Non-metallic Components Research Articles

A New Method for Production of Double-Curvature Dome-Shaped Part: Statistical Analysis of the Effects of Process Parameters on the Radius of Curvature of Obtained Dome Shape

A New Method for Production of Double-Curvature Dome-Shaped Part: Statistical Analysis of the Effects of Process Parameters on the Radius of Curvature of Obtained Dome Shape

INVESTIGATION OF ABILITY LIBERATION OF METALS FROM PRINTED CIRCUIT BOARDS BY MECHANICAL PROCESSES FOR PHYSICAL SEPARATION PROCESSES

Physical separation process was widely applied for the separation of metallic component from Printed Circuit Boards (PCBs) due to their advantages as friendly-environment, facilitated control, and low-cost. However, the efficiency of physical separation depends on a level of the liberation between the metallic and non-metallic components which is conducted by mechanical processing.In this study, the liberation of metals from computer PCBs was conducted in detail by mechanical processes including cutting and crushing. The obtained results demonstrate the distribution metallic and non-metallic component weighs as a function of particle sizes. The separation efficiency of metals was conducted by air separation using vacuum sorter equipment. The results showed that the comminution processes using hammer mill for reach the highest efficiency with 92 % recovery and 87 % grade of metallic components in the heavy fraction with particle size 1.0 - 1.4 mm by air separation process.

Two-step pre-processing enrichment of waste printed circuit boards: Mechanical milling and physical separation

Abstract Printed circuit boards (PCBs), one of the most complex components of e-waste, contain different metallic and non-metallic components. Recycling of waste PCBs is an important issue, from both aspects of hazardous waste management and recovery of valuable materials. In this study, for the first time, a mechanical-physical separation method for recovery of metallic elements of waste PCBs without any chemical or/and thermal processes was introduced. Two milling stages were applied to enhance the liberation degree, followed by a physical flotation process for enrichment. Based on the elemental analysis, the total metal concentration increased by 75% after the second milling in coarser particle size classifications and ceramic components has decreased significantly. Phase identification techniques confirmed that the ceramic portion is mainly CaO+SiO2+Al2O3, which generally exist inside the boards as glass fibres. Using Fourier transform infrared spectroscopy (FTIR) spectra 3 nominees of phenoxy resin, poly vinyl acetate and vinyl chloride were suggested as the major polymer content of the crushed waste PCBs. Scanning electron microscopy (SEM) demonstrated higher degree of liberation in the higher meshes for metallic and non-metallic components but it was lower for fibre glasses. The thermal pyrolysis using infrared gas analyser proved that the most volatile substances are not simple greenhouse gases such as CO, CO2 and CH4. Eventually, beneficiation using bromoform + acetone resulted in two phases of high density (sunk) and low density (float), in which the former one was enriched in metals excluding Al and Sn, and the latter one was almost depleted from metals.

Modification of gas-thermal coatings surface by continuous-generation laser radiation

The results of the researches which determine the dependence of gas-thermal coating porosity on the laser radiation parameters are given in the article. The coatings which are based on the metallic (PN-85-U-15) and non-metallic (Al2O3) components were analyzed. The quantitative assessment of porosity modification were realized by means of the based on Visual Studio 2008 program. This image processing program allows to compare the microstructure of the occupied by pores and coating material areas pixel-by-pixel. It has been established that the action of laser radiation leads to reduction of average porosity of gas-thermal coating. This reduction is: 1. the porosity in the initial position for coating of a PN 85-U-15-based alloy is 17%; after the laser treatment it’s 5-8%; 2.- the porosity in the initial position for ceramic coating of Al2O3is 24,5%; after the laser treatment it’s 15-18%.

Recovery of gold, other metallic and non-metallic components of full-size waste random access memory

In order to increase environmental and economic benefits of waste Random Access Memory (RAM) recycling, this research aims to separate all metallic and non-metallic components of RAM by using chemical treatment and subsequent leaching process to liberate gold from gold-plated components. Chemical treatment was employed to separate metal (copper foils, contacts, through-hole pads) from non-metal by performing organic solvent Dimethylacetamide (DMA) and ultrasonic treatment at a low temperature (50 °C) in order to dissolve Brominated Epoxy Resin (BER) and separate all layers of waste RAMs. The process was carried out in a simple reactor developed specifically for this purpose. After the dissolution process, a rotary decompression evaporator was used to extract epoxy resin from DMA/BER solution and regenerate the solvent. At the same time, leaching by nitric acid was used to liberate gold from parts with high gold concentration, in particular from contacts. SEM-EDS, TGA, DSC, FTIR, and UV-VIS spectroscopy were used to characterize the recovered epoxy resin, metal, and regenerated DMA. Additionally, metallographic microscope was used to examine the DMA/BER solution. The results showed that RAMs were composed of seven layers of plain woven fiberglass, four copper foil layers, conductive tracks, contacts, solder joints of integrated circuits, epoxy resin, and soldermask. Moreover, gold with purity >94% was successfully recovered as a result of applying developed treatment technique with yield ∼12 times higher than traditional milling followed by leaching approach.

Mechanical and thermal characterizations of non-metallic components recycled from waste printed circuit boards

In the framework of reuse of non-metal (woven fiberglass layers (WFG) and epoxy resin (ER)) recovered from waste printed circuit boards (WPCBs) as received and maximization of economic and environmental benefits, this research aims to investigate mechanical and thermal properties of recycled woven fiberglass and ER extracted from WPCBs after separation by using chemical (organic solvent) and ultrasonic treatment The experiments were conducted on five samples cut from five different types of waste motherboards according to ASTM D5035 standard. Also, another sample not containing any notches or holes was cut from a blank PCB in order to be used as a reference for strength tests when compared with motherboard samples. Di-methyl formamide (DMF) was used to dissolve ER of all six samples at a low temperature in a simple reactor developed specifically for this purpose (WPCB separator). The new separator was equipped with a high-frequency ultrasonic wave generator used to accelerate the rate of breakage of internal van der Waals’ bonds of brominated epoxy resin (BER) by DMF thus reducing the dissolution time and facilitating separation of woven fiberglass layers against metal layers. After that, a rotary decompression evaporator was used to extract ER from DMF/ER solution. Universal testing machine was used to characterize mechanical behavior of recovered woven fiberglass, while thermogravimetric (TG-DTG) and calorimetric analyses (DSC) were used to investigate the thermal behavior of recovered ER. The results showed that the average strength of recovered fiberglass decreased by 48% in comparison with the blank PCB due to the presence of notches and degradation while the reduction in elastic modulus was slight. Also, the recovered ER showed high properties in terms of melting temperature and crystalline degree.

Laser Forming Using a High Beam Quality Compact Fibre Laser

Laser forming is an advanced manufacturing technique that can be used for the direct fabrication of high value and low volume metallic and non-metallic components e.g. ship hull; adjustment of small sections of parts to the desired shape e.g. car doors, propellers; and correction of unwanted distortion by controlled laser induced thermal stress. Important benefits of laser forming include no external mechanical tooling needed, wide-range of materials and scale of samples that can be formed, flexibility and automatic control. In the presented investigation, the object is to investigate the formability of the AISI 314 stainless steel thin sheet by fibre pulse laser with low power and high speed. An iterative control approach has then been used to achieve the desired bend angle.

Improvements in the microstructural and mechanical properties of geopolymer concrete containing NMF’s of E-wastes as partial replacement of aggregates

The information and communication revolution in the twentieth century has brought about massive changes in the living style and also economy. Although the quality of lives has been enhanced by these spectacular developments undoubtedly during the modern times, they have led to manifold problems in disposal of e-wastes. The annual generation of e-wastes globally is about 50 million tons, and according to recent studies, the quantity of e-wastes generated in India is 18.5 lakhs MT/year. Therefore, in order to protect the environment and create a sustainable livelihood, proper management of e-wastes is indispensible. Efforts are underway in the construction industry to use the non-metallic components of e-wastes, especially Printed Circuit Boards, as partial replacement for aggregates in concrete. A large portion of non-metallic materials in printed circuit boards (PCBs) are disposed off by disposal in landfill or combustion but it may lead to secondary pollution and wastage of resources. Geopolymer concretes have proved to greatly immobilise hazardous and radioactive wastes, thereby reducing their concentration and the impact on human and environment. Hence, this study aims to identify the possibilities of utilising the crushed PCBs as partial replacement for fine aggregates in Geopolymer concrete. It was observed that up to 30% replacement of crushed PCBs, the mechanical properties improved after which they were found to decrease. This increase in strength was significant at increased percentages (50–75%) of GGBFS replacement in Geopolymer concrete. It is thereby suggested from this study that utilisation of crushed PCBs in Geopolymer concrete will not only reduce the requirement for conventional fine aggregates but will also help in immobilising the heavy metals thereby affecting the conservation of natural resources.

Ni 5 Sm-P/C ternary alloyed catalyst as highly efficient electrocatalyst for urea electrooxidation

Abstract A ternary Ni 5 Sm-P/C electrocatalyst is successfully prepared for urea electrooxidation. Physical characterization reveals that the addition of samarium (Sm) and phosphorus (P) to nickel (Ni) can change the electronic configurations of the Ni 5 Sm-P/C catalyst, leading to more active form of NiOOH. Electrochemical measurements show that the Ni 5 Sm-P/C catalyst exhibits exceptionally high activity and good stability for the electrooxidation of urea. Notably, the anodic peak current of Ni 5 Sm-P/C catalyst is over 1.5 times, 21 times and 29 times higher than that of Ni-P/C, Ni 5 Sm/C and Ni/C, respectively. The high activity on Ni 5 Sm-P/C owes to the synergistic contribution among Ni, Sm and P. All results demonstrate that adding metal and non-metallic components into Ni/C catalyst will provide a valuable resource of research and practical application for improving the performance of direct urea fuel cells.

Recovery of rare and precious metals from urban mines—A review

Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals (RPMs) from urban mines has attracted increasing attention from both academic and industrial sectors, because of the broad application and high price of RPMs, and their low content in natural ores. This study summarizes the distribution characteristics of various RPMs in urban mines, and the advantages and shortcomings of various technologies for RPM recovery from urban mines, including both conventional (pyrometallurgical, hydrometallurgical, and biometallurgical processing), and emerging (electrochemical, supercritical fluid, mechanochemical, and ionic liquids processing) technologies. Mechanical/physical technologies are commonly employed to separate RPMs from nonmetallic components in a pre-treatment process. A pyrometallurgical process is often used for RPM recovery, although the expensive equipment required has limited its use in small and medium-sized enterprises. Hydrometallurgical processing is effective and easy to operate, with high selectivity of target metals and high recovery efficiency of RPMs, compared to pyrometallurgy. Biometallurgy, though, has shown the most promise for leaching RPMs from urban mines, because of its low cost and environmental friendliness. Newly developed technologies—electrochemical, supercritical fluid, ionic liquid, and mechanochemical—have offered new choices and achieved some success in laboratory experiments, especially as efficient and environmentally friendly methods of recycling RPMs. With continuing advances in science and technology, more technologies will no doubt be developed in this field, and be able to contribute to the sustainability of RPM mining.

E-waste flows, resource recovery and improvement of legal framework in Pakistan

Electronic waste (E-waste) is becoming most rapidly expanding solid waste stream of the world. Pakistan receives thousands of tons of E-waste from developed countries like the USA and Europe. At present, quantification of E-waste imported to Pakistan and materials recovered from such waste is not well defined. Therefore, the objectives of this research include estimation of E-waste flow and assessment of potential quantities of recyclable metallic and non-metallic components. As a result, it was found that, on average, 95,415 tons of E-waste is imported into Pakistan annually. It contains a variety of metals such as gold, silver, copper and non-metals like plastics and glass as well as hazardous materials. It was also found out that all the recycling activity takes place in informal sectors without any consideration to environmental pollution and safety of workers. Improvements in the existing legal framework regarding import and recycling of E-waste have been proposed. These proposals include take back, prohibition of illegal import and good environmental management.

Reverse Analysis of Scan Strategies for Controlled 3D Laser Forming of Sheet Metal

Laser forming is an advanced manufacturing technique for the shaping and adjustment of metallic and non-metallic components by controlled laser induced thermal stress. Important advantages of laser forming include the absence of external mechanical tooling, flexibility and potential for automatic control. A large number of relevant two-dimensional laser forming studies have been completed to date. However, for the production of complex 3D shapes, such as ship hull components, airplane fuselages and automotive bodies, two-dimensional laser forming is limited. Therefore, in order to advance process for realistic applications, the investigation of the 3D scanning strategies becomes essential. This includes both in plane shortening and out-of-plane bending. In order to determining the scanning patterns and process parameters for forming any arbitrary 3D shape, numerical simulation is a strong tool to analyse the required stress and strain distribution and related processing parameters. In the presented investigation, the object is to develop optimal irradiation patterns and parameters to form a S275 steel square thin plate to a given generic ship hull shape through finite element simulation and experiment verification. A novel approach was used for the development of scan strategies for controlled 3D laser forming of sheet metal components based on a reverse analysis. A patched modular virtual press tool was employed in a commercial FE package COMSOL Multiphysics to extract the required strain-displacement map to achieve a given shape from a starting condition. The laser processing conditions have then been extracted from the magnitude of strain and displacement of each patch. A closed loop control iterative approach has then been used to ensure part accuracy during experimental verification.

The use of term «sintered powder frictional material»

Powder frictional materials are widely used in frictional couplings and brakes of tractors, automobiles and agricultural machinery. Today various terms are applied for these materials, such as: "ceramic-metal frictional material", "powder frictional material", "sintered frictional material". The term "ceramic-metal frictional material" is the most frequently used in scientific literature. Long-term experience of development and use of frictional materials indicates that the listed terms are not exact. There is the following definition of metal ceramics. It is the artificial material having heterogeneous composition of metals and alloys with nonmetals (ceramics). In modern sintered powder frictional materials the quantity of nonmetallic components could range from 10 to 30% of volume, including graphite, oxides, nitrides, sulfides and other components. For example, the volume of the most widespread composition of MK-5 sintered powder frictional material based on copper contains 23% of graphite that does not interact with the bronze base. According to earlier formulated definition of "ceramic-metal frictional material", the graphite should be qualified as ceramics, which is absolutely incorrect. When studying a microstructure of MK-5 sintered powder frictional material based on copper, it is established that graphite is uniformly distributed across the section surface. It does not interact with the components of frictional material and has the form of isolated particles. Therefore, it is incorrect to define this material as metal ceramics. For these materials it is suggested to use the term "sintered powder frictional materials" that indicates their application and production technology.

A quantitative evaluation model to measure the disassembly difficulty; application of the semi-destructive methods in aviation End-of-Life

Sustainable decommissioning of aircraft with a high content of metallic and non-metallic components is a current challenge in the industry. This process has historically appeared to be economically, environmentally and socially unviable. Literature indicates that, unlike entirely destructive and totally non-destructive techniques, semi-destructive disassembly may bring significant benefits. However, despite their use in a wide variety of applications, there are currently no feasible solutions on how to measure the associated physical difficulties and required efforts without any dependencies on expert views or filling out spreadsheet-like forms. In this paper, a new model is developed to accurately evaluate the disassembly easiness of an airframe quantitatively incorporating both product and process features. Based on a real disassembly of a passenger jet, the cutting and thrust force vectors are selected to evaluate and find the best operation sets. An airliner Horizontal Stabiliser is analysed as a case study. The results indicate that minor drilling, as a hybrid operation, can reduce the disassembly efforts significantly while offering an increased material recovery chance. Such quantitative evaluation can help to: proceed with a viable End-of-Life strategy; and implement newer approaches like automated disassembly by designing better disassembly robots, tool selection and process control.

Development of Scan Strategies for Controlled 3D Laser Forming of Sheet Metal Components

Laser forming offers the industrial promise of controlled iterative shaping of metallic and non-metallic components. In order to fulfil this promise in a manufacturing environment the process must have a high degree of control, be repeatable and have a minimal impact on the material and mechanical properties of the part to be formed. A new approach for the development of scan strategies for controlled 3D laser forming of sheet metal components is presented in this paper based on a reverse analysis. A patched modular virtual press tool is employed in a commercial FE package to extract the required distribution of in-plane strain, bending strain and principal minimal strain to achieve a given shape from a starting condition. The laser processing conditions have then been extracted from the magnitude of strain and displacement of each patch, closed loop control iterative approach has then been used to ensure part accuracy.

Engineering design and experimental research of non-metallic parts and components of the hot section of the advanced gas turbine engine

Technological and experimental research in support of creation of a high-temperature turbine nozzle unit made of diamond dust dispersion-hardened silicon carbide and the flame tube of a high-temperature combustion chamber made of carbon-fiber-reinforced-ray of ceramic composite material based on a ceramic polymer has been conducted. The studies demonstrated: • technological capability of creating a composite structure of the nozzle made of super-hard diamond dust dispersion-hardened silicon carbide compatible with the mating metal turbine units; • the results of testing the non-cooled flame tube made of carbon-fiber reinforced ceramic composite material based on a ceramic polymer. The results will be used in the design, manufacture and tests of non-metallic components of combustion chambers and turbines of auxiliary power units, small-sized gas turbine engines and helicopter engines.

PHYSICAL MODELING OF ROLL PRESSING AT ASYMMETRIC EFFECT ON THE SEALING MATERIAL

The study relates to the preparation of metallic and non-metallic components of blended materials and industrial wastes, for pyrometallurgical processes. The design improvement for roll briquetting press was proposed for compaction of granular materials used as raw materials for pyrometallurgical processes. One of the rolls was invited to perform with cells, and the second – with a smooth surface that can dramatically reduce the cost of manufacturing the tool. The authors have implemented physical modeling of the process using the installation of the original design when changing the confi guration of the cells in two versions: radial and triangular in shape. Physical modeling has shown that in the proposed scheme of the implementation process it is advisable to use cell of radial profi le, which leads to the achievement of large volumetric deformations of compressible material.

Experiences when employing different alternatives for envelope upgrading

The challenges of achieving the 2020 goals in terms of energy savings and improving efficiency are guiding numerous research initiatives looking for more insulated envelopes, dealing with thermal performance of insulation materials and envelope systems. Nevertheless, the envelope integrates within the building and this improvement on the insulation performance has to be properly adopted, taking into account the interrelation of main elements composing the overall system (facade, frame, slabs, openings, partitions etc.), as well as side effects originated not only for new erected buildings, but specifically in renovation and retrofitting works. This paper describes real experiences when considering various options for upgrading the facade through the increase of the insulation capacity, starting from external overcladding prefabricated panels and ventilated facades, advancing to more sustainable low carbon systems and ending with even more highly insulated solutions employing aerogels. Lessons from these cases, where energy and hygrothermal assessments have being carried out, demonstrate the influence of the design and construction phases and the relevance of disregarded effects such as minor thermal bridges, uncontrolled craftsmanship on site, and moisture transfer for the different technologies considered. Finally, possible alternatives are provided to overcome some of the detected difficulties, such as combination with non-metallic structural components and building membranes, and being prepared for future challenges and new developments when these isolative elements are combined with other technologies, as for example, renewable energy harvesting devices.

Electrodeposition and Thermal Treatment of Ni+W+Si and Ni+W+Mo+Si Composite Coatings

The Ni+W+Si and Ni+W+Mo+Si composite coatings were obtained by electrodeposition of crystalline nickel from an electrolyte containing suspension of suitable metallic and non-metallic components (W, Mo and Si). These coatings were obtained under galvanostatic conditions, at the current density of jdep = -0.100 A cm-2 and at the temperature of 338 K. For comparison the Ni coating were also obtained and investigated in the same manner. Obtained coatings were modified in the air atmosphere by thermal treatment at the temperature of 973 K for 1 h. Thus obtained coatings may be useful in application as electrode material for the oxygen evolution reaction.

Production and Electrochemical Characterization of Nickel Based Composite Coatings Containing Chromium Group Metal and Silicon Powders

The Ni+Cr+Si, Ni+Mo+Si and Ni+W+Si composite coatings were obtained by electrodeposition of crystalline nickel from an electrolyte containing suspension of suitable metallic and non-metallic components (Cr, Mo, W and Si). These coatings were obtained galvanostatically at the current density of jdep = -0.100 A cm-2 and at the temperature of 338 K. Chemical composition of the coatings was determined by energy dispersive spectroscopy (EDS). The electrochemical activity of these electrocatalysts was studied in the process of hydrogen evolution reaction (HER) in 5 M KOH solution using steady-state polarization and electrochemical impedance spectroscopy (EIS) methods. The kinetic parameters of the HER on particular electrode materials were determined. It was found that Ni+Mo+Si composite coatings are characterized by enhanced electrochemical activity towards the HER as compared with Ni+W+Si and Ni+Cr+Si coatings due to the presence of Mo and increase in electrochemically active surface area.