Papers by Keyword: Clay

Abstract: In this study, a catalyst based on Montmorillonite clay was implemented for carbon nanotubes (CNTs) synthesizing. The kaolinite clay was used as a supporting material for iron-cobalt bimetallic catalytic nanoparticles. The CNTs have been synthesized by using atmospheric chemical vapor deposition (APCVD). To assess the quality of preparation both the catalyst and CNTs have been characterized by different techniques. The chemical bonding and interactions were verified by FT-IR. The general overview of microstructure was examined using SEM, while, the detailed structure and morphology were examined by HR-TEM, in addition to thermal analysis (DTA); surface area (BET); X-ray fluorescence (XRF), Raman spectroscopy, and XRD analysis. The results revealed that; Fe₂O₃ and Co₃O₄ NPs were uniformly assembled on the clay nanoplatelets. The specific BET surface area of the clay and catalyst was determined to be 46.12 and 57.06 m²/g respectively. Also, from XRD, the peaks at 26° and 42.7° confirm the presence of CNTs. The FTIR absorption bands, D, G, and G^\ bands from the Raman spectrum confirm the hexagonal structure of the CNTs. The obtained results prove the high quality of CNTs preparation.

Abstract: The influence of the dispersion of the nickel slag additive on the strength of ceramic bricks based on low-melting clay of the Khalilovsky deposit in the Orenburg region and nickel slag from the dumps of OJSC "Combine Yuzhuralnickel" (Orenburg region) is considered. The study involves assessing the effect of the preparation method, the dispersion of the additive (nickel slag) on the microstructure of the finished samples. Using modern research methods with the involvement of high-tech equipment, the micro-and macrostructure of ceramic samples with the addition of slag in an amount of 5–60% is considered. The structure of the synthesized samples is studied by the method of mercury porosimetry depending on the percentage ratio of clay / slag and the fineness of grinding of the nickel slag additive. The data on the influence of the material composition of the clay / slag charge, the dispersity of the additive and the firing temperature on the strength of the prototypes are given, and an assessment is made of the technological feasibility of increasing the dispersion of the raw materials used. Intorduction

Abstract: This study aims to determine the optimal conditions of acid-activated clay adsorbent in adsorption of Pb²⁺ metal ions. Clay was taken around East Kalimantan, Karang Joang. This adsorbent was prepared by mixing clay into a solution of KMnO₄, H₂SO₄ and HCl successively, and stirred for 4 hours at a temperature of 80°C. The morphology and active groups of the adsorbent were analyzed using BET and FTIR. The variables of this study were the mass of the adsorbent 0.1, 0.3 and 0.5 grams and the contact time of 5, 30 and 55 minutes. Adsorption capacity of this adsorbent was analyzed using Atomic Absorption Spectrophotometry (AAS). The results of this study indicate that the optimum mass of adsorbent is 0.1 g, and contact time is 30 minutes. Adsorption capacity of Pb²⁺ metal ions by acid-activated clay adsorbent at the optimum condition of 0.1 gram was 23,585 mg/g and adsorption energy was 2,338 kJ/mol. Meanwhile, at the optimum condition for 30 minutes, the adsorption capacity was 0.771 mg/L, and the adsorption energy was 2.895 kJ/mol. So that the adsorption process in this study can be known, namely physical adsorption because the adsorption energy value is less than 40 kJ/mol.

Abstract: This study is devoted to clay modification with a corn starch biopolymer. Authors given the assessment of three different starch thermal modifications (cold, hot and combined), as well as their effect on the clay composite. Described the principle of starch thermal modification and its structural transformations during heat treatment. Incorporation of the gelated starch into clay body contributes to the strength increasing of the clay composite up 18% to 126% for gelatinized and retrograded starch, respectively. Due to its covering properties, the gelled and retrograded starch hydrogel integrates well into the structure of the clay composite and has a positive effect on both its mechanical and physical properties. Also, the obtained clay composite is ecological due to its natural components.

Abstract: The study of the shear strength parameters of mixtures comprising tire-derived aggregates (TDA) and clay was the main objective of this experimental work. The tests were performed using the direct shear box. First, the test was performed on specimens comprising only clay in its natural state and then on mixtures consisting of clay and TDA in increasing contents. A total of four samples (natural clay and natural clay with 2, 4, and 6% tire-derived aggregates)) were made and tested at three normal stress levels (100, 200, and 300 kPa). Then, Mohr-Coulomb failure envelopes were drawn to determine the internal friction angle and cohesion for all mixes. The results were compared to find the optimum TDA content and to study the stress-strain behavior of the mixtures. It was observed that mixing TDA up to 6% by weight with clay significantly changes the shear strength, and the internal friction angle increases from 27.47 to 59.39º (an increase of 46.25%). However, the cohesion significantly decreases from 45 to 26 kPa (a decrease of 57.77%). On the other hand, it was observed that increasing the TDA content reduces the density and increases the shear strength of the mixtures. Also, the addition of TDA increases the mixture consolidation and deformation level at failure.

Abstract: This paper is an investigation of the humidity behavior of clay according to the design of historical monuments related to different dynasties in Morocco and classified as a world cultural heritage by UNESCO. The first step consisted of a diagnosis of the capillarity behavior of different design wall’s dynasties’. The second step consisted of a comparison of the humidity behavior of clay according to a different kind of the wall’s design located in Rabat as c and Fez as a dry and continental climate cities built by those dynasties’ Al Mohade and Alaouite. The method X-Ray was used for the identification of the material studied and samples were produced to analyze the humidity behavior of walls, according to their design: full walls or hollowed ones. Results indicate that the hallowed walls loosed water quickly in a very short time doesn’t exceed five days, however, the full ones keep water until the tenth day. According to the results authors’ advice on the manner of preservation of historical monuments to increase their lifetime.

Abstract: Layered Double Hydroxide (LDH) is ionic clay that is characterized by the union of metal cations and OH^- hydroxides. LDH composites exhibit considerably high releasing and recharging capacity and have applications as bioactive cements. They can be prepared by direct co-precipitation of metal salts at controlled pH. The preparation is carried out from an acid solution of Zn (NO₃)₂.6H₂O, Al (NO₃)₃.9H₂O and a basic solution of Na₂CO₃ and NaOH, with a Zn/Al ratio = 3, the pH is stabilized between 9 and 9.5 at a constant temperature of 45°C. The objective of this study is to incorporate Zinc and Aluminum elements at different percentages in dicalcium silicate phase to produce C₂S phase incorporating LDH composite. The characterizations of the developed phases by XRD and SEM indicate the formation of stoichiometric LDH phases Zn₆Al₂(OH)₁₆CO₃.4H₂O and non-stoichiometric Zn_0.61Al_0.39 (OH)₂(CO₃)_0.195.xH₂O, the incorporation of Zn in the belitic C₂S phase and not Al. The obtained micrographs by SEM(EDAX) analysis show new morphology of the stabilized composite.

Abstract: Geophagists are generally defined by culture, social status and gender, and this paper is to identify the chemical elements of the geophagic material called Machu Rumi. The sample was extracted from the center of the geophagic material. Two micrographs were observed, the 1c micrograph contains: O (8.63%), Al (14.85%), SiO2 (33.07%), Fe (5.93%), K (5.36%), Mg (1.37 %) and Ca (0.81%), these elements are characteristics of the clay minerals, the 1d micrograph, contains: oxygen 62.14%, Silicon 37.80% and Aluminum 0.06%, these elements are present in the clay minerals soils. The results of elemental composition and micromorphology reveals the presence of phyllosilicates, SiO2, Fe, K, Mg, Ca, and Al so the consumption of Machu Rumi would contribute to the benefic geophagy.

Abstract: This paper presents a study of the screw extrusion parameters that affect on the appearance of clay filament for a clay printing machine. Traditionally, pottery models are formed by using paster mold or hand throwing, which require experienced and proficient workers to form the complex pottery models. Therefore, the clay printing machine has been developed to improve manual pottery fabrication to automatic construction. This machine has been modified based on the additive manufacturing (AM). To assess a capability material deposition of the clay printing machine, nozzle diameter, screw extruder velocity, and screw pitch were investigated as the printing parameters to evaluate a quality of clay filament. Analysis of variance (ANOVA) is used to analyze main effect parameters. The experimental results showed that the 6 mm nozzle diameter, 19 mm/s screw extruder velocity and 24 mm screw pitch were the suitable printing parameters for providing an appropriate appearance of clay filament. A mathematical model was formulated to propose the relationship between response and main effects with their interactions.

Abstract: This article presents the results of research on the development of an effective technology for the production of non-fired pellets using a binder additive and a reducing agent. The proposed method will make it possible to obtain pellets using material of class 0-5 mm, i.e. eliminates the costliest part of the pellet production technology - regrinding. It is also important that the non-fired agglomeration of the material almost unchanged the composition and properties of the feedstock, as a result of which the reduction processes in them begin earlier and proceed more intensively. Using the results of physical and chemical studies, a technology has been developed for pelletizing fines of manganese ore from the Western Kamys deposit using clay from the Sazdinsky deposit as a binder and smelting ferrosilicon manganese using manganese pellets.