☢ Radioactive materials

serious

Where you meet it: Thoriated tungsten filaments in large transmitting tubes and TIG electrodes · vintage aviation spark plug ignition aids · some smoke detectors (Am-241) · old aircraft instrument dials (radium) · certain vacuum tubes and spark gaps

What you need to know

Thoriated tungsten is safe intact. The hazard is grinding it — thorium dust is an alpha emitter and an internal hazard once inhaled.
Radium-dial aircraft and clock instruments shed radioactive paint dust when the dial is disturbed. Do not sand, scrape or open them.
Americium-241 sources in ionisation smoke detectors are sealed and safe in place; do not open the chamber, and route detectors to a take-back programme.
Some vintage aviation spark plugs and gas-filled spark gaps contain a small radioactive ignition aid — check before bulk-processing aviation lots.

The rule: NEVER grind, sand, saw or incinerate anything that might contain thorium or radium. Sealed sources stay sealed.

Components this applies to

Laboratory Platinum Ware Other · $20000–32000/lb Pt ~454 g/lb — it is solid metalAu 5% in Pt-5%Au XRF fusion cruciblesBase Rh 5–10% in Pt-Rh crucibles S Noble Thermocouple Wire (Type R/S/B) Other · $18000–31000/lb Pt ~410 g per lb of bare noble wireBase Rh 6–30% of one legBase Type K/J/T/E/N: zero PGM S Precious-Metal Sputtering Targets Other · $32000–50000/lb Au ~454 g/lb — the target is solid metalPt 138 g in a 2 in × 0.125 in discPd 77 g in a 2 in × 0.125 in disc S Thick-Film Hybrid Microcircuits ICs & chips · $15–90/lb Au 1.5–4 g/lb packaged; 5–10 g/lb stripped substratesAg 0–15 g/lb on Ag/Pd conductor variantsPd present in Ag/Pd pastes S Aerospace Connectors & Backshells Contacts & relays · $25–70/lb Au 0.3–0.8 g/lb complete; ~3.6 g/lb de-populated contactsCu ~80 g/lbBase Backshells: ~0 g Au/lb A Ceramic CCD/CIS Image Sensors ICs & chips · $150–400/lb Au 0.02–0.15 g per ceramic package ≈ 1.8 g/lbAu under 0.001 g per mobile/webcam moduleBase Nd-Fe-B in VCM actuators A Industrial Control Boards (PLC/DCS/SCADA) Boards · $3–12/lb Au 0.05–0.20 g/lb typical I/O; 0.25–0.60 g/lb CPU and backplanes; 0.6–1.5 g/lb 1970s–80s ceramic-DIP DCSAg 1–8 g per relay moduleCu ~113 g/lb C Klystrons & Travelling-Wave Tubes RF, power & vintage · $3–40/lb Cu ~250 g/lb (0.35–0.75 lb Cu per lb of tube)Au ~0.5–4 g per tubeAg 2–30 g per tube C Semiconductor Wafers & Fab Tooling Other · $20–200/lb Au 0.0045 g/lb generic research-fab wafer scrapAu 7.4 g/lb for 1 µm gold-backed wafersBase quartz and SiC boats: zero metal C Nixie Tubes, VFDs & Dekatrons Other · $150–900/lb Base nickel cathodesBase tungsten filament (µg) in VFDsBase total metal value $0.02–0.15 per tube D Photomultiplier Tubes (PMTs) Other · $150–900/lb Ag 0.1–2 g per tubeAu 0–20 mg per tubeBase BeCu dynodes with an activated BeO surface D Platinum RTD Probes (Pt100/Pt1000) Other · $45–200/lb Pt ~30–80 mg per lb of complete probesBase 0.9–0.99 lb/lb 316SS or Inconel sheathPt SPRT: 15–30 g per unit D Spark plugs Automotive · $0.5–2/lb Pt 1–8 mg per plugBase iridium 0.6–3 mg on Ir plugs D

All 25 hazards →