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 Parts
FLSmidth Krebs has the most complete line of materials of any hydrocyclone manufacturer. We evaluate each application and recommend the hydrocyclone not only best suited for the separation requirements but also best suited for minimizing maintenance costs. Our sales engineers work with our customers after the hydrocyclone is installed to ensure the optimum materials are in place in the hydrocyclones. We try to mix the materials so the higher wear areas (apex, lower cone, inlet head) wear out at the same time so downtime and replacement costs are minimized. Most of the materials listed below are stocked in the commonly used parts. Our sales engineers will work with the customer on testing various parts to achieve the goal of lowest possible operating costs.
Wear Materials:
Gum Rubber
Gum Rubber is by far the most common material used for the majority of industrial applications. Krebs Engineers utilizes natural gum rubber with a shore hardness of 35. This soft natural rubber provides the longest possible wear life in most applications. Over the years, Krebs has improved the formula of gum rubber, but softness has always been the key to optimum wear life. The new Krebs BPC rubber was developed based on 2 years of extensive testwork at an Arizona copper concentrator. This rubber is used in all of the Krebs Super Cyclones.
Synthetic Rubber
Synthetic Rubber is used in applications in which temperature or the slurry constituents does not allow the use of natural gum rubber. All of the standard Krebs liners are available in Neoprene, Nitrile/BunaN (Hycar), EPDM, and Butyl. Other synthetic rubber may also be available depending upon the part.
Urethane
Urethane is used in application in which the rubber is torn rather than worn. This includes, coal applications and some fine grinding applications such as encountered in iron ore. Urethane rather than synthetic rubber is also used in some applications in which the slurry attacks the natural rubber. Krebs has a standard hard urethane and a softer urethane called ultrane. The soft urethane works well in fine solids applications such as in iron ore grinding. In addition, food grade urethane can also be provided.
Silicon Carbide
Silicon Carbide is used in the high wear areas of the cyclone, typically for the apex and lower cone liners. In the coal industry and some other applications, silicon carbide is used throughout the cyclone. Krebs Engineers has five types of silicon carbide materials available, they are:
**The standard material used by Krebs for apexes and lower cones for over 30 years is nitride bonded silicon carbide (CR). This material has been modified over the years to improve the consistency of the parts, but the basic composition has remained unchanged. The SiC grains are mixed with Si metal and fired in a nitrogen reducing atmosphere. This material is the most cost effective for most applications.
**Reaction bonded silicon carbide (CX) is used in highly abrasive applications normally in closed circuit grinding in the mining industry. The SiC grains are fired in an inert environment to form a part which does not have a bonding matrix with no voids. It will outlast the standard CR material by about 3 times, but is about 2 times more expensive.
**Composite metal ceramic (CMC) manufactured by ALANX, under the 2K+ brand, is also recommended for abrasive applications. This material incorporates densely packed silicon carbide (SiC) particles within a matrix of aluminum oxide and aluminum metal alloy. In this composite structure, the extreme hardness and wear resistance of the SiC withstands abrasion, while the metal alloy assures good bonding between these two very hard ceramic phases. Its wear life is equal to or slightly longer than the CX material at about the same price. It is available for all parts including larger parts such as upper cone sections and inlet head liners.
**Sintered alpha silicon carbide (CZ) is used for extremely abrasive applications in the mining industry. Fine SiC particles are formed together by cold high pressure isostatic pressing and then fired at high temperatures. The final part is pure SiC at 98% density. It is the ultimate wear material as it will outlast CX by 3 to 5 times (CR by ten to fifteen times). It is about twice the cost of the CX material.
**Alumina bonded silicon carbide (CG) is a mixture of SiC and Al2O3 particles and is formed by slip casting and fired in an air environment. It holds up well to tailings and coal applications but is not recommended for coarse abrasive solids.
Alumina (CC and CB)
Alumina is high purity Al2O3 with SiO2 as the primary balance material. Very fine grained particles are isostatically pressed at high pressures and temperature and fired in an air atmosphere. This material holds up very well in coarse abrasive coal applications and in industrial application with coarse tramp material such as glass or steel shot.
Nihard (NH)
Nihard is another material which holds up in industrial applications with coarse tramp material as commonly encountered in recycled pulp installations. Due to relatively low cost, it is used for the vortex finder in most applications. It is an abrasion resistant nickel chromium martensitic white iron with a brinell hardness of 550 to 600.
Housing Materials:
Cast and Fabricated Carbon Steel
Cast and fabricated carbon steel is the most common housing material.
Cast Aluminum
Cast aluminum is used for smaller parts and provides a lighter part which eases handling. Aluminum is prone to chemical attack.
Stainless Steel
Stainless steel is available for all cyclone parts. It is used in chemical applications on the smaller cyclones, and is also available for the larger cyclone parts.
Fiberglass Reinforced Plastic
Fiberglass reinforced plastic housings are available for the 4 inch, 6 inch, and 10 inch cyclones. They are light weight and less expensive than steel, but can crack under certain conditions and cannot be repaired once worn through.
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