Limestone Flux and Calcareous Stone for Lime or Cement Manufacture

Crushed and broken limestone destined for lime kilns, cement plants, or soil-improvement applications enters the US under tariff line 2521000000, distinguished from dimension stone or aggregate by its intended end use in calcination or chemical processing. The heading also covers other calcareous stones — such as chalk and dolomitic limestone — when used for the same manufacturing purposes. Canada is the dominant supplier, with the Dominican Republic and Jamaica serving as significant Caribbean sources. Because this material is a bulk industrial mineral, freight economics and proximity to US cement and steel facilities heavily influence sourcing patterns.