Duechting ceramic pumps demonstrate low cost of ownership in U.S. cement plant

Due to its significant corrosive and abrasive characteristics, gypsum slurry is a very difficult medium to handle. An American cement plant with a yearly capacity of about 2 million metric tons has found a good solution for that issue when it installed the first of two scrubber systems in 1998. This application has similar wear characteristics to FGD.

The housings of the eight pumps in the limestone slurry cycle are not made from metal materials, but from a special material that was designed specifically for extremely harsh conditions. This material is a mixture of silicon carbide (SiC) and epoxy resin that is poured into precision molds and heat cured to form the pump components. The material must be machined with diamond tools due to it exhibiting a hardness close to that of diamonds. The material is completely impervious to corrosion and exhibits extreme abrasion resistance given its metallic-free composition and high hardness value.

The scrubber, recycle pumps in this plant have operated at a flow rate of 1,310 cubic meters per hour (m3/h), 21.1 meters (m) of head and 630 revolutions per minute (rpm) for nearly 20 years, requiring minimum attention and service. Of course, the mechanical seals were exchanged from time to time. Apart from that, four impellers, one casing cover and some minor components were replaced. An additional 24 pumps are installed in the second scrubber system and other applications in the plant.