ZEOLITE AND WOLASTONITE SYNTHESIS FROM RICE HULL ASH / "Síntese de Zeólitas e Wolastonita à partir da cinza da casca do arroz"

AUTOR(ES)

Alberto de Andrade Fernandes

DATA DE PUBLICAÇÃO

2006

RESUMO

Rice hull ash (RHA) is a industry scrap rich in amorphous silica. A simple and low-energy cost method for the extraction of this silica was researched. A low level of impurity and high reactivity material was produced, which is appropriate for the synthesis of zeolites and wolastonite (CaSiO3). The synthetic zeolites, has not similar structures in nature, and they have been more and more valued in the market due to their purity and efficiency in specific applications like ion exchange, molecular sieve and catalysis areas. High purity wolastonite has many applications in manufacturing and agriculture. The mineral wolastonite can be formed in nature in different ways; it is generally accepted two forming processes, both encompassing limestone metamorphism (heat and pressure). In this work, a new process for the synthesis of zeolites and wolastonite from RHA colloidal silica was developed. Moreover, the process is aimed at lower energy costs, fewer stages and fewer reactants consume. In this work, zeolite A used in detergent and zeolite ZSM-5, employed in the petrochemical industry due to its high selectivity in catalytic reactions and its high thermo and acid stability, were synthesized. The first step of the wolastonite synthesis was studied, with the purpose of obtaining calcium hydrosilicate. Eleven different hydrosilicates occur in the system Ca(OH)2-SiO2-H2O, in the second step, it was annealed to form the wolastonite phase.

ASSUNTO(S)

zeólita wolastonita wolastonite zeolites rice hull ash cinza da casca do arroz

Documentos Relacionados

• CARBONATAÇÃO EM CONCRETO COM CINZA DE CASCA DE ARROZ SEM MOAGEM
• Characterization of residual ash from rice husk burning for mortal production
• CARACTERÍSTICAS DE DURABILIDADE DE CONCRETOS COM CINZA VOLANTE E CINZA DE CASCA DE ARROZ COM E SEM BENEFICIAMENTO
• Properties of silica from rice husk and rice husk ash and their utilization for zeolite y synthesis
• Síntese de zeólitas a partir de cinza volante de caldeiras: caracterização física, química e mineralógica