1,721,006 research outputs found
Sulla preconcentrazione della bauxite di Olmedo mediante disaggregazione con getti d'acqua ad alta pressione.
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Sull’influenza della dimensione delle particelle di flottazione: il caso di un minerale di barite.
No full textUse of triboelectric Techniques for Separating Feldspar from Quartz
No full textThe paper shows the results of an investigation carried out to enhance the value of two commercial products currently destined for ceramic industry and to beneficiate the non-magnetic fraction of a granite quarry waste, applying electric separation techniques based on triboelectric charging and the use of a free-fall chamber. The test conducted on the k-feldspar/quartz commercial product, with 5,7 % K2O content, shows that is possible to obtain a 9,7 % feldspar concentrate and a quartz product with less than 1 % K2O content, preheathing the feed, without the use of additives. As concern granite quarry waste, the results obtained without the use of additives and pre-treating the feed material with HF and NaOH solutions are compared. It has been found that the pre-treatment with the above mentioned reagents enables to obtain marketable feldspar and quartz products
Electrostatic K-Feldspar/Na-Feldspar and Feldspar/Quartz Separation: Influence of Feldspar Composition
No full textThis paper aims at contributing to the possibility of electrically separating K-feldspar/Na-feldspar and quartz/feldspar, investigating the behaviour of mixtures composed of K-feldspar, Na-feldspar and quartz concentrates. The findings highlight the importance of preheating the material and of interparticle contact. Tests conducted on binary mixtures of K-feldspar/Na-feldspar, K-feldspar/quartz and Na-feldspar/quartz showed that it is possible to achieve satisfactory results in the separation of these species, by triboelectrical charging of the material, preheated to temperatures above 100 °C, using a free fall chamber. Tests carried out on ternary mixtures have demonstrated that additional pretreatment with HF solutions improves the results
Stabilization of mining tailings containing fluospar and heavy metal using potassium dihydrogen and calcium hydroxide
No full textTailings waste from a mineral processing plant of a fluorite and galena mine is characterized by the release of F together with heavy metals such as Zn, Pb, Cd and Cu. Leaching tests carried out on the tailings waste show that the concentrations of F and Pb exceed the legal Italian limits for characterisation as inert material. To avoid the risk of spreading to areas not directly affected by mining activities and to obtain inert products suitable for reuse as construction material or as backfill in the mine, stabilization has been investigated using potassium dihydrogen phosphate singly or combined with calcium hydroxide. In order to assess the effectiveness of the additives for the stabilization of pollutants, reactor batch tests have been carried out by adding different proportions of these additives to the tailings material. The mixture, with a liquid/solid ratio equal of 10, was agitated for 24 hours and, at the end of the test, the eluate was filtered through a 0.45 μm membrane and analysed. The results show that the use of potassium dihydrogen phosphate in combination with calcium hydroxide allows for the immobilization of F and Pb by formation of stable or poorly soluble compounds. In addition, solidification of the thus inertized material using 10 % cement produces a material of which the leachate is in accordance with the regulatory limits for discharge in groundwater, allowing for its use as backfill in the mine
Beneficiation of high grade feldspar minerals using inverse flotation techniques
No full textThe beneficiation of feldspathic minerals mined from relatively rich albitite occurrences often involves the resort to technically complex and expensive treatments such as selective flotation to remove the impurities. The most widely used techniques rely on inverse flotation either at neutral pH using carboxylic collectors or in acid medium with phosphoric esters. Based on experimental results and the authors’ experience the advantages and disadvantages of the two methods are discussed. Some criteria for the choice of the technically and/or economically more convenient technique are suggested
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