Sodium Isopropyl Xanthate Research Articles

A study on the modified flotation parameters and selectivity index in copper flotation

ABSTRACTSelectivity index (SI) and modified flotation rate constants of copper and iron were evaluated to rougher flotation circuit of the Sarcheshmeh copper ore by a series of batch flotation tests. Kinetics model of Agar was fitted to experimental data. The results indicated that first-order kinetics model of Agar presented the time–cumulative recovery curves of flotation tests quite well for Cu and Fe. Also, the results showed that the selectivity between Cu and Fe enhanced with increasing the pH, solid content, and dosage collector. In addition, performance of collectors showed that the best selectivity between Cu and Fe was in the order of combination of Z11 and MBTs > flomin C4132 > combination of MBTs and flomin C4132 > combination of Z11, MBTs, and flomin C4132 in flotation of copper. It was also found that better results for flotation kinetics were obtained at pH 11.5, solid percentage 28, and dosage collector 40 g/t (15 g/t sodium isopropyl xanthate and 25 g/t mercaptobenzothiazole [MBT]). SI value was determined as 5.12 in optimum condition.

Flotation of copper sulphide from copper smelter slag using multiple collectors and their mixtures

Present work focuses on the differences in the performances obtained in the froth flotation of copper smelter slag with multiple collector viz. sodium iso-propyl xanthate (SIPX), sodium di-ethyl dithiophosphate (DTP) and alkyl hydroxamate at various dosages. Flotation tests were carried out using single collectors as well as various mixtures of the two collectors at different but constant total molar concentrations. Flotation performances were increased effectively by the combination of collectors. The findings show that a higher copper recovery (84.82%) was obtained when using a 40:160g/t mixture of sodium iso-propyl xanthate (SIPX) with di-ethyl dithiophosphate compared to 78.11% with the best single collector. Similar recovery improvement (83.07%) was also observed by using a 160:40g/t mixture of sodium iso-propyl xanthate (SIPX) with alkyl hydroxamate. The results indicate that in both cases DTP and alkyl hydroxamate played important role as co-collector with SIPX for the recovery of coarse interlocked copper bearing particles and has an important effect on the behaviour of the froth phase. However, comparatively higher mass recovery was obtained when hydroxamate was used as a co-collector, accompanied by poorer copper grades. In this context the co-collector DTP is advantageous for the improvement of copper grade and recovery from copper smelter slag.

Extraction of copper from copper slag: Mineralogical insights, physical beneficiation and bioleaching studies

Copper slag was subjected to in-depth mineralogical characterization by integrated instrumental techniques and evaluated for the efficacy of physical beneficiation and mixed meso-acidophilic bioleaching tests towards recovery of copper. Point-to-point mineral chemistry of the copper slag is discussed in detail to give better insight into the association of copper in slag. Characterization studies of the representative sample revealed the presence of fayalite and magnetite along with metallic copper disseminated within the iron and silicate phases. Physical beneficiation of the feed slag (~0.6% Cu) in a 2 L working volume flotation cell using sodium isopropyl xanthate resulted in Cu beneficiation up to 2–4% and final recovery within 42–46%. On the other hand, a mixed meso-acidophilic bacterial consortium comprised of a group of iron and/or sulfur oxidizing bacteria resulted in enhanced recovery of Cu (~92–96%) from the slag sample. SEM characterization of the bioleached slag residue also showed massive coagulated texture with severe weathered structures. FE-SEM elemental mapping with EDS analysis indicated that the bioleached residues were devoid of copper.

Characterisation of coarse composite sphalerite particles with respect to flotation

The flotation response of a typical zinc-lead (Zn/Pb) ore, with respect to coarse composite (sulphide/non-sulphide) particles is reported. The flotation tests were carried out on a selected feed particle size range (−600+75μm, at P80 of 390μm) and the recovery of Zn composite particles analysed on a size by size basis. The best results were achieved with the use of 75g/t sodium isopropyl xanthate (SIPX), obtaining a Zn recovery of 77%, with a significant improvement at the coarse end of the particle size distribution. Computerised scanning electron microscope (QEMSCAN) was used to characterise value mineral grain size and degree of liberation, as well as gangue and sphalerite association in particles reporting to both concentrate and tailings. A new characterisation function (Locking ratio, LR) was developed based on the data from the automated mineralogical analysis to characterise particles into two-phase composites with different degree of locking texture (simple and complex). The function, which is based on the mode of occurrence of sphalerite, grain size, proportion and composition of the constituent minerals in each particle, was used to study the flotation response of the particles with different degrees of locking. The results highlight the difference in recoverability of the sphalerite bearing particles with different degrees of locking, with simple locking texture giving higher recovery than complex locking texture, for the same overall liberation.

Detachment of coarse composite sphalerite particles from bubbles in flotation: Influence of xanthate collector type and concentration

The force required to detach sphalerite ore particles from air bubbles has been measured in flotation concentrates, for particles in the size range of 150–300μm and 300–600μm with different degrees of liberation. An electro-acoustic vibrating apparatus, that produces typical force conditions experienced in a flotation cell, was used to measure particle–bubble detachment as a function of the vibrational acceleration. Sodium isopropyl xanthate (SIPX) and potassium amyl xanthate (PAX) collectors were used in flotation, at different concentrations. At a fixed frequency of 50Hz, the maximum vibrational amplitude at which a particle detaches from bubble was used to calculate the particle detachment force. It was shown that changes in surface hydrophobicity (contact angle), due to variations in reagent conditions have significant impact on particles detaching from bubbles. On average, detachment of particles from oscillating bubble correlated well with xanthate concentration and hydrocarbon chain length of xanthate ions. Particles (300–600μm) with high contact angle obviously required higher force to detach from bubbles than similar particles with lower contact angle. This correlated well with the flotation response at the different reagent conditions. SEM analysis of particles after detachment showed that fully liberated particles attached to bubbles more readily and also gave higher detachment force than composite particles. Moreover larger detachment forces were observed, on average, for particles with irregular shape compared to particles with rounded shape of the same size range.

Critical contact angle for coarse sphalerite flotation in a fluidised-bed separator vs. a mechanically agitated cell

This work investigates the critical contact angle for the flotation of coarse (850–1180μm, 425–850μm and 250–425μm) sphalerite particles in an aerated fluidised-bed separator (HydroFloat) in comparison to a mechanically agitated flotation cell (Denver flotation cell). In this study, the surface chemistry (contact angles) of the sphalerite particles was controlled by varying collector (sodium isopropyl xanthate) addition rate and/or purging the slurry with either nitrogen (N2) or oxygen (O2) before flotation. The flotation performance varied in response to the change in contact angle in both the aerated fluidised-bed separator and the mechanically agitated cell. A critical contact angle threshold, below which flotation was not possible, was determined for each particle size fraction and flotation machine. The results indicate that the critical contact angle required to float coarse sphalerite particles in a mechanically agitated cell was higher than that in the fluidised-bed separator, and increased as the particle size increased. At the same particle size and similar contact angles, the recoveries obtained by the aerated fluidised-bed separator in most cases were significantly higher than those obtained with the mechanically agitated flotation cell.

Biodegradation of sodium isopropyl xanthate by Paenibacillus polymyxa and Pseudomonas putida

Biodegradation of sodium isopropyl xanthate using two types of bacterial strains, Paenibacillus polymyxa and Pseudomonas putida, is demonstrated. At concentrations higher than 50 mg/L, the presence of xanthate in the growth medium resulted in bacterial toxicity, retarding growth kinetics. Adaptation through serial subculturing in the presence of higher xanthate concentrations resulted in the development of xanthate-tolerant bacterial strains. Stress proteins secreted by bacterial cells grown in the presence of xanthate were isolated. Bacterial cells could utilize xanthate as a growth substrate, degrading xanthate species in the process. Acidic metabolic products generated by bacterial metabolism promoted efficient xanthate decomposition. Probable mechanisms for the biodegradation of isopropyl xanthate are illustrated.

Effect of particle size distribution on recovery of coarse chalcopyrite and galena in Denver flotation cell

The flotation recovery by particle size of single mineral chalcopyrite and galena was studied in a Denver flotation cell, using sodium dicresylthiophosphate (DTP) and sodium isopropyl xanthate (SIPX) as collectors and polypropylene glycol (PPG) as a frother. The study was extended to very coarse particle size (up to 1·6 mm). Froth stability was also measured in parallel to the batch flotation tests, in a specifically designed froth stability column, following the Bikerman approach. It is shown that particles up to 850 μm can be floated successfully, provided they are liberated and hydrophobic. However, the recovery of both chalcopyrite and galena was strongly influenced by the overall particle size distribution, decreasing sharply as the fraction of fines (−106 μm) in the feed also decreased. Rheology measurements showed negligible differences in pulp viscosity, and therefore in the collection zone hydrodynamics, between the different conditions tested. Froth stability, on the contrary, decreased as the feed particle size distribution became coarser. Correlation was found between the amount of fines in the pulp, froth stability and flotation recovery. The recovery of mineral particles is critically dependent on froth stability, which in turn is highly influenced by the overall particle size distribution of the feed material. For these reasons, the study also suggests that it is not possible in batch flotation to determine the rate and recovery of the coarse particle size fractions floating them independently from the fine size fractions.Dans une cellule de flottation de Denver, on a étudié la récupération par flottation en fonction de la taille de particule d’un minéral unique de chalcopyrite ou de galène, en utilisant du dicrésyle thiophosphate de sodium (DTP) et de l’isopropyle xanthate de sodium (SIPX) comme agents collecteurs et du polypropylène glycol (PPG) comme agent moussant. On a étendu l’étude à la taille de particule très grossière (jusqu’à 1·6 mm). On a également mesuré la stabilité de la mousse en parallèle aux essais de flottation discontinue, dans une colonne de stabilité de la mousse spécialement conçue, d’après l’approche de Bikerman. On montre que l’on peut faire flotter avec succès des particules ayant jusqu’à 850 μm, à la condition qu’elles soient libres et hydrophobes. Cependant, la récupération, tant de la chalcopyrite que de la galène, était fortement influencée par la distribution globale de la taille de particule, diminuant sévèrement à mesure que la fraction de particules fines (−106 μm) dans l’alimentation diminuait. Les mesures de rhéologie montraient des différences négligeables dans la viscosité de la pulpe et ainsi dans l’hydrodynamique de la zone de collection, parmi les différentes conditions évaluées. Au contraire, la stabilité de la mousse diminuait à mesure que la distribution de la taille de particule de l’alimentation devenait plus grossière. On a trouvé une corrélation entre la quantité de particules fines dans la pulpe, la stabilité de la mousse et la récupération par flottation. La récupération des particules minérales dépend, de façon critique, de la stabilité de la mousse qui, à son tour est hautement influencée par la distribution globale de la taille de particule du matériel d’alimentation. Pour ces raisons, l’étude suggère également qu’il n’est pas possible, en flottation discontinue, de déterminer la vitesse et la récupération des fractions de taille de particules grossières, en les faisant flotter indépendamment des fractions de taille fine.

Adsorption Study of Sodium Isopropyl Xanthate On Chalcopyrite

This paper presents voltammetric and electrochemical impedance studies of the anodic oxidation of chalcopyrite in the presence of highly concentrated sodium isopropyl xanthate solutions. The voltammetric response of the system displays a passivating effect on the chalcopyrite surface with the addition of xanthate due to its adsorption, which also impedes the transportation of oxidized species, i.e., Fe2+ and Cu2+ from the mineral matrix outwards the interface. The impedance spectra obtained near the polarization potential, at which the passivating effect is observed in the voltammograms shows a pseudocapacitive effect in the system, which is associated to the adsorption of xanthate and blocking the interface. The impedance spectra obtained show three time constants associated with the oxidation reactions of chalcopyrite and xanthate and the formation of covellite and cuprous xanthate on the mineral surface, the EIS results are according to the voltammetric response obtained for the system.

Sodium isopropyl xanthate degradation by advanced oxidation processes

This paper presents the results obtained by different oxidative processes when an aqueous solution containing sodium isopropyl xanthate is treated; this reagent is used in the flotation of copper minerals. The advanced oxidation processes used are UV photolysis, direct electrolysis and photoelectrooxidation. The solutions used containing sodium isopropyl xanthate were adjusted to the following concentrations: 6, 8, 10, 25 and 40mgL−1. The results show that the three oxidation processes proved to be suitable for the destruction of xanthate, with the following maximum destruction efficiencies: 76% for electrolysis, 95% for UV photolysis and 99% for photoelectrooxidation.

Effect of pH and environmental ligands on accumulation and toxicity of Ni2+ to Lemna minor

Environmental context Predicting metal toxicity is an important tool for effective and efficient risk assessment and regulation of metal pollution in the environment. The present study aims to provide scientific support for the development of a predictive Ni toxicity model for aquatic plants that is particularly applicable to mining-affected natural waters. We show that the effects of pH and natural organic ligands on Ni accumulation and toxicity can be modelled, but further research is required to understand the effects of flotation ligands used in the mining industry. Abstract Effects of water chemistry and metal speciation on metal uptake and toxicity to aquatic plants such as Lemna minor are not fully understood. The present study examined the effect of pH and environmental ligands (dissolved organic carbon (DOC) and mining related flotation ligands diethylenetriamine (DETA), triethylenetetramine (TETA), sodium isopropyl xanthate), on Ni toxicity to L. minor. Exposure and tissue residue toxicity thresholds were assessed to validate the use of a Biotic Ligand Model (BLM) or a Tissue Residue Approach (TRA) as a framework for predicting Ni toxicity. An increase in the activity of H+ non-linearly decreased the toxicity of free Ni ion activity, whereas Ni accumulation kinetics indicated that the mechanism of Ni2+ and H+ interaction was not competitive inhibition as expected by the BLM framework. The effect of DOC on the toxicity of total Ni concentration was relatively small (toxicity decreased by less than a factor of 2) and was explained solely by the complexation of Ni2+ by DOC. Alternatively, the protective effect of flotation ligands (DETA and TETA) was much less than expected based on estimated Ni complexation. Overall, a TRA model was directly applicable in the presence of organic ligands but not to varying pH, whereas a BLM-type model was applicable with changes in pH and DOC but not in the presence of the lesser studied flotation ligands. Such mechanistic information is essential for the development of reliable Ni toxicity models that would aid in risk assessment and regulation of Ni in the environment, particularly in mining-affected regions.

The effect of different collectors on recovery of copper and precious metals of the ore body Tenka 3

This work presents a part of technological testing that were conducted in order to define the optimum conditions of flotation concentration of the ore from the deposit Tenka 3 - North Mining District, Majdanpek copper mine. Provided description refers to testing the effect of collectors NaIPX, 3418 and AP5500 as well as the pH value of pulp to the certain technical indicators (recovery of copper and precious metals) of the rough flotation process. It was found that generally the best recoveries of copper and gold in the basic copper concentrate are obtained using a combination of collectors 3418 and AP5500, while the best silver recovery in the basic copper concentrate is obtained using the sodium isopropyl xanthate. In addition, higher recoveries of gold and silver were obtained at lower pH value of pulp, while, on the other hand, a clear dependence of copper recovery on pH value was not observed in tested pH range (10.0 to 11.5).

Study of Adsorption of Sodium Isopropyl Xanthate on Galena

This paper deals with a study of the oxidation processes of the PbS-sodium isopropyl xanthate system in alkaline conditions (pH 8, similar to flotation circuits Pb-Cu) by using cyclic voltammetry and Electrochemical Impedance Spectroscopy (EIS). Three oxidation peaks are identified in the voltammograms that correspond to reactions previously reported in the literature. A plot of the differential capacitance of the double layer vs. potential gives a potential of zero charge (PZC) of -0.31 V vs. SCE for the system, that coincides with an oxidation peak attributed to the adsorption of xanthate. EIS at PZC for different xanthate concentrations evidence an adsorption processes via a charge transfer mechanism under diffusional control. EIS data at potentials more positive than PZC display an inductive loop that is related to a charge transfer processes involving the reaction of the adsorbed intermediates with the consequent modification of the PbS-sodium isopropyl xanthate interface.

Estudio de los mecanismos de activación de la esfalerita con Cu(II) y Pb(II)

This article presents results of an experimental study on the sphalerite activation with Cu(II) and Pb(II), whose main objective was to investigate the activation mechanisms and to evaluate the magnitude of the hydrophobization achieved with both chemical species. The hydrophobicity acquired by the mineral due to the interaction with the activator and collector (sodium isopropyl xanthate) is characterized making use of the contact angle technique. The results show that Cu(II) replaces the Zn of the external layers of the mineral, promoting the sulfide (S 2– ) oxidation to produce a mixture of CuS, Cu 2 S and S°, of hydrophobic nature. The subsequent interaction with xanthate increases the hydrophobicity of the mineral surface. In turn, Pb(II) activation of sphalerite is due to the formation of a PbS layer that reacts with xanthate to produce hydrophobic species (e.g., PbX 2 ). It is also observed that the hydrophobicity of sphalerite activated with Pb(II) is favored under air atmospheres, as compared to that obtained under nitrogen atmospheres. It is concluded that the hydrophobicity achieved by lead activation may be of the same order of magnitude to that deliverately induced by copper activation.

Comparison of the depressant action of sulfite and metabisulfite for Cu-activated sphalerite

The depressant action of sulfite and metabisulfite (MBS) for copper-activated sphalerite has been studied in the absence and presence of sodium isopropyl xanthate (SIPX) under both air and nitrogen atmospheres by using the contact angle technique. Results obtained indicate that MBS is a better depressant of sphalerite in the presence and absence of SIPX under both air and nitrogen atmospheres. The simultaneous presence of dissolved oxygen and bisulfate presumably promotes their synergetic action on sphalerite depression. Results corroborate the beneficial effect of using an aeration stage before collector addition in order to maximize the depressant action over the hydrophobizing species present on the sphalerite surface and to avoid xanthate oxidation.

An Exploratory Investigation of Polar Organic Compounds in Waters from a Lead–Zinc Mine and Mill Complex

Surface water samples were collected in 2006 from a lead mine–mill complex in Missouri to investigate possible organic compounds coming from the milling process. Water samples contained relatively high concentrations of dissolved organic carbon (DOC; greater than 20 mg/l) for surface waters but were colorless, implying a lack of naturally occurring aquatic humic or fulvic acids. Samples were extracted by three different types of solid-phase extraction and analyzed by electrospray ionization/mass spectrometry. Because large amounts of xanthate complexation reagents are used in the milling process, techniques were developed to extract and analyze for sodium isopropyl xanthate and sodium ethyl xanthate. Although these xanthate reagents were not found, trace amounts of the degradates, isopropyl xanthyl thiosulfonate and isopropyl xanthyl sulfonate, were found in most locations sampled, including the tailings pond downstream. Dioctyl sulfosuccinate, a surfactant and process filtering aid, was found at concentrations estimated at 350 μg/l at one mill outlet, but not downstream. Release of these organic compounds downstream from lead–zinc mine and milling areas has not previously been reported. A majority of the DOC remains unidentified.

New method for synthesis of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropylthiocarbamates by oxidation of ammonium salt of xhantogenic acid

A synthesis of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates by oxidation of ammonium salt of ethyl and isopropylxanthogenic acid in a presence of sodium hypochlorite and hydrogen peroxide were performed. Ammonium salt of ethyl and isopropylxanthogenic acid was obtained by the reaction of alkylammonium sulfate and sodium ethyl and isopropyl xanthate. Studies on a dependence of N-ethyl-O-isopropylthiocarbamate yield and purity with respect to reaction parameters (reaction time, molar ratio of oxidant and ethylamonium salt of isopropylxanthogenic acid) were performed. Optimal reaction conditions for synthesis of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates were established. Synthesized compounds have been fully characterized by FTIR, 1H NMR and MS data, while purity has been determined by GC method. A plausible pathway for the N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates synthesis, in the presence of the oxidative agents sodium hypochlorite and hydrogen peroxide, was proposed. The presented synthetic methods has been developed at laboratory and applied at semi-industrial level. The developed optimal method provides a powerful and versatile method for the preparation of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates. This new optimized method offer several benefits, namely, simple operation, mild reaction conditions, bypass of hazardous organic solvents, moderately toxic and inexpensive reagents, and also short reaction times and high product yields.

Characterization and recovery of copper values from discarded slag

In any copper smelter large quantities of copper slag are discarded as waste material causing space and environmental problems. This discarded slag contains important amounts of metallic values such as copper and iron. The recovery of copper values from an Indian smelter slag that contains 1.53% Cu, 39.8% Fe and 34.65% SiO(2) was the focus of the present study. A complete investigation of the different phases present in the slag has been carried out by means of optical microscopy, Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. It is observed that iron and silica are mostly associated with the fayalite phase whereas copper is present in both oxide and sulfide phases. These oxide and sulfide phases of copper are mostly present within the slag phase and to some extent the slag is also embedded inside the oxide and sulfide phases. The recovery of copper values from the discarded slag has been explored by applying a flotation technique using conventional sodium isopropyl xanthate (SIX) as the collector. The effects of flotation parameters such as pH and collector concentration are investigated. Under optimum flotation conditions, it is possible to achieve 21% Cu with more than 80% recovery.

Cross-Reactions between Xanthates and Rubber Additives

We previously described allergic contact dermatitis from xanthates used in the recovery of metals from mining ores. We observed cross-reactions with carbamates, believed to be due to the common "dithio" nucleus shared by both groups. The present study was undertaken to establish the rate of cross-reactions between xanthates and rubber additives. Between November 2002 and December 2005, 1,220 consecutive patients were patch-tested with sodium isopropyl xanthate 10% in petrolatum (pet) and with potassium amyl xanthate 10% pet and later 5% pet, in addition to the North American Contact Dermatitis Group standard series and other series as required by their conditions. Fifty-one patients reacted to xanthates, carbamates, or thiurams; 26 reacted to xanthates only, and these reactions were felt to be irritant. Twenty-five patients reacted to xanthates and/or to one or more of the rubber additives, 12 had positive reactions to xanthates and to either carba mix or thiuram mix, 10 reacted to xanthates and carba mix, 9 reacted to xanthates and thiuram mix, and 8 showed positive reactions to xanthates and both mixes. However, 13 patients had positive reactions to carba mix and thiuram mix but did not react to xanthates. Six patients reacted to other rubber additives such as mercaptobenzothiazole, black rubber mix, and mixed dialkyl thioureas. Five of these patients also reacted to xanthates, 4 reacted to xanthates and carba mix, and 3 reacted to xanthates, carba mix, and thiuram mix. Of patients sensitized to carbamates, thiurams, or mercaptobenzothiazole, 50% exhibit cross-reactions with xanthates. Xanthates are irritants, and their patch-test concentrations should be lowered to 5% or less.

Mechanism for the recovery of silicate gangue minerals in the flotation of ultrafine sphalerite

The effect of copper sulphate and sodium isopropyl xanthate on the flotation of a mixed mineral system has been studied at pH 9. The mixed mineral system was composed of colloidal silica and ultrafine sphalerite particles. Batch flotation, zeta potential and rheology have been applied to identify mechanisms by which the silica may misreport to a sphalerite concentrate. The results indicate that, in the absence of both copper sulphate and xanthate, silica was recovered essentially by the entrainment mechanism. However, the addition of copper sulphate and isopropyl xanthate increased particle interactions between silica and sphalerite, promoting aggregation. Consequently, silica may misreport to the concentrate via a combination of both entrainment and aggregation mechanisms. Under the conditions applied in the present study, silica is not likely to be recovered via true flotation, i.e. by attachment of silica particles to bubbles.