Synthesis of ultramarine pigments from Na-A zeolite derived from kaolin waste from the Amazon

Abstract

Ultramarine pigments were synthesized successfully from Na-A zeolite derived from kaolin waste. Na-A zeolite encapsulates the sulfur species formed and which act as chromophores, which circumvents their oxidation and the subsequent liberation of high levels of toxic gases during the reaction. Different Na-A zeolite matrices with various grain sizes (fine to coarse) were mixed with sulfur and sodium carbonate in various proportions to study the influence of these variables on the pigments’ colours and hues. After calcination at 500°C for 5 h, the products were characterized by X-ray diffraction, X-ray fluorescence and Raman spectroscopy and were classified by the Munsell system (colour and hue). Products with colour ranging from blue to green with various hues were obtained. Both colour and hue were affected by the amount of additives and by the particle size.

Uso De Resíduo Industrial (Gesso) Como Reforço a Compressão De Sistemas Epóxi

“…O Pará possui grande destaque no Brasil por ter um dos mais importantes depósitos de caulim a nível internacional e ser o principal distrito brasileiro de produção de caulim para a indústria de papel, no qual o processamento desse material gera uma quantidade considerável de rejeitos, que causam problemas para a região amazônica, pois, grandes áreas são desmatadas para sua disposição, porém existem diversos trabalhos produzidos que visam estabelecer rotas de aplicação para esses materiais (Costa, 2009;Maia et al 2019;Menezes et al 2017).…”

Interzeolitic Transformation of Clinoptilolite into GIS and LTA Zeolite

“…To reduce the production costs of synthetic zeolites, alternative sources of silicon and aluminum have been used. High-quality synthetic zeolites can be synthesized using a wide range of alternative sources, including natural aluminosilicates such as clays [8][9][10][11][12][13][14][15][16][17][18][19], natural zeolites [20,21], diatomite [22,23], and waste resources [24][25][26][27][28][29][30][31][32].…”

Alkali activation of natural clay using a Ca(OH)2/Na2CO3 alkaline mixture

“…The mechanical strength, morphology and physical properties of alkali-activated materials are influenced by several factors such as curing temperature, curing time, and type and concentration of the alkaline activator (Pacheco-Torgal et al, 2014). The alkali activation of natural kaolinite using NaOH commonly produces hydrosodalite (Esaifan et al, 2015;Maia et al, 2015) or A-type and X-type zeolites (Belviso et al, 2015;Menezes et al, 2017). On the other hand, the use of a potassium hydroxide (KOH) solution yields a semi-crystalline potassium aluminosilicate phase (KAlSiO 4 ) identified as kaliophilite (Esaifan et al, 2016).…”