Lime — primarily quicklime (CaO) and hydrated lime (Ca(OH)₂) — is the dominant commercial form of calcium in global trade, with world production of approximately 420 million tonnes per year in 2024. China is overwhelmingly the largest producer at ~74% of world output (310 Mt), with India a distant second at ~4% (17 Mt) and the United States third at ~4% (16 Mt). The US lime industry is essentially self-sufficient (<1% net import reliance), with 26 companies operating 73 primary lime plants in 28 States and Puerto Rico; the five largest companies account for roughly 80% of US production. US lime production was valued at approximately $3.2 billion in 2024. The major end uses — steelmaking, chemical and industrial processing, flue gas desulfurization, construction, water treatment, and nonferrous metal mining — reflect lime's role as an inexpensive, versatile alkali and flux across the industrial economy.

US quicklime prices rose steadily from $131/t in 2020 to an estimated $190/t in 2024, and hydrated lime from $156/t to $240/t over the same period. Production costs — energy (fuel for kilns), labor, and regulatory compliance — have been the primary drivers of price increases; USGS notes that "some of the lime producers have increased product pricing owing to increased costs of production." The lime industry faces a fundamental decarbonization challenge: calcination of limestone releases ~440 kg of CO₂ per tonne of quicklime as unavoidable process emissions, separate from combustion. Several US companies announced plans in 2024 to accelerate decarbonization efforts. The limestone and dolomite resource base is effectively unlimited globally; USGS describes resources as "very large" and states reserves are "adequate for all countries with listed production."

Lime is not classified as a critical material under any major national or multilateral framework (US Critical Minerals List, EU Critical Raw Materials, EU Strategic Raw Materials). The global supply base is geographically distributed — limestone is among the most common sedimentary rocks — and production capacity is closely matched to regional demand because transport costs limit trade radius. Key substitutes exist for specific applications (limestone in agriculture and fluxing, magnesium hydroxide for pH control, cement and fly ash in construction) but none replicate lime's combination of reactivity, availability, and low cost across the full range of applications.