09:00 am
Data-based carbon footprint of Imerys specialty minerals for refractories
Solange Ranaivoharilala | IMERYS | France
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Authors:
Solange Ranaivoharilala | IMERYS | France
Nancy Bunt | IMERYS | France
Dr. Christoph Wöhrmeyer | IMERYS | France
Refractory raw materials are the major contributor to the carbon footprint of unshaped refractories while for fired refractory bricks the firing process adds on to the total carbon footprint. Significant energy and CO2 emissions savings can be achieved by using monolithic refractories instead of fired bricks and a careful selection of raw materials can further reduce the total carbon footprint of refractory products. This paper will explain in detail the boundaries for the quantification of the CO2-equivalents of Imerys specialty minerals for refractories. The analysis leads to product-specific scientific data that allow a transparent calculation of the footprint of refractory products formulated with Imerys products. This paper will compare the impact of different energy sources on the environmental footprint of sintered and fused Imerys aggregates from the system Al2O3-SiO2. Furthermore results will be compared with the un-fired natural refractory mineral andalusite.
09:20 am
Sintering and thermo-mechanical characterization of a novel refractory grade bauxite
Luiz Gustavo Noronha | Federal University of São Carlos | Brazil
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Authors:
Luiz Gustavo Noronha | Federal University of São Carlos | Brazil
Prof. Dr. Dereck Nills Ferreira Muche | Federal University of São Carlos | Brazil
The global market for refractory grade bauxite (RGB) has been supplied by few players located in China and Guyana, mostly because of the chemical and mineralogical restrict specifications required for this class of material. When considering the mineralogical phases of the refractory grade bauxite, the main phases present higher content of corundum, tialite and mullite. Recently, a new Brazilian bauxite mine, located in Barro Alto, State of Goias, is capable of producing bauxite with higher Al2O3, low Fe2O3 and lower TiO2 contents, than those available in the market. Herein, the present work focuses on the processing of the Brazilian RGB highlighting 2 main fronts: i) Improving the sintering of the bauxite to be able to attain the benchmark properties for bulk density and apparent porosity, approximately 3,2 g/cm³ and 9% respectively; ii) Directly comparing the Brazilian Bauxite with the global benchmarks (Guyanese and Chinese Refractory Grade Bauxite) in terms of hot modulus of rupture, refractoriness under load, thermal shock resistance and slag corrosion. Preliminary results so far, have shown that the Brazilian RGB develops only the mineralogical phases corundum and mullite, without the presence of tialite, with a density of ~3,3 g/cm³ and an apparent porosity lower than 10%, showing to be a promising candidate for refractory applications.
09:40 am
Almatis Mission NeutrAL represents our sustainable commitment to the refractory raw materials industry
Dr. Charles Compson | Almatis | United States
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Authors:
Dr. Charles Compson | Almatis | United States
Dr. Andus Buhr | Almatis GmbH | Germany
Dr. Hans-Leo Gross | Almatis GmbH | Germany
Admir Skula | Almatis GmbH | Germany
There is increasing focus on carbon accounting and product carbon footprint throughout the value chain from mined materials to consumer goods. Pressure comes from legislators, financiers, end-users, customers and filters down through all supply chain partners. If the European steel & refractory market is to succeed in carbon reduction transformation, a key component will be transparency and understanding within that value chain. As a crucial alumina raw material supplier within that value chain, Almatis will provide a breakdown of the key components that impact our product carbon footprint and the role of Scopes 1,2 & 3 in determining a roadmap for the future. We will further outline our sustainability ambition, target commitments, strategic initiatives and areas of concern over the coming decade.
10:00 am
Managing Performance of Calcined Aluminas through Manufacturing Process Modifications
Carl Zetterström | Alteo Alumina | France
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Authors:
Paul Soler | Alteo Alumina | France
Carl Zetterström | Alteo Alumina | France
The characteristics of calcined alumina impact greatly on the behaviour of refractory castables and the final refractory properties in application. Calcined aluminas are typically described by a chemical analysis, the specific surface (BET) and the particle size distribution (PSD), and these in turn depend on the manufacturing process.
Over the last century, Gardanne plant has been a major actor in the world of alumina manufacturing using the Bayer process, which consists in dissolving bauxite and precipitating an alumina hydrate. In 2022, the Bayer process in Gardanne was partially closed, and instead alumina hydrates are sourced on the market and used for the manufacturing of Calcined Aluminas.
Following the modifications to the manufacturing process, extensive work was done in order to ensure the quality and stability of the products, independently of variations in the quality of the alumina hydrates. Work was carried out to achieve the same calcined alumina properties in terms of chemistry, BET and PSD of the alumina powder, while using alumina hydrates having varying characteristics, and furthermore also evaluating the impact from the calcined alumina on the properties of refractory castables.
10:20 am
Influence of mineral composition on the processing of iron-rich bauxite raw materials by using hydrochloric acid leaching
Dr.-Ing. Almuth Sax | Universität Koblenz | Germany
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Authors:
Alena Stein | Universität Koblenz | Germany
Dr.-Ing. Almuth Sax | Universität Koblenz | Germany
Prof. Dr. rer. nat. Dr. h.c. Peter Quirmbach | Universität Koblenz | Germany
Bauxite is an essential raw material for the refractory industry, but it can only be used with sufficient raw material quality. For the classification of bauxite as refractory grade, first of all the chemical composition is crucial and especially the Fe2O3 content should be < 2 wt%. The global availability of suitable qualities will, however, become increasingly problematic in the future, which is made clear by the European Commission's classification of bauxite as a critical raw material in 2020. Therefore, it is already of great importance to develop strategies that make different bauxite raw materials, for example those rich in iron, accessible for the refractory industry. In this study, it is demonstrated that a beneficiation of iron-rich bauxite raw materials can be carried out by an acid leaching process. For this purpose, raw material grades of different chemical and mineralogical composition are leached in hydrochloric acid and their Fe2O3 and Al2O3 contents are compared before and after leaching. In addition, the findings of powder X-ray diffraction measurements (PXRD) to determine mineralogical composition before and after leaching are used to draw conclusions about the leachability of various iron and aluminum minerals in bauxite. These findings, in conjunction with methodologies for determining optimal leaching conditions, complete the understanding of the effectiveness of bauxite processing using hydrochloric acid leaching.