Papers by Keyword: Waste

Abstract: Enhancement of the room temperature vulcanization silicone rubber (RTV) tracking resistance with various filler loadings of synthesized wollastonite against electrical surface tracking was prepared. The X-ray diffraction (XRD), Scanning electron microscope (SEM), and X-ray fluorescent (XRF) techniques were involved in characterizing the synthesized substances. The test method IEC-60587 standard was employed to evaluate the surface tracking resistance. The results obtained from the XRF technique confirmed that the raw materials could be synthesized for wollastonite, while the XRD and SEM techniques revealed the formation of wollastonite (CaSiO₃) associated with gehlenite (Ca₂Al₂SiO₇). Moreover, it was found that the electrical surface tracking resistance of composite insulation takes a long time to track when the filler loading is increased more than 5 phr.

Abstract: In this paper we present the current situation related to the legislative framework on the definition of generated waste by ships in the field of maritime navigation and inland waterway navigation, their management on board ships, handover to port facilities and results in the development of proposals to support participants in the shipping activity in the field of pollution prevention of the Romanian Danube sector. The purpose of the paper is to contribute to the improvement of the current measures that are applied in the field of prevention of pollution of the Romanian Danube sector by ships.

Abstract: The article presents a study of the physical and technical properties of ash and slag waste Coal Power Plant. The main problem when using ash-slag mixtures is the variability of the particle size distribution of the material. Determining the characteristics of slag stored in the dumps of thermal power plants will help to choose the separation methods of this material, to address the disposal and accumulation of industrial waste, to expand the scope of their application. The obtained research results of physical and technical properties of waste of the Coal TPP testify to wide potential in the further use in many branches of the industry. Possible applications include fillers for concrete, materials for sandblasting (abrasive material), raw materials for the metallurgical industry, additives for the manufacture of binders, etc.

Abstract: The article presents a study of the possibility of controlling the emission activity of heavy metals from building materials and structures. It has been established that the most active emission processes from building materials obtained using industrial wastes placed in aqueous media occur in the first five days in a neutral medium, and in the first ten days in an acidic medium. After that, the concentration of heavy metals in the aquatic environment begins to decrease. The results obtained on particular examples made it possible to establish dependencies that determine the intensity of emission processes under various conditions of contact between building materials and an aqueous medium. These dependencies are of a general nature and can be used to predict and control the formation of anthropogenic load. It is shown that the control of emission processes from building structures is possible by forming the structure of the material in the direction of increasing its hydrophobicity, density, and the content of alkaline compounds.

Abstract: Bitter tea oil meal (BTOM) is the main waste from the production of bitter tea oil which is squeezed from bitter tea seeds. The purpose of this study is to reuse the BTOM as an additive of the polylactic acid (PLA) to prepare eco-friendly composites. The effects of the addition of BTOM and maleic anhydride grafted polybutylene succinate (MAPBS) on the properties of PLA were investigated. The addition of MAPBS is mainly to increase the toughness of the PLA, and to increase the compatibility between BTOM and PLA. The experimental results show that the compatibility of PLA and BTOM and impact resistance of the composites can be improved by addition of MAPBS. The composite with 5% BTOM and 8% MAPBS exhibited the best tensile strength. In addition, the composite with 5% BTOM and 5% MAPBS has the best impact strength. It was found that the addition of BTOM and MAPBS can promote the crystallization of PLA. Moreover, the addition of BTOM not only can reduce the usage of PLA and the cost of the materials, but also reuse and reduce the waste from food industry.

Abstract: The research on phenolic compound degradation using chemical oxidation methods in a plasma reactor was performed with an Ozone-Plasma Hybrid Reactor (RHOP). This device operates by combining ozonation reactions in the liquid plasma within the reaction room. Furthermore, Ozone gas as a reagent is produced by the standard ozonator type Resun RSO-9805 made in Hong Kong and fed into this device, where the liquid phase is mixed within the injector. This way, the two-phase mixture reacts more intensively in RHOP. Also, this combination is designed to intensify hydroxyl radicals while the liquid phase is in an alkaline condition constantly exposed to plasma. The results demonstrated a continuous circulation for 2 hours at the initial concentration of 50 ppm for p-chlorophenol with a volume of 2 liters. This further obtained an 83.98% removal rate and 42.19% COD value decrease.

Abstract: The management of post-consumer plastic waste (PCPW) is a real challenging issue due to difficulties in effectively identifying and sorting the collected plastics and in their mechanical recycling. Indeed, mechanically recycled post-consumer plastic waste usually shows poor performances compared to virgin materials, due to incompatibility between constituents, presence of degraded materials, hygroscopicity and bad odors. Compatibilizers and nanoparticles can help to improve recycled plastics quality, but to be chosen and dosed properly they require an in-depth knowledge and characterization of the raw waste. In this study, an analysis of polymeric materials obtained from the separation and mechanical recycling of post-consumer plastic wastes from urban collection as pellets (UPW) is reported. In particular, the experimental characterization was carried out in order to identify UPW composition, water content, physical-chemical properties and processability. It was found that UPW samples are mainly constituted of polyethylene (PE) and polypropylene (PP) in equal parts. UPW was submitted to a melt processing operation, using a lab-scale single-screw extruder, obtaining ribbons that were completely characterized. With the aim to investigate the effect of water content on the recycled material processability and performance, the recycling process was carried out both on undried and dried UPW pellets.

Abstract: This work presents studies on the material composition and physico-mechanical characteristics of an alumina-containing estimate formed during the production of aluminum on electrolyzers with self-baking anodes during technological operations. The material is a mixture of fine powder 2.5 mm in size (62.78% on average mass) with the presence of pieces of material ranging in size from 0.5 to 6 cm (average 20.26% by weight). The samples contain pieces of hardened aluminum with sizes from 5 to 20 mm (16.96%). The largest content in the sample has the fineness classes-0.315 + 0.16 mm in the volume of 29.85% and the largest class +2.5 mm-37.22%. B It was established that aluminum is concentrated in the fractions-0.315 + 0.16 mm (45.7%) and 0.16 + 0 mm (48.8%), silicon in the fraction-0.63 + 0.315 mm (1.91%), iron at-1.25 + 0.63 mm (0.601%) and-0.63 + 0.315 mm (0.62%). The material consists of cryolite (Na₃AlF₆), chiolite (Al₃F₁₄Na₅), quartz, feldspar, carbonaceous matter and the technogenic phase of the composition (NaF) 1.5CaF₂ AlF₃. The material is characterized as non-abrasive (working index Ai - 0.0184) and very soft in relation to impact crushing (working index CWi - 3.64), the working index of ball grinding Bond (BWi - 6.47) characterizes a very low resistance to ball grinding. The implementation of the crushing operation of an alumina-containing estimate will allow the use of dry cascade-gravity and centrifugal classification to separate impurities in the form of SiO_2, and Fe₂O₃ for the use of alumina-containing material in primary aluminum technology. On the basis of laboratory tests, it is established that alumina-containing raw materials can be separated and photometric and gravitational separation methods can be used. A mathematical model of the motion of particles of primary and prepared alumina-containing raw materials in a cascade-gravity classifier was developed. The criteria and factors characterizing the alumina-containing material, as well as influencing and determining the maximum material enrichment, are established.

Abstract: The modern development of the construction industry needs to find ways to create new competitive materials. Such materials are polymer composites, since the range of their application can be wide, due to the possibility of regulating their technical properties. This work presents a research on the development and production of polymer composites and products from them with the improved mechanical properties by adding finely dispersed techno-genic mineral raw materials as a functional filler. As a dispersed filler of the polyvinyl chloride composition, waste from the production of refined silicon was used, which is dust from the entrainment of furnaces captured by an electrostatic precipitator. To predict the characteristics of the materials obtained, the applicability criteria of techno-genic raw materials in the polyvinyl chloride composition are studied. Studies of the mechanical and operational properties of the obtained composites have confirmed the possibility of using techno-genic raw materials as functional fillers that affect the mechanics, durability, and also significantly reduce the cost of finished products.

Abstract: The present study considers various technological approaches to the processes of complex utilization of nickel slags with preliminary additional extraction of non-ferrous metals, iron, and ways of utilization of the obtained gangue. The valuable components are often produced from waste using the mineral acids or mixtures; the metals are extracted from acid solutions in a free form or in the form of compounds using electrochemical or chemical methods. Slag dumps have a heterogeneous structure and mineralization; the zone distribution of slag is clearly defined due to different cooling and solidification rates. The slag composition is mostly represented by dense low-porous varieties consisting of dark brown glass. The porous slag fragments are secondary. The third texture diversity in the composition of slag is represented by nodular and kidney-shaped particles. The diversity and size of the ore minerals is directly connected with the distribution of pores in slag. The major ways for utilization of nickel industrial waste are pyro-metallurgical and hydrometallurgical methods. In addition, each of the methods is usually preceded by the stage of mechanical preparation of the raw materials, where the techno-genic waste is crushed.