Papers by Keyword: Mineral

Abstract: The disadvantage of high-strength multicomponent concretes is the high absolute and specific consumption of the binder per unit of strength. The object of research is multicomponent cement systems. The subject is the composition of multicomponent cement systems in order to significantly increase the concentration of the solid phase per unit volume, as well as strength and durability. The creation of a dense, highly filled solid phase in the form of heterogeneous mineral modifiers of a homogeneous dispersed structure ensures the production of high strength concretes with a low binder content. Theoretical and practical studies have shown that there are only three levels of dispersion of mineral modifiers, functionally related to the spatial and geometric parameters of the clinker component and its own pozzolanic activity, providing strength and other construction and technical properties of multicomponent cement systems at the maximum level. The properties and structure of concrete were studied using two fractions of fine aggregate, granite-gabro crushed stone fr. 5-10 mm, Portland cement class CEM I 42.5N, finely dispersed blast-furnace granular slag, microsilica, highly dispersed fraction of cement, superplasticizer Glenium 430 and high-valence hardening accelerator. Research methods: the shape and size of dispersed particles of the components were determined by a laser analyzer, the mobility of the concrete mixture in accordance with GOST 10181–2014, the strength of concrete in accordance with GOST 10180–2012. The structure of the cement stone was studied using scanning microscopy, thermographic and X-ray phase analysis methods. The strength of concrete with an optimized disperse composition, a superplasticizer and a high-valence hardening accelerator at the age of 28 days after hardening under normal conditions was 128; 137; 163 MPa, with the consumption of multicomponent cement, respectively 650, 700, 750 kg / m³.

Abstract: The paper presents the studies’ results of chemical composition, structure, and physico-mechanical properties of high-calcium ashes from the Kansk-Achinsk coals (2017-2019 selection). It was found that ash has a complex poly-mineral composition and contains hydraulically active minerals and oxides of СаОfr, β-C₂S, CA, C₃A, C₄AF, C₂F, CaSO₄. According to the content of CaOfr, MgO does not meet standards’ requirements. The uniformity of the volume change is maintained by the composition with 50% of cement. The structure and hardening kinetics of ash and ash-cement stone compositions, obtained from the test of normal density, were analyzed. It was established that the hardening of compositions with ash from the Kansk-Achinsk coals was largely influenced by ash minerals. An equivalent amount of cement in composite binders cannot be replaced. In order to obtain a positive effect, compositions with ash instead cement of no more than 30% and a part of fine aggregate, without exceeding the ratio of ash: cement = 1: 1, should be used.

Abstract: The article discusses the photochemical effects of sunlight on the soil. Under the influence of light energy the amount of mineral and easy hydrolysable nitrogen, as well as labile humus substances increased in the soil. The photochemical destruction of humus substances was accompanied by an increase in their mobility and loss of colour. The article shows that the process of mineral nitrogen formation in the soil during the photochemical destruction of humus substances has two stages. The first stage includes photochemical reactions with the formation of ammonium nitrogen. The second stage is the microbiological oxidation of ammonium nitrogen to the nitrate nitrogen.

Abstract: Silantek clay deposits were characterized and evaluated for their potential as structutral ceramic products raw materials through chemical, mineralogical and refractory (1250 to 1600^o C) properties determinations. Results show that the main oxides in the samples were SiO₂ and Al₂O₃, whereas the other oxides present only in small quantity. Kaolinite(Al₂Si₂O₅(OH)₄) and quartz(SiO₂) present as dominant mineral phases and the minor phases of mullite(Al₆Si₂O₁₃) and zeolite(Na₂Al₂Si₃O₁₀·2H₂O) also appeared in the samples. From the results of the refractoriness tests up to 1600°C, samples ST11, ST23A, ST31A, ST31B, ST33 have potential for refractory products as they demonstrated high thermal resistance properties(over 1600°C). Silantek clay potential to be used as raw materials mainly for refractory, structural ceramics and other common ceramic products

Abstract: Methods such as processing of ilmenite concentrate by impregnation and roasting, several kinds of CWAO system mineral catalyst is prepared. And to explore under certain conditions of phenol in waste water of phenol removal rate, compare several kinds of preparation methods of catalysts. Studies show that the effort of 723 K calcined after partial acid salt dipping made catalyst is best. Under the condition of 100 r/min at 303K, the 10 mg/L of phenol removal rate can reach more than 98%.

Abstract: Cadmium (Cd) is an environmental pollutant extremely toxic to plants and other living organisms including humans. To assess Cd phytotoxicity, the seedling growth, mineral (K, Fe, Zn) and carbohydrate contents and hydrolase activities in the endosperm and seedlings during rice seed germination subjected to Cd stress were investigated. The results showed that Cd caused a reduction in seedling growth and distribution of biomass, mineral contents, compared to the control. Cd accumulation in seedlings increased in the duration of treatment. Cd exposure caused a deleterious fall in mineral nutrient supply in seedlings. Moreover, Cd decreased the content of starch and sustained a higher level of soluble sugar in the endosperm of rice seeds. Activities of α-amylase and acid invertase were inhibited in Cd-treated seeds during the germination. The results suggest that Cd inhibits early seedling growth due to restriction of mineral and carbohydrate reserves mobilization.

Abstract: We are able to produce nanoscale rutile TiO₂ product from titanium mineral via a modified hydrothermal synthesis method, with the inclusion of an alkaline fusion stage. The mineral was totally dissolved in an acidic solution, and is followed by the nucleation reaction, producing anatase having a crystallite size of 15.4nm. Annealing of the nanoanatase resulted in a phase transformation process, and the rutile phase was detected when annealed at 800°C. Single rutile phase was achieved when the anatase sample was annealed at 1,000°C. As the starting mineral contains a significant amount of Nb and Zr impurities, these elements are naturally doped into the nanosized rutile. A paint formulation was then produced by adding 2g of this nanoanatase/nanorutile into the paint. Using this nanotitania added paint under visible light source, a photocatalytic study on the degradation of methylene blue was conducted. A comparative study was also carried out with commercial grade pure nanorutile under similar condition. The result showed that our nanorutile managed to degrade the methylene blue to almost a similar 85% degradation compared to the commercial pure nanoanatase. A pure nanorutile product resulted in a much lower photodegradation rate, standing at 77%. Tests on the photodegradation of nitrous oxide gas also reveals that the nanorutile paint was able to degrade the VOC in much shorter times compared to the other nanotitania added paints.

Abstract: The coal of Zichang was selected as the sample coal, the physical properties of the ash is analyzed with ICP-AES. The ash fusion temperature was researched by adding different basic oxide contents. The results show that the general trend is decrease firstly, and then increase when adding basic oxides. Blended ash fusion temperatures do not change linearly with blending ratios and ash fusion will decrease when adding the contents of CaO, Na₂O and MgO, but the effect is different. Na₂O is best and CaO is second. Mineral composition and type at addition oxides were determined by XRD analysis. Some combinations of component coals mineral produce eutectic minerals at high temperature;It can explain the reason of oxides decrease the ash fusion. Vitreous minerals are formed to explain increase the fusion temperature.

Abstract: The intention of the research presented in this article was to study the basic physico-mechanical parameters of mineral lightweight renders. Both alternative and primary raw materials were used to modify the filling agent; namely utilized quartz sand, diatomite and hydrophobised perlite. Determining and evaluating the basic parameters of plasters with the modified composition enabled to assess the effect of substituting the filling agent within the particular designed formulas. Emphasis was placed on the parameters in the fresh and hardened conditions of the plasters – workability, water volume, density, compressive and flexural strength. It was found that by appropriately adjusting the water dosage then better parameters could be obtained than in the reference formula – commonly commercially produced renders.

Abstract: This article makes analysis of the composition of the coaly mineral, makes the research on the evolution characteristics of the coaly mineral in the course of combustion, the ashing behavior of the mineral and the generation mechanism of the particle, points out the relationship between the grain size of the particle in the coal and the amount of ash, and finally indicates that the actual amount of ash from the boiler is less than the theoretical amount of ash by test.