The effect of sodium sulphate on the hydrogen reduction process of nickel laterite ore

A series of nickel laterite ores with different calculated amounts of anhydrous sodium sulphate were prepared by physical blending or sodium sulphate solution impregnation. The reduction of the prepared nickel laterite ore by H₂ was carried out in a fluidised-bed reactor with provisions for temperature and agitation control, and the magnetic separation of the reduced ore was performed using a Davis tube magnetic separator. The mineralogical properties of the raw laterite ore, reduced ore and magnetic concentrate were characterised using ICP, TG–DSC, N₂ adsorption, X-ray diffraction and optical microscopy. The catalytic activity of sodium sulphate was also studied by using Hydrogen temperature-programed reduction. The experimental results indicate that Na₂SO₄ could overcome the kinetic problems faced by the laterite ore and that it exhibited noticeable catalytic activity only if the temperature reached at least 750 °C. This high temperature accelerated the crystal phase transition of the silicate minerals and increased the utilisation of H₂. In comparing the results from the two different methods for adding Na₂SO₄, the nickel content and recovery of the magnetic concentrate were increased by using the impregnation method rather than the physical blending method and the increasing amount of sodium sulphate assisted in the further beneficiation of nickel. The partial pressure of H₂ and the reducing time also affected the reduction process of the iron oxides. The results of the microscopic study indicated that the formation of a Fe–S solid solution, which was derived from the SO₂ sulphide reduction of FeO, was conducive to mass transfer and accelerated the coalescence of metallic ferronickel particles. For the nickel laterite ore, under the synergistic effect of sodium sulphate and hydrogen, a nickel content and nickel recovery of 6.38% and 91.07% were obtained, respectively, with high product selectivity.     

The effects of LiOH and NaOH on the carbonation of SrSO4 by dry high-energy milling

In this work, the effects of alkaline hydroxides (NaOH and LiOH) on the direct mechanochemical carbonation using dry high-energy milling of celestine (SrSO₄) under CO₂ atmosphere was investigated with X-ray diffraction (XRD), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and carbon analyses. It was observed that SrSO₄ was not directly carbonated by dry high-energy milling under CO₂ atmosphere without LiOH or NaOH additives. Direct mechanochemical SrCO₃ formation was observed during milling of the SrSO₄ and NaOH mixture under CO₂ atmosphere, and it was shown that a minimum 50% of the initial SrSO₄ was mechanochemically carbonated in the presence of NaOH and CO₂ gas. LiOH does not stimulate the direct carbonation. However, it was observed that washing of the milled mixture with water resulted in strontium carbonate (SrCO₃) formation because of the enhanced dissolution of Li₂CO₃ and SrSO₄, promoted by the activation effect of high-energy milling. Depending on the alkaline hydroxide used during the milling, strontium carbonates with different space group settings were formed, which have different (split or single) main carbonate absorption bands.     

椰子油乙氧基化物与阴离子表面活性剂协同效应研究

摘要：对椰子油乙氧基化物-30EO（COE-30）与直链烷基苯磺酸（LAS）、脂肪醇聚氧乙烯醚硫酸钠（AES-2）及脂肪醇聚氧乙烯醚羧酸钠（AEC-5）复配的二元体系进行研究,运用非理想溶液理论计算混合胶束和混合吸附层的组成及二者在混合胶束和混合吸附层中协同作用参数。结果表明,复配体系在混合胶束和混合吸附层显示出较强的协同作用,混合胶束中作用参数|βm|= 2~6,混合吸附层中作用参数|βσ|= 2~6。三个复配体系在形成胶束能力和降低表面张力效率方面存在协同增效作用,同时COE-30/AES-2和COE-30/AEC-5体系在降低表面张力能力方面也存在协同增效作用。     

壬基酚聚氧乙烯醚硫酸钠微乳液拟三元相图及微观结构研究

以表面活性剂壬基酚聚氧乙烯醚硫酸钠(NPES)为对象,考察了助表面活性剂与复配表面活性剂对NPES形成微乳液体系的影响.通过比较微乳液区域(ME)在拟三元相图中所占比例,发现最优配比为m(NPES):m(DBSA)=1:1,m(复配表面活性剂):m(正丙醇)=1:3,此时形成微乳液区域面积最大,占57%;用电导率法与动态光散射(DLS)分析微乳液结构,结果表明,当w(H2O)＞60%时,形成微乳液为O/W型,粒径为34 nm;该体系对温度不敏感.     

硫酸二甲酯节能环保生产新工艺介绍

由于传统硫酸二甲酯生产工艺用w（H2SO4）98%硫酸作为催化剂生产二甲醚,因此存在生产环境差、能耗高、生产成本高等问题,新开发的硫酸二甲酯节能环保生产工艺用固体超强酸或分子筛催化剂生产二甲醚,解决了硫酸腐蚀及废硫酸处理等问题。并且通过改进工艺流程及设备配置、加强生产过程中低温位废热的回收利用,使硫酸二甲酯生产成本降低,污染物排放也大大减少。     

On-line investigation of anatase precipitation from titanyl sulphate solution

Precipitation of concentrated titanyl sulphate is an important step in the Sulphate Process used for manufacturing titanium white in which titanium dioxide particles are formed and the particles size as well as its distribution is determined. This study investigated the transient changes of TiO₂ precipitation process by using two on-line particle measurement techniques, turbidimeter and focused beam reflectance measurement (FBRM), in order to explore the mechanism of particles formation. Induction period as well as primary nuclei formation of the precipitation process was calculated by turbidity value changes and the influence of feeding rate on primary nucleation, primary crystal sizes and final product particle size distribution (PSD) were also investigated. FBRM was employed for detecting the transient variations of PSD during the process. It was found that the process was divided into four stages: induction, rapid hydrolysis and aggregation, aggregation balance with further reaction, and ripening. The Sigmoidal–Boltzmann model is used to describe these transient phenomena and describes well the formation of TiO₂ particles.     

利用副产品碳酸钙分解制石灰的工程化分析

文章论述了利用碳酸钙滤饼分解制石灰,目的是解决磷石膏综合利用的二次污染问题,只有先解决了碳酸钙产品的出路才能确保硫酸铵装置的顺利实施。根据滤饼的特性,从生产原理和技术方案比选,认为选用回转窑煅烧分解制石灰是可行的,同时也阐明了随着杂质的带入对煅烧分解工程化技术和最终产品质量可能会产生一定的影响,需采用切实有效的对策措施。     

Kinetik des anaeroben Glycerinabbaus mithilfe sulfatreduzierender Bakterien

The efficiency of the production of Biosulfid for the elimination of heavy metals or sulphate from industrial wastewater is crucial on the used substrate and is directly related to the recoverability of the carbon source by microorganisms. Easily accessible and easy to use is glycerol as substrate for the sulfate‐reducing bacteria (SRB). Subject of the presented work was the investigation of the anaerobic degradation of glycerol in the batch fermentation. A mixed culture of SRB and a kinetic model approach was determined.     

硫酸盐还原菌在酸性矿山废水处理中的应用研究

利用硫酸盐还原菌(SRB)处理酸性矿山废水(AMD)具有诸多优点。文章了综述了SRB及其在酸性矿山废水中的应用现状,最后提出了目前在应用中存在的问题。     

O_3/FeSO_4协同处理活性艳红X-3B的研究

采用O3/FeSO4协同对活性染料X-3B进行处理,证明O3/FeSO4协同处理染液的脱色率和CODCr去除率均高于两者单独作用,且CODCr去除率分别比两者高17.67%和27.63%;当染液质量浓度为1 g/L,硫酸亚铁的投加量为4 g/L,通10 g/h臭氧时间为8 min,pH值为9.0,反应温度为40℃时效果最佳,脱色率和CODCr去除率分别为99.34%和81.39%,其反应机理遵循一级动力学过程。