Sorting carbide scrap.

Hard scrap vs. soft scrap

Processors divide the carbide world in two before anything else. Hard scrap is solid material: inserts, end mills, drills, blanks, dies, wear parts, mining buttons. Soft scrap is the fines: grinding sludge, swarf, dust, and powder. The split exists because the two go through completely different recycling routes. Clean, well-sorted hard scrap of known composition goes through the direct zinc process — heated with zinc around 900 to 1,050 °C so the zinc reacts with the cobalt binder, then vacuum-distilled, recovering roughly 95 percent of the tungsten at about a third of the energy of making virgin carbide, with the original grain structure preserved. Soft scrap and mixed material go the chemical route instead: roasting, leaching, and conversion back through APT — effective, but far more processing-intensive. That is why sludge must never share a container with your good solids. One oily rag's worth of coolant in a bucket of inserts will not ruin it, but a drum of sludge poured over clean tooling downgrades everything it touches. Bucket one: inserts and solid tooling. Bucket four: sludge and fines, kept as dry as practical, far away from bucket one.

Grade families apart

Within your hard scrap, the highest-value sorting move is separating grade families. Keep the straight tungsten-cobalt grades — ANSI C1 through C4, ISO K, the red-coded cast-iron and non-ferrous family — apart from the alloyed steel-cutting grades — C5 through C8, ISO P, blue-coded. The straight grades are the cleanest and most tungsten-rich, with no titanium or tantalum additives complicating the chemistry; they recycle most directly and sit at the top of the value picture. The alloyed grades contain TiC and TaC that change the recycling chemistry and need different handling. A bucket of separated K-grade inserts is straightforward, high-recovery feed. The same inserts mixed blind with P-grades become a blended lot evaluated as a blend. You do not need to identify every insert — sort by what you can read: red-coded packaging and K/C1–C4 markings in one pile, blue-coded and P/C5–C8 in another, unknowns in a third. Even rough family separation beats no separation, and it signals to the buyer that the lot was handled by someone who knows the material.

Brazed tips and contaminants out

Brazed carbide — saw tips, tipped cutters, brazed tool bits — contains real carbide on a steel body, and the steel is the problem. Value follows the carbide share of the total weight, so a box of loose tips prices very differently from whole blades carrying heavy steel plates. If you can knock or grind tips free of their steel bodies, do it; the separated tips join your hard scrap and the steel goes to the steel pile. If you cannot separate them economically, keep all brazed material in its own bucket and photograph it honestly — do not hide steel inside a carbide lot. Then the contamination sweep: pull out high-speed steel tools (the great value-killer — HSS mixed into carbide drags the whole lot down), plain steel parts, carbide still sealed in plastic packaging, paper labels, rags, and coolant-soaked debris. Shake off cutting fluid, let sludge settle and pour off free liquid, and never ship containers of liquid. Finally, protect information: do not grind, crush, or wire-wheel your tooling. Manufacturer names, part numbers, and grade codes are valuable identification — destroying them destroys information the buyer would have paid for.

The bench routine

A practical sorting session needs a workbench, four labeled buckets, a magnet, and patience. Work through the pile piece by piece: magnet-check the obvious steel, read markings where they survive, drop inserts by grade family, set brazed tooling aside, and quarantine anything oily or sludgy. Weigh what you can — a bathroom-scale photo works for small lots — and write an honest description: "mostly inserts, some HSS mixed in, about 40 lbs" beats an optimistic guess every time. Surprises at verification slow everything down; accurate descriptions speed up your offer. None of this requires perfection. Processors expect shop material to be shop material. What earns the better offer is the visible effort: dry, separated, honestly described lots consistently out-earn mystery drums of identical weight, because the buyer can verify them quickly and confidently instead of pricing in the unknown.

Carbide questions, answered.