Gypsum

Portland cement is the most common type of cement, produced by grinding clinker with gypsum to control setting time. OPC (Ordinary Portland Cement, Type I/CEM I) is the standard construction grade. Cement is heavy and low-value-per-ton, so trade is typically regional, though bagged cement exports to island nations and Africa are significant.

Clinker is the semi-finished intermediate product of cement manufacturing, formed by heating limestone and clay in rotary kilns at 1,450 degrees Celsius. It is exported to markets where grinding capacity exists but kiln capacity is insufficient. Japan, Thailand, and Turkey are major clinker exporters.

Limestone (calcium carbonate) is a fundamental industrial mineral used in cement manufacturing, steel production (as flux), glass making, and soil conditioning. High-calcium limestone (95%+ CaCO3) is required for cement and chemicals, while lower grades serve construction aggregate markets.

Silica sand (SiO2 95%+) is a high-purity industrial sand used in glass manufacturing, foundry casting, water filtration, hydraulic fracturing (frac sand), and silicon production. Quality is determined by silica content, grain size distribution, and iron oxide levels.