CRT (CRT)

A Cathode Ray Tube (CRT) is the large, evacuated glass vacuum tube that served as the display in television sets, computer monitors, and oscilloscopes until LCD and OLED displays replaced it through the 2000s and 2010s. A standard 21-inch CRT television contains roughly 8–15 kg of glass, of which 20–25% is lead oxide (specifically the funnel glass — the rear-facing cone-shaped section) added historically to absorb X-rays emitted by the electron gun. CRTs are still present in significant numbers in Indian e-waste streams (estimated 3–5 million units per year as legacy stock is finally discarded), and they require specialised hazardous-waste handling.

The lead-containing funnel glass is the central handling challenge. Each CRT TV contains 2–3 kg of elemental lead bound chemically into the glass matrix. Crushing a CRT releases fine lead-containing glass dust that exceeds occupational exposure limits within seconds without proper extraction, and direct landfill of intact CRTs leaches lead into groundwater over decades. Indian E-Waste Management Rules 2022 explicitly classify CRTs as hazardous waste requiring channelisation through authorised dismantlers, with prohibition on disposal in MSW streams. CPCB-registered CRT recyclers must operate under specific consent conditions including negative-pressure dismantling rooms, HEPA filtration, and worker blood-lead monitoring.

Three end-of-life routes exist for CRTs. Glass-to-glass recycling — sending crushed funnel glass to specialised smelters that produce new CRT glass — has collapsed as global CRT manufacturing ceased; only one or two facilities remain worldwide. Glass-to-lead smelting recovers lead in metallic form for battery use, at low margin but high environmental responsibility. Glass-to-cement, where stabilised CRT glass is mixed into low-strength concrete or used in road construction sub-base, is the most economically viable but requires SPCB approval as a stabilisation pathway. Indian recyclers handling CRTs typically charge ₹15–35 per kg gate fee (effectively negative-revenue handling) compensated by EPR certificates at ₹15,000–25,000 per tonne. Most progressive recyclers are now refusing CRT intake or pricing it at sharp premium to reflect the true compliance cost.

• Large glass vacuum tube display from TVs and monitors, now legacy stock.
• 2–3 kg of lead per unit in funnel glass; classified as hazardous waste under E-Waste Rules 2022.
• Disposal options: glass-to-glass (collapsing), lead smelting, stabilised cement aggregate.
• Negative-revenue handling for recyclers; gate fees ₹15–35/kg plus EPR certificate revenue.