由中国有色金属学会和长沙有色冶金设计研究院有限公司共同主办的《稀有金属与硬质合金》杂志,经新一轮遴选再次入编《中文核心期刊要目总览》2014年版(即第七版)冶金工业类核心期刊。这是继2012年、2014年连续两次荣获中国有色金属优秀出版物(期刊奖)二等奖。

WC-12%Co coarse grained cemented carbides were prepared by vacuum sintering and low pressure sintering with coarse grained WC as the raw material.The microstructure and properties of the coarse grained cemented carbides prepared by different processes were investigated by using scanning electron microscopy,optical metallographic microscopy,and microhardness,coercive force and bending strength tests.The results show that compared with vacuum sintering,low pressure sintering can improve the comprehensive performance of the coarse grained cemented carbide.As the inert gas pressure in the furnace increases from 2 MPa to 5 MPa,all the density,coercive force,hardness,flexural strength and impact toughness of the coarse grained cemented carbide have no obvious change.

Based on the example of multi-position fixture improvement for electrical discharge machining of inner hole chute products,electrical discharge machining fixtures were designed and improved up to the requirements of product size and shape tolerance.The original single-position fixtures were designed and improved to multi-position fixtures.After the three-axis CNC electrical discharge machining programs and processing parameters are optimized and the electrode structure is improved,the inner hole chute production efficiency of multi-position fixtures is about 3.86 times higher than that of the original machining fixtures,effectively reducing the manufacturing cost.

Trace nitrate in rare earth hydroxides was determined by spectrophotometry with indigo carmine as the chromogenic reagent.The influence was investigated of different factors on nitrate determination,and the optimum analytical conditions were determined.When nitrate concentration is 0~1.0μg/mL,there is a linear relationship between color fading degree and nitrate content following Beer's law.The relative standard deviation of the measured nitrate content is 2.41%,and the standard addition recovery is 97.6%~101.3%.This method to determine trace nitrate in rare earth hydroxides is characterized by simple operation and accurate test results.

Experimental research was carried out on comprehensive recovery of scheelite from molybdenum flotation tailings with a new reagent YP as the collector of scheelite based on the process of heating cleaning of crude scheelite concentrate.The grade of the resultant scheelite concentrate is 65.07%and its recovery is 82.82% by heated closed-circuit tests,increased by 5.97% and 5.92%,respectively,compared with those by normal closed-circuit tests.

Influences of Fe3+on spodumene flotation and its mechanism were systematically studied through flotation tests of pure spodumene,measurement of electric potential,infrared spectrum test and Fe3+solution chemical analysis.The results indicate that the flotation recovery of spodumene is significantly increased with the addition of Fe3+.The surface potential of spodumene significantly shifts after activated by Fe3+and then interacting with the collector,proving that Fe3+is absorbed strongly on the surface of spodumene.IR characteristic absorption peaks of oleic in spodumene are remarkably enhanced after activated by Fe3+and then interacting with the collector,indicating that the addition of Fe3+contributes to the adsorption of oleic acid on spodumene surface.

Vanadium was extracted by roasting with composite additives and leaching with dilute acid.Impacts were investigated of composite additive dosage,roasting temperature,roasting duration,sulfuric acid dosage,leaching duration,leaching temperature and liquid-solid ratio on vanadium leaching rate.The results show that under the conditions of composite additive dosage 6%,roasting temperature 800 ℃,roasting duration 3h,sulfuric acid dosage 3%,leaching duration 3h,leaching temperature 60℃and liquid-solid ratio 3∶1,the vanadium leaching rate of the above process is85.6%,increased by 13.4%compared with that of calcification roasting process.This technology has a good application prospect as an environment-friendly process with less off-gas pollution during roasting and substantially improved vanadium leaching rate.

Vanadium extraction technology was studied from clay vanadium ore by sulphation roasting-water leaching,and the effects were investigated in detail of concentrated sulfuric acid dosage,roasting temperature and time during sulphation roasting,and water temperature,liquid-solid ratio and leaching time during water leaching.The results show that under the conditions of concentrated sulfuric acid dosage 35%,roasting temperature 250℃,roasting time 3hduring sulphation roasting,and leaching temperature 60℃,liquid-solid ratio 4∶1and leaching time 1.5hduring water leaching,average V2O5 leaching rate is 88.98%,and V2O5 content in the leaching residue is lower than 0.2%.

Industrial experiment and production practice are introduced on tellurium extraction from tellurium slag in silver smelting furnace.The influence factors are emphatically analyzed and discussed of overlimit impurity in each process step.And the improvement measures are put forward.

Sources and properties and treatment measures of three wastes are comprehensively introduced during separation of ion-absorbed rare earth deposits.All kinds of wastes are effectively treated and discharged up to the standard by taking reasonable measures.