scholarly journals RECYCLING OF AURIFEROUS ORE FLOTATION TAILINGS IN SLAG-ALKALINE CEMENT

2016 ◽  
Vol 4 ◽  
pp. 11-16
Author(s):  
Volodimir Gots ◽  
Oles Lastivka ◽  
Elizabeth Volunska ◽  
Oleksandr Tomin
Keyword(s):  
Heavy Metals ◽  
Atomic Spectroscopy ◽  
Cement Matrix ◽  
Cement Stone ◽  
Check Sample ◽  
Flotation Tailings ◽  
Artificial Stone ◽  
Stone Durability ◽  
Metal Bonds ◽  
Research Analysis

Research analysis aimed at stabilizing processes in industrial waste and other, similar hazardous ion containing materials, shows that these materials can be successfully stabilized, if they are bound as a mineral component in cement. Considering that auriferous ore flotation waste contains heavy metals that are useless for any production and accumulated in dumps, storages and sumps, this impairs the ecology of the country. This is why current study is conducted on recycling of auriferous ore flotation tailings by binding it as a cement component, which is also can be one of its effective applications. For heavy metal bonds stability evaluation in the composition of the cement matrix, the method of leaching elements by atomic spectroscopy was applied. According to the research it was found that application of slag-alkaline viscid systems for recycling of auriferous ore dump flotation tailings provides considerable advantages over traditional Portland cement systems based on PC I-500. It was shown that along with the physical blocking in the artificial stone matrix, based on slag-alkaline viscid systems, elements of heavy metals were also bound chemically as a part of structure-forming compounds. In this regard use of auriferous ore dump flotation tailings (10…30 %) in the compound of slag-alkaline cement results in the prolonged solidification and provides the same level of cement stone durability as the check sample compound.

scholarly journals New Indices Determining Heavy Metals Migration in a Sewage Sludge

2015 ◽  
Vol 22 (4) ◽  
pp. 637-644 ◽  
Author(s):  
Andrzej Gawdzik ◽  
Jarosław Gawdzik ◽  
Barbara Gawdzik ◽  
Alicja Gawdzik
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Stability Index ◽  
Organic Soil ◽  
Theoretical Justification ◽  
Mobility Index ◽  
Step Procedure ◽  
Soil Components ◽  
The Stability ◽  
Metal Bonds

Abstract The four step procedure developed by the European Community Bureau of Reference (BCR) is the optimum means of identifying heavy metal fractions in sewage sludge samples. Using the BCR procedure enables to get the date basing on which one can calculate metal stability index which supplies information on the strength of metal bonds with mineral organic soil components. Unfortunately, very popular formulae describing this index do not possess any theoretical justification and do not generate all values in the range of [0; 1]. Hence, in this paper one has presented new formulae describing not only the stability index but also a strictly connected with it the mobility index. In addition, one has suggested that these new formulae depend on the Equivalent Population (EP) indicator.

The Effect of Fine Dispersed Slag Component on the Slag Portland Cement Properties

2020 ◽  
Vol 1011 ◽  
pp. 103-108
Author(s):  
Irina Kozlova ◽  
Olga Zemskova ◽  
Vyacheslav Semenov
Keyword(s):  
Portland Cement ◽  
Structural Characteristics ◽  
Initial Period ◽  
Cement Composite ◽  
Cement Matrix ◽  
Cement Stone ◽  
Ultrafine Grinding ◽  
Slag Component

Cement compositions based on slag Portland cement and fine dispersed slag component are considered. It has been established that the introduction of 1-3% fine slag obtained as a result of ultrafine grinding in a jet mill into the slag Portland cement composition provides an increase in the strength and structural characteristics of cement stone from the first day of hardening, which is important for slag cements. To ensure the fine dispersed slag particles’ stabilization in the cement matrix, the cement compositions were sealed with water with the addition of a plasticizer on either sulfa-naphthalene formaldehyde or polycarboxylate substrates in an amount of 0.5% of the cement composite content. In the research course it was found that in the initial stages of hardening and grade age, the strength of the samples containing a fine dispersed slag component and a sulfa-naphthalene formaldehyde-based plasticizer increased by 20%. When the cement composition is mixed with water with a polycarboxylate-based plasticizer, an increase in strength in the initial period of hardening by 60% is noted, at the vintage age - by 30%. At the same time, the porosity of the samples based on slag Portland cement with the addition of fine dispersed slag and one of the plasticizers in the initial period was reduced by 16-21%, at the vintage age - by 33-35%.

Specifics of Structure Formation of Cement Stone with Silica Raw Material - A Substrate of Photocatalytic Composite Material

2021 ◽  
Vol 1017 ◽  
pp. 153-162
Author(s):  
Viktoriya V. Nelyubova ◽  
Yulia N. Ogurtsova ◽  
M.N. Sivalneva ◽  
Valeria V. Strokova ◽  
P. Zhao
Keyword(s):  
Composite Material ◽  
Structure Formation ◽  
Urban Areas ◽  
Raw Materials ◽  
Raw Material ◽  
Cement Matrix ◽  
Cement Stone ◽  
Silica Substrate ◽  
Technogenic Raw Materials ◽  
Quantitative Assessments

The increasing urbanization of urban areas poses the challenge of the development of materials capable of self-cleaning from organic pollutants formed. Previous papers substantiated the possibility of the coating of titanium oxide as the main agent of the photocatalytic method of cleaning structural materials on silica raw materials in order to increase the degree of its distribution in the volume of cement matrix and, as a result, increase its efficiency.It is obvious that a silica substrate will affect the processes of structure formation during hardening of a cement matrix. During the research, the processes of phase transformations of cement stone modified with silica raw materials of natural and technogenic origin were studied. As a result, the influence of siliceous modifiers on the strength characteristics of the cement stone was determined, which allowed ranking them according to the degree of decrease in efficiency as follows: technogenic raw materials; natural raw materials of silicate composition; natural raw materials of aluminosilicate composition. Quantitative assessments of the degree of efficiency showed the irrationality of using aluminosilicate composition as a silica modifier of natural raw materials, which is explained by its low pozzolanic activity.

scholarly journals Estudio preliminar de la fauna en el morro de basuras de Moravia y presencia de metales pesados en artrópodos y roedores

2010 ◽  
Vol 15 (1) ◽  
pp. 49 ◽  
Author(s):  
María Solange Sánchez ◽  
Alejandra Bedoya ◽  
Rolando Barahona
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Mus Musculus ◽  
Atomic Spectroscopy ◽  
Trophic Chain ◽  
Metal Analysis ◽  
Mammal Species ◽  
Tissue Samples ◽  
Heavy Metal Analysis

<p><strong></strong>Characterization of the species present in a given locality by means of biological inventories provides information about diversity, even if it is done in disturbed environments such as open dumps, which are considered a threat for health due to the accumulation of heavy metals that are well known for their negative effects on human health and the environment. <strong>Objectives</strong>. To carry out a preliminary characterization of arthropods and non-flying small mammals in the <em>Morro de Moravia</em> open dump, and to determine the heavy metal contents in animal tissue samples. <strong>Materials and Methods. </strong>Arthropods were collected with pitfall traps and manually. Rodents were captured with Sherman traps. The heavy metal analysis was carried out with atomic spectroscopy. <strong>Results</strong>. A total of 9 orders, 51 families and 75 morphospecies of insects, 5 families of spiders, two syrphid and a millipede species were identified; <em>Mus musculus</em> was the only small mammal species identified. Heavy metal analysis showed various concentrations mainly of Pb and Cd. The highest content of Pb (45.05 mg/kg) was found in samples of <em>M. musculus</em> and the highest Cd content (10.31 mg/kg) was found in spiders of the family Gasteracantha. <strong>Conclusions</strong>. The <em>Morro de Moravia</em> open dump provides conditions that allow the establishment of an arthropod community with various diets and niches. The transference of heavy metals from the residue matrix towards higher levels of the trophic chain was corroborated.</p> <p><strong>Key words:</strong> arthropods, biological inventories, cadmium, <em>Mus musculus, </em>lead</p><br />

scholarly journals MODEL AND MECHANISM OF CARBON NANOTUBE STABILIZATION WITH PLASTICIZER BASED ON POLYCARBOXYLATE

Vestnik MGSU ◽  
2017 ◽  
pp. 724-732
Author(s):  
Svetlana Vasilevna Samchenko ◽  
Olga Viktorovna Zemskova ◽  
Irina Vasilevna Kozlova
Keyword(s):  
Portland Cement ◽  
High Viscosity ◽  
Matrix Composition ◽  
Cement Matrix ◽  
Cement Stone ◽  
Modern Theory ◽  
Ultrasonic Dispersion ◽  
Cement System ◽  
Electrical Layer ◽  
The Stability

The method for adding into the cement matrix composition the carbon nanotubes (CNTs) in the form of stabilized suspensions for their even allocation in its volume is observed in this article. The aim of the article is to study the aggregative and sedimentary stability of the CNTs suspensions in the presence of the plasticizer based on polycarboxylate under the ultrasonic effect, to determine the kinetic addictions of coagulation, to describe the suspension stabilization models and mechanisms according to the modern theory and to determine the possibility of using CNTs as suspensions for portland cement modification. The object of research is Portland cement, CNts and polycarboxylate-based plasticizer. Mechanism of stabilization of the CNT water suspension with polycarboxylate based plasticizer due to fixing plasticizer functional groups on the nanoparticle surface is proposed. The non-polar part of the plasticizer provides the formation of high-viscosity streak between the CNTs particles and the dispersion medium, and the polar part provides the formation of the double electrical layer (DEL), which supports the formation of the CNT micelle. The Model of the CNT micelle is described. It is established that the ultrasonic dispersion provides the stability of the CNTs suspensions for seven days and more. It is shown that when the stabilized polycarboxylate-based plasticizers of the CNT are introduced in the form of suspensions into the cement paste composition, they are evenly distributed in the volume of the cement system. This causes the production of cement stone with enhanced exploitative properties.

scholarly journals INFLUENCE OF THE SCOPE ADDITION ON THE STRUCTURE FORMATION OF THE CEMENT STONE BY THE METHOD OF QUANTITATIVE X-RAY PHASE ANALYSIS

2019 ◽  
Vol 16 (4) ◽  
pp. 504-518
Author(s):  
I. L. Chulkova ◽  
I. A. Selivanov ◽  
V. D. Galdina
Keyword(s):  
Portland Cement ◽  
Structure Formation ◽  
Phase Analysis ◽  
Mineral Composition ◽  
Large Scale ◽  
Building Materials ◽  
Cement Matrix ◽  
Cement Stone ◽  
X Ray ◽  
Mineral Compositions

Introduction. The processes of structure formation of cement compositions and the development of effective technologies of building materials is an urgent task for building material science. The use of large-scale man-made product of pulp and paper enterprises – osprey as a fibrous filler in organic and mineral compositions is the successful decision of the problem. The paper analyzes the ways of using osprey in the building materials’ production. The aim of the research is to study the osprey influence on the processes of structure formation of cement stone by quantitative x-ray phase analysis.Materials and methods. The organic and mineral compositions were obtained on the basis of portland cement and osprey. The authors studied the compositions’ phase of osprey, portland cement and the processes of cement stone structure formation in organ and mineral compositions by quantitative x-ray phase analysis.Results. The authors determined the compositions’ phase of mineral impurities of osprey, cellulose, cement, cement stone, organic and mineral compositions and two compositions containing 25 and 75% by weight.Discussion and conclusions. The osprey application as a filler in the organic and mineral composition causes inhibition of processes of cement hydration. The presence of osprey in the hardening organic and mineral composition leads to a change in the composition and structure of the cement stone in comparison with the phase composition of the cement stone without additives. The result of these changes is a significant increase in the amount of calcite, waterite and a significant decrease in the amount of portland. The authors establish that the effective joint work of the reinforcing component of the osprey with the cement matrix is possible with a limited amount of osprey in organic and mineral compositions.

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