Study by DTA/TG of the formation of calcium aluminate obtained from an aluminium hazardous waste

A Spanish hazardous waste from tertiary aluminium industry was used as a raw material for the synthesis of calcium aluminate. An amorphous precursor was obtained by a hydrothermal method at different values of pH. The transformation of the precursor in a crystalline aluminate was followed by TG/DTA up to 1300 C. At temperatures between 719 and 744 C, the precursors evolve towards the formation of C12A7 which becomes CA at circa 1016 C. Mass spectrometry coupled to thermal analyser allowed the identification of the decomposition productsMEC for financing project CTM2005-01964 and the company Recuperaciones y Reciclajes Roman S.L. (Fuenlabrada, Madrid, Spain) for supplying the waste and Dr. M. I. Martı´n for the FRX analysis and Dr. I. Padilla for the technical assistance. Laura Delgado-Gonzalo is grateful to the CSIC (Spanish National Research Council) for an I3P contractPeer reviewe

PRESS RELEASE | The Launch of Z-ONA4LIFE: Transforming the Aluminium Industry with Circular Solutions

This press release announced the start of the Z-ONA4LIFE Project, a 48-month journey funded under the Programme for the Environment and Climate Action (LIFE), aiming to revolutionise salt slag management, promote circularity in the aluminium industry, and enhance environmental sustainability. To stay updated on Z-ONA4LIFE, connect with us on our social media platforms: Website: www.zona4life.trust-it.com Twitter: @z_ona4life LinkedIn: company/z-ona4life YouTube: @Z_ONA4LIFEThe Z-ONA4LIFE Press Release is also available in the Spanish language

Study of the transformation of boehmite into alumina by Rietveld method

XXII Congress and General Assembly International Union of Crystallography. IUCr2011. Madrid, 22-30 Agosto, 2011. A publicar en Acta Cryst. (2011) A67, C580The aim of this paper is to study the conversion of boehmite into alumina, by means of the application of Rietveld refinement methodPeer reviewe

Environmental impact and management of phosphogypsum

The production of phosphoric acid from natural phosphate rock by the wet process gives rise to an industrial by-product called phosphogypsum (PG). About 5 tons of PG are generated per ton of phosphoric acid production, and worldwide PG generation is estimated to be around 100–280 Mt per year. This by-product is mostly disposed of without any treatment, usually by dumping in large stockpiles. These are generally located in coastal areas close to phosphoric acid plants, where they occupy large land areas and cause serious environmental damage. PG is mainly composed of gypsum but also contains a high level of impurities such as phosphates, fluorides and sulphates, naturally occurring radionuclides, heavy metals, and other trace elements. All of this adds up to a negative environmental impact and many restrictions on PG applications. Up to 15% of world PG production is used to make building materials, as a soil amendment and as a set controller in the manufacture of Portland cement; uses that have been banned in most countries. The USEPAThe authors are grateful to AECI (project N A/5537/06) and to the Spanish National R&D&I Plan (Project CTQ2008-02012/PPQ) for the financial support of this study. Hanan Tayibi is grateful to the CSIC (Spanish National Research Council) for an I3P contract (I3PDR-6-01).Peer reviewe

Thermal decomposition of single hydroxychlorides of nickel, copper and cobalto

The thermal decomposition reactions of Ni(OH)Cl.l½H20 in still air and in nitrogen and β-CO2(OH)3Cl and γ-Cu2(OH)3Cl in nitrogen atmosphere, have been studied by DTA and TG analysis, and the intermediates and final products have been characterized by x-ray diffraction and infrared spectroscop. The thermal evolution ot the above indicated compounds under dynamic vacuum conditions has be en studied with the aid of an x-ray high teaperature diffraction chamber. They reveals that in these conditions, the pure metallic nickel, copper and cobalt can be obtained at comparative low temperature. The infrared spectra of thése hydroxychlorides have been tentatively assigned

Caracterización de un nuevo hidroxicloruro de magnesio

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Síntesis y estudio del hidroxicloruro de niquel NiOHCl, H2O

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Study of the thermal behavior of the aluminium dust stabilized with gypsum

[ES]El polvo de aluminio (pAl) es un residuo peligroso procedente de la metalurgia secundaría del aluminio. Con objeto de reducir la reactividad del mismo, en el CENIM se ha desarrollado un proceso de estabilización/solidificación mediante su fraguado con yeso. En este trabajo se presenta el estudio del comportamiento térmico del pAl estabilizado con el yeso, con el fin de establecer la influencia del residuo en las reacciones de hidratación/deshidratación del yeso durante el proceso del fraguado, a saber: deshidratación parcial del sulfato calcico dihidrato, deshidratación del hemihidrato, deshidratación del hidróxido de aluminio y transformación de anhidrita soluble en anhidrita insoluble. Asimismo se ha estudiado la cinética asociada a cada una de las reacciones anteriormente mencionadas mediante Calorimetría Diferencial de Barrido.[EN]The aluminium dust is a hazardous waste from the secondary aluminium remelting industry. A stabilization/solidification process was developed at CENIM with the aim of decreasing its reactivity. Gypsum was used as a binder material. Tliis work summarizes the study of the thermal behavior of the aluminium dust stabilized with gypsum, in order to establish the influence of the residue in the reactions of hydration/dehydration of the gypsum during the hardening process, namely: partial dehydration of calcium sulphate dihydrate, dehydration of calcium sulphate hemi'hydrate, dehydration of aluminium hydroxide and anhydrite soluble/anhydrite insoluble transformation. The activation energy associated to all those reactions was determined by Differential Scanning Calorimetry.Los autores agradecen a la Consejería de Educación de la Comunidad de Madrid la financiación del proyecto (07M/0136/2000) y a la empresa Recuperación y Reciclaje Román por el apoyo a esta investigación.Peer reviewe

Sustainable Management of Salt Slag

The management of salt slag, a waste from the secondary aluminum industry, is associated with huge environmental concerns due to the risk of atmospheric pollution (emission of toxic gases), groundwater contamination (high salt content that can percolate and cause an increase in salinity) and soil unavailability (large extensions required for disposal). Therefore, the development of a sustainable process for its treatment and recovery is of the utmost importance. In this work, a two-step process for the valorization of salt slag was developed that rendered zeolite as the main added-value product and NaCl and NH3 as byproducts. First, salt slag was hydrolyzed at 90 °C and at a solid/water ratio of 1/3. More than 90% of salt and ~90% of ammonia were recovered. In a second step, the hydrolyzed slag was completely transformed into a NaP zeolite under mild hydrothermal conditions. The zeolite exhibited specific surface area (17 m2 g−1), cation exchange capacity (2.12 meq g−1) and zeta potential (−52 mV) values that represent good characteristics for use in the removal of metal ions from aqueous effluents. The transformation of salt slag into zeolite can be considered a sustainable process with a high contribution to the circular economy