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Since ancient times, the pulp and paper industry has been an important part of society, providing indispensable materials for communications, packaging, currency and more. 

Throughout its history, the industry has continued to evolve, adopting new technologies to improve efficiency and productivity. The papermaking process requires the handling of various types of slurries such as lime slurry, caustic soda, black liquor and white liquor, making the use of slurry pumps crucial.

The main centrifugal pumps used to handle these slurries in the pulp and paper industry are the same types of pumps used in mills to handle clear water and pulp fiber slurries. 

The only difference between these devices is the material of construction of the impeller, casing, stuffing box and suction wear plate. Equipment that handles slurry typically uses a duplex stainless steel called CD4MCu for these components, while equipment that handles water and young pulp fiber typically uses 316ss and ductile iron. With a Brinell hardness of 240, CD4MCu is more wear resistant than 316ss and ductile iron, but it is also very expensive.

Slurry pumps have a long history and are commonly used in the mining, power and gravel industries where extremely abrasive and corrosive slurries need to be handled. Over the years, advances in slurry pump technology in terms of materials and design efficiencies have become critical to maintaining efficient operation, helping to reduce production costs for mining and power companies.

For many years, slurry pumps have been made of ferrochrome and natural rubber materials and were only used to pump neutral dirt or ore in wet separation processes in the mining industry, but material developments have broadened the market for slurry pumps. Various types of chrome materials are now available to handle materials with a Ph value of 2 and various acids. Elastomeric products that can handle high temperature and corrosive fluids such as EPDM, Neoprene and Butyl are also available. 

In the paper application industry, slurry pumps are more robust pumps designed to handle heavily abrasive and corrosive slurries, significantly increasing the wear life and reliability of pump installations. This equates to cost savings through a significant reduction in pump maintenance, spare parts and downtime.

How do you save money? First of all, a true centrifugal slurry pump is much more robust than an ordinary centrifugal pump. For example, a CD4MCu 6x4-13 ANSI unit weighs about 450 lbs. A Chrome 6/4 CNZKING® slurry pump weighs 1,000 pounds. To break it down further, an ANSI 13.0-inch impeller weighs about 20 pounds. The Schurco slurry pump 13.0-inch impeller weighs 150 pounds. Which impeller has a longer wear life?

Second, technological advances have facilitated the development of specialized slurry pumps that allow paper mills to handle more slurry efficiently. Today, slurry pumps are available in a variety of impeller styles, such as high-efficiency, large-particle, open-type for handling fibrous materials, and high-head applications. 

Today, slurry pumps play a pivotal role in all aspects of the paper manufacturing process. They are widely used to transfer different types of slurries within paper mills, ensuring a continuous flow of material between the different stages of paper production.