Dissolved-Air Flotation of Metal Ions (original) (raw)
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Physicochemical Problems of Mineral Processing
Many industries, especially mining and metallurgy, deal with solutions containing ions. In some cases, these metal ions need to be concentrated and recovered from solutions and sometimes removed from wastewater. The ion flotation method has been applied for wastewater and water treatment, recovery of precious and platinum group metals, preconcentrating of rare earth elements, selective separation of multicomponent ions from dilute solutions, and analytical chemistry. It has been employed to separate heavy metals from a liquid phase using bubble attachment, originated in mineral processing. In these cases, ion flotation has an important place among other methods because it is a cheap and practical method. In this study, many ion flotation studies, especially applied at laboratory scale, were reviewed. This method gives very successful and promising results in removing heavy metals with toxic effects from wastewater and selective separation of metal ions from very low concentrated solutions. Ion flotation may take place in industrial scale operations with the new developments in flotation machines and collectors with better selectivity, high efficiency, lower cost, and environmental friendliness.
Recovery of Metals by Ion Flotation from Dilute Aqueous Solutions
Separation & Purification Reviews, 1991
Flotation, a process originating from l..e minerals in-Jstry, is finding its way as a separation process for dilute aqueous solut ions, with particular interest in metal ions recovery. The present paper reviews the several flotation techniques available in this area, with certain illustrative laboratory examples. Metals investigated are the following : chromium, copper, zinc, arsenic, lead, iron and germanium.
Removal of heavy metal ions from water using ion flotation
Environmental Technology & Innovation, 2017
The effects of different single-chain surfactants obtained by reacting cysteine with octanoyl (C8), decanoyl (C10) and dodecanoyl (C12) chloride were investigated for their use in ion flotation removal of low levels of arsenic, mercury, lead, cadmium and chromium ions from aqueous solution. Re-crystallized octanoyl-cysteine (octanoyl-cys) surfactant showed the highest removal efficiency at 99.9%, for Hg ions, using pure nitrogen gas. Successful removal results of most other ions was found to be in the range 99.1-99.7%, using either air or nitrogen gas. Characterization of the octanoyl-cys surfactant was also carried out using elemental analysis, 1 H NMR, FT-IR, melting point (MP) and critical micelle concentration (CMC) determination.
Precipitate and adsorbing colloid flotation of dissolved copper, lead and zinc ions
International Journal of Mineral Processing, 1996
By combining the precipitate and adsorbing colloid flotation, a possibility for simultaneous removal of metal ions from aqueous solution containing copper, lead and zinc ions (25 ppm each) is investigated. Ferric chloride is used as coprecipitant. Potassium oleate is used as collector and for the inlprovement of precipitation, while extra coprecipitation of the ions still remaining in solution is realized via potassium ethyl xanthogenate. The test is carried out in the pH range of 4.0 to 10. Two cells are used for precipitate and adsorbing colloid flotation, differing in the way the gas bubbles are generated, i.e. dispersed-air and electrolytic flotation. The adsorption on colloid particles containing the precipitated metal ions is checked out by registration of surface tension at the liquid/gas interfaces both in the starting and purified solutions according to the method of Wilhelmy. The concentration of each heavy metal ion in the supernatant liquid is measured via ICP optical emission spectrometry. The amount of heavy metals coprecipitated with ferric chloride is determined from the difference in their concentration before and after coprecipitation. The optimal conditions under which copper, lead and zinc can removed almost quantitatively from aqueous solutions are found.
Sorptive flotation for metal ions recovery
International Journal of Mineral Processing, 2003
In this study, the abstraction of nickel, copper and zinc ions from aqueous solutions has been investigated in a laboratory batch scale mode. A combined two-stage process is proposed as an alternative of the heavy metals removal from aqueous solutions. The first stage is the sorption of heavy metals onto non-living microorganisms followed by dispersed-air flotation of the loaded biomass.
Processes, 2021
This paper presents the results of investigations concerning the simultaneous removal of Al(III), Cu(II), and Zn(II) from dilute aqueous solutions using ion and precipitate flotation methods. The effects of initial solution pH, surface active substance concentration, and the gas velocity on the flotations’ efficiency and course are studied. Experimental results are discussed in terms of physicochemical aspects related to aqueous solutions of metal salts. The results indicate that satisfying simultaneous flotations of aluminum, copper and zinc species are observed if the pH value ranges between 7.0 and 9.0. It was found that an increase in collector concentration results in a decrease in the flotation rate constants. An increase in the gas velocity results in an increase in the ion and precipitate flotation rates.
Copper Ion Recovery from Mine Water by Ion Flotation
Mine Water and the Environment, 2016
Solutions containing copper ions are produced at copper mines due to its dissolution from ores and dumps. It is important to recover these ions to prevent this toxic element from entering the environment and because it could be economical. We investigated the use of ion flotation for extracting Cu ions from diluted mine water from the Veshnaveh Mine in Qom, Iran. Experiments were conducted using floatation cells at pH 6, 9, and 12 with diluted solutions containing 10 mg L-1 of Cu. Sodium dodecyl sulfate and hexadecyl trimethyl ammonium bromide (HTAB) were used as collectors and methyl isobutyl carbinol (MIBC) and ethanol were used as frothers. The best result was achieved by maximizing Cu ion recovery and minimizing water recovery at pH 12, using 100 mg L-1 of HTAB and 0.1 % (v/v) of MIBC. Copper and water recovery were 79 and 24 %, respectively.
Removal of heavy metal ions by adsorptive particulate flotation
Minerals Engineering, 1997
The removal of Zn, Cu and Ni ions, from diluted solutions, by the adsorptive particulate flotation (APF) process, was studied at laboratory scale. Zeolite (Chabazite) fines, in small concentrations, were used as the particulate sorbing for the metal ions and dissolved air flotation was employed for the solid/liquid separation of the loaded "carrier % Results showed almost complete removal (>98 %) of the heavy metal ions using Fe(OH) 3 precipitates to "aggregate" the carrier (coprecipitation). The process efficient: depended on solution and interfacial chemistry and aggregation effectiveness. The potential of APF in the field of effluent treatment is discussed. © 1997 Published by
The effect of water recovery on the ion flotation process efficiency
Physicochemical Problems of Mineral Processing, 2020
The present study deals with nickel ions removal from dilute aqueous solution by ion flotation with emphasizing the process efficiency. The effect of collector structure on ion flotation efficiency and water recovery was evaluated using anionic collectors of sodium dodecyl sulfate (SDS) and functionalized graphene oxide by 2,6-diaminopyridine (AFGO). The results showed that process efficiency enhanced with the increase in pH and reached to complete removal at pH of 9 and 9.7 for SDS and AFGO, respectively. The AFGO showed the multifunctional bindings for complex formations with nickel ions. A coordinate bond may be formed between nickel ions and AFGO at the pH of 9 which increased nickel ion removal. The water recovery as a critical parameter that contributes to removal efficiency was significantly affected by the collector structure. The AFGO doesn't have a frothing property and so decreases the water recovery during the process. The AFGO had significantly lower water recovery than SDS (almost threefold).
A hybrid flotation—microfiltration process for metal ions recovery
Journal of Membrane Science, 2005
In the present study, the removal of two metal ions (copper or chromates) was investigated by employing a hybrid flotation-microfiltration process. Air bubbling, used to limit membranes fouling, could be meanwhile used (under appropriate conditions) as the transport means of flotation. Two flotation techniques were applied; precipitate and adsorbing colloid flotation. In the latter the bonding agent (ferric hydroxide) was in situ produced. The main parameters studied were surfactant, frother and ferric ion concentration. Under the studied conditions, the higher the surfactant or frother concentration the lower the transmembrane pressure was observed while backflush found to have a small effect on hybrid cell operation. Promising results were obtained: the concentration in the outlet was 0.5 mg L −1 for copper and 0.1 mg L −1 for chromium, from initially 50 mg L −1. Attention was also paid to the economics of this integrated process.