Acid-based cement slurry with controllable properties

Intensive occurrence of sand related problems in wells diminishes oil flow rate and leads to heavy expenses on production and equipment maintenance. Hard geological factors on field bedding, heterogeneity of reservoir porosity and permeability, strict constraints on physicochemical property of oil and produced water restrict the efficient application of several available methods and technologies for sand control. The increasing densification of sand related problems at late stages of development gives rise to implementation of different type of workover. There exist several backfilling compositions with a number of draw-backs to control sand influx from the reservoir into the well. With the purpose to work out more effective technology to ensure the consolidation of reservoir there was developed a new grouting mortar. This slurry contains cement, hydrated aluminum silicate and 7-8% hydrochloric acid solution. Barrier of grouting mortar has high resistance and adhesive characteristics and penetrates much deeper into pores increasing consolidation efficiency.

In Situ Synthesis of Structural Hierarchy Flowerlike Zeolite and Its Application for Fluoride Removal in Aqueous Solution

A three-dimensional hierarchically structured flowerlike zeolite was synthesized using naturally occurring nanohalloysite (HNT) by hydrothermal methods. Halloysite a hydrated aluminum silicate with nanohollow morphology, microporosity, and environmentally friendly properties was chosen to be the sole precursor. The morphology and structure of the composite that was prepared was characterized using XRD, FT-IR, BET, TG, SEM, HRTEM, and NMR. SEM and HRTEM images indicated that the synthesized zeolite has a flowerlike hierarchical structure, with well-defined edges and uniform pore channels. FT-IR and NMR spectra indicated that different species of silicon and aluminum were present in the synthesized zeolite. The zeolite was applied in fluoride (F-) removal from aqueous solutions. Single-factor studies, including the initial concentration of F-, initial adsorbent concentration, and the effect of pH value on the adsorption properties, were investigated to evaluate the removal behavior of F- by the zeolite. The zeolite exhibited strong adsorption properties for fluoride ions (F-), with an adsorption capacity up to 161 mg g-1. The pseudo-second-order kinetics and Freundlich models were the best fit to the kinetics and isotherm experimental data, respectively.

RETRACTED:Influence of Fe and Al Dopants on the Optical Properties of Zinc Oxide Thin Films Obtained by Spray Pyrolysis

An investigation has been done to study the influence of the Fe and Al doping concentration on the optical properties of zinc oxide thin films. A spray pyrolysis system was used to obtain ZnO:M films doped with Iron and Aluminum, using zinc acetate dihydrate, hydrated iron chlorate and hydrated aluminum chlorate, respectively. The temperature and the concentration were fixed at 450°C and 0.1mol/L, respectively. Our thin films deposed on glass substrate. UV-VIS spectrophotometer has been used for the layers characterization. The optical transmittance spectra showed that the 2% Al dopand improves the optical transmittance in the visible that the Fe dopand. Zinc oxide thin films is the n type semiconductor with direct optical band gap varied between 3.219-3.346eV for obtain the films in photovoltaic application. But the urbach energy of ZnO thin films undoped and doped by Iron and Aluminum is varied between 101– 202 meV.

Beneficiation of Kaolins by Hydrocycloning

Kaolin is a white clay, formed by hydrated aluminum silicates, which has several industrial applications. Since it is associated to impurities and presents considerable contents of contaminant elements that interfere in its performance and in its applications, kaolin must pass through a beneficiation process in order to meet the market's demands. The purpose of this work is to study the use of a hydrocyclone in the beneficiation of primary kaolins from Província Pegmatítica da Borborema. The samples were characterized by cation-exchange capacity (CEC), granulometric analysis by laser diffraction (GA), chemical composition by X-ray fluorescence (EDX), X-ray diffraction (DRX), differential thermal analysis (DTA) and thermogravimetric analysis (TG). The purification process did not show good results for kaolin in ABNT 200 mesh in the attempt to obtain colloidal kaolin. On the other hand, it presented very promising results for the beneficiation of raw kaolin, proving the feasibility of the application of this technology to the granulometric classification of this mineral, being an alternative route for the processes adopted in the regional kaolin beneficiation plants, which use washing and sieving.