Caracterização tecnológica com ênfase no ataque químico em mármore para uso ornamental

Abstract

The Mudador Marble crops out in the municipality of Caçapava do Sul, being located to the northwest of the Sul-rio-grandense Shield, distant 240 km of Porto Alegre - RS. This lithology occurs in lenticular form, being able to be classified petrographically like a dolomitic marble. Its main characteristic is a very dark coloration, generated by the presence of organic matter, being its visual characteristic the factor that most distinguishes it from the marbles of the region. This study focuses on conducting research for its ornamental use. All the material used as dimension stone must possess certain technical characteristics that allow its application. Thus, the study of the alterability of the Mudador marble was carried out, since rocks applied in coatings can suffer color change, have spots or displacements. Normally specified chemical attacks, color readings and preparation of petrographic slides were performed. The chemical attack used reagents that represent common substances used in the home or work environment. Among these reagents, those used were ammonium chloride, sodium hypochlorite, citric acid, hydrochloric acid and potassium hydroxide. It occurred variations perceptible to the naked eye, measurable variations in coloration and changes in microscopic levels of marble were observed after the analyzes. The contact of the marble with substances that have hydrochloric acid, citric acid and sodium hypochlorite in its formulation is not recommended.