Glass Manufacturing Raw Materials Hub

A soda-lime glass batch is roughly 70–74% silica sand, 12–14% soda ash, 8–12% limestone and dolomite, 1–3% feldspar or nepheline syenite for alumina, a fraction of a percent of sodium sulphate as a fining agent, and as much cullet as the furnace can take. The batch is bought on chemistry that the finished sheet or bottle reveals: iron oxide in the sand (≤ 0.010–0.015% Fe₂O₃ for clear float, ≤ 0.030% for container), chloride and bulk density in the soda ash, MgO and iron in the dolomite, alkali content in the feldspar. A single float line melting 600–800 MT of glass a day consumes on the order of 200,000–250,000 MT of raw materials a year, delivered to a batch house with a few days of silo cover, so a late sand or soda ash vessel stops a furnace that cannot be stopped.

CBIL is a commodity brokerage company and brokers each batch material against the analyses a glass technologist reads — SGS, Bureau Veritas or Intertek certificates of Fe₂O₃, Al₂O₃, TiO₂, Cr₂O₃ and grain size on sand; Na₂CO₃, NaCl and bulk density on soda ash; CaO, MgO and Fe₂O₃ on carbonate stone; K₂O + Na₂O on feldspar; Na₂SO₄ on sulphate. Each input below has its own page on this site with its own trade figures and specifications. Because CBIL also runs a chartering desk (LaycanDesk), the sand, soda ash and carbonate parcels are fixed on Handysize and Supramax tonnage with hold-cleanliness standards written for white minerals, and the bagged feldspar, sulphate and alumina are booked on liner terms to the same port, so the batch house sees one landed cost per tonne of glass.