Mineral Products Industry – Cement and Fly Ash Storage Silos
Concrete batch plants are sources of particulate emissions containing arsenic, beryllium, cadmium, chromium, lead, manganese, nickel, selenium, zinc, and crystalline silica. Concrete is a mixture of water, sand, aggregate, and cement occasionally supplemented by small quantities of fly ash and organic additives. The composition of a typical yd3 (4000 lbs) is; 1900 lbs course aggregate, 1240 lbs sand, 500 lbs cement / fly ash, and 360 lbs water. Production equipment usually consists of aggregate bins, conveyors, cement storage silos, fly ash storage silos, a weigh hopper, a mixer, and transport trucks. The concrete may be centrally mixed (at batch plants), transit mixed (added wet to trucks and mixed enroute), or dry batch loaded (mixed with water at destination). All of these concrete batch plants utilize enclosed silos with sock (bag) filters for cement and fly ash storage.