Papers by Keyword: Process Variables

Abstract: Bentonite clays, after treated with surfactants, are called organofilic clays. The objective of this work is the development of organofilic clays, using ionic surfactants, based on a variety of smectite from Cubati, PB, for application in organic media. The following materials were used: Superior Gray bentonite clay from the town of Cubati, PB, Brazil, and the ionic surfactants Praepagen WB® and Praepagen HY®. The clay was characterized with basis on the granulometric analysis by laser diffraction (AG), chemical composition by X-ray fluorescence (EDX), X-ray diffraction (XRD), thermogravimetric analysis (TG) and thermal differential (DTA). The clay was processed and then turned into sodic and later into organofilic clays. The results prove that there was intercalation of the ionic surfactant into the clay fraction, and that the process variables did not affect the organofilization process, but the surfactant type has influence on the process.

Abstract: Organoclays are used as disperse agent in the composition of drilling fluids, which play important roles during the drilling of petroleum wells. This work is intended to develop several kinds of smectite from Cubati-PB for use in drilling fluids, using the ionic surfactant Praepagen WB. The following materials were used: natural Gray and Superior Green bentonite, from the town of Cubati-PB, and quaternary ammonium salts: Praepagen WB® with 45% active matter. The organoclays were characterized by laser diffraction granulometric analysis, chemical composition by X-ray fluorescence, thermogravimetric analysis, differential thermal analysis and X-ray diffraction. In general, we noticed that the clays present diffractograms and thermal behavior typical of bentonites. The results showed that the studied clay has potential for organofilization. With respect to the process variables, we observed that they do not interfere in the organofilization process.

Abstract: This work aimed on the granulometric characterization of flotation products and to analyze the effect of the variables (that were investigated in a flotation work) on the particle size distribution parameters. Besides to compare the parameter values of the granulometric analysis for the concentrate and tailing both results were compared with the parameter values of the flotation feed samples. The analyzed parameters showed lower values for the concentrate products as compared with the parameters for tailing and feed samples. For coarse and fine particle size fractions the column height was the variable that more influenced on the parameter values.

Abstract: This work aims at the development of organoclay from two varieties of bentonite for use in organic media using ionic surfactants, studying the influence of process variables in the organophilization process. We used the following materials: natural bentonite clay from Cubati-PB District, and the ionic quaternary ammonium salt: Praepagen WB® with 45% active matter. The clays were benefited and then turned into sodium form and subsequently into organoclays. The bentonites were characterized by laser diffraction (GA) X-ray fluorescence chemical composition (EDX), thermogravimetric analysis (TGA), thermogravimetry (DTA) and X-ray diffraction (XRD). The organoclays were characterized by (XRD) thermogravimetric analysis (TGA) and thermogravimetry (DTA). The results showed that the clay has potential for application in the organophilization process and that there is influence of process variables.

Abstract: Froth flotation is an adsorptive-bubble separation method based on the selective attachment of particles on the surfaces of gas bubbles passing through a suspension. Reagents as collectors, frothers and pH modifiers are added to perform specific roles to facilitate and to improve the separation. In the present work the process of apatite flotation in column has been investigated experimentally. The influence of the reagents (collector and frother dosages and interactions), percentage of solids and pH value on the column flotation of coarse particles of apatitic ore was analyzed. Percentage of solids was the variable that more influenced on the apatite recovery and the P2O5 grade was more affected by varying pH. The best results were achieved by using lower pH values and lower pulp density. Frother addition only had significant effect for lower collector dosage.

Abstract: Wear modeling makes it possible to predict the evolution of wear profile and explain wear mechanism from process variables, such as temperature, pressure and sliding velocity etc. A composite crater wear model considering adhesive and diffusion wear is established by means of experiment and modeling in conventional speed machining. A series of cutting tests are performed to obtain wear profiles and corresponding process variables. The constants in wear model are fitted by regression analysis with crater wear tests. This crater wear model shows a good predictive capability in conventional cutting speed.

Abstract: Technology requirements for a billet micro globular structure development and following deformation are the basic inputs in a conceptual forging equipment design. The R&D team has studied the features of the Aluminum alloy thixoprocess experimentally on a crank press as well as with a help of computer simulation and have formulated requirements for SSM technology CNC prototype unit development.