The ceramics industry has traditionally included products used in building, ornamental and culinary designs. However, today’s advanced ceramics are being exploited to create novel components designed to control air pollution, energy production, green buildings, improved energy storage, and environmental engineering.
Ceramic Rubble for Green Building Technology
Dumping waste, as well as inefficient waste management in various areas of manufacturing, has led to a high level of noise pollution, as well as contamination of air, water and soil. This is not only environmentally dangerous but produces a significant economic burden.
On the other hand, appropriate recycling of waste can convert it to a usable and useful resource that saves materials, prevents climate degradation, and promotes sustainable change.
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Ceramic roofing tiles and other ceramic rubble have been reused as an additive or as a substitute in the production of structural concrete. Coarse recycled aggregates can be mixed in to produce pozzolanic cement. Up to 30% can be added without any negative impact on the mechanical strength and other properties.
Ceramic tile itself is a natural alternative to other building materials, and can be manufactured from recycled old ceramic tile. Ceramic products for buildings include wall and floor coverings, sanitaryware, roofing materials, and ceramic objects for purely ornamental or household use.
Ceramics Used in Environmental Engineering
Technical ceramics are also useful in environmental engineering because of their mechanical properties, stress resistance, high surface area, and stability at high temperatures. Thus they are used to produce filters for processes involving hot gases. For instance, the lambda sensor is a sensor used to detect oxygen in exhaust gas, which is therefore useful in regulating the ratio between air and fuel, reducing engine emissions via a three-way catalytic converter.
These ceramics can resist heat at up to 1500 oC, and are resistant to heat shock and corrosion, as well as heat-induced wear. They can save up to 50% of fuel when used in heat exchangers, making them ideal for use in water purifier or waste treatment plants.
Ceramics in Clean Energy Production
Again, ceramics play a unique part in technologies related to energy production such as chemical and nuclear energy, and light harvesting.
Ceramic electrolytes and insulators may be key in helping build nuclear fuel plants.
Ceramic thermal barrier coatings in gas turbines, or in diesel engines, enhance the operational efficiency enormously, reduce service requirements, increase the operating lifetime, and improve the fuel efficiency. Zirconia composites are commonly used in this area with their chemical inertness, low sintering, thermal expansion matching that of substrates, poor heat conductivity, and phase stability. However, their low operating temperature range is a disadvantage at present.
Piezoelectric ceramic actuators in fuel injection diesel engines are used to reduce pollution and noise. Insulating ceramics can improve the heat efficiency to 65% when used in the combustion and exhaust components.
Heat exchangers in solar plants can now make use of newer cost-effective materials such as zirconium carbide-tungsten composite. This possesses superior heat transfer properties relative to their conventional stainless steel or nickel alloy-based counterparts, because of the built-in channels between the two components of the composite.
The solid oxide fuel cell (SOFC) which run on oxygen and hydrogen or hydrocarbon fuel is a promising source of clean energy. They are very efficient while producing little carbon dioxide or other greenhouse gases. These rely on the ionic conductivity of oxygen radicals or protons to produce electricity via charge transport across a solid electrolyte or membrane composed of oxide. Here advanced ceramics with high ionic conductivity, like yttria-stabilized zirconia, are used as the electrolyte component to produce electricity. These ceramics have high density and electrical resistance, and high ionic conductivity, while being stable at up to 500 oC.
Piezoelectric ceramics are essential components of energy harvesting systems. In remote locations, for instance, they can produce and store power, to run devices that harvest electricity from environmental vibrations, or other mechanical forces like movement, tension or compression.
In many applications, the efficiency and cost-effectiveness have zoomed up when one or a few critical components were replaced with ceramics, such as low-maintenance silicon nitride roller bearings in wind turbines, tidal power plants and chemical power plants.
Porous Ceramics in Clean Technology
Ceramics with high porosity are also essential to multiple applications in fields from transportation to defense. The porosity can be tailored to suit each application.
A special type of ceramic material is acicular mullite (ACM) which is composed of intertwined needles with a unique microstructure capable of providing physical and performance characteristics that go far beyond what ordinary ceramics can offer. These include extreme strength, high melting temperature, excellent stability to chemicals, high porosity and permeability, in addition to tunable pores.
Ceramic foams are porous ceramics suited to contact processes involving solids and fluids, because they enable good mixing of fluids, high rates of mass transfer and low drops in pressure at the same time. On the other hand, better filters are being designed to filter out nanoparticle pollutants as in diesel exhausts, which are being found in various types of environment.
Porous ceramics are also used to support catalytic action, adsorb particles, provide heat shields and insulation, in various processes involving the generation and storage of energy.
The great advantage of their use in this way is the ability to produce customized parts over a large spectrum of applications within a broad array of environments.
Conclusion
Both in their multiplicity of uses in producing environmentally clean devices and their capability of being recycled into useful in-demand products, ceramics play an important role in clean technology.
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