CEH Report

Table of Contents

Abstract

Lime, or calcium oxide (CaO), is derived through the decarbonation of limestone. The primary product of limestone decarbonation is called quicklime; it can be hydrated to form hydrated lime or calcium hydroxide (Ca[OH]₂). The most frequently occurring types of lime are hydraulic lime and quicklime.

Production of lime increased strongly during 2005–2007, spurred by a worldwide production increase in the major consuming industries. The increase slowed dramatically in 2008, as a result of decreasing consumption in the European and North American markets.

With the dramatic increase in Chinese production, the regional breakdown has changed substantially. China was by far the largest producer in 2008, accounting for over 60% of total production. In the developed regions—Europe, North America (the United States and Canada) and Japan—production of lime is a mature industry characterized by many regional producers, each serving its regional markets. There is relatively little world trade, primarily because lime is readily available in all parts of the world and transportation costs can account for a signif­icant portion of the product value.

Consumption had increased until 2007, as a result of worldwide growth in the major consuming industries—steel, soda ash, pulp and paper, refractories, and the construction industry. Growth in the latter segments came mostly from demand growth in developing regions, in particular China. In the United States and Europe, total consumption had been growing moderately.

The following pie chart shows world consumption of lime:

In 2008 consumption decreased in most world regions, except for China and India, where consumption growth only slowed. In 2009, consumption has declined further, and recovery is expected to be slow.

Lime operations have been subject to environmental regulations since the mid-1960s. These regulations have resulted in the closing of a number of installations and kilns that could not economically comply with the restrictions, especially regarding the particulate emissions released during processing operations. In many cases, the cost of building new, more efficient installations has been prohibitive.

In the United States, the lime industry produces large amounts of by-product lime kiln dust (LKD), primarily from the operation of rotary kilns. At current production levels, the lime industry produces an estimated 3 million metric tons of LKD per year, which must be collected by dust control systems. Potential markets for LKD include agricultural liming, acid neutralization, road and soil stabilization, and use as a supplemental source of calcium for Portland cement manufacturing.

Lime production also generates large volumes of carbon dioxide, which, because of its relatively low concentration, generally cannot be economically recovered. Furthermore, the lime industry is increasingly challenged to minimize air, water and noise pollution. In 2003 the National Lime Association signed an agreement with the U.S. Department of Energy to voluntarily reduce carbon dioxide emissions intensity by 8% between 2002 and 2012. As the lime industry cannot reduce emissions from the calcination of limestone, the agreement focused on achieving energy-related reductions.