Resumo

RESTREPO BAENA, OSCAR JAIME; VASQUEZ JIMENEZ, CARLOS FEDERICO  e  BUSTAMANTE RUA, MOISES OSWALDO. INFLUENCE OF PH IN THE PROPERTIES OF SYNTHETIC GOETHITE AS A PIGMENT. Dyna rev.fac.nac.minas [online]. 2008, vol.75, n.155, pp.163-170. ISSN 0012-7353.

Several aqueous suspensions were prepared, with a synthetic iron oxide as goethite, aFeOOH, which was previously characterized chemically, physically and mineralogically. Different pH variations were then carried out to the suspensions in a range of 2 to 12, in order to obtain changes in its surface chemistry as a colloid, and so, look at the variations as a pigment. Measurements of viscosity were taken to each suspension in a Brookfield® viscosimeter to determine this colloidal characteristic, and then the resultant materials were dried out to evaluate its pigment properties, just like intense shade paint, brightness, Hegman dispersability and reduced shade paint. Results show that properties of the resultant pigments at pH values far from the natural suspension pH (regularly acid), i.e. at alkaline values, were in general superior, and show pathways of research in industrial applications.

Palavras-chave : Goethite; inorganic pigments; colloids.

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