Papers by Keyword: Clay

Abstract: The paper considers the existing problems of the production of ceramic products in the territory of the Russian Federation, presents the priority directions of development of this industry. The study includes the determination of the properties of samples based on the raw material base of the Orenburg region, namely, waste generated during the development of brown coal from the Tyulgansk deposit - white and red clays and nickel slag of OJSC Yuzhuralnickel Combine of the Orenburg region. The study presents data from the study of the technological properties of the raw materials, the development of the composition of the ceramic mixture. The influence of the material composition of the clay / slag mixture on the physic mechanical characteristics of the products of the experimental compositions was determined: compressive strength, fire shrinkage, water absorption and density.

Abstract: An effort to improve electrical property of Polypropylene (PP)/Clay nanocomposite was conducted. Carbon black (CB) was introduced into PP/Clay to enhance that property as required for conductive polymer composites (CPCs) application. The compositions of CB on PP/Clay were varied at 3, 5, and 7 percent hundred resin (phr). In this research, all composites were prepared by melt mixing using an internal mixer at 222 °C, 83 rpm, and 10 minutes. A compatibilizer, PP-grafted-Maleic Anhydride (PP-g-MA), was used to facilitate dispersion of clay layers and CB particles on PP matrix. The electrical property of composite was evaluated from their surface resistivity using insulation tester. Meantime thermal-oxidative stability property was analyzed from oxidative induction time (OIT) data using Differential Scanning Calorimetry (DSC) instrument. The presence of CB dramatically decreased surface resistivity of PP/Clay from 6.98 x 10¹³ ohm to 7.35 x 10⁶ ohm by adding CB 7 phr. OIT of PP/Clay dropped 155% compare with neat PP. On the other hand, the addition of CB 7 phr into PP/Clay improved OIT of PP/Clay up to 22 %. The interlayer structure of clay was investigated using X-ray Diffraction (XRD) to find out the synergistic effect between clay and CB. Actually, clay interlayer spacing did not change due to the addition of CB.

Abstract: Constitutive models for soils are usually adopted in numerical method to analyze the behavior of geotechnical structures. This study performs a series of consolidated-undrained triaxial tests to establish the stress-strain curve of clay. A constitutive model that considers continuous strain hardening-softening is proposed based on the results of triaxial tests. Triaxial test results reveal that undrained shear strength linearly increases with an increase in consolidated pressure , the normalized undrained shear strength is about 0.52 not only for this study but also for the other two cases around Taipei Basin. Due to undrained condition, an associated flow rule between plastic strain increment and stress tensor is adopted. As accumulative plastic strain or/and consolidated pressure change, the mobilized undrained shear strength also changes. All parameters needed for the proposed model can be expressed as a function of undrained shear strength S_u, The mobilized undrained shear strength for the proposed model during strain hardening-softening can be in term of accumulative plastic strain. This model can calculate the stress-strain curves of clayed soils accurately.

Abstract: This objective of this study was to produce organoclay, analyze it, and evaluate its use in the process of removing oil emulsion from an oil–water system. The organoclay was prepared by the direct method and was characterized using X-ray diffraction, Cation Exchange Capacity (CEC), and Infrared Spectroscopy (IV). A finite bath system was used to evaluate the effects on the removal capacity, using a stirring speed (A) of between 100 and 300 rpm and an initial concentration of oil-water solution (C₀) evaluated in the range of 100 to 500 mg/L. The XRD and infrared results indicated that CTAC was intercalated between the layers of Bofe clay. The percentage of oil removal from oil-in-water emulsions was between 55.99 and 96.62%. These results indicate that OC can potentially remove up to 97% oil from oil-in-water emulsions. Consequently, the OC could be considered an excellent medium for treating oily water.

Abstract: This study investigated moisture diffusion in natural rubber (NR) hybrid composites filled with silica and bentonite clay. Natural bentonite (BNT) was treated with tetradecyldimethylammonium chloride and coco diethanolamide to produce modified bentonite (M-BNT). Varied proportions of silica, M-BNT, and BNT fillers were added to raw NR according to a third-degree simplex lattice mixture design of experiment. The addition of fillers affects the vulcanization characteristics, mechanical properties, and hardness of NR hybrid composites. Moisture diffusion behavior was studied by monitoring the water uptake of NR composites during immersion in deionized water at 80^°C. Data from sorption experiments were fitted on the classical Fickian and Langmuir-type diffusion models. The Fickian model overestimates and underestimates the water uptake of NR composites in the early and later stages of moisture diffusion, respectively. On the other hand, the Langmuir-type model adequately captures the anomalous diffusion behavior of moisture in NR composites. Parameters of the Langmuir model (equilibrium water uptake and diffusion coefficient) vary with the composition of hybrid fillers. Optimum proportions of silica, M-BNT, and BNT in rubber composites were obtained by considering the effect of fillers on mechanical properties and moisture diffusion characteristics of NR.

Abstract: An alternative daily cover (ADC) is a recommended part of the modern waste landfill. Developed by ADC, involving clay minerals available in Latvia as well as wood fibers; 2 appropriate composites are selected. The coating's effectiveness has been estimated for odour in the environment, and the coating has been tested in field conditions. The obtained coating shows the ability to maintain a physical condition more than a month without changing its consistency. Compared with commercially available daily cover, which is many times higher in price, the developed coating exhibits the same odour characteristics. It is recommended to continue testing and assess the ability to absorb harmful elements by using this coating.

Abstract: The production of low-temperature clay lightweight aggregates is pursued eagerly as low energy and cost lightweight aggregate concrete (LAC) building blocks becomes more popular. Clay ceramic hollow spheres (CCHS) with waste glass (WG) additive was developed and studied as aggregate in cement composite. CCHS with diameter ranging in 6/8mm were produced by a sacrificial template technique with subsequent sintering under temperature of 900 °C and different WG content of 0, 5, 7 and 10 wt%. The effect of the sintering temperature and WG content on the physical properties and morphology of the CHS-cement composites were studied by means of optical microscopy and mechanical properties. Obtained composite materials were compared with commercially available lightweight fillers such as foamed glass granules and lightweight expanded clay aggregates (LECA). The results compressive strength of CCHS containing LAC is much higher from 4.8 to 7.1 MPa in comparison with the LECA-cement LAC - 3.5 MPa. Reduction of CCHS open porosity due to higher content of WG (10%) leads to lower absorption of cement paste, as result lower cement consumption, lower bulk density and compression strength. LAC with CCHS proved to be promising construction material due to low-temperature production process (i), widely available raw material (clay) and secondary material (glass cullet) use (ii), reduction of cement paste needed for material production (iii).

Abstract: The aim of this study was to study and characterize the properties of raw material for standard clay, Lampang province. The raw materials used in the study are from local sources. They are Lampang kaolin clay (WC-1) and Lampang kaolin residual (WC-2). The characterization of raw material was analyzed by particle analyzer, X-ray fluorescence (XRF) and X-ray diffraction (XRD). The mixing ratio of standard clay as an addition Lampang kaolin clay 50-90% and Lampang kaolin residual 10-50% on physical-mechanical properties of standard clay. The properties of standard clay after firing at temperature at 1200°C were studied. The shrinkage, water absorption and bending strength of standard clay were tested. The results showed that the chemical components of 60%lampang kaolinite clay and 40% Lampang kaolin residual included of large amount of 67.47wt% Silicon oxide and 20.92wt%Aluminum oxide. The physical properties of standard clay had a shrinkage of 11.2%, water absorption of 1.9 % and bending strength of 659 kg/cm2. The standard clay produced fulfilled the requirements of Thai industrial standard (TIS 485-2542).

Abstract: The paper shows fundamental possibility of processing of gold-bearing technogenic raw materials using the method of electric explosion. A series of experiments using a laboratory and pilot-production high-voltage pulsed discharge (HVPD) installation for the processes of enrichment of gold-bearing mineral raw materials of Komsomolsk mine tailings in Kemerovo region is conducted with a relatively low energy electrical discharge in the pulse of up to 112.5 Joules and the cost of electric power of about 1.5 kW/ton of raw material, that allows complete destruction of clay components agglomerations to less than 0.045 mm (micron and submicron sizes). Solid minerals such as quartz are simultaneously destroyed by defects in the grains and withdrawn from the installation with water, thus increasing gold degree of the concentrate. The results of particle-size and X-ray structural analyses of gold-bearing mineral raw materials of Komsomolsk mine tailings in Kemerovo region obtained by the method of electric explosion are discussed.

Abstract: Polyurethane (PU) materials are extensively used in the construction industry as core material insulation for sandwich panel application, such as wall cladding, structure insulation and roof panel. Demands on PU application have escalated given its significant advantages to reduce energy consumption. Meanwhile, rigid PU (RPU) foams are combustible materials characterized by rapid flame spread, high heat-release rates, and ability to produce large quantities of toxic gases in original form. Thus, flame-retardant (FR) additives are used to improve the thermal properties of PU. However, some commercial additives used today have are hazardous to humans and the environment, and their extensive application is limited by their negative effects on polymer mechanical properties. Accordingly, identifying materials that are environmentally friendly and harmless to humans has become urgent. Some alternative additives that are gaining research interest are clay and fly ash, which are natural and recyclable resources that can enhance the FR properties of other polymers. However, room for improvement is always present as the related technology is continually being developed. This review focuses on studies aiming to enhance the flame retardancy of RPU foam using fly ash and local clay as additives.