Evidence-first editorial standard
This guide separates observed facts, engineering assumptions and data that still require confirmation. It does not promise a universal service life or replace the exact product data and project specification.
Four constructions answer the same question differently
A slurry line that wears through can be rebuilt in Ni-Hard cast iron, with wearback fittings, with a rubber lining or with a ceramic lining, and each of them is the right answer somewhere. The choice depends less on which material is hardest than on where the line wears, how coarse and sharp the solids are, how the line is supported and how often it can be opened. Comparing them on purchase price alone usually selects the construction that has to be replaced most often, which is why the life-cycle cost of a wear lining is the better yardstick.
Ni-Hard: hard cast iron, heavy and difficult to modify
Ni-Hard designates a family of white cast irons alloyed with nickel and chromium, whose hard carbide structure resists abrasion well. Fittings are cast, so shapes are limited to the patterns available, wall sections are thick, and the parts are heavy to support and to handle. The material is brittle and impractical to weld or cut on site, so a change of routing or a damaged flange usually means a new casting. Where impact from coarse lumps is moderate and the geometry is standard, it remains a dependable option.
Wearback fittings: sacrificial mass where the wear lands
A wearback elbow or tee adds material — a thickened back, a cast block or a replaceable wear box — on the outer radius, where the particles strike. It accepts that the bend will wear and simply gives it more to lose, which is simple and predictable. The limits are weight, the space the added mass occupies, and the fact that the extra thickness only protects the zone it was designed for: if the flow pattern changes with velocity or solids concentration, the wear moves to an unprotected area. Our article on outer-radius wear in slurry bends explains how that pattern forms.
Rubber-lined pipe: resilient against fine particles, vulnerable to coarse sharp ones
Natural rubber and similar elastomers deflect fine particles instead of being cut by them, which gives long service in fine wet slurries at moderate velocity, with a light pipe and low noise. Coarse, angular or tramp material can cut or tear the lining, high temperature and oils degrade it, and a local cut can let slurry reach the steel behind it unseen. In bends, where impact angles are steeper, rubber linings are often the first part of a line to fail; the trade-offs are set out in ceramic, rubber or composite.
Ceramic-lined pipe: the hardest face, provided joints and retention are right
Alumina tiles or sleeves bonded inside a steel shell give a continuous hard surface that resists sliding abrasion and erosion, in straight runs as well as in bends, and allow elbows, tees and reducers to be lined in the shapes the line actually needs. The weak points are known: brittleness under heavy impact, the bond line at temperature, and steps at the joints between spools. A line built with aligned flanges and a controlled bond line, as with IC PIPE, removes most of those risks; the article on flange bore misalignment shows what happens when it is not.
Mixing constructions along the same line
Most slurry lines do not need one construction from end to end. Straight runs at moderate velocity may stay in rubber or steel while elbows, tees, reducers and the first spools after a pump or a cyclone are upgraded to ceramic, because that is where the wear concentrates. Decide fitting by fitting from the measured wear pattern, the cost of each replacement including the outage, and the access available. The ceramic-lined pipe specification checklist lists the data a supplier needs, and the ceramic-lined pipes and elbows page shows how such a line is built.