for electrowinning when the loaded D2EHPA was washed with water. Mathematical simulation was used to further develop the process. Based on a feed concentration of 120g/L Zn, 60g/L Fe(II) and 1mol/L HCl, the simulation predicts that 99.2% zinc can be recovered, yielding a product with 106g/L Zn.

Characterizations of TiO2@Mn-Zn ferrite powders for magnetic photocatalyst prepared from used alkaline batteries and waste steel pickling liquor

We successfully prepared the TiO2@Mn-Zn ferrite composite powder for magnetic photocatalyst. The core Mn-Zn ferrite powder was synthesized by using steel pickling liquor and used alkaline batteries as the starting materials. The shell TiO2 nanocrystal was prepared by sol–gel hydrolysis precipitation of titanium isopropoxide (Ti(OC3H7)4) on the Mn-Zn ferrite powder. The thickness of the titania shell was found to be approximately 2nm. The core of Mn-Zn ferrite is of spherical or elliptical shape and the particle size of the core is in the range of 20–40nm. The magnetic Mn-Zn ferrite nanopowder is uniformly encapsulated in a titania layer forming the core–shell structure of TiO2@Mn-Zn ferrite powder. The magnetic photocatalyst can be successfully used to treat dye waste waters.

Magnetic nanomaterials recovered from co-treatment of CN-containing electroplating wastewaters and pickle acid liquor

CN− has been widely used in electroplating and mining, generating a vast amount of CN-containing heavy-metal wastewaters. In this research paper, we present a strategy to recycle these cyanide-containing electroplating wastewaters (Ni, Zn, Cr and Fe) with pickle acid liquors (Fe) and produce magnetic nanomaterials. The process includes formation of layered double hydroxides (LDH) as the intermediates and their conversion to valuable magnetic materials. LDH intermediates were first precipitated from these two wastewaters and then thermally converted into superparamagnetic mixed oxide nanomaterials, with the crystallite size of 10–25nm and the saturation magnetization up to 40emu/g. Specifically, during the conversion, secondary pollution resulting from CN− was significantly reduced. This research thus demonstrates a cost-effective and safe way to treat CN-containing wastewaters and transfer to useful nanomaterials.

Discussion of a Treatment Technique for Spent Picking Solution Recycling

Pickling is a necessary process in many metal processing industries, such as wire rod, iron and steel sheet plate, and tubing processing industries, screw and nut manufacturing and processing industries, corrosion resistant plate processing industries, and paint industry. Pickling is used to remove black rust, oxides, and other contaminants from metal surfaces in order to improve processing quality. Hydrochloric acid is often used in the pickling process. As the acid concentration decreases gradually during the process, while metal (Fe and Zn) concentrations increase gradually, when the residual concentration of hydrochloric acid in the spent pickle liquor decreases to about 3%, or the specific gravity of spent pickle liquor is greater than 1.3 (iron ion concentration is greater than 100g/L), the aged pickle liquor must be discharged and fresh pickling solution is prepared. In the wire rod industry in Taiwan, the pickling process results in highly corrosive spent pickle liquor. Although there have been multiple resource processing schemes developed, including spray roasting process, fluidized bed roasting process, and sulfuric acid displacement process, it is limited to various factors, such as the treatment capacity, initial cost, operating cost, selling prices, purity of recycled products, and market scale. This study reviewed related patented processing modes in literature, and considered the reclamation cost of waste pickling solution (SPS). The proposed technique adopts wet-process metallurgy, combined with diffusion dialysis, for reclamation of SPS and mineralization crystallization of heavy metal of residue iron. The mineralization crystallization treatment produces high-purity recycled products of ferrite and goethite processes. SPS is reclaimed, and the ferric heavy metal recycling meets the economic benefit of an actual plant. The research site of this study produces 12 tons of SPS per day, which is about 300 tons monthly, and about 3,600 tons annually, with the removal cost of 7.2 million NTD annually. If the proposed treatment system is adopted, the costs of fresh hydrochloric acid, removal, and the traditional neutral agent treatment and subsequent landfill could be greatly reduced, thus effectively reducing the environmental load. In comparison to other recycling treatment techniques, the main advantage of the proposed technique is that the treatment capacity depends on the amount of SPS, the energy consumption is relatively low, the treatment scheme is simple, the operating and maintenance costs are low, and the mineralization can produce magnetic ferrite and iron oxide recycled products with high purity.

Rapid purification of spent pickling liquor into ferrite by microwave hydrothermal method

AbstractsSpinel ferrite was synthesized from two kinds of spent pickling liquor (SPL) by microwave hydrothermal method. X-ray diffraction (XRD) and toxicity characteristic leaching procedure (TCLP) showed that the synthesized product (VSPLA:VSPLB = 1:1) was well crystallized as well as had relatively high saturation magnetization (48.57 emu/g) and BET surface area (76.67 m2/g). Scanning electron microscope (SEM) and transmission electron microscope (TEM) revealed ferrite nanoparticles in size of around 20 nm. An adsorption experiment indicated that the obtained product was a kind of efficient and powerful magnetic adsorbent for the removal of methylene blue (MB) from aqueous solution. The effect of contact time, solution pH, and initial concentration was investigated. Adsorption kinetics data followed the pseudo-second-order model and adsorption isotherm data were fitted well to the Langmuir model with a maximum MB adsorption capacity of 33.07 mg g−1. Furthermore, higher reaction temperature was beneficia...

Preparation of polymeric aluminium ferric chloride from bauxite tailings

Bauxite tailings are the main solid wastes in the ore dressing process. The Al2O3 and Fe2O3 contents in bauxite tailings can reach 50% and 13% respectively. The present study proposed a feasible method to use bauxite tailings to prepare polymeric aluminium ferric chloride (PAFC), a new composite inorganic polymer for water purification. Bauxite tailings roasted reacting with hydrochloric acid under air, pickle liquor which mainly contains Fe3+, Al3+ was generated, then calcium aluminate was used to adjust pH value and the basicity of the pickle liquor, the PAFC was subsequently prepared after the polymerization process. The optimal synthesizing parameters for the preparation of PAFC obtained were as follows: the concentration of hydrochloric acid of 24 wt%, ratio of hydrochloric acid to bauxite tailings of 6:1, temperature of 90?C, leaching time of 2.5 hours, ration of pickle liquor to calcium aluminate of 12:1, polymerization temperature of 90?C and polymerization time of about 3 hours. The basicity of PAFC was higher than 68%, the sum concentration of Al2O3 and Fe2O3 was beyond 12.5%. The results of flocculation tests indicate that the PAFC has a better performance of removing the turbidity of wastewater compared to PAC, and PAFC prepared by bauxite tailings is a kind of high quality flocculants.

CN and heavy metal removal through formation of layered double hydroxides from mixed CN-containing electroplating wastewaters and pickle acid liquor

The common ligand CN− has been widely used in some core industries, such as electroplating and mining, as it significantly enhances process efficiency and product quality. The use of CN− however generates a vast amount of CN-containing heavy-metal wastewaters, harming both environmental and human health. In this research paper, we present a co-precipitation strategy to treat CN-containing heavy-metal wastewaters (Ni, Zn, Cr and Fe) and pickle acid liquor (Fe) via formation of layered double hydroxide (LDH). Our experimental data demonstrate that Zn, Cr and Fe were completely removed and Ni was reduced from 100–400 to 3.0mg/L, and about 60% CN− was simultaneously removed (from 6–8 to 2.5–4mg/L). This efficiency was constantly achieved under varied experimental conditions, including a wide range of heavy metal concentrations and their ratio with pH in 7–11 at 25–60°C.

Neutralization of red mud with pickling waste liquor using Taguchi’s design of experimental methodology

'Red mud' or 'bauxite residue', a waste generated from alumina refinery is highly alkaline in nature with a pH of 10.5-12.5. Red mud poses serious environmental problems such as alkali seepage in ground water and alkaline dust generation. One of the options to make red mud less hazardous and environmentally benign is its neutralization with acid or an acidic waste. Hence, in the present study, neutralization of alkaline red mud was carried out using a highly acidic waste (pickling waste liquor). Pickling waste liquor is a mixture of strong acids used for descaling or cleaning the surfaces in steel making industry. The aim of the study was to look into the feasibility of neutralization process of the two wastes using Taguchi's design of experimental methodology. This would make both the wastes less hazardous and safe for disposal. The effect of slurry solids, volume of pickling liquor, stirring time and temperature on the neutralization process were investigated. The analysis of variance (ANOVA) shows that the volume of the pickling liquor is the most significant parameter followed by quantity of red mud with 69.18% and 18.48% contribution each respectively. Under the optimized parameters, pH value of 7 can be achieved by mixing the two wastes. About 25-30% of the total soda from the red mud is being neutralized and alkalinity is getting reduced by 80-85%. Mineralogy and morphology of the neutralized red mud have also been studied. The data presented will be useful in view of environmental concern of red mud disposal.

Pickling Waste as an Inexpensive Iron Source for Fenton Oxidation of Synthetic Dye Bath Waste

AbstractA simple, low cost, highly effective, and useful Fenton oxidation treatment of synthetic dye bath waste with pickling liquor as a source of iron (Fe2+ catalyst) is reported. Optimizations of contact time, Fe2+ and H2O2 doses are carried out. Oxidative de‐colorization and degradation of Reactive Blue 4 and Reactive Orange 16 was measured in terms of decrease in absorbance at their wavelength of maximum absorption (RB4, 599 nm; and RO16, 493 nm) and also as reduction in chemical oxygen demand (COD). Approximately, 62% COD was removed in 2 h at optimized doses of Fe2+ (8.95 mM) and H2O2 (61.8 mM) by using pickling waste as a source of Fe2+ catalyst. Similar performance efficiency was observed when neat FeSO4 was used as a source of Fe2+, indicating that pickling liquor can be a low cost source of Fe2+ to treat synthetic dye bath waste by Fenton method.

Studies on solvent extraction of iron(III) as a step for conversion of a waste effluent to a value added product

Solvent extraction of iron(III) from actual sulphate waste pickle liquor was investigated using trialkylphosphine oxide diluted with kerosene. The waste pickle liquor was procured from a local company which deals with the manufacturing of pipes and tubes made of iron and steel. Various parameters were studied to optimise a suitable condition for the maximum extraction of iron. The composition of the aqueous feed used in the experiment was 60.88g/L Fe(III), 53g/L acid with traces of Cu, Ni and Co. An ambient extraction at 30°C yielded acceptable kinetics and loading efficiency for 40% trialkylphosphine oxide with a saturated loading capacity of 51.85g/L in four contacts at O/A ratio of 1/1 in a multiple contact mode. Iron from the loaded organic was stripped using various strippants such as distilled water, H(2)SO(4) and oxalic acid. Since only 32% of loaded Fe could be stripped with 2M H(2)SO(4) in five contacts, further stripping was done with 5% oxalic acid which showed a very promising result. It was found that almost 100% of Fe(III) could be stripped out with 5% oxalic acid at O/A of 1/1 in five contacts.