It is common in today’s modern cement plant to achieve up to 2,500 tonnes per day of clinker production; some plants are even capable of exceeding twice this value. Hence, to meet these ever-increasing demands, cement kilns must have consistent, reliable feed of the necessary cement ingredients, such as limestone, clay, gypsum, sand, slag, and bauxite. Unfortunately, these bulk solids can present flow problems, like arching and ratholing, during typical storage and transfer operations. In many cases, these materials will tend to plug or cause excessive wear in chutes, stick on conveyors, generate dust during stockpile formation, and cake in silos. The common handling problems with these materials cause many cement plants to operate inefficiently, and often require extra labor and maintenance to keep these materials flowing through processing equipment.

Environmental initiatives have also affected cement plants, with particular emphasis on fugitive dust and combustion byproducts. Dust escaping from poorly designed transfer chutes, stackers, conveyor belts, and unloading machines can be a significant source of emissions.

In an attempt to reduce energy costs, numerous cement plants are actively seeking alternative fuel sources, like shredded tires, biomass components, and plastics. Although these fuels can offer some financial benefits, they can also present significant flow problems and cause feed upsets to kilns. Studies have shown that spikes in CO2 and NOx production have been directly linked to erratic kiln fuel feed. In other words, to help minimize the emission of these harmful gas byproducts, cement plants must ensure a reliable, consistent fuel feed to their kilns; this can be achieved by properly designing equipment based upon the flow characteristics of the bulk solids being handled.

If your cement plant is currently experiencing solids handling difficulties with cement, cement products, or ingredients used in its manufacture, Jenike & Johanson can help you eliminate them. Or, if you are designing a new cement plant, we can utilize our industry-leading technology and experience to help you avoid process upsets due to solids handling problems. We can provide sound, practical engineering solutions to:

• improve your cement production efficiency (thereby increasing profit margins);
• minimize environmental impact during material handling (thereby avoiding costly regulatory violations);
• improve worker safety (eliminating the need to hammer on bins and poke at material to keep it flowing);
• improve product quality (by ensuring homogenous and consistent raw meal feed to the cement kilns).

• Maximized the reclaim capacity of high and low bench limestone stockpiles
• Designed a novel silo for high strength clay materials
• Developed reliable silo designs for handling natural and synthetic gypsum
• Designed clay transfer chutes to minimize pluggages, dusting, and wear
• Recommended air slide arrangements and operational strategies for maximizing discharge of OPC from flat-bottomed silos
• Minimized dust and segregation [220K QuickTime video] in cement storage equipment

Client confidentiality prevents us from discussing most of our projects. The following case studies were written with the consent of our clients.

Some of the cement industry equipment we have designed and supplied:

• Mass flow hopper, screw feeder, and conveying screw for limestone
• Solids Pump™ (sealing screw) for coal grinding mill isolation
• Mass flow belt feeder interface for diatomaceous earth
• BINSERT® bin with mass flow screw feeder for limestone

Some of the cement manufacturing materials we have handled:

A partial listing of the cement industry companies with which we have worked: