The Peculiarities of Combustion and Phase Formation during SHS of Mechanically Activated Mixtures Quartz – Calcite

The work with the influence of mechanochemical treatment (MCT) of minerals (quartz-SiO2, calcite-CaCO3) on the process of their combustion under the conditions of SHS with aluminium. It is shown that activation of the charge mixture in the mill increases the power state of the material and contributes to the change of kinetic characteristics of combustion process: the decrease in the induction period of ignition and the increase in combustion rate. The change in combustion temperature is of a complex character due to activation of both exothermal reactions related to formation of such compounds as anothite, helenite, wollastonite. The use of deferent organic modifiers of the charge mixture results in formation of nitride and carbide compounds in the process of SHS. It is shown that changing the conditions of MCT, modifiers and ratios between the charge components it is possible on the basis of activated and modified systems to synthesize composition SHS-materials different in their phase compositions

Production of Ferro Alloys from Wolframite Concentrate Using Pressure

The temperature of aluminotermic processes changes largely depending on appointment, structure and property of received products. Optimum conditions steal up for each concrete process. One of important practical questions is influence of temperature and external pressure upon extraction of restored elements in an ingot. In work concentration and high-speed limits of burning of system WO3-Al are defined. Limits of burning of system (4.3 – 19.1 g/sm3) are established at dilute from 10 to 300% by a ballast. The factors influencing for speed of burning mixture from tungsten concentrate are investigated. Influence of superfluous pressure on fusion indicators is investigated at reception ferrotungsten from various raw materials. Modes of preparation of initial raw materials to process of fusion are defined and parametres of carrying out of process of reception ferrotungsten under pressure are established. It is shown that superfluous pressure does not shift balance of reaction of restoration of tungsten only suppresses disorder of a reacting mix and prevents ablation of a reacting mix that promotes increase in an exit of an alloy

Reception Ferrotungsten from Wolframite Concentrate by Alumimotermic Method

For the smelting ferrotungsten of raw materials (mineral) took us to calculate the charge for each experiment. To optimize the process of obtaining ferrotungsten of wolframite carried out the following activities: to reduce speed and combustion temperature. A change batch positive impact on the development of the combustion process. Experimental results have shown the effectiveness of the introduction of aluminium additives in excess of stoichiometry because the explosive burning regime turned into stationary. In this work the charge calculated on 300 g volframite concentrate so that as a result of the aluminotermic reaction in the alloy contained 70% of tungsten. Calculations of charge showed that in the case of the smelting of ferro-alloys and master alloys used in this work and have a high melting point (ferrotungsten, ferromolybdenum, etc.) – temperature process of melting alloy is indispensable for the success of melting. To reduce the speed of combustion and the temperature were conducted experiments on selection of ballast additives which allows you to bring the process to a smooth flow of the reaction. As ballast additives used aluminium oxide. It was found that an increase of more than 20 additives reducing the release of the alloy and metal extraction. Also included experiments on selection of warm additives. Use as a warm additive of ammonium nitrate is not desirable because of the rapid reaction and loss of metal slag. The output and the extraction of metal in the application of potassium and sodium nitrate are the same but in the case of kalievoj nitrate slag can be used as a prolonged potash fertilizer. From the X-ray spectrometer alloys were analyzed