Process intensification of fine coal separation using two-stage flotation column

Flotation column is widely used as the separation equipment for fine mineral due to its high selectivity. However, this device may be unsuitable for the coarse particle flotation and has high handling ability. A two-stage flotation column with dimensions of 2 000 mm× 1 000 mm×4 000 mm was designed to enhance the column flotation process. The energy input was modified by adjusting the flow rate and the head of circulating pump. The flotation column was designed with low energy input in the first stage （speed flotation stage） to recover easy-to-float materials quickly, and high energy input in the second stage （recovery stage） to recover difficult-to-float minerals compulsorily. Contrast experiments on the throughput and coarse coal recovery of high ash coal from the Kailuan Mine were conducted using conventional single-stage flotation column and the two-stage flotation column. The results show that the combustible matter recovery of the two-stage flotation column is 5.25% higher than that of the conventional single-stage flotation column. However, the ash contents of clean coal for both columns are similar. Less coarse coals with low ash are obtained using the two-stage flotation column than that using the single-stage column flotation with the same handling ability. The two-stage flotation column process can enhance coal flotation compared with the conventional single-stage column flotation.     

高效反浮选捕收剂的合成与应用

针对传统脂肪酸捕收剂选择性差、常温下分散性和溶解性差的问题,以工业棉籽油酸为原料,经高温高压使脂肪酸的双键水解而引入羟基活性基团,进一步与助剂按比例复配得到一种高效反浮选捕收剂HY.将其用于宜昌某高镁磷矿的浮选试验,经一反一扫简单浮选工艺流程获得了精矿五氧化二磷品位34.59%,五氧化二磷回收率96.46%,氧化镁品位0.28%的良好浮选选指标,氧化镁脱除率高达95%,各指标优于公开招标各项指标要求,且浮选在常温下进行,药剂用量仅0.84kg/t.表明反选捕收剂HY具有良好的浮选性能,其化学修饰改性改善了捕收剂的常温溶解性同时增强了其对钙离子、镁离子的选择性.     

Nano-microbubble flotation of fine and ultrafine chalcopyrite particles

As is well known to mineral processing scientists and engineers, fine and ultrafine particles are difficult to float mainly due to the low bubble-particle collision efficiencies. Though many efforts have been made to improve flotation performance of fine and ultrafine particles, there is still much more to be done. In this paper, the effects of nano-microbubbles (nanobubbles and microbubbles) on the flotation of fine (−38 + 14.36 μm) and ultrafine (−14.36 + 5 μm) chalcopyrite particles were investigated in a laboratory scale Denver flotation cell. Nano-microbubbles were generated using a specially-designed nano-microbubble generator based on the cavitation phenomenon in Venturi tubes. In order to better understand the mechanisms of nano-microbubble enhanced froth flotation of fine and ultrafine chalcopyrite particles, the nano-microbubble size distribution, stability and the effect of frother concentration on nanobubble size were also studied by a laser diffraction method. Comparative flotation tests were performed in the presence and absence of nano-microbubbles to evaluate their impact on the fine and ultrafine chalcopyrite particle flotation recovery. According to the results, the mean size of nano-microbubbles increased over time, and decreased with increase of frother concentration. The laboratory-scale flotation test results indicated that flotation recovery of chalcopyrite fine and ultrafine particles increased by approximately 16–21% in the presence of nano-microbubbles, depending on operating conditions of the process. The presence of nano-microbubbles increased the recovery of ultrafine particles (−14.36 + 5 μm) more than that of fine particles (−38 + 14.36 μm). Another major advantage is that the use of nano-microbubbles reduced the collector and frother consumptions by up to 75% and 50%, respectively.     

窄粒级煤泥浮选经典动力学模型的改进

通过煤泥窄粒级浮选速率实验,以煤泥浮选一级动力学为基础,对煤泥浮选动力学的关键参数进行研究,包括最大可燃体回收率ε∞的计算、浮选级数n的确定、浮选速率常数K的变化.结果表明:浮选动力学模型中ε∞的经验解比模型解更符合实际;窄粒级煤泥的浮选动力学级数最符合一级动力学;窄粒级煤泥的浮选速率常数K是时间的函数,可用幂函数或经验公式表达,先求出ε∞的经验解,再求解K(t)函数,所得模型非常符合煤泥浮选特征的浮选动力学模型.     

A comparison of anionic and cationic flotation of a siliceous phosphate rock in a column flotation cell

Flotation performance of a de-slimed (-150 + 53 μm)Jordanian siliceous phosphate was evaluated in a batch laboratory flotation column 100 cm high and 5 cm inside diameter. The collector used during anionic flotation was sodium oleate while an amine acetate (AEROMINE 3100C) was used for cationic flotation. Flotation comparison at different collector dosage, superficial gas velocity, and frother concentration showed that the maximum difference in performance between cationic and anionic flotation was obtained with these flotation parameters: 30 × 10 6 (mg/L) frother concentration, 250 g/tcollector concentration, and 3.4 cm/s superficial gas velocity. At these operating conditions amine (cationic) flotation gave 7% higher flotation recovery, a 6% cleaner concentrate grade, and was 6% more efficient at removing silica.     

颗粒尺寸与药剂性质对胶磷矿浮选过程的影响

通过磷矿颗粒的分级浮选、药剂对比及组合浮选对湖北保康钙质磷矿和大峪口硅钙质磷矿进行了系统研究.结果表明:分级后粒径为-65μm的小颗粒磷矿更有利于反浮选,且保康磷矿反浮选效果优于大峪口磷矿;复合药剂和酸性抑制剂均能改善保康钙质磷矿浮选效果,最终磷精矿品位达到36.14%,磷回收率为96.10%;药剂表面张力降低能增强药剂对磷矿颗粒的湿润.最后,通过测量电动电位和亲水亲油平衡值,对浮选过程效率进行了分析,并对浮选机理进行了讨论.     

絮凝浮选技术的研究进展

絮凝浮选具有选择性高、工艺设备简单、环境污染小等优点,在处理含有微细颗粒的悬浮料液方面具有明显的优越性,其分选效果优于常规浮选。就浮选方法、浮选药剂和浮选设备等方面总结了浮选技术的现状,并对其发展趋势进行了展望。     

Synthesis and application of antimony pent（isooctyl thioglycollate）

A new type of thermal stabilizer, antimony pent (isooctyl thioglycollate) (Sb(SCH2 COOC8 H17 )5), was synthesized by using antimony trioxide, isooctanol and thioglycolic acid in 2 steps. Firstly, antimony trioxide was oxidized into colloidal antimony peroxide. Then antimony peroxide and isooctyl thioglycollate reacted stoichiometrically for 2 h with the yield of 87%. This compound was used as thermal stabilizer for polyvinyl chloride(PVC).The results show that the thermal stability time is 52 rain at 200℃ by heat-ageing oven test when adding 2. 5% thermal stabilizer to PVC resin. Compared with antimony tris(isooctyl thiolycollate), the initial thermal stability of antimony pent(isooctyl thioglycollate) is better than that of antimony tris(isooctyl thioglycollate), while the longterm thermal stability time is shorter than that of antimony tris(isooctyl thioglycollate). Meanwhile, the synergism of antimony pent(isooctyl thioglycollate) with calcium stearate was studied, indicating that when the mass ratio of antimony pent(isooctyl thioglycollate) to calcium stearate is 2:1, the thermal stability time of PVC is 58 min.     

浮选柱反浮选胶磷矿的影响因素

浮选柱是一种高效的细粒物料分选设备,但应用于胶磷矿浮选仍然受诸多因素制约.为考查浮选柱结构特征、工作参数和操作条件等因素对其分选效果的影响,采用试验室浮选柱对贵州瓮安磷矿进行了单一反浮选试验,重点研究了矿浆浓度、药剂用量、筛板充填方式和充气量对浮选柱反浮选效果的影响.结果表明,在磨矿细度为-0.074 mm占88％、矿浆浓度为25％（质量分数）、油酸钠用量为1.8 kg/t、硫酸用量为5 kg/t和充气量为400 L/h时,反浮选的分选效果较好.由于浮选柱可以通过充填筛板来改善其分选环境,因此在较优条件下,其分选效率比用浮选机时高1.57％.     

水质硬度对煤泥浮选的影响

用循环水和自来水作为浮选试验用水,用石膏和硫酸钾作为水质调整剂,通过实验室和工业试验,研究水质硬度对煤泥浮选的影响．结果表明：水质硬度是影响煤和黏土颗粒之间分散稳定性的关键因素．随着水质硬度的升高,浮选精煤灰分提高了1％～2％,但精煤产率没有明显变化．水质硬度小于35。DH时,水质硬度越高,煤和黏土颗粒之间的凝聚作用越强,精煤灰分越高;水质硬度大于35°DH时,这种凝聚作用不再增强,精煤灰分也不再提高．     

Effect of filler on the self-lubrication performance of graphite antimony composites

Graphite antimony composites were prepared using a mechanical pressure infiltration method to force molten antimony into graphite preforms having a percolation micro-structure and a hop-pocket power filler. The micro-structural and macroscopic properties of the graphite antimony composites were analysed. Observations included metallographic analysis, physical properties and friction and wear behaviour. The results show that the wear loss is decreased by 12.24% and that the friction coefficient is re-duced by 32.61% after hop-pocket power was used. The research indicates that the hop-pocket power method gives a useful way to reduce friction coefficients and wear loss, and to increase service life and self-lubrication properties, of the graphite antimony seal-ing material as compared to carbon black.     

脂肪酸增效剂在浮选中的应用

概述了脂肪酸增效剂种类、结构以及脂肪酸增效剂在浮选中的作用机理,着重介绍增效剂在浮选中（主要是萤石矿、磷矿）的应用是强化非硫化矿浮选的有效途径.     

浮选光度法研究进展

浮选光度分析法是一种灵敏度高、选择性好的分析方法,具有处理样品量大(0.5~2.0L)、分离系数大(>104)、回收率高(>90%)、易于实现自动化等优点。常用的方法有:泡沫浮选(离子浮选、沉淀浮选)和溶剂浮选(萃取溶剂浮选、气体溶剂浮选)两种。文章综述了浮选光度法及其在大多数离子的浮选中的应用。     

Electrochemical flotation of diethyldithiocarbamate-pyrrhotite system

Using sodium diethyldithiocarbamate as a collector the flotation behavior of pyrrhotite was investigated.The relationship between potential and pH range for pyrrhotite flotation was established. The results show that the flotation of pyrrhotite is dependent on pulp potential at certain pH values. Pyrrhotite has good floatability from pH 2 to pH 12, and poor flotability at pH＞12. Cyclic voltammetry and Fourier transform infrared spectrum analysis show that the major adsorption product of DDTC on pyrrhotite is tetraethylthiuram disulfide. The intensity of Fourier transform infrared signals of tetraethylthiuram disulfide adsorbed on pyrrhotite and the anode current of a pyrrhotite electrode and flotation response of pyrrhotite are correlated with pulp potentials.     

Effect of solids on pulp and froth properties in flotation

Froth flotation is a widely used process of particle separation exploiting differences in surface properties. It is important to point out that overall flotation performance（grade and recovery） is a consequence of the quality and quantity of the solid particles collected from the pulp phase, transported into the froth phase, and surviving as bubble-particle aggregates into the overflow. This work will focus on studying these phenomena and will incorporate the effects of particle hydrophobicities in the 3-phase system. Solids are classed as either hydrophilic non-sulphide gangue（e.g. silica, talc）, hydrophilic sulphide（e.g. pyrite）, or hydrophobic sulphide（e.g. sphalerite）. Talc is a surface-active species of gangue that has been shown to behave differently from silica（frother adsorbs on the surface of talc particles）. Both are common components of ores and will be studied in detail. The focus of this work is to investigate the role of solids on pulp hydrodynamics, froth bubble coalescence intensity, water overflow rate with solids present, and in particular, the interactions between solids, frother and gas on the gas dispersion parameters. The results show that in the pulp zone there is no effect of solids on bubble size and gas holdup; in the froth zone, although hydrophilic particles solely do not effect on the water overflow rate, hydrophobic particles produce higher intensity of rates on water overflow and bubble coalescence, and many be attributed to the water reattachment.     

Influences of collector DLZ on chalcopyrite and pyrite flotation

The interaction mechanism of collector DLZ in the flotation process of chalcopyrite and pyrite was investigated through flotation experiments, zeta potential measurements and infrared spectrum analysis. Flotation test results indicate that DLZ is the selective collector of chalcopyrite. Especially, the recovery of chalcopyrite is higher than 90% in neutral and weak alkaline systems, while the recovery of pyrite is less than 10%. When using CaO as pH regulator, at pH=7-11, the floatability of pyrite is depressed and the recovery is less than 5%. Zeta potential analysis shows that the zeta potential of chalcopyrite decreases more obviously than that of pyrite after interaction with DLZ, confirming that collector DLZ shows selectivity to chalcopyrite and pyrite. And FT1R results reveal that the flotation selectivity of collector DLZ is due to chemical absorption onto chalcopyrite surface and only physical absorption onto pyrite surface.     

Study on interaction energy between flotation reagent and mineral surface

Ｏｒｇａｎｉｃｃｏｍｐｏｕｎｄｓｐｌａｙｉｍｐｏｒｔａｎｔｒｏｌｅｓｉｎｔｈｅｍｉｎｅｒａｌｆｌｏｔａｔｉｏｎ,ａｎｄａｌｃｏｌｅｃｔｏｒｓａｎｄｓｏｍｅｄｅｐｒｅｓｓａｎｔｓａｒｅｏｆｏｒｇａｎｉｃｃｏｍｐｏｕｎｄｓ［１－４］．Ｂｅ－ｃａｕｓｅｔｈ...     

Process mineralogy of copper-nickel sulphide flotation by cyclonic-static micro-bubble flotation column

In our study we investigated a refractory copper-nickel sulfide ore separation by using a cyclonic-static micro-bubble flotation column (FCSMC). The process mineralogy of the main products was studied. Using a scanning electron micro-scope-energy dispersive system (SEM-EDS) and an X-ray spectrometer the mineral category and content of samples were analyzed. By using a mineral liberation analyzer (MLA) the mineral liberation characteristics were revealed. It is shown that in roughing feed the monomers liberation degree of nickel pyrite and chalcopyrite take up 84.11% and 88.82%, respectively. In tailings, the lost nickel pyrite and chalcopyrite are mainly monomers. Therefore, strengthening the micro-fine particle recovery capacity is the key to increase recovery.