Australia has a rich history of lime production dating back to colonial times. Lime and its various forms have played an important role in Australia's infrastructure and continues to do so today.

Early Lime Production
Some of the earliest lime production in Australia occurred in the 1820s, largely to support the growing construction needs of the new colonies. Traditional kilns were used to calcine limestone quarried from local deposits. Key early producers included Richmond in New South Wales and Tower Hill in Victoria. The lime was used mainly for mortar in stone buildings and limewash on wooden structures.

Growth of the Cement Industry
In the late 19th century, Portland cement started to replace lime for most construction applications as its properties allowed for stronger and harder materials. Several large cement plants were established across Australia in the 1890s. While this reduced lime production briefly, lime still found many niche uses such as agricultural lime. The cement industry's growth also drove demand for limestone aggregates.

Modern Lime Industry
Today, Australia Lime manufacturing techniques are vastly more advanced and efficient. The main quicklime production methods used are rotary kilns and fluidized bed kilns. Limestone is crushed, dried and fed into the kilns where it is heated to high temperatures to release carbon dioxide and produce calcium oxide (quicklime). Major quicklime producing states include Queensland, New South Wales, South Australia and Western Australia.

Uses of Lime in Construction
Quicklime has numerous construction applications both as a chemical additive and building material. As a chemical, lime is added to mortar, concrete, plaster and rendering to act as a plasticizer and improve workability. It reacts with water to form calcium hydroxide which hardens the material. Pre-mixed lime/cement products like limecrete are also widely used. Quicklime is converted to hydrated lime by slaking with water, producing a dry powder with self-hardening properties useful for masonry mortar and whitewash.

Agricultural Lime Usage
A large portion of quicklime production, around 70%, is also converted to chalky agricultural lime. Applied as a soil amendment, lime neutralizes acidity and provides calcium and magnesium to crops. The majority of ag lime is spread on grazing pastures and croplands across the wheatbelt and dairy regions. Coastal marine lime is also an important soilconditioner for fruit and sugar cane growing areas. Australia's fertile yet often acidic soils have high ongoing demand for ag lime to support agricultural production.

Pulp and Paper Industry Applications
The pulp and paper industry is another major end market, consuming around 20% of Australian lime output. Causticized lime mud is recovered from the kraft pulping process and re-calcined, while quicklime is added directly for its caustic qualities. Lime assists in cleansing, brightening and increasing strength of paper products. The colocation of lime plants with integrated pulp mills provides efficiencies.

Ensuring Supply with New Projects
To ensure ongoing lime supply for construction and industry, companies periodically expand or develop new production facilities. Recent examples include Cockburn Cement’s additional rotary kiln at Kwinana WA in 2015 and Boral’s Wagga Wagga NSW upgrade in 2018. Lime producer Lime Australia is also currently commissioning a new $200 million plant at Coolaroo in Victoria to supply Melbourne's future infrastructure needs. With proper planning, Australia's lime resources and industry infrastructure can support continued growth.

Environmental Performance & Sustainability
Lime manufacturing is an energy intensive process which produces carbon dioxide emissions. However, as limestone is a naturally abundant mineral, it is considered a sustainable resource. Manufacturers also capture exhaust gases to minimize CO2 entering the atmosphere. Rotary kilns allow for energy efficiency through heat recovery. The end use of lime in construction sequesters carbon in durable materials like concrete. Overall, lime makes positive contributions to sustainable development through its myriad applications supporting infrastructure and agriculture.

Future Outlook
With urban expansion and infrastructure renewal continuing across Australian cities and regions, steady demand is forecast for lime and lime-based building materials. Agricultural lime usage is equally resilient given annual soil acidification. Ongoing efficiency gains and investment in production capacity position the Australian lime industry well for ongoing supply into the medium term at least. Properly sourced lime will remain indispensable for durability and productivity across multiple sectors of the national economy.

Overview of Australia's lime industry from early colonial production through to its modern applications and future outlook. The versatility and performance benefits of lime ensure it maintains relevance across construction and agriculture well into the future. Australia's lime resources and manufacturing infrastructure continue generating economic and social value through myriad forms of lime and limestone products.

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