Environmental Science

Mixed plastics recycling

November 30 2012

There are three types of process that can be used for recycling mixed plastic waste: mechanical, chemical, and energy recovery (Al-Salem, et al., 2009).

Mechanical recycling generally involves cutting, shredding, or milling and some form of cleaning, before forming it into a new product (Al-Salem, et al., 2009). For most purposes, mechanical recycling requires single polymer plastics, but there are processes which can deal with mixed plastic – for example, forming it into construction materials.

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High temperature incineration of hazardous waste

November 3 2012

Abstract

The aim of this report is to explain the processes of high temperature incineration of hazardous waste, as well as its environmental risks and benefits and its advantages and disadvantages. Modern industrial processes generate a certain amount of hazardous waste that must be dealt with somehow. High temperature incineration aims to dispose of this waste as completely and safely as possible. However, even state of the art incinerators produce emissions and residues which are themselves hazardous. Modern incineration operations aim to minimize the environmental impacts of these emissions and residues and must abide by environmental legislation. Research completed in 2011 showed that continuous monitoring of dioxins in incinerator stack emissions is viable. Due to a lack of high temperature incineration facilities in Australia, considerable effort has been put into developing processes to recycle hazardous waste. The availability of incineration is a disincentive to such research and development, however it may reduce the risks of accidental pollution from stockpiles and the incidence of illegal dumping.

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Land degradation and rehabilitation in coastal sand mining

August 14 2011

Introduction

Australian beaches and coastal dune systems have been mined for several reasons. The earliest sand miners extracted gold from the deposits of black sands that were found from the south coast of New South Wales to the beaches of central Queensland. Later mineral sand mining focussed on the heavy minerals, rutile, zircon, ilmenite, and monazite (Morley, 1981).

Rutile and ilmenite contain titanium, which is mainly used in the form of titanium dioxide (TiO₂) as a white pigment in paints, plastics, paper, and other products that require a bright white pigment. Titanium metal is as strong as some steels, but only about half the weight, and is used in heart pacemakers, artificial joints, jewellery, and spacecraft, among other things.

Zircon contains zirconium, which is used in electronics, ceramics, engines, and spacecraft.

Monazite contains cerium, lanthanum, neodymium, and thorium, which are used in rechargeable batteries (Crow, 2011), x-ray screens, fibre optics, high performance magnets, ceramics, television tubes, and as a nuclear fuel (thorium) (Geoscience Australia, n.d.).

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