Non-metallic Waste Research Articles

Sustainable composite panels from non-metallic waste printed circuit boards and automotive plastics

In this study, non-metallic waste from printed circuit boards (PCBs) and waste automotive plastics (WAP) were used to produce sustainable composite panels, with a wide range of potential uses comparable to products such as MDF (medium density fibreboard). The composite panels, made from differing proportions of non-metallic PCB waste and WAP, were fabricated by using a hot press. The physical properties of the fabricated panels were studied by density measurements. The panels were characterised mechanically through flexural, tensile and compression tests and fractured surfaces were observed using scanning electron microscopy (SEM) for interface interaction studies. The density of the produced panels increased linearly, as the proportion of non-metallic PCB waste increased, in a range of 0.956 g/cc for 100/0 (WAP/non-metallic PCB) to 1.227 g/cc for 60/40 (WAP/non-metallic PCB) panels. SEM images clearly show that the non-metallic glass fibres of the PCB waste were encapsulated by the plastics of the automotive waste. The homogeneous distribution and increase in interfacial adhesion between non-metallic glass fibres of the PCBs and WAP were observed. The results demonstrate that the addition of non-metallic PCB waste greatly improves the flexural, tensile and compression properties of composite panels, compared to 100% WAP panels. The flexural and tensile modulus of the 80/20 (WAP/non-metallic PCB) panel was, up by ∼50% and ∼280%, compared to 100% WAP. This sustainable and eco-friendly recycling approach provides an opportunity to utilise two problematic waste streams; complex non-metallic PCB waste and automotive plastics.

Exploited application of sulfate-reducing bacteria for concomitant treatment of metallic and non-metallic wastes: a mini review.

A variety of multidimensional anthropogenic activities, especially of industrial level, are contaminating our aquatic and terrestrial environments with a variety of metallic and non-metallic pollutants. The metallic and non-metallic pollutants addressed specifically in this review are heavy metals and various compound forms of sulfates, respectively. Direct and indirect deleterious effects of the both types of pollutants to all forms of life are well-known. The treatment of such pollutants is therefore much necessary before their final discharge into the environment. This review summarizes the productive utility of sulfate-reducing bacteria (SRB) for economical and concomitant treatment of the above mentioned wastes. Utilization of agro-industrial wastes and some environmental contaminants including hydrocarbons, as economical growth substrates for SRB, is also suggested and proved efficient in this review. Mechanistically, SRB will utilize sulfates as their terminal electron acceptors during respiration while utilizing agro-industrial and/or hydrocarbon wastes as electron donors/carbon sources and generate H2S. The biogenic H2S will then react vigorously with dissolved metals present in the wastewaters thus forming metal sulfide. The metal sulfide being water insoluble and heavier than water will settle down in the water as precipitates. In this way, three types of pollutants i.e., metals, sulfates and agro-industrial and/or hydrocarbon wastes will be treated simultaneously.

Effect of disposal of aluminum recycling waste in soil and water bodies

This study evaluated environmental contamination by disposal of waste from tertiary aluminum industry in soil and water bodies. The main wastes of this industry are dross, non-metallic waste (product of dross leached with water) and liquid effluent. The water at the bottom of the pond, where the alkaline and saline aluminum effluent is discharged, presented high values of pH (>9) and high concentration of ammonia (N-NH3). However, dross disposal in soil decreased pH (<4) of groundwater and increased concentrations of Al3+, Na+, K+, Ba2+, Ni2+, Pb2+, Cu2+ and Zn2+. The N-NH3 produced from the reaction with water and some components of dross (aluminum nitride) probably promoted the increase of the nitrifying microbial activity in soil, which was responsible for the decrease in pH. In this condition, many components of dross were also easily leached into groundwater. The disposal of non-metallic waste into soil did not change the groundwater pH, but increased concentrations of Mn2+, Ba2+, Pb2+, Fe3+ and Ni2+. The disposal of aluminum recycling wastes without any treatment can change the quality of groundwater and surface waters, mainly due to high level of N-NH3, which modifies the pH of these waters and is very toxic to aquatic organisms.

Biotesting as a Method of Evaluating Waste Hazard in Metallic Mineral Mining

As the result of identifying content of each chemical element it has been revealed that metallic mineral wastes have a considerable amount of valuable useful metals. Thus, large-tonnage inorganic wastes are considered to be an additional raw source of metal production. This paper highlights the necessity of supplementary biotesting metallic mineral wastes in order to bring into correlation with corresponding hazard classes and facilitate efficient recycling of these wastes in future. It has been found out that determined in this way waste class can be dumped or used after recycling. It has been also indicated that mill tailings are to be stored according to contained metals without messing up dissimilar metal-containing wastes. After winning metals these wastes are similar to the group of inorganic non-metallic wastes and can be used in building material production, for filling mined-out spaces, in road construction etc.

Encapsulation of nonmetallic fractions recovered from printed circuit boards waste with thermoplastic

The present work includes a process for encapsulation by combining substantially simultaneously dry nonmetallic printed circuit boards (PCBs) powder and recycled high-density polyethylene (rHDPE) in an extruder to form a homogenous matrix. The extruded materials were then molded into standard tensile, flexural, and impact properties testing specimens. Nonmetallic PCB mainly consists of large amount of glass fiber–reinforced epoxy resin materials. Incorporation of 50 wt% nonmetallic PCB in rHDPE matrix had increased the flexural strength and modulus by 35% and 130%, respectively. Tensile strength reported to be constant without much improvement. However, the Young’s modulus has increased by 180%, with incorporation of 50 wt% nonmetallic PCB. The addition of 6 phr (parts per hundred) maleated polyethylene (MAPE) resulted in 2-fold increase in tensile and flexural strength. Regarding the leaching properties, Cu was identified as the metal that leached at the highest level from the raw nonmetallic PCB, at 59.09 mg/L. However, after the nonmetallic PCB was filled in rHDPE/PCB composites, the concentration of Cu was reduced far below the regulatory limit, to only 3 mg/L. Thermal properties of composites were studied, and it was found out that incorporation of nonmetallic PCB fillers in rHDPE resulted in low thermal conductivity, whereas mechanical strength of the composites showed maximum improvements at 220 °C. Overall, the encapsulation technique using nonmetallic PCB waste has formed a monolithic waste form that provides a barrier to the dispersion of wastes into the environment.ImplicationsNonmetallic materials reclaimed from waste PCBs were used to analyze the chemical composition, and it was found that nonmetalllic PCBs mainly consist of glass fiber–reinforced epoxy resin materials. With such millions of glass fibers in nonmetallic PCBs, there are mass-excellent supporting bodies that enhance the mechanical properties of composites. In fact, utilization of nonmetallic PCB waste as filler in composites can dramatically restrain the solubility of heavy metals in leachate solution, thus making it safe to be used in practical products.

Recycling of Bag-House Dust from Foundry Sand

Non-metallic foundry waste is generally composed of spent green sand, core sand, and dust collected in the ventilation baghouse systems of the foundry facility. Currently, practices exist for the recovery of sand particles from green sand and core sand at the expense of the other constituents via combustion or degradation. However, new methods are necessary to extract values other than sand from the bag-house dust material. This is important, because the dust of composed of as much as 50 weight percent non-sand recoverable materials, such as coal and clay. This research evaluates the potential to beneficiate bag-house dust material by way of froth flotation. The coal constituent of the dust was extracted at grades near 60 weight percent and recoveries near 70 weight percent. The clay constituent was extracted at grades near 30 weight percent and recoveries near 40 weight percent.

Carbon-14 analysis in solidified product of non-metallic solid waste by a combination of alkaline fusion and gaseous CO2 trapping

In order to establish a simple and rapid analytical method for (14)C in solidified products made from non-metallic low-level radioactive solid wastes such as concrete, mortar and glass by melting treatment, a radiochemical analysis in combination with alkaline fusion as a sample decomposition method was examined. A simulated solidified product containing (14)C, which was prepared by using nuclear reaction (14)N(n, p)(14)C with thermal neutron irradiation, was analyzed by the present method to compare with a conventional radiochemical analysis using oxidizing combustion. The reproducible and quantitative recovery of (14)C from the simulated solidified product indicates that the present method is more efficient for (14)C analysis in solidified products than the conventional method using oxidizing combustion.

A Study on the Problems of the Usage of Incinerators in Malaysia

Incineration is one of the options available to dispose municipal solid wastes (MSW) as it is capable of breaking down hazardous non-metallic wastes besides destroying bacteria and viruses. In terms of volume of wastes, incineration can reduce almost instantaneously by 90 %. In 1998, the government of Malaysia embarked on a pilot project to use incinerators to dispose MSW in four popular resort islands to see the effectiveness of this technique of waste disposal. Seven units of mini incinerators were installed on the islands and the local municipals were made responsible to manage and maintain.This project looked into the problems arises when incineration is used for MSW disposal on these islands. Data collected revealed that the plants were not properly managed and maintained. This was due to the lack of funds available for effective and smooth operation and the absence of highly expert personnel required to maintain the plant. Other factors that contribute to the inefficiency are inadequate air pollution control facilities and the infrastructure which do not condon the foul odour. Further research work need to be done to monitor the operation of these incinerators in order to explore its potential to dispose waste safely, effectively and cleanly.

Rapid Dissolution Techniques with Microwave Heating Devices for Solidified Products Made from Non-Metallic Wastes by Plasma Melting

A relatively large quantity of sample solutions have to be prepared for the radiochemical analysis of solidified products yielded by a plasma melting treatment of non-metallic radioactive wastes. In order to dissolve a sample of solidified products rapidly, a dissolution method with microwave heating devices was applied. In a conventional method involving only external heating with various mixtures of acids (HNO3, HF, HClO4 and H2SO4), a 0.1 g amount of the sample was dissolved with difficulty. However, upon applying the microwave-assisted dissolution method, a 1 g amount of the sample was completely dissolved in a shorter time. Thereby the time for dissolution procedures was shortened to less than one-tenth. The present dissolution method was successfully applied to blast furnace slag as a reference material to determine the main elements with good precision.

Effects of basicity and FeO concentration on the retention of 137Cs and 60Co in slag made from non-metallic radioactive wastes

Summary Simulated non-metallic wastes containing 60Co, 137Cs and 152Eu were melted to examine the effects of basicity and FeO concentration on the retention of the radioactive nuclides in a resulting solidified product (Al2O3-CaO-FeO-SiO2 quaternary slag). The retention of 60Co was almost independent of chemical composition of slag. On the other hand, the retention of 137Cs decreased with an increase of the basicity of slag, defined as a ratio of CaO to SiO2 in wt. independent of FeO concentration. Energy dispersive X-ray fluorescence spectroscopic analysis and Mössbauer spectroscopic measurement were also conducted for the solidified product. Mössbauer spectra indicated that Fe2+ ions as well as Ca2+ ions existed as network modifying cations in a silicate network structure of slag. Referring to a structure model of silicate glasses, it is inferred that the retention of 137Cs reflects differences in chemical properties between Ca2+ and Fe2+ in the internetwork region formed by modifying cations and anionic non-bridging oxygen.

Characterization of Solidified Products Yielded by Plasma Melting Treatment of Simulated Non-Metallic Radioactive Wastes

As a part of an advanced volume reduction program for low level radioactive wastes in JAERI, melting tests of non-metallic solid wastes have been conducted with the aim of establishing the optimum melting condition for preparation of a stable solid that is suitable for disposal. Simulated non-metallic wastes containing 60Co, 137Cs and 152Eu tracers were melted with a plasma torch of a non-transferred type, and the examination was carried out on chemical composition and physical properties of solidified products and the distribution of tracers in each product. The products were almost homogeneous and possessed satisfactory mechanical strength for disposal. The radioactive nuclides were almost uniformly distributed in the products. The amount of 137Cs remaining in the products depended on the basicity of slag, while that of 60Co was not. A small amount of fine metal particles containing 60Co was observed in a slag. This was attributable to partial reduction of metal oxides under the relatively reductive atmosphere.

Characterization of Solidified Products Yielded by Plasma Melting Treatment of Simulated Non-Metallic Radioactive Wastes.

Characterization of Solidified Products Yielded by Plasma Melting Treatment of Simulated Non-Metallic Radioactive Wastes.

Hydrocarbon generation during the inert gas pyrolysis of automobile shredder waste

When junked automobiles are shredded to recover the ferrous and non-ferrous metals, a large quantity of non-metallic waste is generated. These waste materials consist mainly of rubber and plastics. In this paper, the product yields and compositions obtained during inert gas pyrolysis of a representative shredder non-metallic waste fraction in three different experimental systems (batch thermogravimetric analyzer, bench scale batch pyrolyzer, and continuous rotary kiln) are compared. Analysis of the products by GC, HPLC, GC-MS, IR spectroscopy, H + NMR and GPC show the presence of many hydrocarbon compounds with no single species present in large concentrations. Weight loss kinetics during the pyrolysis are also presented and discussed. The products obtained without additional processing are complex and contain compunds that prevent their direct use as a fuel in many applications. As a result, commercial exploitation of this process must await evaluation of the products obtained and, if necessary, the costs of purification and modification of the products to more useful compositions.

Toxicology and nationally important industries

It was at the request of many of the participants at the first Toxic Substances in the Environ~nent symposium in 1981 that we decided to organize a sequel. The emphasis of the first symposium was on the major research approaches in toxicology in Canada. It included an overview lecture on environmental toxicology by G. &. Plaa, a discussion of the effects of chemicals on heme biosynthesis by G. %. Marks, and a presentation on the aerial spraying and toxicity of fenitrothion and aminocarb by B. J . Ecobichon, as well as several other excellent papers. These presentations were published as symposium proceedings in this Jouri~al in 1982. The theme of this second symposium was toxicological implications of nationally important industries. Accordingly, the topics of the four sessions were chemical and radioactive waste handling, acid rain and its effects on the environment, neurotoxicology of metals, and toxic substances in agriculture. These are all areas of active toxicology research, but more importantly, they all have implications for the health of Canadians and the economic and social fabric of contemporary Canadian life. The first session focussed on methods and strategies regarding toxic waste handling. A discussion of the strategies of high level nuclear waste disposal was included because many of the problems encountered here are also relevant to the disposal of highly toxic chemical wastes; yet most often these two problems are thought of in isolation from one another. A lecture on the kinetics sf the translocation of halogenated hydrocarbons into streams from land disposal sites served to put into perspective the long-term requirements of disposal solutions. It also seemed appropriate to include a presentation on the plasma-arc furnace, which is one cpf the newest developments in methods of disposal of industrial organic wastes, including halogenated hydrocarbons and other nonmetallic wastes. The next two sessions covered two related topics, namely, acid precipitation and metal ion toxicity. Clearly, solutions of low pH enhance the dissolution rate of metallic oxides and salts resultlng in increased mobility of metal ions from solid substrates to biological receptors. The relationship between acid precipitation and living organisms can be manifested through a series of steps which include changes in soil chemistry and water cheinistmy and interactions of metal ions with biological macromolecules. New techniques for neurotoxicity testing of xenobiotics and innovative research methods in iaeurotoxicology were described along with research advances in the elucidation of the mechanisms of the neurotoxicity of aluminum, cadmium, and lead. The final session emphasized the regulation and use of chemicals in the agricultural sector and the spreading of municipal wastes on agricultural land. In addition, a poster session provided the opportunity for participants to describe their research efforts. This was intended to help in attaining another goal of this sympcxsium; to increase communication amongst academia, govenmment, and industry. This goal was also a criterion in the selection of the speakers who were invited; eight came from universities, four were federal government employees, and two were from the industrial sector. The following 14 papers represent the full complennent of presentations given at the symposium.

Integrated Water and Waste Management System for Future Spacecraft

Over 200 days of continuous testing have been completed on an integrated waste management-water recovery system developed by General Electric under a jointly funded AEC/NASA/AF Contract. The 4 man system provides urine, feces, and trash collection; water reclamation; storage, heating and dispensing of the water; storage and disposal of the feces and urine residue and all of other nonmetallic waste material by incineration. The heat required for the 1200 deg F purification processes is provided by a single 420-w radioisotope heater. A second 836-w radioisotope heater supplemented by 720 w of electrical heat provides for distillation and water heating. Significant test results are no pre-or-post treatment, greater than 98 percent potable water recovery, approximately 95 percent reduction in solids weight and volume, all outflows are sterile with the water having no bacteria or virus, and the radioisotope capsule radiation level is only 7.9 mrem/hr unshielded at 1 m (neutrons and gamma).