Papers by Keyword: Sodium Sulfate

Abstract: The rare earth element is a critical element in many industrial sectors. Due to unbalanced supply and demand, it is necessary to look for an alternative source. Coal ash is a waste product of power plant combustion. Previous research revealed that coal ash contained levels of rare earth elements. This research uses coal fly ash from the Paiton power plant. The objectives of this study were to determine the effect of the Na₂SO₄ concentration, stirring rate, and temperature on the recovery of REE concentrate. The experiment was conducted in four steps: (1) alkaline leaching, the process was carried out for 2 hours at 90°C with fly ash solid to 8 M NaOH solution ratio of 1:4 to break the aluminosilicate bonds. (2) Acid leaching of residue for 4 hours at 90°C in 3 M HCl. (3) Precipitation of residue to remove the impurities such as Fe using 1 M NaOH at pH 5. (4) Precipitation of filtrate from process (3) using Na₂SO₄ to produce REE concentrate precipitates. The best condition to obtain the highest REE residue is conducting recovery at the concentration of 20% Na2SO4, stirring rate of 500 rpm, and temperature of 50°C, with a yield of 88.72%.

Abstract: The paper summarizes partial results of a study of degradation of materials based on alkali-activated blast-furnace slag (AAS) and comparative on cement CEM III/A 32.5 R after exposure to aggressive environments. It further specifies the possibilities for utilising destructive and non-destructive techniques to determine the progress of degradation and characterizes the degree of their correlation. After 28 days of ageing in a water environment, the produced test specimens (40×40×160 mm beams) were placed in aggressive media (ammonium nitrate solutions; sodium sulfate, rotating water) and after subsequent 28, 56 and 84 days of degradation were subjected to testing. Testing comprised both a destructive form (determination of compressive strength and flexural strength) and a selected non-destructive technique (Impact-echo method). The partial outputs were supplemented by the results acquired from monitoring weight changes. In addition, the development of Ultrasonic Pulse Velocity in relation to the progress of the degradation processes was also monitored. While the exposure of both test specimens to water and sodium sulfate did not result in any significant changes, the exposure to the ammonium nitrate solution exhibited rapid signs of degradation associated with a significant reduction in functional characteristics.

Abstract: This study was conducted to investigate the effect of palm shell charcoal reductant in the selective reduction of nickel ore with the addition of additive at various temperatures and times. In this present work, 10 wt. % of sodium sulfate as additive and 5, 10, 15 wt. % of palm shell charcoal as reductants were used. The reduction of nickel ore was performed at 950oC, 1050oC, and 1150oC for 60, 90, and 120 minutes. A wet magnetic separation method was then carried out to separate the concentrates and tailings. Characterization of reduced ore was performed by X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), while the composition of ferronickel in concentrate was identified by X-Ray Fluorescence (XRF). The result showed that the higher temperature reduction, the higher of nickel grade, and its recovery at the concentrate. Nevertheless, the longer reduction time and the more reductant in nickel ore lowering the nickel grade and its recovery in the concentrate. The optimum condition in this selective reduction process was obtained with the addition of 5 wt. % of reductant and 10 wt. % of sodium sulfate in nickel ore, which was reduced at 1150oC for 60 minutes. It resulted in 4.60% and 73.23% for nickel grade and its recovery, respectively.

Abstract: The article presents a technique for assigning the composition of the agglutinant sand, which is based on the calculation and experimental approach to determining the composition, taking into account the quality of raw materials used and the requirements for the properties of concrete products produced. The obtained results served as the basis for the practical implementation of the proposed technological method of increasing the small-sized products durability made of fine-grain concrete.

Abstract: Early strength of the blended Portland cements containing granulated blast furnace slag and natural pozzolanas (zeolite tuff, etc.) can be enhanced by the alkali-sulfate activation. High early strength of the blended Portland cements as a result of alkali-sulfate activation can be attributed to acceleration of pozzolanic reaction at the early stages and formation of more quantities of ettringite at the early stages of structure formation. The results of the study showed that with high amounts of sodium sulfate in the alkali-sulfate activator, contents of gypsum dihydrate as a setting regulator of the blended Portland cements could be reduced. The effect of sodium sulfate activator on properties of the blended Portland cements was studied and the results are discussed.

Abstract: Using ultrasonic method for various corrosion instars of clear water, sodium sulfate solution corrosion respectively after block of NDT, polypropylene mortar test results calculated according to the theory of strength. Through the press again the compressive strength test, it is concluded that polypropylene mortar test block intensity of real value^[4]. Through the press again the compressive strength test, it is concluded that polypropylene mortar test block intensity of real value.

Abstract: The fluorine gypsum was used as research object in this paper. In order to recognize the basic properties of fluorine gypsum fully, the physical and chemical properties were analyzed through different testing means. The chemical modification (additive A, sodium sulfate, quick lime) on the activity of fluorine gypsum excitation effect were studied. The best way to compound modification was determined and the mechanism of the admixture was analyzed. On this basis, the fluorine gypsum base self-leveling mortar materials was prepared and its performances were tested. Research shows that, the optimal ratio of: additive A content 2.0% (mixed), sodium sulfate content 0.8%, quick lime content 1.5%, the fluorine gypsum self-leveling material initial setting time is 2.4h, the final setting time is 5.3h, 24h flexural strength of 2.60MPa, compressive strength of 6.05MPa, the dry flexural strength of 7.68MPa, compressive strength of 22.89MPa, the performance indicators have reached the JC/T1023-2007《Gypsum based self-leveling mortar》 requirements.

Abstract: Through to join in processing of titanium gypsum naphthalene series water reducing agent and sodium sulfate, study the effect of admixtures on the physical properties of titanium gypsum and mechanism analysis, and to determine the optimum content of admixtures. Research shows that when the content of naphthalene series water reducing agent was 3% water reducing effect is best, the titanium gypsum sample standard consistency water consumption is 126%,2h flexural strength was 1.06MPa, 2h compressive strength was 1.97MPa, absolutely dry flexural strength was 2.21MPa and absolutely dry compressive strength was 2.76 MPa. When the dosage of sodium sulfate is 1.5%, titanium gypsum physical performance is best,initial setting time and final setting time of 8 min and 10 min respectively,2h flexural strength was 1.35MPa, 2h compressive strength was 2.42MPa, absolutely dry flexural strength was 2.43MPa and absolutely dry compressive strength was 3.32 MPa.

Abstract: The process of aluminum anodizing forms an oxide layer constituted of nanotubes where it is possible to insert compounds, amongst these are the pigments and dyes. This study has as its main aim to study the behavior of aluminum alloy 6000, anodized and dyed with monolite red in Na₂SO₄ 0.5 mol L^-1 and pH = 4. The techniques employed were: anodic potentiostatic polarization, open circuit potential, chemometry, polarization resistance and optical micrograph. The factorial planning was proposed using four variables (anodizing time, current density, electrolyte concentration, and dye), the response to the planning was the charge transfer resistance. Polarization curves revealed that the anodized and dyed aluminum samples are much more resistant than the non-anodized aluminum. Optical microscopy analyses demonstrated that the dissolution of dye occurs in the solution, but not enough to break the film. As the main result, efficient coloring of aluminum parts was verified with reduction in costs in relation to the energy employed in the process, associated to reduction in time spent for the anodizing process, which makes it suitable to increase industrial production of dyed aluminum parts.

Abstract: Replacement or repair of corrosion damaged equipment is the largest maintenance requirement for the industry. One technique for reducing the corrosion of metals is to coat them with thin layers of less reactive metals or alloys. Unfortunately, most metallic coatings are inherently porous and historically have been of little value as barriers against corrosion. Recently, with the development of new alternative material such as electrodeposited CoNiFe, these problems have largely been overcome. This paper investigated the effects of different aggressive environments on the corrosion behavior of electrodeposited CoNiFe. Interestingly, the mixed morphologies with spherical and dendritic structure were found in the neutral and alkaline environment. This morphology exhibited the smallest particle size with less percentage of oxygen elements. Besides, alkaline environment experienced the slowest corrosion rate due to the mixed morphology. It was found that spherical and dendritic refinement provides higher corrosion resistance. The corrosion rate of the sample prepared in alkaline environment was the lowest compared to the others due to the reduction of particle size.