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- Author or Editor: M. Jabłoński x
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Abstract
The reaction of sulphuric acid with titanium raw materials runs violently with simultaneous emission of gases. Such run of reaction creates danger of explosion. This process is very complicated from the reason of complexity of reactions and variety of compounds in reaction mixture. To determine safe conditions of reaction with high efficiency, it is necessary to investigate phase composition products of reaction. Products of reaction were investigated by using X-ray diffraction. However reaction products show high amorphy and this is the reason of difficulties to determine all phases. For this reason also was used additional method — ‘drop’ calorimeter. This method is used for determination of average specific heat of liquid or solid samples. In this case, this method was used for verification of phase composition of products of reaction. On the basis of investigation the phase composition of reaction product is following: titanyl sulfate, iron(III) sulfate, monohydrated iron(II) sulfate, magnesium sulfate and unreacted remainders of ilmenite and magnesium silicate.
Abstract
The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500C appears structure of hematite Fe2O3. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data.
Abstract
The kinetic of the reaction ilmenite with sulphuric acid was studied using non-adiabatic and non-isothermic calorimetric device system. The kinetic model based on interphase surface and kinetic models found in literature which are usually applied were tested. The best agreement between experimental and calculated values was found with model based on first order of reaction and model of contracting volume.
Abstract
Titanium raw materials play important role as a source of titanium and titanium dioxide. The investigation of the rate of oxidation and phase transformation of titanium slag in static air atmosphere by use of thermogravimetry (TG) and X-ray diffractometry (XRD) were presented. The investigation were carried out for three different particle size fractions to determine influence of this parameter on rate of reaction. To estimate kinetic parameters was used the kinetic model of contracting volume. The value of kinetic parameters show that influence of heating rate and particle size on rate of reaction is not so large. The thermogravimetric investigations of the oxidation of titanium slag in air atmosphere shown that reaction proceeds in two stages. The XRD investigation shown that titanium slag has the pseudobrookite structure and its diffraction pattern is very close to the diffractogram of magnesium titanate MgTi2O5 and iron magnesium titanium oxide (Fe-Mg-Ti-O). At elevated temperature the structure of slag transforms to the ferric pseudobrookite structure and excess titanium dioxide forms the rutile phase.
Abstract
The reaction of ilmenite titanium raw material with sulphuric acid was investigated in ‘hazard’ type calorimetric system. The investigations show the essential influence of initial temperature, particle size distribution and concentration of sulphuric acid on rate and heat power of reaction and determine the limits of safety of the process and also its efficiency.
Abstract
The reaction of ilmenite titanium raw materials with sulphuric acid has been studied in a non-isothermal-non-adiabatic type calorimeter. The influence of different starting conditions, temperature and ilmenite particle-size distribution on the thermo-kinetics of the reaction was investigated. A kinetic model is presented for this heterogeneous system for a specified ilmenite particle-size distribution and starting temperature. On the basis of this model and experimentally determined parameters it it possible to analyse by simulation the autothermic reaction of digestion of different titanium ores with sulphuric acid.
Abstract
Ilmenite is a valuable source of titanium and is applied as the main raw material in the technology of titanium white pigment production. Ilmenite is found in many places in the earth, and its elemental as well as phase compositions very strongly depend on the place of origin. Deposits located in Australia, China, India, and Norway in Europe are well known places where ilmenites are exploited industrially. Main phases that were identified in these ilmenites are ilmenite FeTiO3, hematite Fe2O3, geikielite MgTiO3 and pseudorutile Fe2Ti3O9. Enstatite MgSiO3, MnTiO3, and kleberite (determined also as hydroxylian pseudorutile with approximate formula FeTi3O6(OH)3) are minor phases present in ilmenites. Calorimetric investigations of reactions of these ilmenites with sulphuric acid in standard conditions demonstrated significant differences in the shape of temperature and thermal power curves. On the basis of these investigations, it can be concluded that the shape of the thermal power curve is different for each of ilmenite and can be treated as a fingerprint of their phase composite.
Abstract
Results of calorimetric determination of integral enthalpies of solution of some hydrates (monohydrates and heptahydrates) of 3d transition metal sulphates such as FeSO4, NiSO4 and MnSO4 in three-component systems at sulphuric acid concentrations up to 2M are reported. Measured values of integral enthalpies of solution are the basis for calculation of activity coefficient temperature dependences according to Pitzer's model.
Abstract
A series of controlled pore glasses (CPG) was made from the same raw glass by means of different chemical and thermal treatments. BET specific area, selectivity of cesium adsorption in relation to sodium, ionosorption capacity under dynamic conditions of these CPG were measured and potentiometric titrations carried out. 0 vs. pH curves show i.e.p. and c.i.p. values similar to those for silica. KOH treatment leads to increase of BET specific surface but ionosorption capacity is decreased.