Preparation of magnesium hydroxide as antiflame in polymers

• Grant number: 01/03259-8
• Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE
• Duration: September 01, 2001 - May 31, 2002
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Pompeu Pereira de Abreu Filho
• Grantee: Pompeu Pereira de Abreu Filho
• Host Company: Itatex Indústria e Comércio de Cerâmica Ltda
• City: Campinas

Abstract

The project involves the development of an original chemical process for the preparation of magnesium hydroxide to be used as an antiflame product in polymer compounds. The starting materials will be commercially available natural magnesite or caustic magnesite (MgO). If the starting material is magnesite, the chemical process will entail its thermic decomposition using formed briquettes with hollow perforations in one of their extensions and prepared mixing magnesite and water, in the presence and in the absence of an organic agglutinant (dextrine). These briquettes must be mechanically resistant to withstand the manipulations and contraction stresses during thermal treatments. The magnesite briquettes will be transformed into caustic magnesia by thermal decomposition (between 600-800ºC) in an oven with forced air renovation and, immediately, ground to obtain caustic magnesia in the form of powder. If the starting material is commercially obtained caustic magnesia, the chemical process will not include the stages of briquetage and thermal decomposition and will begin at the hydration stage. In this stage, the caustic magnesia in the form of powder will react with water vapor in the interior of a reactor built for this purpose. The reaction of the caustic magnesia plus the water vapor producing magnesium hydroxide will be monitored using thermogravimetry and/or x-ray diffraction to determine the fractions of magnesium hydroxide formed and caustic magnesia remaining during the reaction process. The starting materials and the magnesium hydroxide will be characterized physico-chemically by instrumental methods and by humid method. Chemical composition, specific surface area, chemical reactivity, density and granulometry will be determined. Crystalline structures and degrees of crystallinity will be determined by x-ray diffraction. The variables of each stage of the process will, when necessary, have their effect studied by chemiometric techniques. The results obtained will be analyzed to verify the technical and economic viability of the process in the production of magnesium hydroxide on an industrial scale. (AU)