17 documents found, page 1 of 2
Recovering lead from cupel waste generated in gold analysis by Pb-Fire assay
Cerceau, Cristiane Isaac; Carvalho, Cornélio de Freitas; Rabelo, Ana Carolina Silveira; Santos, Cláudio Gouvea dos; Gonçalves, Sabrina Mayra DiasBecause of its precision and accuracy, Pb-Fire assay is the most employed method for gold analysis in geological materials. At the second stage of the method, namely cupellation, lead is oxidized to PbO which is absorbed by the cupel, leading to metallic gold as a tiny bend at the bottom of the recipient. After cupellation, cupel becomes highly contaminated with lead, making its disposal a serious risk of envir...
Recovering lead from cupel waste generated in gold analysis by Pb-Fire assay.
Cerceau, Cristiane Isaac; Carvalho, Cornélio de Freitas; Rabelo, Ana Carolina Silveira; Varejão, Eduardo Vinícius VieiraBecause of its precision and accuracy, Pb-Fire assay is the most employed method for gold analysis in geological materials. At the second stage of the method, namely cupellation, lead is oxidized to PbO which is absorbed by the cupel, leading to metallic gold as a tiny bend at the bottom of the recipient. After cupellation, cupel becomes highly contaminated with lead, making its disposal a serious risk of envir...
Caracterização e biodegradabilidade aeróbia e anaeróbia dos esgotos produzidos ...
Bertolino, Sueli Moura; Carvalho, Cornélio de Freitas; Aquino, Sergio Francisco deO presente trabalho caracterizou e avaliou a tratabilidade dos efluentes líquidos produzidos no campus da Universidade Federal de Ouro Preto. Os parâmetros físico-químicos mostraram que o efluente do campus possui uma característica típica a dos esgotos domésticos, com valores médios de DBO5 total, DQO total, NTK e P total de 300 mg.L-1, 670 mg.L-1, 56 mg.L-1 e 6 mg.L-1 respectivamente. Dos metais monitorados s...
Morphological and thermal analyses of flexible polyurethane foams containing co...
Sant’Anna, Sabrina Sá; Souza, Denilson Arlindo de; Carvalho, Cornélio de Freitas; Yoshida, Maria IreneUma das cargas mais utilizadas na fabricação de espumas flexíveis de poliuretano é o carbonato de cálcio (CaCO3) por ser não abrasivo, não tóxico e de fácil pigmentação. Contudo, é observado que o excesso de CaCO3 comercial usado nas indústrias causa deformações permanentes, o que prejudica a qualidade do produto final. No presente trabalho é proposto o estudo do efeito da concentração de CaCO3 comercial na fab...
Caracterização e tratabilidade biológica dos efluentes líquidos gerados em cabi...
Santos, Anselmo Rogério Lage; Aquino, Sergio Francisco de; Carvalho, Cornélio de Freitas; Vieira, Laura Aparecida; Gontijo, Erik Sartori JeunonO objetivo deste trabalho foi caracterizar os efluentes gerados em cabines de pintura de uma indústria moveleira e avaliar a eficiência de sistemas biológicos (anaeróbio e aeróbio) para o seu tratamento. O efluente industrial apresentou elevado teor de matéria orgânica (DQO total de 634 a 2.790 mg.L-1; DBO5 total de 360 a 972 mg.L-1) e baixos teores de macronutrientes (NTK de 1,9 mg.L-1 e Ptotal de 0,5 mg.L-) e...
Adsorption studies of etherdiamine onto modified sugarcane bagasses in aqueous ...
Gusmão, Karla Aparecida Guimarães; Gurgel, Leandro Vinícius Alves; Melo, Tânia Márcia Sacramento; Carvalho, Cornélio de Freitas; Gil, Laurent FrédéricIn this study sugarcane bagasse was modified with succinic anhydride and EDTA dianhydride to obtain SCB 2 and EB adsorbents, respectively. These adsorbents were used to remove etherdiamine, which is used for iron ore flotation from single aqueous solutions. The removal and recovery of etherdiamine is important for environmental and economic reasons due to its toxicity and high cost. The results demonstrated tha...
Manganese ore tailing : optimization of acid leaching conditions and recovery o...
Santos, Olívia de Souza Heleno; Carvalho, Cornélio de Freitas; Silva, Gilmare Antônia da; Santos, Cláudio Gouvêa dosManganese recovery from industrial ore processing waste by means of leaching with sulfuric acid was the objective of this study. Experimental conditions were optimized by multivariate experimental design approaches. In order to study the factors affecting leaching, a screening step was used involving a full factorial design with central point for three variables in two levels (23). The three variables studied w...
Positronium formation and inhibition in binary solid solutions on Al (III) and ...
Machado, José Caetano; Carvalho, Cornélio de Freitas; Magalhães, Welington Ferreira de; Netto, Antonio Marques; Abbé, J. Ch.; Duplâtre, G.Positron annihilation lifetime spectroscopy has been applied in mixtures and in solutions of solid Al(W), Al(acac),, and Co(III), Co(acac)g, tris(acetylacetonates). For the solid solutions of Co(acac), in Al(a~+c)~, a strong inhibition of positronium formation is observed with increasing cobalt complex concentration, while there is no quenching of the positronium lifetime. In the solid mixtures the positronium ...
Rendering wastes obtained from gold analysis by the lead-fusion fire-assay meth...
Magalhães, Fernanda Batalha de; Carvalho, Cornélio de Freitas; Carvalho, Eduardo Lyse Corrêa Netto; Yoshida, Maria Irene; Santos, Cláudio Gouvêa dosThe classical method of melting lead by fire-assay (Pb-FA) is the most frequently used analytical technique in gold prospection. The crucible solid waste which is generated in this process is usually characterized by chemical and mineralogical composition, granulometric size distribution, and classified according to Brazilian Environmental Regulations. This study demonstrates how acid leaching can be used to re...
Estudos comparativos entre carvão ativado e resina de troca iônica para adsorçã...
Araujo, Danielle Marques de; Yoshida, Maria Irene; Stapelfeldt, Frank; Carvalho, Cornélio de Freitas; Donnici, Cláudio Luiz; Kastner, Geraldo FredericoO objetivo desse trabalho é a adsorção de cianocomplexos de ouro, cobre e ferro de efluentes que são gerados no processo de beneficiamento do minério de ouro. Para a adsorção foram testadas duas alternativas: resina de troca aniônica com base fraca e o carvão ativado quimicamente modificado. A resina utilizada foi a LEWATIT MP 62 da Bayer S.A. O processo de modificação química do carvão ocorreu em duas etapas: ...