J. M. Cartaxo

Purified Smectite Clays Organofilized with Ionic Surfactant for Use in Oil-Based Drilling Fluids

The main bentonite reservs in Brazil are located in Boa Vista, PB. In order on widening the reserves, on the mineral production and on the consolidation of the state as the largest producer in the country, many studies have been carried out by UFCG on the clays recently discovered in the Districts of Cubati and Pedra Lavrada. This work is intended for the characterization of new deposits, for the development of natural and organofilic clays, which will be employed in oil-based drilling fluids. The characterization of the clay was done by means of the following techniques: GA, XRD, EDX, TG and TGA. For purification, a hydrocyclone was used, and in the organofilization process, the Praepagen-WB surfactant was used, in three proportions. The results suggest that the characterization is typical of bentonite. The purification process proved to be efficient and the rheological study revealed that just one of the clays is suitable for application in oil-based drilling fluids.

Influence of Firing Conditions on Properties of Red Ceramic

In the ceramic industry, the firing is one of the main stages of the production process. There are two heating rates prevailing at this stage: low heating rate (long residence time) and high heating rate (fast residence time), the low rate is more used in traditional ceramics. This study aims to evaluate the influence of firing conditions on technological properties of three compositions of clay, used in the manufacture of red ceramic products. Initially, the mixtures were characterized subsequently were extruded, dried and submitted to firing at temperatures at 900 and 1000 °C with heating rates of 1, 2, 5, 15, 20 and 30 °C/min. The crystalline evolution of the different samples was analyzed using X-ray diffraction and the technological properties were determined. For the mechanical resistance, it was not observed significant change with the increase of the temperature and heat rate

Influência das variáveis de processo na obtenção de argilas organofílicas

As argilas bentoniticas, usadas como agente viscosificante e nanocompositos, nao podem ser usadas sem um previo tratamento orgânico para que suas superficies se tornem hidrofobicas e possam ser dispersas em meios orgânicos. Estas argilas depois de tratadas sao chamadas de argilas organofilicas, e sao geralmente obtidas atraves da adicao, em meio aquoso, de um agente organofilizante, geralmente um tensoativo, ionico, anfotero ou nao ionico. O processo de organofilizacao, composto de varias etapas, nem sempre garante a obtencao de argilas organofilicas de boa qualidade, sendo importante destacar as variaveis de processo bem como a escolha das materias-primas a serem utilizadas. Propoe-se entao um estudo detalhado das variaveis envolvidas no processo de dispersao das argilas bentoniticas, e tambem no processo de organofilizacao procurando relacionar as viscosidades aparente e plastica das dispersoes argilosas com a eficiencia do processo de organofilizacao. O processo de organofilizacao sera controlado pelos resultados de difracao de raios X e termogravimetria. As variaveis de processo tanto envolvidas na dispersao das argilas quanto na organofilizacao, do ponto de vista da caracterizacao, nao tem grande influencia na incorporacao do tensoativo as argilas bentoniticas, sendo influentes o tipo de argila e tensoativo e a presenca de sodio como agente defloculante, o que e muito importante de vista industrial pela melhor operacionalidade das condicoes de processamento.

Synthesis of Mulita Nanometric from Delaminated Bentonite-Study of the Percentage of Stages and Size of Crystal

A wide variety of synthesis methods have been proposed for obtaining mullite, however, some techniques produce powders with heterogeneous morphology and a large amount of glassy phase, forming large clusters making it difficult to obtain nanopowders. The microwave synthesis offers advantages over conventional methods, the heating is rapid and uniform, avoiding an undesirable grain growth. The aim of this work was the synthesis of nanoscale mullites powders from delaminated bentonites. For the process of delamination samples were initially treated, then rehydrated, frozen and deagglomeration in ball mill and subsequently subjected to centrifugation, in order to produce a nanosized precursor for the synthesis of mullite. The powders obtained after peeling were characterized chemical and mineralogical. The synthesis of mullite was performed in a microwave oven and the powders were characterized by XRD and SEM. The results showed that the delamination of the bentonite and microwave synthesis were essential in obtaining nanopowders mullite.

Avaliação de argilas bentoníticas policatiônicas do estado da Paraíba com aditivos para aplicação em perfuração de poços de petróleo e tintas à base de água

Com o surgimento das novas ocorrencias de bentonitas no estado da Paraiba, ha necessidade da otimizacao de sua reologia de forma a adequa-las as exigencias da industria nacional, visando seu uso em fluidos de perfuracao e tintas a base de agua. Foram utilizadas tres argilas (Chocolate Campos Novos, Chocolate Corredor e Chocobofe Primavera) com o objetivo de avaliar as propriedades tecnologicas para uso como agente tixotropico na formulacao de fluidos de perfuracao e tintas a base de agua; esta pesquisa trata da reologia de dispersoes de argilas aditivadas com MgO de forma conjunta e isolada com o Na2CO3. O comportamento reologico foi estudado em viscosimetro em dispersoes de 4,86% e 6,00% (em massa) e com aditivos variando de 2% a 3% (em massa) na forma simples e combinada. Os resultados obtidos foram comparados com as especificacoes da Petrobras, API e ISO. As amostras estudadas apresentaram caracteristicas tipicas das bentonitas oriundas do estado da Paraiba, apresentando os argilominerais caracteristicos esmectiticos, cauliniticos e acessorios; as analises reologicas evidenciaram que as argilas em estudo utilizando o Na2CO3 exibiram resultados promissores para aplicacao tecnologica em fluidos de perfuracao de pocos e que a aditivacao das amostras com Na2CO3 em conjunto com o MgO exibiram resultados promissores para aplicacao tecnologica em tintas a base de agua.

Estudo da incorporação de pó de concha de marisco em massa de porcelanato

The fishing of shellfish is one of the most important commercial activities of the fishing community of the municipality of Cabedelo (Paraíba, Brazil). The step of processing, after the extraction of the mollusk, generates a large amount of shells, whose discharge, in considerable volume, causes silting of large areas and consequent environmental imbalance. In the search for the use of these residues (mollusk shells) and aiming at reducing the environmental problems caused, this work had the aim of studying the incorporation of mollusk shell powder in the mass of porcelain tile. Ceramic compositions were formulated from an industrial standard mass and mollusk shell powder or commercial CaCO3 ranging from 0 to 7% by weight. Samples prepared by uniaxial pressing had their technological properties evaluated as a function of the sintering temperature. The results indicated that the use of up to 7 wt% of the mollusk shell powder maintains the technological properties within the standards required by the ABNT (Brazil) for classification as BIa type porcelain tiles.

Effect of carboxymethylcellulose on the rheological and filtration properties of bentonite clay samples determined by experimental planning and statistical analysis

Over the past few years, considerable research has been conducted using the techniques of mixture delineation and statistical modeling. Through this methodology, applications in various technological fields have been found/optimized, especially in clay technology, leading to greater efficiency and reliability. This work studied the influence of carboxymethylcellulose on the rheological and filtration properties of bentonite dispersions to be applied in water-based drilling fluids using experimental planning and statistical analysis for clay mixtures. The dispersions were prepared according to Petrobras standard EP-1EP-00011-A, which deals with the testing of water-based drilling fluid viscosifiers for oil prospecting. The clay mixtures were transformed into sodic compounds, and carboxymethylcellulose additives of high and low molar mass were added, in order to improve their rheology and filtrate volume. Experimental planning and statistical analysis were used to verify the effect. The regression models were calculated for the relation between the compositions and the following rheological properties: apparent viscosity, plastic viscosity, and filtrate volume. The significance and validity of the models were confirmed. The results showed that the 3D response surfaces of the compositions with high molecular weight carboxymethylcellulose added were the ones that most contributed to the rise in apparent viscosity and plastic viscosity, and that those with low molecular weight were the ones that most helped in the reduction of the filtrate volume. Another important observation is that the experimental planning and statistical analysis can be used as an important auxiliary tool to optimize the rheological properties and filtrate volume of bentonite clay dispersions for use in drilling fluids when carboxymethylcellulose is added.

Influência do uso de resíduo de quartzito na expansão por umidade de massas de revestimentos cerâmicos planos

The moisture expansion (ME) is characterized as an increase in physical dimensions of ceramic body when in contact with water (liquid or vapor). The ME phenomenon may contribute to the appearance of serious pathology in ceramic tiles such as cracks, detachment or more severe damages. This work aimed to study the problem of ME in ceramic masses added with quartzite waste for use in tiles using the dilatometry and three-point flexural strength methods. The raw materials were processed and characterized by laser diffraction particle size analysis, plasticity, chemical analysis, thermogravimetric and differential thermal analysis, and X-ray diffraction. The results showed that the addition of quartzite waste generally elevated ME values for bodies fired at temperatures below 1100 °C. For bodies fired at 1200 °C the results indicated high mechanical performance and ME decrease, and the best results for additive formulations was 15% of quartzite.

Influência das variáveis de processo do hidrociclone para tratamento de argilas esmectitícas

Recentemente foram descobertos novos depositos de argilas esmectiticas no estado da Paraiba, localizados nos municipios de Cubati, Olivedos, Sossego e Pedra Lavrada. Estudos preliminares evidenciaram que estes depositos apresentam na sua composicao mineralogica elevados teores de minerais acessorios como mica, silica livre e carbonatos. A presenca desses minerais restringe em muito o uso industrial, sendo necessarios estudos sobre tratamento dessas argilas para reducao desses contaminantes. Estudos recentes mostraram que o uso do hidrociclone e uma alternativa viavel por requerer um baixo investimento de instalacao e manutencao, sendo amplamente utilizado na industria mineral. Este trabalho teve como objetivo estudar as variaveis de processo do hidrociclone para tratamento de argilas esmectiticas de um novo deposito do estado da Paraiba. A argila esmectitica antes e apos hidrociclonagem foi caracterizada fisica, quimica e mineralogicamente, pelas seguintes tecnicas: analise granulometrica por difracao a laser, difracao de raios X, analise quimica por fluorescencia de raios X e analise termica. A argila foi dispersa na concentracao de 4% e com defloculante hexametafosfato de sodio sob agitacao por 24 h. As variaveis de processo utilizadas no hidrociclone foram: pressao, aberturas do vortex e apex. Os resultados conduziram a um aumento do concentrado da fracao argila, reducao do diâmetro medio equivalente das particulas e reducao dos minerais acessorios.

Modelagem de propriedades reológicas de argilas esmectitas do estado da Paraíba para uso em fluidos de perfuração de poços de petróleo

Atualmente mais de 79% das argilas bentoniticas industrializadas sao oriundas das jazidas de Boa Vista, PB. Estes jazimentos vem sendo minerados de forma desordenada ha mais de 40 anos, resultando no esgotamento das variedades mais nobres, havendo serio prejuizo para qualidade do produto final. As empresas mineradoras impoem rigidas condicoes de comercializacao para os produtores, condicionando a aquisicao das variedades menos nobres junto as variedades que ainda apresentam propriedades mais adequadas e frequentemente as variedades menos nobres sao descartadas no processo produtivo. Este trabalho teve o objetivo otimizar as propriedades reologicas das novas ocorrencias de argilas bentoniticas do estado da Paraiba, utilizando a tecnica de planejamento experimental de misturas, a fim de adequa-las as exigencias da Petrobras e da industria nacional. As argilas utilizadas foram provenientes dos municipios de Olivedos e Boa Vista, PB. As amostras de argilas foram misturadas utilizando a tecnica mencionada e caracterizadas fisica, quimica, termica e mineralogicamente. Apos caracterizacao as argilas foram transformadas em sodicas e foram determinadas suas propriedades reologicas para uso em perfuracao de pocos de petroleo de acordo com a norma da Petrobras. As variaveis respostas, viscosidade aparente, viscosidade plastica e volume de filtrado, foram avaliadas mediante analises das superficies de respostas. Os resultados obtidos evidenciaram que as argilas estudadas sao promissoras para usos em fluidos de perfuracao. Observaram-se ainda melhoras significativas de suas reologias apos mistura com as argilas de Boa Vista, PB.