极硬矿石碎磨工艺探讨

本文探讨了半自磨工艺在处理极硬矿石的优势和面临的问题,提出在传统半自磨工艺中引入细粒磨矿设备立磨机,形成了SABCV半自磨工艺流程。该工艺既能克服传统球磨机在处理细粒级矿石方面的低效,降低单位矿石的能耗,又能避免过粉碎,提高磨矿效率。实现了将某极硬矿石从P_(80)=120 mm连续碎磨至P_(80)=53μm的目标,并获得了良好的经济指标,为研究极硬矿石的碎磨工艺提供了一个新的思路。

硬锰矿石催化过氧化氢制备氧气的实验探究

人教版初中教材中“二氧化锰催化过氧化氢分解的探究”实验中存在催化剂质量不易保证,难以回收等不足.为此,采用硬锰矿石作为催化剂,探究证明其具有良好的催化活性,验证催化剂质量在反应前后保持不变;另将硬锰矿石应用于启普发生器制备氧气,能够很好地控制反应发生或停止.整个实验催化剂可再回收利用,具有更精确、简便、环保等优点.

龙头山金矿破碎工艺流程改造及设备选型实践

贵港市金地矿业有限责任公司龙头山金矿选矿厂针对该矿特硬矿石的特点,从破碎工艺流程、设备选型两方面进行了工艺改造实践。最终,在更换合适破碎设备的条件下,采用三段两闭路破碎工艺流程,其产品粒度由原来的-12 mm降到-10 mm,处理量增加了100 t/d,各项技术指标均达到了设计要求。经过工艺流程的改造,提高了选矿厂处理能力,实现了降本增效、"多碎少磨"的目的,并取得了较好的经济效益。

Mineralogy, liberation and leaching characteristics of iron oxide phases in an Indian diaspore sample

The removal of iron from an Indian diaspore sample was studied using magnetic separation and leaching techniques aided by an in-depth mineralogical characterization study involving quantitative mineralogical evaluation by scanning electron microscope（QEMSCAN）, electron probe micro-analyzer（EPMA） and X-ray diffraction（XRD）. The characterization studies indicate that extremely fine-sized hematite grains are associated with several other mineral phases in a complex manner with around 60% of the hematite not liberated even below the size of 38 μm limiting the scope of physical separation processes to remove the iron. Wet high intensity magnetic separation（WHIMS） studies reveal that only 49% of iron can be removed. Further, leaching studies using oxalic acid suggest that around 76% of the iron can be removed under conditions such as a solid to liquid ratio of 0.05：1, a temperature of 90 ℃ a time period of 120 min and an acid concentration of 1 mol/L. The dissolution of iron in oxalic acid is found to be controlled by chemical reaction and the activation energy is calculated as 35.15 k J/mol.

Efficient separation of alumina and silica in reduction-roasted kaolin by alkali leaching

Alkali leaching was employed to investigate the separation of alumina and silica in roasted kaolin obtained by roasting kaolin alone in air at 1273 K for 60 min and in clinker prepared by roasting the mixed raw meal of kaolin,ferric oxide and coal powder with Fe2O3/Al2O3/C molar ratio of 1.2:2.0:1.2 in reducing atmosphere at 1373 K for 60 min.The thermodynamic analyses and alkali leaching results show that the composition of the Al-Si spinel in roasted kaolin is close to that of 3Al2O3·2SiO2 and the spinel is dissolved with increasing leaching time,resulting in difficulty in deeply separating alumina and silica in kaolin by the traditional roasting-leaching process.On the contrary,the efficient separation of alumina and silica in kaolin can be reached by fully converting kaolinite into insoluble hercynite and soluble free silica,namely quartz solid solution and cristobalite solid solution,during reduction roasting,followed by alkali leaching of the obtained clinker.Furthermore,experimental results from treating high-silica diasporic bauxite indicate that the reduction roasting-alkali leaching process is potential to separate silica and alumina in aluminosilicates.

Effects of different factors during the de-silication of diaspore by direct flotation

Most of the bauxite resources in China are kaolinite-diaspore bauxite of middle to low grade, with a fine dissemination, and are difficultly separated. Direct flotation de-silication has been shown to be an effec- tive method for de-silication of diaspore. In this study the effect of different factors, including pulp tem- perature, density, pH value, depressant, and collector dosage, on direct flotation of diaspore were investigated by laboratory experiments. The optimum conditions were identified and the flotation perfor- mance was improved. The results show that under optimum conditions （a pulp temperature around 40℃, a pulp density from 30% to 33g, a pH value from 9.0 to 10.0, an air flow rate of 0.5 m3/（m2 rain）, a dispersant level from 35 to 70 g/t, and a collector level around 1000 g/t） an AI/Si ratio of 6.97 is obtained starting from an initial Al/Si ratio of about 4.71. The recovery of A1203 under these conditions was 86.94%.

Separation of diaspore from bauxite by selective flocculation using hydrolyzed polyacrylamide

Selective flocculation is a new method to solve the problem of China's bauxite de-silication besides flotation and reverse flotation. The method of selective flocculation of bauxite using hydrolyzed polyacrylamide as flocculant was experimented and evaluated. The results of diaspore and kaolinite single mineral settling tests show that the difference between settlement yield of kaolinite(settling 15 min) and diaspore(settling 3 min) increases from 16% to 60% by adding flocculant at pH=7. Results of selective flocculation experiment of bauxite show that the higher concentrate grade(65.75) and Al-Si ratio(7.34) could be obtained with sodium carbonate as dispersant compared with sodium hexametaphosphate; under the action of flocculating agent, the concentrate grade and Al-Si ratio increase to 67.99 and 9.01. These results could meet the requirements of Bayer production, and the simpler process was expected to cost far less than traditional flotation method and a promising de-silication method of bauxite.

Breakage Distribution Estimation of Bauxite Based on Piecewise Linearized Breakage Rate

Laboratory tests were carried out to study the breakage kinetics of diasporic bauxite and determine its breakage distribution function. Non-first order breakage with different deceleration rates for different size intervals is found, which is most probably caused by the heterogeneity of the ore. Piecewise linearization method is proposed to describe the non-first order breakage according to its characteristics. In the method, grinding time is divided into several intervals and breakage is assumed to be first order in each interval. So, the breakage rates are calculated by taking the product of the last interval as feed and then established as a function of particle size and grinding time. Based on the predetermined breakage rate function, the breakage distribution of the ore is back-calculated from the experimental data using the population balance model (PBM). Finally, the obtained breakage parameters are validated and the simulated data are in good agreement with the experimental data. The obtained breakage distribution and the method for breakage rate description are both significant for modeling the full scale ball milling process of bauxite.

Study on the accelerant to the sodium oleate during bauxite flotation

The conventional collector for diaspore mineral is oleic acid （OLA）, which is highly insoluble and must be used in high dosage in bauxite flotation. Firstly flotation experiments with every reagent （sodium oleate, tween-20）were carried out and it was shown that sodium oleate was an effective diaspore collector, whereas nonionic surfactant tween-20 showed little collectivity. Then experiments were carried out with sodium oleate as the main collector with the addition of tween-20 to study the influences of potentiator on diaspore flotation. It could be seen from the experiments that potentiator had a marked influence on the recovery of diaspore, which was raised by more than 12 % and that addition sequence also affected the flotation behavior. It gave the best results with the reagents mixed thoroughly before added and the best ratio of collector oleic acid and potentiator tween-20 slLood at 10： 1. From the calculation of the ingredients in the sodium oleate solution, at the pH 9, sodium oleate acted with surface of the mineral with the acid-soap polymer [ HOL ~ OL- ]. Zeta potential test showed that the potentiator promoted the absorption of collector on the mineral surface, which lowered zeta potential. As could be seen from surface tension experiments, the addition of potentiator tween-20 lowered the CMC （ critical micelle concentration） value of oleic acid solution, which was equivalent to raise the power of the agents. By the adsorptive capability tests, with the addition of tween-20, the adsorption of oleic acid on diaspore got more.

Enrichment of Low Grade Eti Mine-Espey Colemanite Stocks Using Microwave Methods

In this study, the benefication of low-grade Espey -10 mm. colemanite stocks of more than 30,000 tons, which have been waiting for longer years, can not be evaluated in any way in Emet Boron Works in order to get salable product. Chemical, physical, mineralogical and thermal characterization of low-grade colemanite stock, in the sizes of 10 mm, are located in Espey region primarily conducted. Grades of 10 mm size of Espey used in this study is 28.87% B203. In the microwave experiments, a concentrate of 50.82% B203 was obtained with the efficiency of 88.13%. Evaluating colemanite concentrate by microwave technology may have great importance in solving environmental problem.