scholarly journals Polyurethane Recycling and Disposal: Methods and Prospects

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1752 ◽  
Author(s):  
Aleksandra Kemona ◽  
Małgorzata Piotrowska
Keyword(s):  
Raw Materials ◽  
Waste Recycling ◽  
Synthetic Polymers ◽  
Biological Degradation ◽  
Mechanical Recycling ◽  
Polyurethane Waste ◽  
Wide Range ◽  
The Moment ◽  
Biological Methods ◽  
Physical And Chemical

Growing water and land pollution, the possibility of exhaustion of raw materials and resistance of plastics to physical and chemical factors results in increasing importance of synthetic polymers waste recycling, recovery and environmentally friendly ways of disposal. Polyurethanes (PU) are a family of versatile synthetic polymers with highly diverse applications. They are class of polymers derived from the condensation of polyisocyanates and polyalcohols. This paper reports the latest developments in the field of polyurethane disposal, recycling and recovery. Various methods tested and applied in recent years have proven that the processing of PU waste can be economically and ecologically beneficial. At the moment mechanical recycling and glycolysis are the most important ones. Polyurethanes’ biological degradation is highly promising for both post-consumer and postproduction waste. It can also be applied in bioremediation of water and soil contaminated with polyurethanes. Another possibility for biological methods is the synthesis of PU materials sensitive to biological degradation. In conclusion, a high diversity of polyurethane waste types and derivation results in demand for a wide range of methods of processing. Furthermore, already existing ones appear to be enough to state that the elimination of not reprocessed polyurethane waste in the future is possible.

scholarly journals OPTIMIZATION OF RAW MIX COMPOSITION OF SEREBRYANSKY CEMENT PLANT

2020 ◽  
pp. 13-20
Author(s):  
M. Nikitina ◽  
A. Erygina ◽  
T.I. Timoshenko
Keyword(s):  
Cost Efficiency ◽  
Raw Materials ◽  
Cement Industry ◽  
Cement Clinker ◽  
Chemical Transformations ◽  
The Moment ◽  
Physical And Chemical ◽  
To Receive ◽  
Selection Of

now a top trend of technical development in the cement industry of Russia, is optimization of all technological repartitions of production. Obtaining the quality portlandtsement is multiple-factor process. It is influenced not only by the physical and chemical transformations of raw materials occurring during the firing of cement clinker, but also what will be the composition of the raw mixture and whether this mixture is prepared qualitatively. Work consists in a research and selection of an optimum compounding of raw mix, with the purpose to receive cement with high rates of quality. This direction will allow: first, to expand a source of raw materials, to process raw materials which go to dumps because in it is mute a large amount of quartz and impurity connections contains; secondly, to make small reconstruction of the line of preparation of raw mix. At the moment, the plant works on mixed mixtures of aluminosilicate raw materials, i.e. two types of aluminosilicate raw materials which are previously mixed in certain ratios therefore it affects on the accuracy of dispensing of components are used. Accuracy of dispensing of modern batchers, a component ± (1 … 2) %, is often insufficient. In this regard, the new option of optimum composition of mix is offered and investigated. This option of a "clean" mixing of components, will allow to improve process of mixing of initial raw materials, to operate process of drawing up proportions of mixes in a supply line of materials. And also it will allow to eliminate long-term deviations, guaranteeing the solution of problems at the earliest stage of their emergence. Receiving a qualitative ready-made product, reduction of costs for energy resources and cost efficiency of the proposed solution is result of this work

Systemic Approach to Design of Gel Compositions of Combined Effect

1970 ◽  
Author(s):  
Olga S. Kudrjashova ◽  
Galina A. Aleksandrova
Keyword(s):  
Sodium Citrate ◽  
Raw Materials ◽  
Water System ◽  
Combined Effect ◽  
Solubility In Water ◽  
Wide Range ◽  
Low Toxicity ◽  
Main Components ◽  
Short Time ◽  
Physical And Chemical

A systematic approach to desing of gel compositions of combined effect has been proposed and practically tested. The scientific approach is based on the physical and chemical analysis of polycomponent systems containing the main components of the compositions. This approach allows achieving the maximum result with rational use of raw materials. Solubility in the Vilagin – Surfactant "Progress" – Sodium citrate – Coriolate – water system at 25 ° C was studied. The components of the system were selected in such a way that their mixtures showed disinfectant and deactivation properties. Vilagin is a highly effective bactericide, but its low solubility in water significantly limits its application. It is found that the surfactant "Progress" is a fairly good homogenizer of the Vilagin-water stratifing system, and does not negatively affect on its bactericidal activity. Sodium citrate and corylate are capable of binding radioisotopes of alkaline earth and heavy metals to soluble complex anions that are removed from the surface to be treated together with the solution. It is found that the value of the homogeneous region of the system depends to a greater extent on the concentration of Vilagin and salts. The first component is insoluble in water, and the salts are sparingly soluble. The viscosity of the obtained gels depends on the ratio of Vilagin and surfactant. The components concentration intervals at which there are stable gels that possess not only disinfectant, but also deactivation properties are found. Gel mixtures, which compositions are located near the binodal curve, can be diluted with water over a wide range of concentrations to obtain solutions with a specified content of Vilagin and salts. It is proved that the developed gel compositions are effective in small concentrations in a short time, have low toxicity, multifunctionality, good solubility in water, and a long shelf life of concentrates.

scholarly journals Recycling of Waste Sludge: Preparation and Application of Sludge-Based Activated Carbon

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Yongning Bian ◽  
Qian Yuan ◽  
Guocheng Zhu ◽  
Bozhi Ren ◽  
Andrew Hursthouse ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Agricultural Development ◽  
Raw Materials ◽  
Environmental Pollutants ◽  
Chemical Properties ◽  
Cost Effective ◽  
Adsorption Performance ◽  
Wide Range ◽  
Pollutants Removal ◽  
Physical And Chemical

With the rapidly increasing industrial and agricultural development, a large amount of sludge has been produced from much water treatment. Sludge treatment has become one of the most important environmental issues. Resource utilization of sludge is one of the important efficient methods for solving this issue. Sludge-based activated carbon (SBAC) materials have high adsorption performance and can effectively remove environmental pollutants including typical organic matter and heavy metals through physical and chemical processes. Therefore, developing efficient SBAC materials is important and valuable. At present, preparation, modification, and application of SBAC materials have gained widespread attention. This paper provides a review of the research on SBAC preparation and modification and its utilization in removing environmental pollutants. It included the following topics present in this review: conventional and new methods for preparation of SBAC were clearly present; the effective methods for improving SBAC performance via physical and chemical modification were reviewed; and the correlation of their physic-chemical properties of SBAC with pollutants’ removal efficiencies as well as the removal mechanisms was revealed. SBAC has a better adsorption performance than commercial activated carbon in some aspects. Furthermore, it is a cost-effective technique and has a wide range of raw materials. However, there are still some drawbacks to its research; thus, some suggestions for further research were given in this review.

scholarly journals Towards Circular Economy: Different Strategies for Polyurethane Waste Recycling and the Obtaining of New Products

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1490 ◽  
Author(s):  
Lorena Ugarte ◽  
Tamara Calvo-Correas ◽  
Itziar Gonzalez-Gurrutxaga ◽  
Cristina Peña-Rodriguez ◽  
Oihane Etxeberria ◽  
...  
Keyword(s):  
Circular Economy ◽  
Waste Recycling ◽  
Polyurethane Foams ◽  
Chemical Recycling ◽  
Mechanical Recycling ◽  
Great Volume ◽  
Thermoplastic Polyurethanes ◽  
Polyurethane Waste ◽  
High Production ◽  
Flexible Foam

As a consequence of the high production and simultaneous consumption of polyurethanes (PU) a great volume of PU waste is landfilled. In this scenario, suitable and efficient routes for PU waste recycling have been searched for many years. In this work two series of PUs using different recycled PU sources were synthesized: a thermoplastic PU series using a glycolysated polyol obtained from the glycolysis of elastomeric PU waste (chemical recycling) and a PU flexible foam series loaded with PU dust waste created in the shaping of PU surf tables (mechanical recycling). Results showed that the incorporation of recycled components in the formulation improved mechanical properties both in the case of thermoplastic polyurethanes and polyurethane foams. The optimum glycolysated polyol was fixed in 15% over the total polyol weight for thermoplastic PUs. In the case of foams, a maximum of 20% PU dust over the polyol weight was incorporated.

scholarly journals DEVELOPMENT OF THE DESIGN OF A PYROLYSIS INSTALLATION FOR WASTE DISPOSAL WITH DIRECTED DISTRIBUTION OF HEAT FLOWS

2021 ◽  
pp. 41-48
Author(s):  
Rostyslav Iskovich-Lototskyy ◽  
Nataliia Veselovska ◽  
Bohdan Bratslavets ◽  
Olha Yalina
Keyword(s):  
Heat Transfer ◽  
Waste Disposal ◽  
Raw Materials ◽  
Waste Recycling ◽  
Heat Extraction ◽  
Water Steam ◽  
Working Chamber ◽  
Urgent Task ◽  
Chemical Conditions ◽  
Physical And Chemical

Waste recycling is now gaining in importance around the world. The range of drugs used, the volume and degree of danger of waste generated by the activities of industrial institutions is increasing. As a result, the risk of epidemics increases. Therefore, the creation of an effective design of the furnace as the main unit of the pyrolysis unit is an urgent task. The purpose of the furnace environment is to create in the working chamber the necessary and optimal physical and chemical conditions for the implementation of thermotechnological, thermotechnical and mechanical processes and protection of raw materials and obtained target products from unwanted chemical processes. The following substances are used as heat extraction reagent: air, inert and recirculating gases, water, steam, etc. If necessary, a slow decrease in temperature, cooling of materials and products is carried out together with the oven. Heat transfer processes in the waste disposal plant take place in difficult conditions and are characterized by a number of specific features. One of the main features is the high intensity of heat transfer. Another feature of thermal processes is the non-stationary temperature field in the working chamber of the furnace. Heat exchange in the working chamber of the furnace is carried out in three types - thermal conductivity, convection and thermal radiation, any combination of them or all types simultaneously, but one type of heat transfer always prevails over others in full or in a certain area of the furnace.

scholarly journals ANALYSIS OF PLASTIC WASTE RECYCLING METHODS

2021 ◽  
pp. 80-89
Author(s):  
Evgeniіa Mykhailova ◽  
Dmytro Deineka ◽  
Hanna Pancheva
Keyword(s):  
Waste Management ◽  
Raw Materials ◽  
Polymeric Materials ◽  
Waste Recycling ◽  
Plastic Waste ◽  
Chemical Recycling ◽  
Mechanical Recycling ◽  
Advantages And Disadvantages ◽  
Secondary Raw Materials ◽  
Plastic Waste Recycling

Methods of plastic waste management, the amount of which is constantly growing due to the high demand for polymer products with high performance properties, are considered. The urgency of the problem is explained by longevity of plastic, which, once in the environment, gradually degrades with the formation of substances dangerous to living organisms. The most common ways of plastic waste management are its storage on specially designated land plots or incineration with / without getting heat. Each of these methods has certain disadvantages, which necessitates the introduction of other measures. Recycling of plastic waste into secondary raw materials, energy or products with certain consumer properties can be the promising method of plastic waste management from ecological and economic points of view. The purpose of this work is to analyze the methods of plastic waste recycling, to establish their advantages and disadvantages, to determine the optimal ways for the disposal of polymeric materials with different properties. Two main groups of polymer recycling methods: physical and chemical, are considered. Physical method includes mechanical recycling, which is based on the physical grinding of plastic waste to obtain secondary raw materials without significant changes in the chemical structure of the material. This process is quite simple in terms of technical design, but requires careful sorting and cleaning of waste, and has limitations on the reuse of recycled material. Chemical recycling takes place through the processes of solvolysis (hydrolysis, glycolysis, alcoholysis) and conversion (pyrolysis, gasification). In this case, the plastic waste decomposes into the original molecules – monomers, from which it is possible to get a polymer product with the same properties. Chemical methods allow disposing of unsorted and contaminated polymeric materials many times without losing their quality. Thus, the introduction of the described methods will reduce the amount of plastic waste, turn them into valuable secondary raw materials and reduce using of natural resources used to obtain primary plastic materials.

Analysis of the Degradation of External Plasters in the Buildings with ETICS

2014 ◽  
Vol 1041 ◽  
pp. 15-18
Author(s):  
Veronika Kučeriková ◽  
Michal Kraus ◽  
Darja Kubečková
Keyword(s):  
Carbon Dioxide ◽  
Composite System ◽  
Raw Materials ◽  
Chemical Properties ◽  
Ambient Air ◽  
Temperature Extremes ◽  
Biological Degradation ◽  
Physical And Chemical ◽  
And Chemical Properties

The external plaster are currently the most common finish coat of buildings. The characteristic technological and chemical properties of plasters protect supporting structure against weather and temperature extremes. Quality of plaster is determined by its durability, which depends primarily on the quality of raw materials, the quality and porosity of the substrate, the temperature during application, concentration of carbon dioxide and humidity of the ambient air. The physical and chemical and biological degradation of plaster is caused due to weathering and exposure to aggressive substances of environment. The paper deals with the analysis of the causes of degradation (green facades) and the possibilities of remediation of biotic attack of plasters buildings with External Thermal Insulation Composite System (ETICS).

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

Industrial Labour Force of Russia in 20-30s of XX Century in Russian Historiography

2020 ◽  
pp. 431-449
Author(s):  
Oleg V. Shekatunov ◽  
Konstantin G. Malykhin
Keyword(s):  
Labour Force ◽  
Historical Period ◽  
Russian Industry ◽  
Wide Range ◽  
Scientific Papers ◽  
Potential Formation ◽  
The Moment ◽  
Force Potential ◽  
Modern Russian

The article is devoted to the specifics of studying the industrial labour force of Russia in the 1920s - 1930s in Russian historiography. The various stages of study from the 1920s through the 1930s and up to the last years are concerned. The relevance of the study is due to several factors. These include contradictions in the assessments of Bolshevik modernization of the 1920s and 1930s; projected labour force shortages in modern Russia; as well as the existing labour force shortage in industry at the moment. This determines the relevance of studying the historical period, which was characterized by the most acute personnel problems in the country. The novelty of the study is due to the fact that in modern Russian historiography there is no holistic, integrated view of the problems of the labour force potential formation of Russian industry in the 1920s and 1930s. It is noted that there is no research aimed at analyzing the historiography of these problems. The main stages of the study of industrial labour force are highlighted. The analysis of scientific works correlated with each stage of the study of the topic is performed. The problems and methodology of each stage are considered. A review of a wide range of scientific papers both articles and thesis is presented.

Gluten-Free Dry Mixtures with Rice and Amaranth for Children over Three Years Old with Gluten Intolerance

Food Industry ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 23-31
Author(s):  
Sergey Urubkov ◽  
Svetlana Khovanskaya ◽  
Ekaterina Pyrieva ◽  
Olga Georgieva ◽  
Stanislav Smirnov
Keyword(s):  
Celiac Disease ◽  
Treatment Effectiveness ◽  
Raw Materials ◽  
Calculated Data ◽  
Limited Range ◽  
Gluten Free ◽  
Fruit And Vegetable ◽  
Organoleptic Evaluation ◽  
Free Products ◽  
Wide Range

Diet therapy is one of the main approaches to the treatment of a wide range of diseases of the digestive system. The treatment effectiveness of celiac disease depends on how strictly the patient adheres to a gluten-free diet. It is often disrupted due to the limited range of recommended foods and dishes, especially for children who are particularly sensitive to dietary restrictions. In this case, the development of new types of specialized gluten-free products is relevant, allowing to expand the diet both in terms of nutritional value and taste diversity. This study concerns the recipe developments of dry gluten-free mixtures using rice and amaranth with the inclusion of fruit and vegetable and berry raw materials intended for the nutrition of children over three years old suffering from celiac disease. When developing the recipes, researchers used various combinations of rice and amaranth flour, as well as fruit and vegetable powders. The rice flour composition varied in the range from 15 to 75%; amaranth – from 15 to 45%; fruit and vegetable and berry powders – up to 10%. The finished product was gluten-free cookies, muffins, pancakes made of rice and amaranth. Organoleptic evaluation showed that the studied samples of gluten-free cookies have high quality characteristics, have a pleasant taste and aroma. According to the calculated data, specialized gluten-free dry mixtures intended for children over three years with celiac disease can serve as an important source of: vegetable carbohydrates – from 26.81 to 55.19 g / 100g of finished products; protein – from 4.06 to 11.82 g/100g of finished products; dietary fiber – from 3.82 to 6.36 g/100g of finished products; and energy – from 158.12 to 333.96 kcal/100g of finished products) The developed recipess of gluten-free products can help to provide children with an adequate amount of nutrients and energy.

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