Utilization of a waste from titanium oxide industry for the synthesis of sodium ferrate by gas–solid reactions Kanari, N., E-mail: ndue.kanari@univ-lorraine.fr [Université de Lorraine, GeoRessources UMR CNRS 7359, 2 rue du Doyen Marcel Roubault, TSA 70605, 54518 Vandoeuvre-les-Nancy Cedex (France)]; Filippova, I.; Diot, F. [Université de Lorraine, GeoRessources UMR CNRS 7359, 2 rue du Doyen Marcel Roubault, TSA 70605, 54518 Vandoeuvre-les-Nancy Cedex (France)]; Mochón, J.; Ruiz-Bustinza, I. [CENIM – CSIC, Av. Gregorio del Amo 8, Madrid 28040 (Spain)]; Allain, E.; Yvon, J. [Université de Lorraine, GeoRessources UMR CNRS 7359, 2 rue du Doyen Marcel Roubault, TSA 70605, 54518 Vandoeuvre-les-Nancy Cedex (France)] 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHLORINE; FERRATES; HYDRATION; ILMENITE; IRON; IRON SULFATES; OXIDATION; RAW MATERIALS; SODIUM; SODIUM HYDROXIDES; SYNTHESIS; TEMPERATURE RANGE 0273-0400 K; THERMAL GRAVIMETRIC ANALYSIS; TITANIUM OXIDES; WATER TREATMENT Highlights: • We studied the sodium ferrate (VI) synthesis by solid–gas reactions. • Thermal behavior of iron sulfate is followed through thermogravimetric analysis. • Synthesis of Na–ferrate is achieved at room temperature. • Water and chlorine content affect strongly the synthesis process. • Conversion efficiency of Fe(II) to Fe(VI) of the proposed process is about 30%. - Abstract: This work is focused on the preparation of alkali ferrates, especially sodium ferrate, using ferrous sulfate as iron bearing material and chlorine as oxidant. Ferrous sulfate heptahydrate is mainly generated during titanium oxide extraction from ilmenite through the sulfate route; it is considered as a waste for this industry. Obtained alkali ferrates belong to the compounds where iron is in the rare hexavalent state and they are becoming a substance of growing importance for water treatment and industrial effluent cleaning. Two methods are developed for the ferrate synthesis. The first method consists of simultaneous reactions of two solids (iron sulfate and sodium hydroxide) and one gaseous oxidant (diluted chlorine). The second method involves a homogenous premixing of both solids prior to the oxidation by diluted chlorine. The synthesis process is performed in a rotary reactor at room temperature; however, since the overall reaction is exothermic, temperatures as high as 150 °C are often recorded. The effects of several parameters such as hydration extent of raw materials, Na/Fe ratio, chlorine content of the reactive gases on the sodium ferrate synthesis are investigated to determine the optimal processing conditions. The conversion efficiency of Fe(II) to Fe(VI) during the sodium ferrate synthesis reaches about 30%. Available from http://dx.doi.org/10.1016/j.tca.2013.11.008 Netherlands 2014-01-10 English Journal Article Journal Name: Thermochimica Acta; Journal Volume: 575; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA) Medium: X; Size: page(s) 219-225 https://doi.org/10.1016/J.TCA.2013.11.008 PII: S0040-6031(13)00570-4 [] 575 Journal ID: ISSN 0040-6031; CODEN: THACAS; Other: PII: S0040-6031(13)00570-4; TRN: NL14S6988114337 NLN 2015-01-07 22292816