红土镍矿干燥焙烧工艺条件选择研究

以红土镍矿为原料,用热重分析(TG)和X射线衍射分析(XRD)等方法,对红土铁矿干燥焙烧条件进行研究.结果表明,在矿石粒度为0~3 mm且小于180目颗粒占25%,配焦粉量8%,焙烧温度850℃,焙烧时间90 min,干燥焙烧效果最佳.     

Preparation of zeolite NaA for CO2 capture from nickel laterite residue

Zeolite NaA was successfully prepared from nickel laterite residue for the first time via a fusion-hydrothermal procedure. The structure and morphology of the as-synthesized zeolite NaA were characterized with a range of experimental techniques, such as X-ray diffraction, scanning electronic microscopy, and infrared spectroscopy. It was revealed that the structures of the produced zeolites were dependent on the molar ratios of the reactants and hydrothermal reaction conditions, so the synthesis conditions were optimized to obtain pure zeolite NaA. Adsorption of nitrogen and carbon dioxide on the prepared zeolite NaA was also measured and analyzed. The results showed that zeolite NaA could be prepared with reasonable purity, it had physicochemical properties comparable with zeolite NaA made from other methods, and it had excellent gas adsorption properties, thus demonstrating that zeolite NaA could be prepared from nickel laterite residue.     

红土矿的过去与未来

从红土矿中生产镍自新喀里多尼亚的硅镁镍矿的处理开始已有100多年了。然而，直到今天。全世界的镍主要采自硫化矿。纵观未采，作者预测产自硫化矿的镍量变化不大，在今后的10年里镍产量的扩大主要来源于红土矿。因此新的红土矿项目的投资和生产费用将对镍的供应和镍价有较大的影响。此文回顾了红土矿项目的历史并分析了近期不同的红土矿项目和在“图板上”的项目的投资和生产费用，也评估了这些项目的风险，并将讨论这些因素对进一步开发红土矿项目的影响。     

Key factors affecting nickel recovery during the segregation of laterite ores

The segregation process as applied to nickel laterite ores involves the formation of gaseous nickel and iron chlorides which are subsequently reduced to form ferronickel on the surface of a solid carbon reductant. A fundamental study of the process has been carried out using limonite, nontronite and garnierite ores. The study highlighted the significant impacts that ore mineralogy and carbon addition have on the amount of nickel which is segregated rather than retained within the ore due to in situ reduction. These important aspects affecting nickel recovery and the success of the process are discussed in this paper.     

碱性固化材料对红土地基的化学侵蚀

碱性材料的固化措施对红土地基产生了不可忽视的长期侵蚀.在岩土工程现场进行了取样和原型试验,分析了导致材料损伤的化学反应,有针对性地设计了红土的碱液加速侵蚀试验,对比讨论了化学损伤前后红土的工程支撑指标变化、红土的工程支撑离子衰减,研究了碱性固化材料在酸性红土的接触带造成损伤的机制,认为化学反应是导致红土地基寿命降低、远期效益低下,乃至诱发灾难性事故的重要原因.     

High‐performance polymer‐supported extractants with phosphonate ligands for scandium(III) separation

As the market demand for scandium has grown, a great deal of interest has been generated in its recovery. To substantially simplify the process and provide a green alternative for scandium separation, novel polymer‐supported extractants containing di(2‐ethylhexyl) phosphonate and bis(2,4,4‐trimethylpentyl) phosphonate, [D201][DEHP] and [D201][C272] are proposed because they demonstrate improved adsorption capacity and selectivity toward scandium(III). Scandium(III) adsorption is significantly affected by the solution pH, with the maximum adsorption occurring at a pH of approximately 0.78. The batch adsorption data fit well with the Langmuir isotherm and pseudo‐second‐order kinetic models. A combination of the Fourier transform infrared and XPS spectra suggest that the complexation of oxygen atoms in phosphate groups with scandium(III) is the predominant adsorption mechanism. Additionally, the two resins were used to recover scandium from leaching liquor of nickel laterite ore. [D201][DEHP] exhibits unusual selectivity for scandium and low competitive behavior with other metals, thus increasing its market potential. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2479–2489, 2016     

红土镍矿分解实验研究

提出了酸碱交替分解、互为活化的工艺思路,通过实验确定了优化工艺条件和工艺流程。在优化工艺条件下,红土镍矿中Fe2O3、NiO、MgO、Co、SiO2分解率分别达到96.78%、99.62%、94.39%、100%和98.60%,从而为实现对红土镍矿的全元素综合利用奠定了基础。     

Comparative leaching of minerals by sulphuric acid in a Chinese ferruginous nickel laterite ore

The Yuanjiang nickel laterite ore containing mainly maghemite, goethite and lizardite was leached by sulphuric acid at atmospheric pressure and the residues were characterized using X-ray diffraction and scanning electron microscopy/X-ray energy dispersive spectroscopy. The relationship was discussed between the extraction of nickel, cobalt, iron, magnesium, aluminum, and the dissolution behaviour of the laterite minerals; as well as the extent of congruency of nickel, cobalt and iron extraction. The results show that the solubility of the laterite minerals in sulphuric acid decreases in the following order: lizardite > goethite > maghemite > magnetite ≈ hematite > chromite ≈ ringwoodite. Lizardite dissolved rapidly in 0.6 mol/L sulphuric acid at 60 °C whilst goethite dissolved completely in 2.5 mol/L sulphuric acid at 80 °C. The dissolution of the primary mineral maghemite was slow, but increased with increasing acid concentration and leaching temperature. Magnetite dissolved more slowly than maghemite; and hematite was only dissolved in > 6.2 mol/L sulphuric acid at 105 °C. Chromite and ringwoodite were not dissolved. The leaching behaviour of the laterite minerals may be explained by the bond strength differences of Me–O and the substitution of metal cations in the mineral structure.     

Extraction of cobalt from laterite ores by citric acid in presence of ammonium bifluoride

Citric acid was used to selectively extract cobalt from limonite-type laterite ores in the presence of ammonium bifluoride. The results show that ammonium bifluoride enhances the leaching of cobalt by citric acid, and 84.5% cobalt is extracted from a laterite ore containing 0.13% Co when leached at ambient temperature for 2 h with 30 g/L citric acid and 10 g/L ammonium bifluoride. Pyrolusite is reduced by citric acid during leaching, cobalt intergrown with which is liberated and subsequently chelated by the citric acid. The extraction of cobalt is enhanced in the presence of ammonium bifluoride because the matrix of silicate minerals is destroyed by ammonium bifluoride and the adsorbed cobalt is subsequently liberated.