难处理金矿二次包裹现象研究

进行了难处理高砷金精矿回转窑、沸腾炉两段焙烧、氰化提金工业试验,金浸出率只有80%左右,氰化尾渣含金高达20g.t-1。对回砖窑焙烧矿分粒级后进行二次焙烧和氰化,结果表明金浸出率与焙烧矿的团聚粒度密切相关,直径大于5mm的粗颗粒焙烧矿浸出率达到90%,小于5mm焙烧矿浸出率只有72%。细分粒级研究表明,粒度越小,金浸出率越低。氰化渣金物相分析表明,未浸出的金主要是氧化铁包裹金。电子显微镜形貌研究表明,较细回砖窑焙烧矿存在严重的过烧,氧化铁包裹金主要发生在细团聚颗粒矿物上。回砖窑补热方式不合理是造成过烧的主要原因。     

提高焙烧炉气力输送能力的措施

介绍了气力输送的类型，浓相输送的基本原理，经验公式局限性以及通过对成品氧化铝输送装置的改造，使气力输送装置的能力达到最佳经济状态。     

高砷高硫金精矿固化焙烧-氰化浸出试验研究

介绍了高砷高硫金精矿矿物成分、固化焙烧-氰化浸出工艺条件，探讨了焙砂氰化浸出的机理。试验结果表明，金精矿经固化焙烧，焙砂氰化浸出时加入适量混合氧化剂(H2O2 KMnO4)和助浸剂G能显著提高金的浸出率，金浸出率为88．4％，砷、硫固化率均为90％。     

The effect of rolling at different temperatures on the fracture toughness anisotropy of a C-Mn structural steel

Abstract

The toughness of rolled plates of a plain C-Mn steel was evaluated for three sections, at different temperatures, by means of small-scale Wedge Open Loading (WOL) specimens. These were machined to orient the fracture plane parallel to the rolling plane, the transverse plane or the longitudinal plane which, according to the ASTM Standards code (12) are termed the S-L, the L-T and the T-L orientations, respectively. In addition, small tensile specimens having the tensile axis perpendicular to the rolling plane were tested at different temperatures.

The plates had been soaked at various temperatures between 1200°C and 680°C (finishing temperatures ～980°C to ～680°C) and then continuously rolled to the final thickness of 3/4-in. (10). The observed toughness depended on finishing temperature and also on specimen orientation; the S-L orientation being the least and the L-T orientation the most tough in any given plate. Brittle fractures were observed on the rolling-plane (S-L orientation) of WOL specimens made from. plates that had been soaked at temperatures ≤800°C (finishing temperatures ≤760°C) and these were attributed to the microstructure and texture. Scanning electron micrographs disclosed that elongated MnS inclusions were principally responsible for the fracture toughness anisotropy for higher soaking and finishing temperatures.

Résumé

La résistance de plaques laminées d'un acier au carbone et manganèse fut évaluée à differentes températures, selon les trois orientations possibles du plan de rupture par rapport au plan de laminage. Les éprouvettes ont été usinées conformément à une homothétie: reduite de la géométrie WOL (wedge open loading) et de sorte que le plan de rupture soit parallèle au plan de laminage, au plan transversal ou au plan longitudinal Ces orientations sont appelées S-L, L-T, et T-L respectivement, suivant les normes de l'ASTM (12). De plus, de petites éprouvettes de traction dont les axes de traction sont perpendiculaires au plan de laminage, furent expérimentées a differentes températures.

Les plaques ont été maintenues à differentes températures entre 1200°C et 680°C (températures finales de 980°C a 680°C), puis laminées en continue jusqu'à une épaisseur finale de 3/4 po. (10). On trouve que la resilience observee depend de la température finale et de 1'orientation de l'eprouvette. L'orientation S-L a été la moins résiliente tandis que 1'orientation L-T a été la plus résiliente de toutes les plaques expérimentées. Des cas de rupture fragile ont été observés sur le plan de laminage (orientation S-L) d' éprouvettes WOL obtenues de plaques ayant été maintenues à des températures ≤ 800°C (températures finales ≤760°C), et ceux-ci sont attribués à la microstructure et la tex ture du rnateriau. Des micrographics obtenues du microscope électronique a balayage révélèrent que des inclusions allongées de MnS étaient en grande partie responsables de l'anisotropie de la résistance a la rupture pour de plus hautes températures de maintien et températures finales.     

CeO2对Fe2O3压团焙烧行为及强度的影响

在 Fe2 O3试剂中添加CeO2制成压团试样，对其进行预热及焙烧，利用 X射线衍射、DSC和 SEM相结合的方法，研究CeO2含量对试样抗压强度的影响机理。结果表明，在975℃预热压团中形成了Ce-Fe-O 固溶体，使Fe2 O3晶粒间的连接增强，预热压团强度增大；在1250℃焙烧压团中Ce-Fe-O 固溶体发生了脱溶和分解，析出的高熔点氧化物CeO2存在于 Fe2 O3晶粒间，阻碍了 Fe2 O3晶粒之间的连晶生长，使焙烧压团的强度随 CeO2含量增多而降低。     

Comprehensive recovery of the components of ferritungstite base on reductive roasting with mixed sodium salts,water leaching and magnetic separation

Ferritungstite ores have great commercial value because of the huge reserve and high content of W, Mo and Fe. But their economic recovery has long been a challenge due to its complex mineralogy and heterogeneous. The current study investigated how reductive roasting of ferritungstite ores with mixed sodium salts affected the phase evolution of W, Mo and Fe through Micro-area XRD and Powder XRD, with the goal of comprehensive transformation of ferritungstite. Reductive roasting with mixed sodium salts at 800 °C transformed ferritungstite to Na₂WO₄ and magnetite (Fe₃O₄), which were easily recovered by water leaching and magnetic separation. Furthermore, a lot of pores and gaps rather than sintering or agglomeration was observed in the ore particles after roasting by SEM-EDS, which was beneficial for the water leaching of W and Mo. As a result, 96.40% of W and 96.64% of Mo were extracted after water leaching, while an iron concentrate with an Fe content of 55.65% and recovery of 83.30% was obtained after magnetic separation. These results suggested such process would be applicable to the comprehensive recovery of valuable metals from ferritungstite ores, as well as similar tungsten ores and scraps.     

Study on sulphidization roasting and flotation of cervantite

A new technology, sulphidization roasting of antimony mineral cervantite with elemental sulfur followed by froth flotation is reported in this paper. The effects of roasting temperature and time, sulfur to antimony molar ratio on the properties of treated product and its flotation behavior were studied. Optimum roasting conditions are: roasting temperature 723 K; roasting time 30 min; and sulfur to antimony molar ratio of 1.5. Under these conditions, the mineral phase changed from cervantite to stibnite as expected. The flotation recovery of the sulphidized cervantite is over 90%. A flotation concentrate grading 21.04% Sb with a recovery of 77.15% is achieved by sulphidization roasting and flotation from a feed grading 1.11% Sb in which cervantite is the main antimony mineral.     

含锌冶金尘泥特性分析及锌铁分离

为实现含锌冶金尘泥节能、环保、低碳的资源化利用，对原料进行水分、粒度、化学成分、物相组成、SEM-EDS等物理化学特性分析。结果表明：含锌冶金尘泥的水分为3.43%、水分容易脱除，颗粒大小不一、细小颗粒会聚集成团和黏附于大颗粒表面，具有回收利用价值的成分主要为锌和铁，含量分别为5.06%和29.24%,其中锌主要以ZnFe₂O₄的形式存在于细小颗粒中、铁主要以Fe₂O₃的形式存在。含锌冶金尘泥的锌铁分离试验研究表明：直接磁选和常规焙烧—磁选的锌铁分离效果均不理想，微波焙烧—磁选可以达到较好的锌铁富集分离效果；在微波焙烧温度700℃、焙烧时间10 min的条件下，磁选精矿产率为61.67%、铁含量为54.39%、锌含量为2.62%,磁选尾矿锌含量为12.15%、铁含量为9.74%,磁选精矿和磁选尾矿均能实现较好的资源化回收利用。     

Optimization of Lithium Extraction from Lepidolite by Roasting Using Sodium and Calcium Sulfates

The lithium extraction from a lepidolite concentrate using roasting, followed by water leaching, was studied. Several alternative additives were initially tested. The use of sodium and calcium sulfates as additives was evaluated in more detail. The influence of some process variables, namely the roasting time, roasting temperature and the additive/concentrate mass ratio, was studied applying a design of experiments. The lithium extraction was modelled and the fitted and validated model was used to optimize the process response. The increase in the additive/concentrate mass ratio, roasting time and temperature seems to result in solid state reactions and transformations that lead to phase, morphological and particle size distribution modifications, which were assessed by XRPD, SEM, and particle size analyses. In this process, lithium sodium sulfate formation constitutes a crucial step enabling the Li water leaching. High lithium extractions were estimated for several combinations of factors. At 850°C, lithium extractions over 90% are obtained when the roasting time is above 1.90 hour and the additive/concentrate mass ratios are over 0.77. An increase in the temperature to 875°C also leads to lithium extractions over 90% for a roasting time of 1 hour and an additive/concentrate mass ratio of 0.60.     

不同的配比对LiCoO_2和NaHSO_4·H_2O混合物在酸性焙烧产物中元素赋存状态的研究

了解废旧锂离子电池回收利用的现状和存在的问题对回收金属元素具有非常重要的意义。将LiCoO_2与NaHSO_4·H_2O按照摩尔比1∶1、1∶2、1∶3、1∶4进行混合,混合均匀后进行酸性焙烧,采用TG-DSC-MS、XRD和SEM研究了焙烧产物中元素的存在形式和赋存状态,研究结果表明:Na元素是以LiNa(SO_4)和Na_2Co(SO_4)_2的形式存在,Li元素的赋存形式是LiNa(SO_4),Co元素的赋存形式是Co_3O_4和Na_2Co(SO_4)_2,焙烧产物致密,形状不规则。