黑钨矿可浮pH及其在钨细泥异步浮选中的应用

Floating pH of Wolframite and Its Application in Asynchronous Flotation of Fine Tungsten Slime

钨细泥是赣南钨矿山选矿分选对象的重要组成部分,一般钨细泥金属量占矿山总量的12%以上,加强钨细泥回收对提高宝贵钨资源回收利用率有重要作用。我国黑钨矿选别以重选法为主,但该法对细粒级回收效果差。实践表明,浮选法的回收粒度可达5μm左右。随着矿产资源的日趋贫细杂,充分利用不同矿物及同种矿物可浮性和浮游速度的差异,实现矿物的个性化、差异性浮选的异步浮选技术研究值得重视。试验中黑钨矿纯矿物试样为-40μm占99%,-20μm占85%以上的微细颗粒,纯度在98%以上。通过黑钨矿纯矿物p H条件试验及4种经典的浮选动力学模型动力学分析表明,黑钨矿浮选速率常数k在p H值为6.5~9.5之间逐渐增大,至9.5达最大值,p H〉10,k值明显减小。赣南某矿以黑钨矿为主,其钨细泥应用此p H条件进行浮选分离。分选中进行了一次作业中浮选不同浮游特性钨矿物的同步浮选和不同p H的多个作业点浮选不同浮游特性钨矿物的异步浮选两种方案对比。在异步浮选试验中按9.5,9.0,8.0及7.0等p H点作业依次浮钨,分选效果明显改善,在回收率接近的情况下钨粗精矿选矿富集比大幅提高,达同步全浮的3倍以上,这大大利于矿物分选。

Fine tungsten slime is an important part of ore processing objects of tungsten mine in southern Jiangxi. Normally, the a- mount of metal of fine tungsten slime accounts for over 12% of the total mine metal amount. It plays an important role in improving the recovery rate of valuable tungsten resources by strengthening the fine tungsten slime recovery. Gravity separation is the main method to recover wolframite in China, but this method has a bad recovery effect for fine tungsten slime. The recovery particle size of flotation could reach about 5 μm. With the mineral resources becoming low-grade, fine-grained and complicated, the researches on asyn- chronous flotation technology which made full use of the differences of floatability and floating rate of different minerals and the same mineral to realize mineral individualization and difference flotation were very worthy of paying more attention. The wolframite pure min- eral sample in the experiment was - 40 tzm accounting for 99%, - 20 μm accounting for more than 85% and the purity was over 98%. The pH conditional experiment and kinetics analysis by 4 classic flotation kinetics models of wolframite pure mineral showed that the wolframite flotation rate constant （k） increased gradually with pH varying from 6.5 to 9.5, and reached the maximum value at pH = 9.5 ; when pH 〉 10, k decreased obviously. The flotation separation of fine tungsten slime in southern Jiangxi, for which wolframite was the main mine, was studied based on the pH condition. A comparison was made between the synchronous full flotation in the same operating point and the asynchronous flotation by multiple different pH operating points for tungsten minerals of different flotation char- acteristics. The separation of tungsten by asynchronous flotation was improved obviously as pH decreased from 9.5, 9.0 and 8.0 to 7.0. The enrichment ratio of rough tungsten concentrate increased sharply, which was more than 3 times that of the synchronous full floatation, and meanwhile the recovery rate changed little.