Recycling Of Secondary Raw Materials Research Articles

FORMATION OF PROFESSIONAL COMPETENCIES OF FUTURE TEACHERS OF LABOR EDUCATION AND TECHNOLOGY BY MEANS OF UPCYCLING TECHNOLOGY

The article is devoted to the problem of the formation of professional competences of future teachers of labor education and technology by means of upcycling technology in the process of designing eco-bags. The project activity is aimed at the development of critical thinking, reflects the pedagogical process as a system based on the theory of universal human values, humanization, a person-oriented approach, the priority of subject-subject relations, and is effective in shaping the personality of future teachers. The main features of the process of designing eco-bags using upcycling technology are determined - interdisciplinary, communicative and dynamism through the use of information services of social networks, environmental friendliness under the conditions of recycling of secondary raw materials; creative project and practical activity. The working hypothesis was accepted that the professional competences and creative abilities of the future teacher of labor education and technology are formed under certain conditions of project activity on upcycling: structuring of the project and stages of project activity; definition of educational and educational goals and tasks; implementation of an integrated program of technological activity; development of a criterion basis for determining the levels of educational achievements of education seekers for the implementation of eco-bag projects; development of information-subject and materialtechnical support of the educational process; modeling of systems of interdisciplinary connections of technologies with natural, mathematical and graphic knowledge; cooperation of teachers of subjects of general and professional training cycles regarding the content, organization of training, improvement of educational and methodological and software training of technologies of processing of secondary raw materials. In the study of the problem, methods of theoretical and empirical research were used: analysis and synthesis to clarify the main concepts and categories of professional training of future teachers of labor education and technology; study of psychological-pedagogical and scientific-methodological literature and advanced pedagogical experience on the problems of learning technologies in institutions of higher education; distinguishing regularities and formulating conclusions from the investigated problem. A three-stage pedagogical experiment was conducted at Mykhailo Kotsyubynskyi State Pedagogical University of Vinnytsia (Ukraine) (2020-2023): ascertaining experiment - a preliminary slice of knowledge (levels of formed professional competences of future teachers were determined); a formative experiment - the organization of teaching the technologies of making eco-bags by the upcycling method with the involvement of information arrays of the Pinterest social network and the formulation of pedagogical conditions of the project activity); control and generalization stage – analysis, processing of research results using statistical methods, formulation of theoretical-experimental conclusions and recommendations.

Universal eco-friendly biodegradable packaging for storage and transportation of food and industrial goods based on shives of bast plants

Integrated processing of plant raw materials refers to the primary areas of use of natural resources and their rotection. During the primary processing of bast plants, a large amount of waste remains – a shives. Part of the shives is burned, the rest goes into the dump. Due to its chemical composition, high content of cellulose shives can be used in the production of eco-friendly packaging. Packaging can be obtained with the complete or partial replacement of waste paper in its composition. Thanks to this, the issue of the shortage of waste paper at the enterprises of recycling of secondary raw materials will also be resolved. The purpose of the work is the production of eco-friendly biodegradable packaging from flax shives in industrial conditions. The paper presents the results of samples of lumpy egg packaging obtained by vacuum casting with the use of flax production waste. In industrial conditions, it was possible to replace part of the waste paper on the fire. For more efficient use, the shives was pre-ground to the consistency of wood flour M-560. The following indicators were determined: humidity, strength, moisture absorption capacity, antibacterial properties. The obtained results showed the optimal ratio of the mixture components, processing modes. According to all indicators, the packaging with a bone is not inferior, and in the case of tensile strength and antibacterial properties exceeds the normalized values.

Life-cycle assessment for municipal waste management systems

One of the important tasks of the environmental policy of the Russian Federation is to implement an integrated regional waste management system through the active involvement of production and consumption waste in the economic turnover, the use of environmentally sound recycling methods, the solution of environmental problems related to waste management and resource conservation. Environmental assessment of the existing municipal waste management system is carried out by analyzing the environmental impact and alternative waste management scenarios in order to develop an integrated waste management system for Irkutsk region. Modelling of production and consumption waste flows and their potential impact on the environment was performed. The method of material flow analysis using STAN software was used to estimate the fractional composition of waste. The method of life cycle assessment (LCA) was used to determine the environmental indicators, using the EASETECH software package, which allows for creating various scenarios of environmental impacts, comparing them and choosing the most optimal and environmentally safe one. The modelling of alternative future waste management scenarios for Irkutsk Region showed that all alternatives can improve the current waste management system, which primarily involves landfilling in an uncontrolled landfill without environmental measures. Construction of a new landfill with gas disposal and leachate treatment is a significant improvement, and recycling of secondary raw materials can reduce the environmental pressure. From an environmental point of view, the current waste disposal system is not efficient. Uncontrolled landfill is the main impact on global warming. Although a new landfill could significantly reduce this impact, it is worth reconsidering the waste management systems paying more attention to recycling rather than to landfilling.

Analysis of suitability of TPP ash-slag waste as materials for hydrogen fuel storage

The current trends in energy were described, the main of which is the use of alternative energy sources, especially hydrogen. The most common methods of hydrogen accumulation were proposed: accumulation of compressed gaseous hydrogen in high-pressure tanks; accumulation of liquid hydrogen in cryogenic tanks; storing hydrogen in a chemically bound state; accumulation of gaseous hydrogen in carriers with a high specific surface area. Based on the combination of advantages and disadvantages, the most promising methods of accumulation were selected: storage of liquid hydrogen and storage of hydrogen in carriers with a high specific surface area. The main requirement for materials for hydrogen storage by these methods was revealed – a high specific surface area. Prospects for the development of waste-free low-emission technologies due to the recycling of secondary raw materials and the development of low-temperature technologies for the synthesis of functional and structural materials were substantiated. The applicability of large-scale ash and slag waste from coal-fired thermal power plants as a raw material for obtaining materials by low-temperature technologies was shown. The traditional ways of using ash and slag waste as a raw material, active additive and filler in the production of cements were described. Modern technologies for the production of innovative materials with a unique set of properties were presented, namely carbon nanotubes, silica aerogel and geopolymer materials. The prospect of using geopolymer matrices as a precursor for the synthesis of a number of materials was described; the most promising type of materials was selected – geopolymer foams, which are mainly used as sorbents for purifying liquids and gases or accumulating target products, as well as heat-insulating materials. The possibility of obtaining products of any shape and size on the basis of geopolymer matrices without high-temperature processing was shown. The special efficiency of the development of the technology of porous granules and powders obtained from a geopolymer precursor using various methods was substantiated. The obtained granules can be used in the following hydrogen storage technologies: direct accumulation of hydrogen in porous granules; creation of insulating layers for liquid hydrogen storage units.

АНАЛИЗ ВЛИЯНИЯ МЕТОДОВ ВВЕДЕНИЯ ОРГАНОМИНЕРАЛЬНОЙ ДОБАВКИ В СТРОИТЕЛЬНЫЕ РАСТВОРЫ НА МЕЛКИХ ПЕСКАХ

the use of technogenic raw materials in the production of building composites is an urgent direction in the technology of production of building materials in view of its economic efficiency, environmental effect and wide possibilities of their application. Recently, the issues of environmental safety in the production of building materials, the possibility of their processing and disposal have come to the fore. All this is dictated by the need for energy and resource conservation, the massive depletion of natural reserves and the progres-sive pollution of the environment due to anthropogenic activities. Construction composites provide ample opportunities for recycling of secondary raw materials, as their structure allows them to be used not only as a filler, but also in some cases as additives for regulating certain properties. More studied and widely used are ash and slag mixtures on the basis of which various organomineral additives are developed. So, on the territory of the Chechen Republic there are dumps of ash and slag mixtures, which, according to their chem-ical and mineralogical composition, are suitable for the design of organomineral additives and fillers in con-struction concretes and solutions. Building solutions are widely used for interior and exterior finishing works during the construction of construction projects in the Chechen Republic, which is characterized by high humidity in the winter, which provokes deformations of the plaster layer on facades. In this article, the de-velopment of an organomineral additive based on an ash-slag mixture is considered to improve the quality of mortar mixtures resistant to such conditions.

The Organizational and Economic Mechanism of Implementing the Concept of Green Logistics

The article analyses the preconditions for shaping and developing the concept of a green economy. The stages of the evolutionary development of the circular economy are considered: work with waste; environmental performance strategies; maximum conservation in the era of resource depletion. Having analysed the scientific opinions on the emergence of “circular economy”, the paper has found out that this concept is identified with the terms “round economy”, “cyclical economy”, “recovery economy”, “closed-cycle economy”, “green economy”. The approaches of different scientific schools to the category of “circular economy” are analysed and conventionally systematized into 12 groups: closed-cycle economy; renewable resource economy; alternative to traditional linear economy; global economic model; closed-loop economic system based on R-principles; the concept of economic development; sustainable development strategy; a "green" economy instrument; business philosophy; economic activity; use of production waste; recycling of secondary raw materials. There is proposed the authors' formulation of the circular economy as an innovative approach to organizing logistics processes based on the closed movement of resources with their minimum losses in the form of waste and the maximum involvement of secondary resources in production in order to achieve sustainable development of logistics systems. The article identifies the barriers preventing the implementation of the circular economy concept, among them being regulatory, institutional, economic, financial and investment, market, technological, informational, and cultural. The article considers the best practices of effective implementation of circular economy solutions on the example of Finland. The indicators of the development of the green technologies market in the world and the national logistics system of Ukraine under conditions of a circular economy are analysed. It has been established that many conceptual approaches to the definition of the terms “green logistics” and “environmental logistics” are generally accepted and have a broader meaning, without taking into account the functioning specificity of various spheres of economic activity, including transport and logistics. Scientific views on interpreting the essence and content of the concept "green logistics" are generalized. It is proposed to consider the term "green logistics" from three angles: a circular economy instrument; a component of business corporate social responsibility; and a type of economic activity aimed at reducing the negative impact on the ecosystem and the environment. In order to effectively implement the concept of green logistics, an organizational and economic mechanism has been developed, the main elements of which are: diagnostics of the current state, features and trends in the logistics systems' development, taking into account the environmental component; exogenous and endogenous factors affecting the development of logistics systems; risks in organizing the processes of logistics activities; subjects and objects of management, goals, objectives, principles, functions, tools, methods, management tools, information technology, criteria. The priority principles of forming an organizational and economic mechanism include consistency, integration, reliability, dynamism, compliance with the goals of sustainable development, and efficiency. A structural diagram of forming an organizational and economic mechanism for implementing the concept of green logistics is proposed, including the following blocks: management of material resources’ supplies and purchases; products manufacturing; warehousing and stocks; logistic flows; the risks of logistics activities; logistics service processes; recycling of waste; innovation and transformations. Introduction of the proposed organizational and economic mechanism will reduce the cost of managing the movement of logistics flows and increase the level of environmental safety. This is one of the most important requirements for implementing the concept of business corporate social responsibility in a circular economy.

ON INTEGRATION OF WASTEWATER TREATMENT TECHNOLOGIES AND PRODUCTION OF RENEWABLE ENERGY SOURCES

The work is devoted to the study of technological processes corresponding to the requirements of the developing closed-loop economy, which will be based on the wide use of renewable resources, maximum recycling of secondary raw materials, with the transition from fossil fuels to renewable energy sources as one of the objectives. A study of the possibility of producing fatty acid esters from renewable raw materials of plant origin - microalgae Chlorella vulgaris - with the use of municipal wastewater was carried out. Approaches to the development of technologies of fatty acid esters production and promising ways to improve the key stages of such production are considered. It is shown that under certain conditions (temperature of 10-32 °С, illumination of 7-14 klx) municipal wastewater can be treated and at the same time serve as a nutrient medium in the process of cultivation of microalgae biomass with lipid content of 10-18% of dry matter. Depending on the conditions of cultivation, the cells of the Chlorella vulgaris IPPAS C-2 strain of microalgae reduce the concentration of ammonium cations, phosphate anions and total microbial number in municipal wastewater by 93 - 95% (wt.), 90 - 97% (wt.) and 86 - 95%, respectively. The influence of technological conditions of the process on the biomass growth rate and fatty acid composition of accumulated lipids is analyzed. It is experimentally established that triglycerides, O-dialkylmonoglycerides and fatty acids have the greatest inhibiting effect on the microflora of wastewater. Using Hansen solubility parameters, a system of polar and non-polar solvents consisting of ethanol and petroleum ether in the ratio of 1:2 (vol). was selected, which ensures the efficient conduct of the extraction process. The yield of fatty acid esters of КFAE = 45% was obtained in the course of transesterification reaction with the use of ethanol in the ratio with lipids 6:1 (mole) at the reaction temperature of 60 °C in the presence of an alkaline catalyst - sodium hydroxide (3% of the mass of lipids).

Environmental Protection in Industry 4.0. Opportunities and Threats in Selected Areas

Abstract In recent years, the importance of production in cyberphysical systems – CPS characteristic of the new industry concept, which is Industry 4.0 – I 4.0, is gaining importance. Industry 4.0 enforces modification of traditional perception of production. The basis for changes in Industry 4.0 has become Internet of Things – IoT, which gives the opportunity to connect and communicate with each other such areas as mobile solutions, cloud computing, sensors, analytics and cyber security. By new technology, areas that previously operated in enterprises as separate systems can be combined and create new opportunities for industrial production (modernization of production methods and reduce employment). Industry 4.0 brings with it a number of new challenges for producers in the field of environmental protection, and related to the inclusion of cybernetic technology in physical production processes as well as distribution. Production starts and ends on the customer. Industry 4.0 is a collective term for technologies and concepts of value chain organization. The United Nations Organization for Industrial Development indicates the following environmental aspects in the perspective of the development of Industry 4.0, such as: climate change and limited access to resources, primarily to clean energy. It is assumed that changes in the production and functioning of economies will result in a decrease in the emission of harmful compounds into the atmosphere and increase the flexibility of activities for environmental protection. The purpose of this work is to present general directions of changes in the field of environmental protection in Industry 4.0. Authors present the following areas of change: energy management and material management. These areas are opportunities for environmental. In the category of threats, the growing costs of environmental protection and household expenses are pointed out. The work is based on a literature study and statistical data. Statistical data are used: integrated technologies, expenditure and costs of environmental protection, recycling of secondary raw materials and energy consumption for the EU and Poland.

Design development of a continuous industrial drying plant for drying pomace of walnuts, peanuts and pistachios

The object of research is the drying process of the pomace of a walnut kernel, peanuts and pistachios in a fluidized bed dryer with an inert support. One of the most problematic places is the issue of recycling of secondary raw materials, which represent significant potential for the food industry. The solution to the problem that is urgent is the preservation of pomace of the walnut kernel, peanuts and pistachios for their further use in the food industry. At the same time, the advantages of dried semi-finished products:– ability to transport over long distances;– long shelf life of dried products;– use in food technology;– use as a protein supplement.Therefore, the work is devoted to the development of new and modernization of existing drying methods. One of such methods is drying in a fluidized bed of an inert support; this product has not been used before for drying because of the complexity of the process.During the study, the method of microscopic determination of the dispersed composition of the product is used, which allows measuring particles with a size of 0.3-100 microns. Test powders of different fineness are investigated using USB Digital Microscope. The mathematical processing of the results using modern computer programs is carried out. The data obtained are processed in the Mathcad environment and presented as integral and differential particle distribution functions for each analyzed sample. This is due to the fact that the analysis of the determination of the dispersed composition is a mandatory control method in all technological processes. Thanks to this, it is possible to obtain a given product size. In the course of the study, a design of a continuous industrial drying unit for drying pomace of walnut kernels, peanuts and pistachios was developed. The drying method proposed in this work has several advantages over other methods, the main of which are the reduction of energy consumption and improving the quality of the finished product.

Wastes recycling in the construction

For many years fuel and energy and ore-dressing industries have been the sources of industrial waste which, if treated correctly, can be reused as secondary raw material resources accumulating earlier wasted investments and power costs. The article introduces possible ways of recycling both in our country and abroad. Basing on this, ways of reusing man-produced wastes in Grozny as bottom ash waste and chippings from rock crushing into spalls have been described. Study results showed that secondary man-produced raw material can compete with and substitute non-renewable natural resources as their chemical composition and quality parameters prove their unique nature, also it is possible to take into account solution of ecological problems. Developed formulas of multi-component bindings based on finely dispersed fly-ash and concretes with the use of enriched artificial aggregates promoted recycling of secondary raw materials and improving ecological situation in the region.

CONCEPT OF THE TRANSBOUNDARY CLUSTER ON PROCESSING OF SECONDARY RAW OF WINE FOOD IN UKRAINE AND MOLDOVA. PROBLEMS OF FORMATION AND DEVELOPMENT STRATEGY

Topicality. Secondary raw materials of winemaking are a rich source of biologically active compounds, which makes it possible to use it for the production of a wide range of products of high value for various industries: food, pharmaceutical, perfume and cosmetic, chemical, etc. However, currently in Ukraine and in Moldova there are no specialized enterprises for the integrated processing of secondary raw materials of winemaking. In the vast majority of cases, in particular, crests and squeezes are uncontrolledly exported to agricultural lands without special treatment, which leads to acid soil erosion and environmental pollution by metabolites of micromycetes. At the present stage of technological development there is a wide range of innovative developments in the field of recycling of secondary bio-materials, in particular grape excrements, in order to obtain biologically valuable components. The main task in this direction is to create an organizational and economic mechanism that will unite the interests of winemaking enterprises (owners of secondary raw materials), processing enterprises (producers of secondary products of winemaking), representatives of local authorities and potential consumers of innovative products. A cluster ideology may be an effective tool for consolidating the interests of stakeholders in this direction. Aim and tasks. Development of the concept, formation and functioning of the cross-border cluster on the processing of secondary raw materials of winemaking, the core of which is the innovation-investment center, which provides cooperation of science, business and administrative resources, allows to provide non-waste technologies and use innovative solutions. In the process of recycling of secondary raw materials of winemaking in Ukraine and Moldova (about 100 thousand tons) is the possibility of obtaining more than 50 secondary winemaking products, which are in high demand in various sectors of the economy. The main objectives of this study are: ensuring sustainable development and the principles of the "green economy" in the development of viticulture and winemaking in Ukraine and Moldova; creation of high value-added biologically valuable products; obtaining social and synergistic effect in the process of forming a cluster. Research results. A systematic approach to the complex processing of grapes on the basis of cluster ideology is proposed. The proposed architecture of the cluster as managerial innovation in the subregional, regional, national and transboundary context allows us to form the poles of economic growth by consolidating and converting different types of capital: human, social, productive, natural, financial and intellectual to obtain additional economic benefits. The developed concept shows that sustained efficiency is achieved, first and foremost, enterprises are able to combine efforts and capital. Conclusions. The analysis of technology of processing of grapes on wine materials in Ukraine and Moldova is carried out. The following is the list of the most promising products obtained from secondary raw materials of winemaking. The concept of creating a cross-border cluster for the processing of secondary raw materials of winemaking, which is based on the principles of the green economy.

Oxidation Sulfuric Acid Autoclave Leaching of Copper Smelting Production Fine Dust

Lead, zinc, and arsenic are associated elements in copper ores. Due to deterioration of concentrate quality and involvement in recycling of secondary raw materials, these impurities are increasingly circulated in copper-smelting production, most often collected in fine dusts. Recovery of these dusts for pyrometallurgical processing leads to contamination of black copper with arsenic and lead. Results are provided for sulfuric acid autoclave leaching of OAO SUMZ dust and dust obtained after recovery melting, containing alongside copper and zinc considerable amounts of lead and arsenic. The effect of temperature and acid concentration on autoclave leaching indices is studied. Optimum dust leaching parameters are obtained: temperature 160°C, H2SO4 /(Pb+Zn+Cu) = 2.1, $$ {P}_{{\mathrm{O}}_2}=0.3\mathrm{MPa} $$ , τ = 2 h, and with these parameters the maximum degree of leaching for arsenic, copper and zinc is observed. Direct oxidizing sulfuric autoclave leaching of fine dust makes it possible to extract up to 89% copper and 92% zinc. Arsenic passes into a cake in the form of iron arsenate, which complicates subsequent processing. In order to exclude deposition of arsenic during autoclave leaching it is necessary to remove arsenic from dust where it is present in the form of oxidized compounds, and therefore it is possible to use atmospheric sulfuric acid leaching for its extraction. During two stages of atmospheric and autoclave oxidation leaching, it is possible to extract up to 93% Cu, 96% Zn, and 99% As.

Use of periclase-carbon lining in DC arc melting furnaces during processing of secondary raw materials

The experience of operating a DC arc furnace in JSC "Krastsvetmet" for recycling of secondary raw materials using periclase-carbon products as a working layer of lining is presented. A comparative analysis of the operation of a DC arc furnace with periclase and periclase-carbon lining is described.Ill.2.

Recovery of Phosphorus and other Nutrients during Pyrolysis of Chicken Manure

Feedstock recycling of secondary raw materials is the backbone of the Circular Economy (CE). The efficient recovery of resources, energy, along with achieving minimal environmental impact is mandatory for the successful realization of CE. Chicken manure is an interesting waste stream due to its content of nutrients, in particular of phosphorus, which makes it a suitable feedstock for fertilizer applications. However, the contamination caused by antibiotics, organic pollutants, and sanitary aspects demand the manures treatment before further recycling. Thermochemical treatment based on intermediate pyrolysis targets decentral application to produce carbonized solids for fertilizer application. This work evaluated pyrolysis char from the pyrolysis of chicken manure in comparison to the original feedstock using state-of-the-art thermal treatment, i.e., combustion in grate furnaces. The samples were evaluated in terms of chemical and mineralogical composition by applying several analytical techniques. Bio-availability of the main nutrients (NPK) was assessed by adopting standard methods. Additionally, the effect on toxicity was discussed by means of heavy metals analysis, as well as of pot tests. Results showed, that pyrolysis had a far more positive effect on nutrient availability compared to combustion, and it provided a suitable method for the thermal treatment of contaminated feedstocks.

High-Strength Concretes Based on Multicomponent Binding and Fractionated Aggregates from Waste from Processing of Subsurface Rocks

A review of the use of industrial wastes in our country and abroad was conducted, and prospects for using man-made raw materials at the Grozny CHP and wastes of subsurface rocks crushing were considered. The analysis of the results of the conducted research is carried out, which showed that secondary technogenic raw materials can successfully compete and replace exhaustible natural resources, since the chemical composition and qualitative parameters of the materials under study confirm its uniqueness and, moreover, there is can see a solution of environmental problems. The formulation of multicomponent binders and concretes based on fine-dispersed ash microspheres and enriched artificial aggregates promoted recycling of secondary raw materials and improvement of the ecological situation in the region.

Preparation of Alternative Hydraulic Binder Based on Secondary Raw Materials

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.

Recycling of the product of thermal inertization of cement-asbestos in geopolymers

Recycling of secondary raw materials has become a priority of waste handling in the worldwide environmental agenda. A novel secondary raw material of great importance is the product of the thermal transformation of cement-asbestos, which is chemically comparable to a Mg-rich clinker. Recently, this secondary raw material called KRY•AS has been successfully used for the production of concrete. In this work it has been used for the production of geopolymers. Geopolymers represent a class of synthetic alumino-silicate based materials potentially used in several industrial fields, and in particular in substitution of cements or mortars, with the positive advantage of reducing the emissions of carbon dioxide developed during the clinkering phase. Geopolymers are the result of a reaction of an alumino-silicate, usually metakaolinite, activated with an alkaline silicate solution at room temperature. In the present work, geopolymers obtained from alumino-silicate natural materials mixed with KRY•AS were prepared and characterized. The composition with 2.5wt.% of KRY•AS presents the best physical and mechanical properties. The presence of KRY•AS introduces about 30wt.% of amorphous phase in the system. The crystalline component of KRY•AS decomposes in strong basic conditions releasing elements such as calcium and silicon that promote the formation of calcium precipitates and/or minor paracrystalline silicate hydrates. These are responsible for the improved technological performances.

A streamlined life-cycle assessment and decision tool for used tyres recycling

In order to achieve progress towards sustainable resource management, it is essential to evaluate options for the reuse and recycling of secondary raw materials, in order to provide a robust evidence base for decision makers. This paper presents the research undertaken in the development of a web-based decision-support tool (the used tyres resource efficiency tool) to compare three processing routes for used tyres compared to their existing primary alternatives. Primary data on the energy and material flows for the three routes, and their alternatives were collected and analysed. The methodology used was a streamlined life-cycle assessment (sLCA) approach. Processes included were: car tyre baling against aggregate gabions; car tyre retreading against new car tyres; and car tyre shred used in landfill engineering against primary aggregates. The outputs of the assessment, and web-based tool, were estimates of raw materials used, carbon dioxide emissions and costs. The paper discusses the benefits of carrying out a streamlined LCA and using the outputs of this analysis to develop a decision-support tool. The strengths and weakness of this approach are discussed and future research priorities identified which could facilitate the use of life cycle approaches by designers and practitioners.

Recycling of the product of thermal inertization of cement–asbestos for the production of concrete

A novel field of research in materials science is the recycling of secondary raw materials for construction and building materials such as concrete. This paper describes the successful recycling of as much as 20 wt% of the product of thermal transformation of cement–asbestos for the formulation of concrete. The main mineralogical phases present in the product of transformation of cement–asbestos are C2S, ferrite, and Al-, Ca-, Mg-rich silicates such as akermanite (ideally Ca 2MgSi 2O 7) and merwinite (ideally Ca 3Mg 2Si 2O 8). The behavior of this secondary raw material, termed KRY·AS, in commercial concrete was investigated using five different mixtures in which various portions (0, 5, 10, 15 and 20 wt%) of cement were substituted by KRY·AS. The results of preliminary technological tests (slump test, compressive strength, flexural strength after 28 days, and depth of penetration of water under pressure after 28 days) were discussed and interpreted with the aid of chemical, mineralogical and SEM analyses. One of the major results is that after 28 days, although all the concrete samples are invariably classified as “ordinary concrete” according to the UNI 6132 tests, those diluted with KRY·AS display a lower resistance to compression with respect to the standard. On the other hand, they recover compressive strength and display values identical to that of the standard after 90 days. The addition of the secondary raw material has the effect to slow down the kinetics of setting/hardening because the main cement phase present in KRY·AS is C2S which has a slower rate of hydration with respect to C3S.

Recycling of the product of thermal inertization of cement–asbestos for various industrial applications

Recycling of secondary raw materials is a priority of waste handling in the countries of the European community. A potentially important secondary raw material is the product of the thermal transformation of cement–asbestos, produced by prolonged annealing at 1200–1300 °C. The product is chemically comparable to a Mg-rich clinker. Previous work has assured the reliability of the transformation process. The current challenge is to find potential applications as secondary raw material. Recycling of thermally treated asbestos-containing material (named KRY·AS) in traditional ceramics has already been studied with successful results. The results presented here are the outcome of a long termed project started in 2005 and devoted to the recycling of this secondary raw materials in various industrial applications. KRY·AS can be added in medium-high percentages (10–40 wt%) to commercial mixtures for the production of clay bricks, rock-wool glasses for insulation as well as Ca-based frits and glass–ceramics for the production of ceramic tiles. The secondary raw material was also used for the synthesis of two ceramic pigments; a green uvarovite-based pigment [Ca 3Cr 2(SiO 4) 3] and a pink malayaite-based pigment [Ca(Sn,Cr)SiO 5]. The latter is especially interesting as a substitute for cadmium-based pigments. This work also shows that KRY·AS can replace standard fillers in polypropylene plastics without altering the properties of the final product. For each application, a description and relevant results are presented and discussed.