Flotation Of Smithsonite Research Articles

Synthesis of a cationic organic silicone surfactant and its application in the flotation of smithsonite

A cationic organic silicone surfactant (DTA) with specially designed functional groups was developed as a flotation collector for smithsonite. This surfactant was synthesized via the reaction between hexaethyldisiloxane and N-β-(aminoethyl)-γ-aminoisobutylmethyldimethoxy silane using tetramethylammonium hydroxide as a catalyst. Its flotation performance was validated by flotation tests using pure minerals. The results illustrated that DTA has strong collecting ability and better selectivity for smithsonite against quartz, calcite and dolomite compared to the traditional collectors such as octadecylamine, tetradecylamine and dodecylamine. Based on the analysis of FTIR spectra, zeta-potential measurements, X-ray photoelectron spectroscopy and density functional theory calculations, it can be concluded that the adsorption mechanism of DTA on the surface of smithsonite was mainly dominated by chemisorption and electrostatic adsorption. DTA's unique properties, which include two coordination sites (NH2 and NH), and the “parachute” shape structure of OSi(C2H5)3, resulted in superior collecting powers for smithsonite.

Contribution of ammonium ions to sulfidation-flotation of smithsonite

Sulfidation-flotation is commonly performed to recover base metal oxide ores. Sulfidation could become the key process in recovering zinc from zinc oxide ores. We investigated the common zinc oxide mineral. An ammonium salt was used to enhance sulfidation-flotation of smithsonite. The effect of ammonium ions on sulfidation and flotation of smithsonite was investigated by microflotation, inductively coupled plasma analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy. Addition of the ammonium salt facilitates flotation of smithsonite and improves the flotation recovery by ∼25%. Solubility tests under different conditions indicate that the surface solubility of smithsonite in the presence of ammonium ions significantly decreases. Energy-dispersive X-ray spectroscopy based semi-quantitative analysis shows that the concentration of sulfur on the ammonium enhanced sulfurized smithsonite surface is 8.55%, whereas that on the sulfurized smithsonite surface is 2%. XPS analysis reveals that smithsonite is more easily sulfurized by sodium sulfide in the presence of ammonium ions. Therefore, ammonium ion addition can be used to enhance sulfidation of smithsonite and improve the flotation performance.

The Effect of Polystyrene on the Carrier Flotation of Fine Smithsonite

Carrier flotation is a common technique used to improve flotation recovery of ultrafine ores. In this study, we used coarse polystyrene as the carrier material to enhance flotation recovery of fine smithsonite (ZnCO3) particles. Sodium oleate was used as the collector and played a role in the adhesion of fine smithsonite to polystyrene due to its amphipathic properties. The carrier feature of polystyrene was demonstrated using particle size analysis, total organic carbon, and scanning electron microscopy. The fine smithsonite particles coated the polystyrene particles through a reaction between the active zinc sites and the carboxyl head groups of the oleate adsorbed on smithsonite and through a hydrophobic interaction between polystyrene and the hydrocarbon chains of the oleate. Newly enlarged particle aggregates with smithsonite shells enhanced collision and attachment of the hydrophobized aggregates with bubbles, which accelerated smithsonite flotation recovery.

Smithsonite Flotation from Zinc Oxide Ore using Alkyl Amine Acetate Collectors

Flotation of smithsonite from tailing coming from a cerussite flotation circuit was investigated using Armac C and Armac T as alkyl amine acetate collectors. The results showed that the dosage of Na2S, collector type and dosage, collector's mixture ratio, and desliming are the main affecting parameters on the Zn grade and recovery of smithsonite flotation concentrate. The contact angle measurement on smithsonite and calcite minerals indicated that Armac T acts more selectively than Armac C and enhances the Zn grade of the concentrate. At the mixture ratio of Armac C:Armac T, 1:6, the collectors' consumption are decreased significantly and an optimal concentrate with 94.4% recovery and 42.3% Zn grade is obtained without any gangue depressant reagents. Nevertheless, using NaOH as a pH regulator, the dosage of Na2S is decreased significantly but the flotation results are affected negatively. The recovery of Zn in the concentrate is more sensitive to the slime than Zn grade. The Zn minerals lost in the tailing are mostly in the form of very fine disseminated particles. About 11% of smithsonite with particle sizes finer than 10 µm is lost in the slime. Overall Zn flotation recovery is estimated to be about 84%.

Flotation of zinc oxide ore using cationic and cationic-anionic mixed collectors

Flotation of smithsonite coming from a cerussite flotation circuit was investigated using Armac C and Armac T as cationic collectors and their mixtures with potassium amyl xanthate (KAX) as an anionic collector. Under optimum condition using Armac T with sodium hexamethaphosphate as a de- pressant, a smithsonite concentrate with 42% Zn and 89.6% recovery is obtained while in the presence of sodium silicate depressant Armac C produces a concentrate containing 40.8% Zn with 92.5% recovery. However, Armac T acts a little more selectively than Armac C but their mixture with KAX act inversely. The KAX-Armac C mixed collector improves the Zn grade and recovery of the flotation concentrate while KAX-Armac T does not. At the mixture ratio of KAX - Armac C 2:1, the amine collector consump- tion is decreased and an optimal concentrate with 94% recovery and 43% Zn grade is obtained without any gangue depressant reagents.

Role of dissolved mineral species in selective flotation of smithsonite from quartz using oleate as collector

Quartz is, in most cases, the major gangue mineral found in the zinc oxide ores. Although it possesses a negative surface charge at pH 9, quartz nevertheless, reports to the concentrate with Zn in oleate flotation. In this study, it was found that quartz can be activated with Zn(II) and Pb(II) and floated with oleate in the pH regions of 9–11.5 and 6.5–10.5, respectively. In these pH regions, zinc and lead hydroxides are the stable species, and can be adsorbed on the negatively surface charge of quartz by adsorbing/precipitating. Therefore, the adsorption of the oleate on the activated quartz surface was being made possible. Furthermore, the effects of sodium silicate, sodium sulfide, sodium hexametaphosphate (SH), sodium fluoride, carboxymethylcellulose (CMC), and starch as depressants of dissolved Zn(II) and Pb(II) were also studied. The CMC was a quite adequate depressant without having adverse effect on smithsonite flotation. In order to probe the validity of the findings, zeta potential and real flotation experiments were also carried out successfully.

Electrokinetic properties of smithsonite and its floatability with anionic collector

The effect of the smithsonite/water interface properties on the floatability of the mineral without and in the presence of sodium carbonate was examined through zeta potential measurements, microflotation tests, and the concentration of Zn2+ ions measurement, in the pH range from 7 to 11. The isoelectric point value of the mineral was achieved at pH 8.0, and the species Zn2+, OH−, HCO3−, CO32−, and H+, as well as the reabsorption of hydrolysis products would determine the smithsonite–solution interface properties. Smithsonite presents high floatability with sodium oleate (1.5×10−4mol/L) between pH 7.0 and 8.0. Above pH 8.0, the smithsonite floatability decreases abruptly, and the polymeric zero-charged Zn(II) hydrolyzed species [Zn(OH)2(H2O)2]n0 is proposed for depressing the floatability of smithsonite. With the sodium carbonate added into the solution, the isoelectric point value of the mineral was achieved at pH 8.2. The smithsonite interface, having more surface cation sites and zinc species in the Stern layer, gives rise to the floatability in the pH range from 7.0 to 8.7. Due to the formation of Zn(CO3)22−, the decrease of the concentration of the hydrolyzed species [Zn(OH)2(H2O)2]n0 makes smithsonite more floatable than that without the Na2CO3 at 8.7<pH<10 (flotation recovery from 30% to 75% at pH 9.5). The results show that the anionic flotation of smithsonite is a promising route to recover Zn with the sodium carbonate.

Flotation of zinc oxide ores by cationic and mixed collectors

The flotation of smithsonite from tailing which comes from the cerussite flotation circuit was investigated using Armac C and Armac T as amine collectors. The results indicated that the dosage of sodium sulfide, collector type, and desliming are the main affecting factors on the Zn grade and recovery of smithsonite flotation concentrate. Armac T acts a little more selectively than Armac C, and enhances the Zn grade of the concentrate, while Armac C improves the recovery of Zn. At the mixture ratio of Armac C:Armac T=1:6, without consumption of any gangue depressants, an optimal concentrate with 94.4% recovery, and 42.3% Zn grade is obtained. In this condition, the collectors’ consumption is decreased significantly. Desliming prior to flotation is essential for successful recovery of smithsonite.

Influence of important factors on flotation of zinc oxide mineral using cationic, anionic and mixed (cationic/anionic) collectors

In this study, the influences of important factors on smithsonite flotation are investigated. Dosages of sulphidizing agent and collector, desliming prior to flotation and the use of sodium hydroxide instead of sodium carbonate as the pH regulator are essential to the effective recovery of smithsonite in cationic flotation. The appropriate temperature for flotation was found to be 30–40 °C. Sodium hexametaphosphate (SH) and sodium silicate had the greatest selectivity between smithsonite–calcite and smithsonite–quartz, respectively. The results of oleic acid flotation showed that the grade and recovery of zinc were relatively low in comparison with the sulphidization-cationic flotation method. Despite using sodium silicate and SH as depressants in oleic acid flotation, flotation was not selective. Flotation using mixed collectors (Armac C + Potassium Amyl xanthate) showed promising results. The ratio of the mixed collectors and the sequence of addition of mixed collectors were important criteria in attaining true mixed collector flotation.

Studies on selective flotation of smithsonite from silicate minerals using mercaptans and one stage desliming

The separation of oxide zinc mineral from silicate minerals in smithsonite mineral, associated silicate minerals and oxide zinc ore samples was assessed using methyl mercaptan (CH3SH), ethyl mercaptan (C2H5SH) and hexyl mercaptan (C6H13SH; HM) as collectors. The optimal flotation conditions were defined through Hallimond tube, contact angle and batch flotation and the results were applied to a natural Angooran oxide zinc ore. The microflotation and artificial mixture flotation results showed a maximum of 78% flotation recovery using HM. Selective flotation of oxide zinc ore was also accomplished by using an HM collector at pH 9. The flotation recovery was 55% without desliming. When the initial feed was deslimed before bench scale flotation tests, the recovery increased from 55 to 75% with 22·5% zinc content in the concentrate. When methyl mercaptan or ethyl mercaptan was used, lower zinc recoveries and grades compared to HM flotation were achieved.

The effect of reagents on selective flotation of smithsonite–calcite–quartz

In this paper the effects of sodium sulphide, sodium hexa methaphosphate (SH), sodium fluoric, starch and sodium silicate adsorption on smithsonite, quartz and calcite surfaces at various pH values, and using Armac C and oleic acid as collectors were investigated through microflotation. Also, the effects of various primary amine collectors (Armac C, Armac T, Flotigam SA, Flotigam TA and Armeen TD) were investigated for smithsonite flotation. The flotation tests were performed using purified samples from Angooran mine by the microflotation technique. The cationic flotation results showed that the maximum recovery of smithsonite could be improved to 92% using 400 g/t Armac C and 500 g/t sodium sulphide at pH 11. Also, the quartz and calcite recoveries reached 98% and 89%, respectively, at the above mentioned conditions. Moreover, using 1250 g/t SH and 1500 g/t sodium silicate as a depressant, the quartz and calcite recoveries decreased to 70% and 20%, respectively, and also the smithsonite recovery was reduced to 82%. Furthermore, the experiments showed that the behavior of sodium fluoric as a quartz depressant is similar to that of sodium silicate. Flotation results using oleic acid revealed that the maximum recovery of 90% occurs at pH 9 and 500 g/t oleic acid. Also, the quartz and calcite recoveries reached 26% and 87%, respectively, in the anionic flotation conditions. Increasing amount of sodium silicate to 2000 g/t caused a decrease in the smithsonite recovery to 87% and also decreased the calcite and quartz recoveries by 10% and 15%, respectively.

95/05629 A further investigation of the novel multi-stage agitated column for fine coal beneficiation

The interaction between sulfide-ion species and smithsonite surfaces and its response to flotation performance were investigated by means of microflotation experiments, surface-adsorption tests, zeta-potential determination, and X-ray photoelectron spectroscopy (XPS) analysis. The microflotation experiments results indicated that addition of Na2S elicited a positive effect on the smithsonite floatability within an appropriate concentration range (<7.5 × 10−4 mol/L), otherwise it showed an obvious negative influence. The surface adsorption tests showed that a significant difference in amounts of sulfide-ion species retained in the pulp solutions was exhibited after smithsonite samples were sulfidized with different concentrations of Na2S. The negativity of the zeta-potential increased with increasing Na2S concentration but decreased under alkaline conditions after adding NaAX. The XPS analysis results revealed that zinc sulfide species formed on the smithsonite surface after sulfidization, and its contents increased with increasing Na2S concentration. Moreover, the sulfidization product formed on the mineral surface was composed of monosulfide and polysulfide, and polysulfide played an important role in the sulfidization flotation of smithsonite. These results demonstrated that excess Na2S concentrations could enhance smithsonite sulfidization but could inhibit the adsorption of collector onto the sulfidized smithsonite surfaces due to the abundant sulfide-ion species retained in the pulp suspension.