A strategy for the identification of optimal flotation circuits

This article presents a strategy for the identification of optimal flotation circuits based on experimental data and the assumption that the flotation circuit structure are not very sensitive to stage recovery. The main objective is to find a set of optimal flotation circuit configurations, including the best metallurgical conditions for the process and cell design. The optimization process maximizes the Net Present Value (NPV). This methodology consists of two steps. The first step of the methodology entails obtaining data from the laboratory. Different metallurgical conditions are tested for different flotation stages. Each metallurgical condition is evaluated to determine its kinetics. The second step of the methodology is the optimization process. The optimization process achieves the best solution by optimizing cell design, flotation circuit structure and metallurgical conditions. The optimization process has three phases. The first phase assumes that every flotation stage has the same residence time and calculates feasible flotation circuits, metallurgical conditions and cell volumes. This process is performed for several residence times and, therefore, a set of feasible solutions is generated. The second phase takes the previous set of feasible solutions and calculates the residence time at each flotation stage. Then, for each phase two solution, the optimal flotation circuit, metallurgical conditions and cell design are calculated. The final product is a set of optimal solutions than can be considered for further study. The procedure is illustrated by the design of a zinc flotation plant, considering seven flotation stages and five species.     

The dependency of the critical contact angle for flotation on particle size - Modelling the limits of fine particle flotation

The flotation behaviour of fine particles is studied in this work. Fine methylated quartz particles within the size range from 0.2 to 50 μm, and with varying contact angles, were floated in a mechanical flotation cell. Results indicate that particles of a given size need to possess a minimum critical contact angle, which increases in value as particle size decreases, for flotation to be initiated. As a consequence, a non-floating component exists within a given size fraction. This is interpreted as a fraction consisting of particles below the critical contact angle for flotation for that size. The critical contact angle for flotation is explained in terms of the existence of an energy barrier for bubble-particle attachment. The flotation results are interpreted by means of [Scheludko et al., 1976] and [Drelich and Miller, 1992] models for the floatability of fine particles. The experimental data compared very well with calculations using the Drelich and Miller equation, allowing extension to the prediction of the critical contact angle for flotation down to particle sizes well below the previous limits investigated, bridging the gap existing in the literature.     

Mathematical models of the column flotation process a review

Mathematical modelling is a valuable quantitative instrument, which is being effectively employed to the column flotation process in order to predict its metallurgical performance. This paper presents an up-to-date assessment of the various mathematical models for column flotation currently available under the categories of kinetic models and non-kinetic models and also identifies a number of associated shortcomings.     

Amine flotation of fine quartz and glass beads

The effect of pH on the n-dodecylamine flotation of −20 μm quartz and glass beads was studied. A microflotation cell suitable for use with very fine particles was used in the flotation experimentation. The amount of agglomeration of particles at different pH values was compared using 80% passing sizes (P₈₀) estimated from size distribution data.Results obtained show that in such flotation systems agglomerates, instead of individual particles, are generally present and floated. The presence and flotation of agglomerates suggests that low recoveries in very fine particle systems may have little to do with single particle — bubble contact, but rather are related to other problems associated with such systems.     

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 150–300 μm and 300–600 μm 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 50 Hz, 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 (300–600 μm) 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.     

Surface morphologies and floatability of sand-blasted quartz particles

Significance of morphological properties of minerals in flotation has been recognized for several decades but sufficient research efforts have not been devoted to this problem. In this study, a special design laboratory scale blasting equipment was used to produce quartz particles with different shapes and roughness values, and develop a new method by which flotation characteristics of quartz particles could be enhanced. For this purpose, micro-flotation experiments were carried out with un-blasted and blasted quartz particles, and the results were correlated with their shape and roughness values analyzed with SEM, BET, and Image analysis methods. The results indicated that the blasted quartz particles with more angular and rougher surfaces gave better floatability compared to the un-blasted quartz particles.     

A new collector for rare earth mineral flotation

A new collector for bastnaesite flotation - modified hydroxamic acid (MOHA) has been developed through several years laboratory research. The experimental results of flotation of pure bastnaesite mineral and rare earth ores, and the application experience in flotation plants showed that MOHA is an efficient collector for bastnaesite flotation. MOHA has stronger collector ability and higher selectivity compared to the other commonly used collectors. Through the measurements of zeta-potential, adsorption and infrared adsorption spectrum and in terms of the electronegativity theory of reagent groups, the flotation mechanism has been discussed. It was concluded that the adsorption of MOHA on bastnaesite surfaces is chemical adsorption in nature through three oxygen atoms in the polar group of MOHA chelating the surface Ce(III) of bastnaesite to form a pentagon-cycle chelate: O---C=N---O---Ce(III)---). Additionally, the chemisorption is accompanied with the multilayer and non-homogeneous physical adsorption of the MOHA molecules. The MOHA adsorption equation at the surfaces of bastnaesite can be expressed as: Γ = 6.76×10⁻²C^1/1.02, while the adsorption rate constant k is: k = 2.64×10⁵min⁻¹mol⁻¹m².     

Metal ions released from fluid inclusions of quartz associated with sulfides

The release of fluid inclusions has a strong potential for the unintentional activation of minerals during flotation. The present study aims to characterize fluid inclusions in natural quartz from a complex sulfide ore deposit. The results indicate that many fluid inclusions exist in the quartz. Under the experimental conditions of 2 g of quartz cleaned in 40 ml of pure deionized water under an inert atmosphere, the concentrations of Cu, Pb, Zn and Fe in aqueous solution reach concentrations of 1.92 × 10⁻⁷, 8.88 × 10⁻⁷, 8.31 × 10⁻⁷ and 90.33 × 10⁻⁷ mol/L, respectively. These values are significantly greater than those from the experimental non-oxidative dissolution of the quartz. In addition, the concentrations of metal ion released from fluid inclusions in the quartz sample at conditions approached “typical” industrial flotation environment are determined. The results indicate that the fluid inclusions of quartz represent the considerable sources of Cu, Pb, Zn and Fe in the aqueous solution. The present investigation provides a new understanding for the source of the unavoidable metal ions in the flotation pulp and may benefit understanding of the flotation theory.     

Developing critical coalescence concentration curves for industrial process waters using dilution

Critical coalescence concentration (CCC) is commonly used to characterize frothers. The CCC is determined from a plot of Sauter mean bubble size (D₃₂) vs. frother concentration, referred to here as the ‘addition’ method. Industrial flotation systems can encounter a number of naturally occurring surfactants and salts that also influence bubble size. In effect there is a ‘system’ CCC. This paper introduces a dilution method to identify the system CCC. The study verifies the dilution technique using the commercial frother DF-250. It is shown that the system CCC can be expressed as an equivalent DF-250 concentration to provide context and a means of comparing water samples. The viability of using gas holdup to provide an estimate of process water D₃₂ is also explored. To illustrate the procedure three samples of process water from the Albian Sands bitumen processing plant were examined. They proved to be similar and yielded a system CCC equivalent to about 20 ppm DF-250. It is concluded that the dilution and frother equivalent techniques can be used to help identify system hydrodynamic properties.     

新型JM-208起泡剂在钼浮选中的应用研究

金堆城钼业公司钼矿浮选原采用的起泡剂成分复杂,质量不稳定,造成粗选起泡、精选易发粘等问题。采用新型JM-208起泡剂进行实验室试验和工业试验结果表明,JM-208可完全替代钼浮选现用杂醇类起泡剂,能有效改善操作条件,提高技术指标,降低药剂成本。     

某矿业公司三选厂铜系列浮选工艺流程优化改造

玉溪大红山矿业有限公司三选厂铜系列主要产品为铜精矿和铁精矿，自2012年2月份投产以来，生产运行平稳。随着入选铜原矿品位下降，铜精矿生产成本有所提高。为积极响应公司在不影响铜指标前提下降低生产成本，对铜系列浮选流程进行优化改造。     

Ionic strength effects in diamine flotation of quartz and magnetite

The flotation of quartz and magnetite was studied as a function of pH when using N-alkyl-1, 3 diaminopropanes and n-dodecylamine as collectors. The alkyl chains of the diamines were 8, 12 and 16 carbons in length. Two collector concentrations were used and flotation studied in the absence of additives and in the presence of NaCl. The chain length effect on flotation using the diamines is comparable to that observed in flotation using monoamines. All the amines are relatively stronger collectors for quartz than for magnetite. The NaCl, in the concentration studied, 0.6 kmol/m³, functions as a depressant for the minerals. The 12 C diamine is a stronger collector for the minerals than the 12 C monoamine. Probable surface chemical phenomena giving rise to the observed experimental results are discussed.     

Determining frother-like properties of process water in bitumen flotation

In oil sands flotation, bitumen is known to release natural surfactants into the process water following the addition of NaOH. These surfactants appear to replace the need for frother. Measuring the Sauter mean diameter (D₃₂) vs. dilution, it was possible to characterize the frother-like properties of process waters as an equivalent concentration of a known frother commonly used in mineral flotation, DF-250. Process water samples from the thickener overflow at the Shell Albian plant were examined. The study showed equivalent concentrations up to 60 ppm DF-250 and variations between samples. Reasons for the variability are discussed. A gas holdup vs. D₃₂ correlation was established which reduced the experimental effort.     

730A与松醇油两种起泡剂在昆钢大红山铁矿150万t/a选矿厂的生产应用

介绍了730A和松醇油两种起泡剂在昆钢大红山铁矿150万t/a选矿厂的生产应用。生产实践表明,根据不同的矿石性质、工艺流程、设备性能使用两种起泡剂, 可以增强起泡剂的适应性,稳定浮选泡沫层,提高选矿指标,降低药剂成本。     

Calcium ion effects in amine flotation of quartz and magnetite

The flotation of quartz and magnetite was studied as a function of pH when using N-alkyl-1, 3 diaminopropanes as collectors in the presence of Ca(II). The alkyl chains of the diamines were 8, 12 and 16 carbons in length. Two collector concentrations were used and flotation studied in the absence of additives and in the presence of CaCl₂. All the amines are relatively stronger collectors for quartz than for magnetite in both the absence and presence of CaCl₂, in the concentration studied, 0.1 mol/dm³, functions as a depressant for the minerals. Probable surface chemical phenomena giving rise to the observed experimental results are discussed.     

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 (850–1180 μm, 425–850 μm and 250–425 μm) 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.     

某低品位钾长石矿提纯工艺研究

分析了某低品位钾长石矿的主要矿物成分,K2O+Na2O含量为7.47%。针对该钾长石矿的性质,进行了单一磁选、脱泥-磁选、浮选、脱泥-磁选-浮选四个除铁流程试验,结果表明浮选法除铁效果较佳。试验首先采用阴离子捕收剂十二烷基磺酸钠和石油磺酸钠反浮选除去长石矿中细粒的含铁矿物,再经HF法用十二胺捕收剂对长石-石英进行分离,结果表明,可得产率43.57%、含Fe2O30.25%、K2O13.10%、Na2O0.21%、SiO266.77%的长石精矿和产率41.33%、含Fe2O30.18%、SiO297.66%的石英精矿。      

某低品位稀土矿浮选工艺的改造实践

四川省某轻稀土矿山,原矿伴生萤石、重晶石及等多种有用矿物组分,原有选别原则流程分为稀土重选、稀土浮选、重晶石浮选和萤石浮选四个模块。该工艺方案稀土浮选与重晶石萤石浮选属于两套独立的生产系统,同时,又不可避免地存在着稀土浮选精矿品位与回收率受重晶石萤石浮选的回水相互影响等因素,导致了自投产以来稀土品位与回收率均未能达到设计指标。为此,选矿厂对流程开展了许多长期的考查与改进,对稀土浮选工艺进行其它方案可行性研究。最终确立新的工艺方案将独立的稀土浮选取消,形成了重晶石优先浮选,后稀土与萤石混合浮选,再通过湿式高梯度磁选作业回收浮选精矿中稀土的工艺。新的工艺最终达到了重选加浮选稀土综合回收率到72%以上,浮选精矿ROE品位65%以上的良好指标。     

Fe(III) as an activator for the flotation of spodumene,albite, and quartz minerals

The effect of Fe(III) ions on the flotation of spodumene, albite, and quartz minerals using sodium oleate (NaOL) was investigated by micro-flotation tests, zeta-potential measurement space, pyrene fluorescence spectroscopy and X-ray photoelectron spectroscopy (XPS). These minerals were difficult to float in the presence of NaOL alone. However, when Fe(III) ions were used as the activator, the flotation of the minerals improved. Zeta potential testing found the addition of Fe(III) at pH conditions <8 to reduce the negative charge on the spodumene, albite and quartz surfaces, which supports a mechanism where Fe(III) adsorbs onto these mineral surfaces, resulting in an expected increase in NaOL collector adsorption with a concomitant increase in the flotation recoveries. Subsequent pyrene fluorescence spectroscopy of these minerals in the presence of NaOL collector, with and without Fe(III) activator, showed the mineral surfaces to switch from polar to non-polar.     

蒙古国萤石矿浮选试验研究

通过对蒙古国的萤石矿样进行选矿试验研究,确定采用一次粗选、一次扫选、六次精选、中矿顺序返回的选矿工艺,获得了Ca F2品位为98.27%、回收率为90.14%的萤石精矿,其中Si O2含量为0.68%,Ca CO3含量为0.29%,杂质含量较少,为该资源的开发利用提供了基础依据。