scholarly journals ESTIMATION OF THE EFFICIENCY OF MECHANICAL ACTIVATION OF SILICA-CONTAINING ROCKS

Author(s):  
A. Shamanina ◽  
Arkadiy Ayzenshtadt ◽  
V. Kononova ◽  
V. Danilov

Rocks of various chemical and mineralogical composition are widely used as raw materials in the construction materials industry. At the same time, preliminary mechanical activation of mineral raw materials to a finely dispersed state contributes to a change in the energy potential of the system and affects the tendency of the surface of a finely dispersed system to transformations. Studies of the physicochemical activity of mechanically activated rocks allow to determine the rational areas of use of mineral components. The paper presents the results of evaluating the efficiency of mechanical activation of silica-containing raw materials by the values of surface activity (ks), defined as the ratio of the value of the free surface energy to the specific mass energy of atomization. Fine powders are obtained by grinding in a planetary ball mill to a different specific surface area of quartz sand (1200 – 3000 m2/kg) and polymineral sand (700 – 1335 m2/kg). The presence of a functional dependence of the surface activity on the time parameters of mechanical activation of the studied rocks is shown. The mechanical activation of the feedstock at the optimal time of its grinding makes it possible to achieve a given value of the surface activity. It is recommended to use the ks parameter as a criterion for assessing the efficiency of the process of mechanical activation of silica-containing rocks

2021 ◽  
Vol 1017 ◽  
pp. 91-100
Author(s):  
Ekaterina V. Fomina ◽  
Natalia I. Kozhukhova ◽  
Evgeny A. Belovodsky ◽  
V.A. Klimenko ◽  
Marina I. Kozhukhova

The influence of the genesis of quartz-containing rocks on the strength of particles and changes in morphology during destruction from the standpoint of the mineralogical approach in the development of the scientific direction "geonics" ("geomimetics") has been investigated. The kinetics of dry grinding of raw materials in a laboratory ball roller mill was carried out. The features of the formation and development of cracks, particle size distribution, changes in the morphology and microstructure of fragments have been studied. It was found that in natural quartz cracks develop along the surface, where the highest concentration of impurities creates a defect structure with destruction into small particles. The purest structure of hydrothermal quartz is susceptible to brittle fracture into fragments similar in morphology to the base particle. Reducing the defectiveness of the structure increases the strength of the crystals. The internal energy potential of techno genic raw materials is determined by its defective structure, which undergoes the greatest deformations during grinding, allowing obtaining the maximum values of the specific surface area and reduce the grinding time. A difference in the degree of crystallinity of quartz, which composes the polymineral techno genic raw materials, makes it possible to obtain the optimal granulometry of fine particles. The conducted research is aimed at identifying the mechanisms of destruction of quartz rocks and can be used in solving engineering problems not only in construction materials science, but also in geotechnics.


2020 ◽  
Vol 10 (18) ◽  
pp. 6222 ◽  
Author(s):  
Girts Bumanis ◽  
Jelizaveta Zorica ◽  
Diana Bajare

The potential of phosphogypsum (PG) as secondary raw material in construction industry is high if compared to other raw materials from the point of view of availability, total energy consumption, and CO2 emissions created during material processing. This work investigates a green hydraulic ternary system binder based on waste phosphogypsum (PG) for the development of sustainable high-performance construction materials. Moreover, a simple, reproducible, and low-cost manufacture is followed by reaching PG utilization up to 50 wt.% of the binder. Commercial gypsum plaster was used for comparison. High-performance binder was obtained and on a basis of it foamed lightweight material was developed. Low water-binder ratio mixture compositions were prepared. Binder paste, mortar, and foamed binder were used for sample preparation. Chemical, mineralogical composition and performance of the binder were evaluated. Results indicate that the used waste may be successfully employed to produce high-performance binder pastes and even mortars with a compression strength up to 90 MPa. With the use of foaming agent, lightweight (370–700 kg/m3) foam concrete was produced with a thermal conductivity from 0.086 to 0.153 W/mK. Water tightness (softening coefficient) of such foamed material was 0.5–0.64. Proposed approach represents a viable solution to reduce the environmental footprint associated with waste disposal.


2019 ◽  
Vol 974 ◽  
pp. 379-385
Author(s):  
Alexander E. Fomin ◽  
Ruslan V. Lesovik ◽  
E.S. Glagolev ◽  
Sergey V. Biryukov

The paper investigates the surface wet magnetic separation (WMS) technogenic raw materials concentration tailings particles properties. The mechanical activation effect nature on the binder structural and phase characteristics is revealed. High pozzolan activity of WMC tails, which consists in genetic and morphological features of the surface of poly-mineral structures has been established. During mechanical activation of lime together with WMS tailings, an increase in the number of neoplasms occurs in the amorphous phase form with a low degree of polymerization, which is confirmed by the acid-soluble SiO2presence, as well as by X-ray phase analysis. The work results indicate a WMC waste particles surface high energy potential for its use in building materials for autoclaved hardening. This study will contribute to the energy and resource-saving technologies development, the solution of environmental problems in order to create a comfortable environment for life and work.


2020 ◽  
Vol 4 (1) ◽  
pp. 41-48
Author(s):  
Teodoro Astorga Amatosa ◽  
Michael E. Loretero

Bamboo is a lightweight and high-strength raw materials that encouraged researchers to investigate and explore, especially in the field of biocomposite and declared as one of the green-technology on the environment as fully accountable as eco-products. This research was to assess the technical feasibility of making single-layer experimental Medium-Density Particleboard panels from the bamboo waste of a three-year-old (Dendrocalamus asper). Waste materials were performed to produce composite materials using epoxy resin (C21H25C105) from a natural treatment by soaking with an average of pH 7.6 level of sea-water. Three different types of MDP produced, i.e., bamboo waste strip MDP (SMDP), bamboo waste chips MDP (CMDP) and bamboo waste mixed strip-chips MDP (MMDP) by following the same process. The experimental panels tested for their physical-mechanical properties according to the procedures defined by ASTM D1037-12. Conclusively, even the present study shows properties of MDP with higher and comparable to other composite materials; further research must be given better attention as potential substitute to be used as hardwood materials, especially in the production, design, and construction usage.


2021 ◽  
Vol 11 (8) ◽  
pp. 3545
Author(s):  
Fernanda Andreola ◽  
Isabella Lancellotti ◽  
Paolo Pozzi ◽  
Luisa Barbieri

This research reports results of eco-compatible building material obtained without natural raw materials. A mixture of sludge from a ceramic wastewater treatment plant and glass cullet from the urban collection was used to obtain high sintered products suitable to be used as covering floor/wall tiles in buildings. The fired samples were tested by water absorption, linear shrinkage, apparent density, and mechanical and chemical properties. Satisfactory results were achieved from densification properties and SEM/XRD analyses showed a compact polycrystalline microstructure with albite and wollastonite embedded in the glassy phase, similar to other commercial glass-ceramics. Besides, the products were obtained with a reduction of 200 °C with respect to the firing temperatures of commercial ones. Additionally, the realized materials were undergone to leaching test following Italian regulation to evaluate the mobility of hazardous ions present into the sludge. The data obtained verified that after thermal treatment the heavy metals were immobilized into the ceramic matrix without further environmental impact for the product use. The results of the research confirm that this valorization of matter using only residues produces glass ceramics high sintered suitable to be used as tile with technological properties similar or higher than commercial ones.


2014 ◽  
Vol 1000 ◽  
pp. 12-15
Author(s):  
Jiří Švec ◽  
Tomáš Opravil ◽  
Jiří Másilko

Reusing and recycling of secondary raw materials from high-volume industrial productions (especially form construction materials and binders fabrications) is very important way of conserving environment and it is also interesting from the economical point of view. The production of common hydraulic binders, especially Portland cement, burdens the environment with considerable amount of combustion gases and consumes energy in massive scale. Alternative (low – energy) binder can be used as Portland cement substitution in applications with lower mechanical properties requirements. Mined limestone wash sediments contain large amount of clay components, but there is also indispensable share of fine calcite. This composition makes these sediments a promising material for the preparation of hydraulic binders as Roman cement or hydraulic lime.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yasin Erdoğan

Handere clay deposits were discovered at Adana in Turkey. These clay units primarily consist of uncoloured claystone, pebbly sandstone, sandstone, siltstone, and mudstone marl and include gypsum lenses and clay levels of various thicknesses in places. The physicochemical properties of these clays have been investigated by different techniques including Scanning Electron and Elemental Analysis (SEM and EDS), mineralogical analyses, chemical and physical analyses, X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), and Atterberg (Consistency) Limits Test. The mineralogical composition deduced from XRD is wide (smectite + palygorskite + illite ± feldspar ± chlorite ± quartz ± calcite ± serpentine) due to the high smectite contents (≈85%). SEM studies reveal that smectite minerals are composed of irregular platy leaves and show honeycomb pattern in the form of wavy leaves in places. The leaves presenting an array with surface edge contact are usually concentrated in the dissolution voids and fractures of volcanic glass. Organic matter content and loss on ignition analysis of raw materials are good for all the studied samples. In summary, Handere clays can be used as building materials in bricks, roof tiles, and cement and as a binder.


2010 ◽  
Vol 63 ◽  
pp. 420-424
Author(s):  
Riva Rivas-Marquez ◽  
Carlos Gomez-Yanez ◽  
Ivan Velasco-Davalos ◽  
Jesus Cruz-Rivera

Using Mechanical Activation it is possible to obtain small grain size and good homogeneity in a ceramic piece. For ZnO varistor devices Mechanical Activation appears to be a good fabrication technique, since good homogeneity and small grain sizes are advantageous microstructural features. The typical formulation is composed by ZnO, Bi2O3, Sb2O3, CoO, MnO2 and Cr2O3 as raw materials, and during sintering, several dissolutions and reactions to form pyrochlore and spinel phases occur. When Mechanical Activation is applied to the entire formulation, it is difficult to know what processes are being mechanically activated due to the complexity of the system. The aim of the present work was to clarify how the mechanical activation is taking place in a typical ZnO varistor formulation. The methodology consisted in the formation of all possible combinations of two out of the five oxides above mentioned and to apply mechanical activation on the mixture of each pair of powders. The results showed that systems containing Bi2O3 are prone to react during mechanical activation. Also, reduction reactions were observed in MnO2. In addition, the powder mixture corresponding to the whole formulation was milled in a planetary mill, pressed and sintered, and varistor devices were fabricated. Improvement in the nonlinearity coefficient and breakdown voltage was observed.


Author(s):  
V.A. Logvin ◽  
◽  
S.A. Sheptunov ◽  

The conditions for the hardening of tools in accordance with the author’s technological routes in the optimal time interval are considered using the functional dependence of the serviceability of plasma generators. This dependence takes into account the workability of the technical devices involved in processing the laying batch of tools in the speci ed time interval. The probability of performing the production process in the estimated time is represented by the product of the trouble-free operation of each glow discharge plasma generator involved in the nishing processing of tools that require a different type of plasma exposure in a certain sequence and duration.


2020 ◽  
Author(s):  
Carlos Galhano ◽  
Pedro Lamas ◽  
Diogo Seixas

The massive growth of the ceramic industry and the consequent demand for construction materials worldwide has motivated the search for alternative solutions aimed at reducing the use of mineral / natural resources as the main source of raw materials. One of the strategies frequently adopted by the scientific community is the reuse of industrial waste. It is beneficial not only to reduce the overexploitation of mineral resources but also to reduce the environmental, economic and social impacts resulting from their incorrect disposal/treatment and consequent deposition on land unsuitable or that purpose. Duetoconsiderationssuchasphysico-mechanical characteristics and the high production rate, two different types of industrial waste were selected for this work, ashes resulting from the burning of coal in thermoelectric power plant, commonly known as bottom ash (B), and the Marble Powder (MP). It was intended to test the technological feasibility of the manufacture of ceramic materials produced from clay mixtures containing these two residues. For this purpose, the fine fraction(<63μm)obtained from the sieving of the marbleresidue(MR)and slag(Bf)was used,aswellasacoarsergrainslagfractionrangingfrom63-125μm(Bg). The resulting test samples were subjected to a firing of 950 °C under an oxidizing atmosphere, following a primary drying process. Faced with the standard values, the new ceramic materials obtained from MP have seen their mechanical and porous characteristics decrease and increase, respectively. Atthesametime,althoughtheadditionofBinno way influenced the mechanical characteristics,a significant improvement the porous characteristic was observed. The incorporation of these residues produced a color very close to the original sample material. Keywords: industrial waste, ceramic, construction materials, bottom ash, Marble Powder


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