Metal Flotation Research Articles

Development of Reagents - Blowing Agents Based on Local Raw Materials and their Research

The development and search for effective reagents and optimal technological conditions is one of the main factors for improving the coal flotation process. Solving these problems increases the technological and economic efficiency of flotation enrichment. The article discusses methods for producing foaming regents based on waste from the distillation process of cottonseed oil - gossypol resin and methods of flotation of various classes of fine coal. The advantages of this foaming agent include the availability of raw materials, which are a product of domestic industry, produced at the enterprises of the Kattakurgan MJK and amino alcohols (mono- , di- and triethanolamine) , sufficient resources and relative low cost. Conducted research to assess the effectiveness, surface activity and foaming ability of the resulting reagents - in foaming agents, according to the proposed technology of the studied technical products, the resulting product belongs to the surface-active reagents and has high flotation activity. The physico-chemical and foam-forming properties, foam stability, destruction kinetics and other properties of flotation reagents - foaming agents SK-1 and SK-2 - have been studied. The results of studies of the influence of foaming reagents in the process of flotation and extraction of precious and non-ferrous metals are presented. The optimal option for the effective composition of composite chemical flotation reagents - foaming agents and their parameters was selected. The results of scientific research conducted at JSC NMMC on the use of analogues of the foaming agents SK-1 and SK-2 are given in comparison with the reagents (Oxal) currently used at the plant. The elemental composition of man-made waste samples using reagents SK-1 and SK-2 was determined.

Extraction of andradite from flotation tailings as a potential material for As(III) removal from simulated wastewater

Arsenic is a toxic and carcinogenic metalloid widely distributed in nature. It can enter water bodies through natural or man-made routes, posing a serious threat to the ecological environment and human health. In recent years, arsenic pollution in water has become a global problem. This study introduces the utilization of andradite from scheelite flotation tailings as a potential material for As(III) removal. The experimental results showed that after 30 min of milling, 5 g/L andradite achieved a removal rate of over 90 % for As(III), reducing its concentration from 1 mg/L to 0.09 mg/L. Scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) were carried to reveal the underlying mechanism of As(III) removal with andradite. Results indicated that the calcium atom and iron atom on the surface of andradite may react with As(III) to form calcium arsenite and ferric arsenite, and the products adhere to the surface of andradite. Based on the obtained results, andradite is a promising material for the remediation of arsenic pollution. Moreover, the source of andradite is very wide, and the cost of extraction and preparation is low. The extraction of andradite from non-ferrous metal flotation tailings as an adsorbent to remove As(III) not only improves the utilization rate of tailings resources, but also provides a new method for the prevention and control of arsenic pollution.

Improving the Copper-Molybdenum Ores Flotation Technology Using a Combined Collecting Agent

The search for effective reagents for the flotation of non-ferrous metals from mineral raw materials is an actual problem. The article discusses the results of research on improving the technology of processing copper–molybdenum ores using a combined collector emulsion. The object of research was copper–molybdenum ore containing 0.43% copper and 0.0089% molybdenum. Copper minerals are represented by chalcopyrite 1.2% and chalcocite 0.015%, while covellite is present in a much smaller amount. The main mineral of molybdenum is molybdenite. The cycle of collective copper–molybdenum flotation includes the main flotation, control flotation, and three re-cleanings of concentrate. In the basic mode, the collective Cu–Mo concentrate was produced with the copper content of 16.25% with an extraction of 77.79% and with the molybdenum content of 0.45% with an extraction of 79.38%. Reaflot, thionocarbamate, and butyl xanthate were used in a ratio of 1:3:15 to prepare a combined collector agent. In order to produce the combined collector emulsion, the best degree of dispersion, which amounted to 99.5% of particles with a size of −3.6 μm, was chosen. During the Cu–Mo ore flotation using an optimally dispersed microemulsion of the combined collector agent, a collective Cu–Mo concentrate was obtained with a copper content of 18.2% with an extraction of 83.58%, and with a molybdenum content of 0.49% with an extraction of 88.46%. The use of a combined collector agent increases the extraction of copper into the collective Cu–Mo concentrate by 5.79%, while the extraction of molybdenum increases by 9.08%.

The Selection of Reagents for Ionic Flotation of Non-Ferrous Metals in the Series of N-Acyl-N'-Mezylhydrazines

A series of new ligands — N-acyl-N'-mesylhydrazines (MSH) — of the general formula RC(O)NHNHSO2CH3 has been obtained and considered as reagents for ionic flotation (IF) of non-ferrous metals (M(II). Reagents with a radical length of C6H13 and above form hardly soluble complexes with M(II) so it is possible to implement a kind of the ionic flotation techniques — “precipitate flotation”. The ranges of pH values of the most complete precipitation of cations from solutions have been determined. Precipitates of the metal complexes were isolated; their composition was confirmed by IR spectroscopy and elemental anal-ysis. The conditional values of the solubility product (SP) of the complexes [M(HL)2] were calculated. The dependence –lg SP = 11.8 + 0.61N is fulfilled for the MSH series and Cu(II) ions. The surface-active proper-ties of compounds with R > C6H13 were established. The reagents with optimal radical length for ionic flota-tion were selected. The ionic flotation of non-ferrous metals with N-nonanoyl-N'-mesylhydrazine was carried out. The up to 95–99 % recovery of metal ions, separation of copper and associated metal ions in diapason of pH 5–6.5 was shown to be possible.

UTILIZATION OF FLOTATION IN COPPER EXTRACTION FROM POLYMETALLIC ORE

The aim of this study was to examine flotation of utility metals from poor polymetallic ores and verify the potential for profitable yields in connection with potentially economic deposits of non-ferrous metals. The paper describes results in flotation concentrate research to recover copper from polymetallic ore. The polymetallic ore from Zlate Hory deposit (Czech Republic) was subjected to crushing, grinding, and screening to prepare feed for separation with mesh size under 200 microns. The heavy medium separation was performed in tetrabromethane with a density of 2.967 g.cm-3. The float and sink products were obtained and tested for chemical composition. Next, the treated polymetallic ore sample was subjected to flotation. In flotation, various dosages of collector (PAX) and various pH were tested, at which pyrite was depressed. The recovery of metallic copper in the concentrate increased with the collector dose. As the pH of the medium increased, the pyrite content in the concentrate dropped. The lowest content of pyrite, i.e. 4.01 %, was obtained at pH 10. In the original polymetallic ore, the Cu content was 0.41 % after subsequent treatment and flotation tests, the Cu content increased to 1.38 % with Cu recovery 86.18 %. Keywords: Copper; Flotation; Polymetallic ore; Potassium amylxanthate (PAX); Zlate Hory   DOI 10.35180/gse-2020-0030

Study effects of conventional flotation reagents on bioleaching of zinc sulfide

Although flotation and bio-extraction of metals from its products are extensively investigated, there are few studied which evaluated the effects of reagents on bioleaching process. Both structure and concentration of flotation reagents are effective factors on microorganism activities. In this study, Kendall’s tau (τ) as a statistical method was used to statistically access the effect of typical sulfide flotation surfactants (collectors: potassium amyl-xanthate, potassium isobutyl-xanthate, sodium ethyl-xanthate, potassium isopropyl-xanthate, and Dithiophosphate), and frothers: pine oil and methyl isobutyl carbinol) on the bioleaching of Zn sulfides in a mixed culture (Leptospirillum ferrooxidans, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans). To consider both structure and concentration of these reagents, their molarities were used for the statistical evaluations. The Kendall assessments indicated that by increasing in the molarity of reagents, the pH value (the most effective factors of bioleaching) was increased (τ: 0.56) while the ORP value (τ: −0.54), Fe3+Fe2+ ratio (τ: −0.51) and numbers of oxidizing bacteria (τ: −0.38) in the solution were decreased. Therefore, as a result of these multi-interactions, by increasing the molarity of reagents, Zn recovery was decreased (τ: −0.45). These results potentially can be used for selection of flotation reagents when bioleaching would be the metallurgical metal extraction method.

Nonionic Glycolipids for Chromium Flotation- and Emulsion (W/O and O/W)-Based Bioactive Release.

Biosourced surfactants are endeavored as a green alternative to biosurfactants and petrochemical surfactants having industrial utilization. Nine glycolipids with headgroup and chain length variation were derived from renewable resources like vegetable oils, carbohydrates, and amino acids. The concentration-dependent interfacial activity, foamability, wetting power, emulsification power, and solubilization capacities of glycolipids were investigated to provide a structure-activity relationship. Later, the metal flotation and emulsification experiments were performed. In general, for metal flotation, the surfactant should contain a hydrophobic tail, hydrophilic head, and chelating function. In the present investigation, it was observed that the headgroup of a glycolipid can serve as a hydrophilic head as well as perform a chelating function. Moreover, heat energy generated from the sunlight was utilized for metal flotation. Additionally, these glycolipids are capable to form stable sunflower oil-water (W/O and O/W) emulsions. The mechanical and thermal stabilities and hydrophobic chain length dependency of the prepared emulsions at different water volume fractions are explored. Furthermore, encapsulation and release of water-soluble (riboflavin and l-ascorbic acid) and oil-soluble (curcumin and α-tocopherol) bioactives in glycolipid emulsions were monitored. Thus, glycolipids under investigation had shown the possibility for pretreatment of chromium-containing wastewaters and bioactive-loaded emulsions toward the controlled release.

Use of centrifugal-gravity concentration for rejection of talc and recovery improvement in base-metal flotation

The possibility of using a centrifugal-gravity concentrator to reject Mg-bearing minerals and minimize metal losses in the flotation of base metals was evaluated. Sample characterization, batch scoping tests, pilot-scale tests, and regrind-flotation tests were conducted on a Ni flotation tailings stream. Batch tests revealed that the Mg grade decreased dramatically in the concentrate products. Pilot-scale testing of a continuous centrifugal concentrator (Knelson CVD6) on the flotation tailings revealed that a concentrate with a low mass yield, low Mg content, and high Ni upgrade ratio could be achieved. Under optimum conditions, a concentrate at 6.7% mass yield was obtained with 0.85% Ni grade at 12.9% Ni recovery and with a low Mg distribution (1.7%). Size partition curves demonstrated that the CVD also operated as a size classifier, enhancing the rejection of talc fines. Overall, the CVD was capable of rejecting Mg-bearing minerals. Moreover, an opportunity exists for the novel use of centrifugal-gravity concentration for scavenging flotation tailings and/or after comminution to minimize amount of Mg-bearing minerals reporting to flotation.

Ion flotation of non-ferrous metals with sulfonyl aminothiophene derivatives

The paper studies sulfonyl aminothiophene derivatives as potential collecting agents in ion flotation of non-ferrous metals. The study determines optimal flotation conditions of Cu(II), Co(II), Ni(II), Zn(II) and Cd(II): range of pH values, process time, and amount of reagent. It demonstrates effectiveness of compounds as collecting agents for non-ferrous metals in standardized test solutions by the method of ion flotation.

Evaluation of rhamnolipid (RL) as a biosurfactant for the removal of chromium from aqueous solutions by precipitate flotation

Rhamnolipid (RL) is a biosurfactant which is produced by the bacterial species Pseudomonas aeruginosa. Although applications of this material have been examined in various fields, its applications in the flotation of heavy metals remain to be explored. In this research, rhamnolipid was applied as a collector in the flotation of Cr(III) from aqueous solutions. FeSO4 was used for the precipitation of Cr(VI) to Cr(III) which was subsequently removed by flotation. A two level full factorial design (with center points) was used to evaluate the effects of pH, air flow rate, RL/Cr and Fe/Cr molar ratios on the performance of the flotation system. The results showed that the biosurfactant was highly effective in the removal of chromium, and all of the factors had significant effects on the flotation performance. The chromium removal efficiencies of greater than 95% were obtained with the initial chromium concentration of 40 ppm within 5 min. Kinetic studies showed that a first order kinetic model was appropriate to describe the precipitate flotation of Cr(III) using rhamnolipid as a collector. The interference of NaCl, CaCl2, CaSO4, and CaCO3 on the Cr removal was also investigated, and it was demonstrated that CaSO4 and CaCO3 as sparingly water soluble salts, and CaCl2 as a contributor to water hardness had significant negative impacts on Cr removal efficiency of rhamnolipid.

The link between operational practices and specific energy consumption in metal ore milling plants – Ontario experiences

An energy audit was conducted on a base metal milling facility where a top-down, bottom-up approach was presented to balance data measurements and estimates. The relation between throughput and specific electricity consumption, presented as a part-load efficiency curve for a milling operation, was established from the audit data. Unsurprisingly, the most efficient use of electricity occurred when the mill was operating at design capacity, but a survey of 14 metal mills operating in Ontario showed that 12 were operated under design capacity during 2012. For base metal flotation mills, 16–36% electricity cost savings could be realized by modification to the operating schedule, which would ensure that these facilities operated at design capacity even if plant operation was intermittent. With the Ontario electricity tariff arrangements, additional cost savings from strategic scheduling could reduce demand during coincident peak hours, which could provide financial benefit to these milling facilities.

Optimization of Operating Parameters for the Selective Flotation of Heavy Metals from Contaminated Fine Sediment Using Response Surface Model

In this study, the effect of different flotation operating variables, such as pH, pulp density, collector concentration, impeller speed, frother concentration, and air flow rate, on selective flotation of heavy metals, especially Cu, from fine dredged sediment has been evaluated. Parameter optimization was done using the single parameter at a time method and response surface method (RSM) using Box-Behnken design and was assessed in terms of metal removal, metal recovery, metal concentration factor, and mass recovery. Among the operating variables studied, pulp pH, collector concentration, pulp density, and impeller speed were found to have significant effect on metal flotation selectivity. A validation study of the response surface model showed its aptness to predict the optimum values of operating parameters and their interactions on flotation responses which evaluate flotation performance. Flotation experiments under optimum operating parameters showed good flotation selectivity for Cu (3.3 ± 0.2) with a mass recovery of (mass of sediment in the froth) 14.1 ± 1 and Cu removal of 37.4 ± 3.6%.

Surface Characterization of Metallic Particles in Printed Circuit Board Comminution Fines and the Processing Implication

From the background of poor responses of metallic particles in printed circuit board comminution fines to chemical conditioning froth flotation schemes, contrary to expectations based on native metal flotation, surface studies were carried out on samples of these metallic particles in quest for the probable causatives. Auger electron spectroscopy combined with argon beam depth profiling was employed in studying the surface make-up of the metal particles. The composition profiles down to 340 nm surface depth obtained showed that the supposed metallic particles consist of organics, oxides, and various trace alloys different from the bulk material of the particles. The profiles reveal the peculiar surfaces of the particles and the matrix from which the particles were liberated. The study provides insight for better appraisal of the flotation system the sample presents. Implementing chemical conditioning flotation scheme on this sample must carefully consider the peculiar surface make up in contrast to native metal occurrences.

Ion flotation of rare-earth metals with sodium dodecyl sulfate

Ion flotation of rare-earth metals with sodium dodecyl sulfate and the effect of chloride ions on this process were studied. Values of the distribution coefficients were obtained.

Synthesis of new chelating surfactants from octyl d-glucopyranosiduronic acid and amino acids for metal flotation

A new family of surfactants with metal-chelating properties was synthesized in few steps from octyl d-glucopyranosiduronic acid. The complexing function was either a carboxylic acid or a hydroxamic acid function introduced after coupling with glycine, aspartic acid, or glutamic acid and finally hydroxylamine. Interfacial properties were determined. Flotation experiments on a laboratory scale have been performed with Fe(III) solutions as model contaminant metal.

Statistical applications in planning and analyzing plant flotation trials of evaluating a collector

The routine variations of metal flotation recovery always exist in every concentrator due to existing fluctuations in daily operations. It should be taken into consideration when conducting a plant trial of evaluating a reagent. The reference distribution was used in this paper to quantify these existing variations and to plan a plant trial. Finally, paired T-test was employed to analyze the trial results. The trial results showed that the average Cu recovery was increased by 3% for the tested collector or 1.8% after taking into consideration the routine Cu recovery variation of 1.2% during the trial. With the application of these statistical tools in planning a plant trial and analyzing the results, a more convincing and accurate conclusion about the real benefit of selecting a collector can be drawn.

Interaction of sodium diisobutyl dithiophosphinate and platinum in aqueous solutions and on sulphide surface

For the noble metal flotation reagents, the authors propose a new test method of selective adsorption on surface of minerals covered with noble metal grains, by using a scanning electron microscope equipped with an X-ray energy-dispersive microanalyzer. Sorption of DTPINa was recorded by SEM and thin layer chromatography on surface of platinum metal grains in the form of a compound identical to the synthesized compound Pt[(iso-C4H9)2PS2]2. It has been found that interaction of DTPI and platinum ions can run in unheated aqueous solutions at a rate sufficient for flotation. In pH 4–9 range, the rate of platinum DTPI formation is maximal.

Bacís flotation cell for gold- and silver-beard pyrite recovery

In mineral processing, poor froth-flotation performance translates into both an enormous loss of revenue and an unnecessary waste of the ore reserve. In this context, Bacis Mining Company developed a versatile new, high-performance flotation-cell design that can be incorporated into various flotation circuits. The main feature of this circular cell is that it is comprised of two separate sections, namely, a flotation cell that uses wash water to minimize the entrainment of fine gangue particles into the froth product and an external bubble generator that produces small bubbles of relatively uniform size at a specified aeration-rate. The air/water mixture is blended with the pulp by gentle agitation, so as to enhance particle-bubble aggregate-stability. Comparative metallurgical performance with conventional flotation cells show that the power requirements and operating costs for precious metal flotation are three times lower, while the concentrate grade is 7% higher and the recoveries of precious metals are 5% higher.

The use of flotation techniques in the remediation of heavy metal contaminated sediments and soils: an overview of controlling factors

The potential use of flotation as a remediation technique for heavy metal contaminated sediments and soils is discussed. In general, the flotation process is much less selective for heavy metals in sediments and soils compared to the results obtained in common mineral ore flotation practice. The following factors could be isolated as responsible for this different behaviour: the metal distribution over the different geochemical phases (metal partitioning), the metal distribution over the different size fractions (metal fractionation) and the presence of organic matter (humic substances). These controlling factors were illustrated by performing Denver flotation experiments on a natural canal sediment and column flotation tests on synthetic sediments. It is emphasised that sequential extraction techniques can be used as a tool for determining the original metal partitioning in sediments and soils and as a result helps to select the most appropriate procedure of flotation (e.g. a phase-specific collector). A chemical pre-treatment step (e.g. sulphidisation, hydroxylation) prior to the flotation of sediments and soils can be beneficial depending on the in-situ metal partitioning and serves to transfer heavy metals, which are associated with different speciation sources (oxides, sulphides, clay minerals, organic matter, etc.), into one unique-good floatable-chemical speciation form (e.g. oxides, sulphides). The selective flotation of metal-bearing particles from fine-textured sediments and soils is very difficult and therefore a major challenge for future research is to tackle the problems related with the flotation of these fines. Organic matter, which is rather selectively flotated, has an adverse effect on the metal (sulphide) flotation selectivity due to its adsorption onto mineral surfaces.

Novel Multivariate Calibration Methods for X-Ray Analyzer

The key measurement instruments in the control of the base metal flotation are the on-line elemental analyzers like the Courier X-ray fluorescence analyzer. The calibration of the analyser is one of the key factors in the operation of the X-ray fluorescence analyser. The quality of the analyses is limited by the quality of the calibration of the assay calculation model. The co-linearity of the measurement information is problematic for the multi-linear regression used in the assay calculation and calibration. In this study two new regression methods are introduced for the assay calculation and calibration: Principal Component Regression and Partial Least Squares regression. These methods utilize the idea of internal structure of data - latent structure that handles the co-linearity internally.