scholarly journals Role of Natural Stone Wastes and Minerals in the Alkali Activation Process: A Review

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2284
Author(s):  
Bartolomeo Coppola ◽  
Jean-Marc Tulliani ◽  
Paola Antonaci ◽  
Paola Palmero
Keyword(s):  
Raw Materials ◽  
Natural Stone ◽  
Partial Substitution ◽  
Alkali Activation ◽  
Activation Process ◽  
Active Components ◽  
Curing Conditions ◽  
Mineral Additions ◽  
Alumino Silicate

This review aims to provide a comprehensive assessment concerning alkali activation of natural stone wastes and minerals. In particular, the structure of the review is divided into two main sections in which the works dealing with alumino-silicate and carbonatic stones are discussed, respectively. Alumino-silicate stones are generally composed of quartz and feldspars, while carbonatic stones are mainly made of calcite and dolomite. The role of these minerals in the alkali activation process is discussed, attesting their influence in the development of the final product properties. In most of the works, authors use mineral additions only as fillers or aggregates and, in some cases, as a partial substitution of more traditional raw powders, such as metakaolin, fly ash, and granulated blast furnace slag. However, a few works in which alumino-silicate and carbonatic stone wastes are used as the main active components are discussed as well. Not only the raw materials, but also the entire alkali activation process and the curing conditions adopted in the literature studies here reviewed are systematically analyzed to improve the understanding of their effect on the physical, mechanical, and durability properties of the final products and to eventually foster the reuse of natural stone wastes for the purposes of sustainability in different applications.

scholarly journals Mine Tailings Geopolymers as a Waste Management Solution for A More Sustainable Habitat

2019 ◽  
Vol 11 (4) ◽  
pp. 995 ◽  
Author(s):  
Helena Paiva ◽  
Juho Yliniemi ◽  
Mirja Illikainen ◽  
Fernando Rocha ◽  
Victor Ferreira
Keyword(s):  
Waste Management ◽  
Mine Tailing ◽  
Effect Of Temperature ◽  
Alkali Activation ◽  
Activation Process ◽  
Fine Aggregate ◽  
Curing Conditions ◽  
Waste Valorisation ◽  
Binder Type ◽  
Hardened State

The demand for low environmental impact of materials in our habitat is one of the current societal challenges. Along with other solutions of waste valorisation, alkali activation as geopolymers can be one possible solution of waste valorisation because they may allow, for instance, an alternative solution for cement-based materials in some applications and it is one contribution for circular economy. This work has focused on the development and processing of geopolymers that incorporates as a fine aggregate a high-sulfidic mining waste (mine tailing), a difficult waste to process. Rheology analysis was applied as an important step to understand not only the geopolymers behaviour but also its transition from the fresh to the hardened state. The effect of precursor binder type (metakaolin or blast furnace slag), of mine tailing content and also the effect of temperature and curing conditions of different formulations were studied in this solution. It was possible to conclude that although this particular mine tailing is not a geopolymer binder precursor, it may be incorporated as an alternative fine aggregate in construction products. Furthermore, rheology could be used to follow up the geopolymer alkali-activation process and even to setup proper curing conditions and components contents in order to optimize the final mechanical strength of this material as a waste management solution. The final properties of these geopolymers compositions were adequate and after 28 days of curing, these geopolymers exhibit significant chemical resistance under severe test conditions.

scholarly journals Recycled Waste Powders for Alkali-Activated Paving Blocks for Urban Pavements: A Full Laboratory Characterization

2019 ◽  
Vol 4 (4) ◽  
pp. 73 ◽  
Author(s):  
Piergiorgio Tataranni
Keyword(s):  
Raw Materials ◽  
Low Cost ◽  
Alkali Activation ◽  
Activation Process ◽  
Construction Technology ◽  
Laboratory Characterization ◽  
Visual Impact ◽  
Materials Used ◽  
Surrounding Landscape ◽  
Recycled Waste

Paving blocks are today a popular paving solution for urban surfaces. Considering the wide variety of products currently on the market, it is possible to build pavements that differ in terms of functionality, bearing capacity, skid resistance, visual impact, and aesthetic integration with the surrounding landscape. Interlocking concrete paving block is the most common construction technology considering its low cost and its easy installation. Different wastes and second-hand materials have recently been tested in order to completely or partially replace the raw materials used for the production of paving blocks. In this paper, a waste basalt powder is used for the production of alternative paving blocks through the alkali-activation process. Two different synthetic blocks were produced, with and without aggregates. Taking into account the EN 1338 standard for concrete paving blocks, a complete laboratory characterization is proposed for the two experimental blocks. Tests highlighted positive results and downsides that need to be optimized in order to convert the laboratory production to an industrial scale.

scholarly journals Alkali-Activated Metakaolin and Fly Ash as Unfired Ceramic Bonding Systems

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 197
Author(s):  
Jozef Vlček ◽  
Michaela Topinková ◽  
Miroslava Klárová ◽  
Petra Maierová ◽  
Hana Ovčačíková ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Water Glass ◽  
Raw Materials ◽  
Alkali Activation ◽  
Activation Process ◽  
Laboratory Conditions ◽  
Naoh Solution ◽  
Bonding Systems

Metakaolin (MK) prepared by the calcination of kaolin at 550 °C and fly ash (FA) from the combustion of black coal in a granulating boiler were used to prepare unfired ceramic bonding systems via the alkali activation process. A long-term stability of the mechanical properties of the prepared samples similar to the unfired ceramic systems was observed. The optimal metakaolin and fly ash ratio, the type of the activator (NaOH or water glass) and its concentration were evaluated after the hydration in: a) laboratory conditions; b) hydration box; and c) under the hydrothermal activation. Raw materials and the samples prepared by alkali activation process were characterized by XRD, XRF, TG/DTA, and FTIR methods. The mechanical properties of the prepared samples were tested using a compressive strength test after 2, 28 and 56 days of hydration. The compressive strengths of 16 and 24 MPa after 28 days of hydration were reached for FA samples activated with water glass. The alkali activation of MK was successful in the NaOH solution of the molar concentration above 5 M. The compressive strength values of metakaolin, activated hydrothermally and hydrated at laboratory conditions, reached 11.2 and 5.5 MPa, respectively, for 5 M activator of NaOH.

Optical analysis of ink and other contaminants in process waters

TAPPI Journal ◽  
2012 ◽  
Vol 11 (8) ◽  
pp. 51-58
Author(s):  
ANTTI HAAPALA ◽  
MIKA KÖRKKÖ ◽  
ELISA KOIVURANTA ◽  
JOUKO NIINIMÄKI
Keyword(s):  
Optically Active ◽  
Process Water ◽  
Paper Machine ◽  
Optical Analysis ◽  
Direct Process ◽  
Active Components ◽  
Water Contaminants ◽  
Dependent Measurement ◽  
Measurement Methodology

Analysis methods developed specifically to determine the presence of ink and other optically active components in paper machine white waters or other process effluents are not available. It is generally more interest¬ing to quantify the effect of circulation water contaminants on end products. This study compares optical techniques to quantify the dirt in process water by two methods for test media preparation and measurement: direct process water filtration on a membrane foil and low-grammage sheet formation. The results show that ink content values obtained from various analyses cannot be directly compared because of fundamental issues involving test media preparation and the varied methodologies used to formulate the results, which may be based on different sets of assumptions. The use of brightness, luminosity, and reflectance and the role of scattering measurements as a part of ink content analysis are discussed, along with fine materials retention and measurement media selection. The study concludes with practical tips for case-dependent measurement methodology selection.

GREEN BONDS AS A NEW FINANCIAL INSTRUMENT

2020 ◽  
Vol 3 (7) ◽  
pp. 98-102
Author(s):  
M. V. DUBROVA ◽  
◽  
N. N. ZHILINA ◽  
Keyword(s):  
Raw Materials ◽  
Financial Burden ◽  
Environmental Problems ◽  
Green Economy ◽  
Non Profit ◽  
The Public ◽  
Economic Problems ◽  
Green Finance ◽  
Non Profit Organizations

The relevance of the article is determined by the fact that in Russia there is no effective mechanism of state support for the activities of non-profit organizations in the field of “green Finance”. The role of non-profit organizations is leveled, which can become a serious help in solving economic problems, in particular, the problems of recycling and processing of secondary raw materials, the placement of industrial waste and household garbage, and landscaping of large megacities. The main financial burden in the field of “green economy” falls on States and large enterprises. Meanwhile, we cannot ignore the important role of non-profit organizations that can not only draw attention to environmental problems to the public, but also offer their own measures to solve environmental problems. In this regard, it becomes relevant to consider the participation of non-profit organizations in the implementation of environmental projects by attracting “green Finance”.

POTENTIAL DEVELOPMENT OF «GREEN BONDS» IN THE RUSSIAN ECONOMY

2020 ◽  
Vol 1 (8) ◽  
pp. 119-123
Author(s):  
M. V. DUBROVA ◽  
◽  
N. N. ZHILINA ◽  
Keyword(s):  
Raw Materials ◽  
Financial Burden ◽  
Environmental Problems ◽  
Green Economy ◽  
Non Profit ◽  
Russian Economy ◽  
Green Finance ◽  
Potential Development ◽  
Non Profit Organizations

he relevance of the article is determined by the fact that in Russia there is no effective mechanism of state support for the activities of non-profit organizations in the field of «green Finance». The role of non-profit organizations is leveled, which can become a serious help in solving economic problems, in particular, the problems of recycling and processing of secondary raw materials, the placement of industrial waste and household garbage, and landscaping of large megacities. The main financial burden in the field of «green economy» falls on States and large enterprises. Meanwhile, we cannot ignore the important role of non-profit organizations that can not only draw attention to environmental problems to the public, but also offer their own measures to solve environmental problems. In this regard, it becomes relevant to consider the participation of non-profit organizations in the implementation of environmental projects by attracting «green Finance».

scholarly journals Recent Advances in Fabrication of Non-Isocyanate Polyurethane-Based Composite Materials

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3497
Author(s):  
Piotr Stachak ◽  
Izabela Łukaszewska ◽  
Edyta Hebda ◽  
Krzysztof Pielichowski
Keyword(s):  
Raw Materials ◽  
Synthesis Method ◽  
Polymeric Materials ◽  
Original Research ◽  
Significant Group ◽  
Oh Groups ◽  
New Class ◽  
Hazardous Chemical ◽  
Wide Range

Polyurethanes (PUs) are a significant group of polymeric materials that, due to their outstanding mechanical, chemical, and physical properties, are used in a wide range of applications. Conventionally, PUs are obtained in polyaddition reactions between diisocyanates and polyols. Due to the toxicity of isocyanate raw materials and their synthesis method utilizing phosgene, new cleaner synthetic routes for polyurethanes without using isocyanates have attracted increasing attention in recent years. Among different attempts to replace the conventional process, polyaddition of cyclic carbonates (CCs) and polyfunctional amines seems to be the most promising way to obtain non-isocyanate polyurethanes (NIPUs) or, more precisely, polyhydroxyurethanes (PHUs), while primary and secondary –OH groups are being formed alongside urethane linkages. Such an approach eliminates hazardous chemical compounds from the synthesis and leads to the fabrication of polymeric materials with unique and tunable properties. The main advantages include better chemical, mechanical, and thermal resistance, and the process itself is invulnerable to moisture, which is an essential technological feature. NIPUs can be modified via copolymerization or used as matrices to fabricate polymer composites with different additives, similar to their conventional counterparts. Hence, non-isocyanate polyurethanes are a new class of environmentally friendly polymeric materials. Many papers on the matter above have been published, including both original research and extensive reviews. However, they do not provide collected information on NIPU composites fabrication and processing. Hence, this review describes the latest progress in non-isocyanate polyurethane synthesis, modification, and finally processing. While focusing primarily on the carbonate/amine route, methods of obtaining NIPU are described, and their properties are presented. Ways of incorporating various compounds into NIPU matrices are characterized by the role of PHU materials in copolymeric materials or as an additive. Finally, diverse processing methods of non-isocyanate polyurethanes are presented, including electrospinning or 3D printing.

A true gift of mother earth: the use and significance of obsidian at Çatalhöyük

2011 ◽  
Vol 61 ◽  
pp. 1-19 ◽  
Author(s):  
Tristan Carter
Keyword(s):  
Raw Materials ◽  
Daily Practice ◽  
Social Identities ◽  
Raw Material ◽  
Central Anatolia ◽  
Social Significance ◽  
Key Issues ◽  
Raw Material Variability ◽  
Mother Earth

AbstractThis paper reviews 50 years of obsidian studies at Neolithic Çatalhöyük in the Konya plain, central Anatolia. A number of key issues are addressed: (1) the source of the site's raw materials, the means and forms by which the obsidian was introduced to the site and the role of Çatalhöyük in the supra-regional dissemination of these raw materials; (2) the alleged gender associations of certain obsidian goods in the burial record and beyond; (3) a more general consideration of the social significance of the circulation and consumption of obsidian at the site, including the phenomena of hoarding and gifting, plus the important role of projectiles in the creation of social identities and various forms of ritual behaviour, not least the termination of the life of a building/individual; (4) the technotypological and raw material variability through time; (5) the use of obsidian in daily practice and craft-working.

Pots on mats: mat-impressed salt-extraction pottery at Chalcolithic Provadia-Solnitsata, Bulgaria

Antiquity ◽  
2021 ◽  
pp. 1-16
Author(s):  
Mila Andonova ◽  
Vassil Nikolov
Keyword(s):  
Material Culture ◽  
Large Scale ◽  
Raw Materials ◽  
Salt Production ◽  
Production And Consumption ◽  
Late Chalcolithic ◽  
South Eastern Europe ◽  
Materials Used ◽  
The Relationship

Evidence for both basket weaving and salt production is often elusive in the prehistoric archaeological record. An assemblage of Middle–Late Chalcolithic pottery from Provadia-Solnitsata in Bulgaria provides insight into these two different technologies and the relationship between them. The authors analyse sherds from vessels used in large-scale salt production, the bases of which bear the impression of woven mats. This analysis reveals the possible raw materials used in mat weaving at Provadia-Solnitsata and allows interpretation of the role of these mats in salt production at the site. The results illustrate how it is possible to see the ‘invisible’ material culture of prehistoric south-eastern Europe and its importance for production and consumption.

Development of two dosimetry systems based on basic violet dye for possible use as radiation dosimeters

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nehad Magdy ◽  
Sameh Gafar
Keyword(s):  
Gamma Ray ◽  
Raw Materials ◽  
Absorbed Dose ◽  
Chemical Yield ◽  
Radiation Sensitivity ◽  
Vital Role ◽  
Radiation Chemical ◽  
Content Type ◽  
Before And After

Purpose The purpose of this research paper is to study a comparison between two dosimetry systems, both of them based on basic violet dye (BV). Design/methodology/approach The first system depends on (BV) (incorporating polyvinyl alcohol) as a thin-film dosimeter. The second system also relies on (BV) as a solution dosimeter, which is more sensitive to gamma rays. The two prepared film/solutions have a considerable signal that decreases upon irradiation and the strength of the signal decreases with increasing radiation dose. Findings The gamma ray absorbed dose for these dosimeters was found to be up to 35 kGy for films and 1 kGy for the liquid phase. All dosimetric characteristics as radiation chemical yield, additive substance, dose-response function, radiation sensitivity, also before and after-irradiation stability under various conditions were considered. Practical implications It is expected the vital role of gamma radiation on this dye in its two forms or two media. This reveals their wide applications in the field of gamma irradiation processing. Originality/value These two dosimetry systems which depend upon the same dye are safe to handle, inexpensive, available raw materials and can be applied in various dosimetry applications as mentioned above.

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