Reaction between chromium(III) oxide and oxygen in the presence of sodium carbonate
01 Apr 1977-Journal of Thermal Analysis and Calorimetry (Akadémiai Kiadó, co-published with Springer Science+Business Media B.V., Formerly Kluwer Academic Publishers B.V.)-Vol. 11, Iss: 2, pp 323-326
TL;DR: The large scale manufacture of sodium chromate is carried out by heating finely ground chromite ore mixed with sodium carbonate and lime in air as discussed by the authors, and the essential reaction leading to the formation of the sodium chromates is the reaction of the mixture of chromite and lime.
Abstract: The large scale manufacture of sodium chromate is carried out by heating finely ground chromite ore mixed with sodium carbonate and lime in air. The essential reaction leading to the formation of sodium chromate is
$$2Cr_2 O_3 + 4 Na_2 CO_3 + 3 O_2 \xrightarrow{{\Delta {\rm H}_{R^0 } }}4Na_2 CrO_4 + CO_2 $$
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TL;DR: In this paper, a thermal decomposition of aluminium nitrate and chromium nitrate was carried out by means of chemical analysis, IR, diffuse reflectance and X-ray diffraction.
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TL;DR: In this paper, the effects of three corundum structure oxides, α-Al 2 O 3, α-Cr 2O 3, and α-Fe 2 O3, on the thermal decomposition of sodium and potassium peroxodisulfates (persulfates) under non-isothermal static air conditions and using various oxide/persulfate molar ratios, have been thermoanalytically investigated.
9 citations
TL;DR: A comprehensive review of thermal analysis and calorimetric techniques for coordination compounds can be found in this paper, where the major investigations have focussed on thermal analysis studies of coordination compounds, particularly the metal dithiocarbamate complexes.
Abstract: The research in thermal analysis and calorimetry, conducted by the author over the period 1964 to 1993, is summarised and concisely reviewed. The major investigations have focussed on thermal analysis studies of coordination compounds, particularly the metal dithiocarbamate complexes. A significant solution calorimetric study of some metal dithiocarbamate complexes has also been undertaken. DSC has been applied to determine the sublimation enthalpies of many metal dithiocarbamate and metal pentane-2,4-dionate complexes and solution calorimetry has been applied to study the thermochemistry of the latter group of complexes. Thermal analysis investigations of several inorganic molten salt systems have been initiated. Thermometric titrimetry has been applied to study metal-macrocyclic ligand systems in aqueous media and particularly those systems of environmental significance. Temperature calibration standards for TMA have been proposed and TMA has been applied to study the mechanical properties of several common inorganic compounds. DTA has been applied to study a wide variety of phenols and has subsequently been applied as an analytical technique to determine the components of solid state phenol mixtures. Thermometric titrimetry has been applied to determine the phenolic content of wines. A comprehensive thermal analysis study of Australian brown coal has been undertaken, involving the DSC determination of coal specific energy, a TG/DTA study of the coal pyrolysis and combustion processes and a TG/DTA and EGA study of the cation catalytic effect on the coal pyrolysis process. Thermal analysis and calorimetric techniques have been extensively publicised and promoted by the publication of specialist reviews, the presentation of symposia review papers and the oral presentation of short courses, particularly in the SE Asian region. This review essentially reveals the diversity of possible application of thermal analysis and calorimetric techniques and the primary significance of thermodynamic data in the fundamental rationalisation of chemical phenomena.
8 citations
01 May 1995-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, low temperature isothermal kinetic studies were performed on alkali roasting of Cr2O3 with progressive replacement of Na2CO3 in the reaction mixture by NaNO3 in a temperature range of 573 to 873 K. The influence of the nitrate on the course of the reactions was studied.
Abstract: Low temperature isothermal kinetic studies were performed on alkali roasting of Cr2O3 with progressive replacement of Na2CO3 in the reaction mixture by NaNO3 in the temperature range of 573 to 873 K. The influence of the nitrate on the course of the reactions was studied. Statistical design of experiments was employed to asses the relative influence of different process variables. Kinetic analysis of the experimental data shows that the reaction with NaNO3 follows a simple first-order model, and the activation energy of the reaction is 22.7 kJmol-1, as compared to 72 kJmol−1 for Na2CO3 flux.
4 citations
TL;DR: In this paper, the authors summarized and concisely reviewed significant advances have been made in the solution calorimetric determination of the standard formation enthalpies of coordination compounds, particularly metal dithiocarbamates, and the application of thermometric titrimetry as an analytical technique for the determination of metals in aqueous systems of environmental significance.
3 citations
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TL;DR: In this article, the acid K 2 Cr 2 O 7 was titrated potentiometrically against the three bases K 2 CO 3, Na 2 O 3, and NaHCO 3 in molten KNO 3 at 350°.
30 citations
TL;DR: In this article, thermal decomposition studies of intimate mixtures of different molar ratios of potassium nitrate and chromium(III) oxide were made by employing thermogravimetry differential thermal analysis, chemical analysis, infrared spectral measurements and X-ray powder diffraction patterns.
11 citations
TL;DR: Sodium silicate, or a mixture of silica and sodium carbonate, reacts with chromium(III) oxide in the presence of oxygen to give sodium chromate, within the approximate temperature range 300-900° as discussed by the authors.
Abstract: Sodium silicate, or a mixture of silica and sodium carbonate, reacts with chromium(III) oxide in the presence of oxygen to give sodium chromate, within the approximate temperature range 300–900°. Above 900° the reaction is reversed and chromium(III) oxide regenerated.
5 citations