Investment casting produces complex, near-net-shape parts for aerospace, energy, medical and automotive customers. Those parts are critical, so most are inspected by radiography before they ship. The inspection department is where a waste stream begins that few people outside the foundry think about: silver.
Why castings are X-rayed
Porosity, shrinkage, inclusions and cracks can hide inside a casting where no surface inspection will find them. Radiography reveals them without damaging the part, and film remains the standard for many casting specifications. High-volume foundries run their own film radiography departments, often with several processors running every shift.
Where the silver goes
- Fixer. The fixer dissolves the unexposed silver halide from every film, so used fixer leaves the processor saturated with silver.
- Developer. Spent developer carries silver as well.
- Wash water. The rinse after the fixer carries residual silver. It is a larger, more dilute stream, and it still has to meet discharge limits.
- Volume. A busy foundry processes a lot of film, so the silver adds up quickly.
Why it matters
- Compliance. Silver is a regulated heavy metal, and sewer discharge limits are strict.
- Value. Dissolved silver is recoverable. Sending it down the drain or paying to haul it discards money.
- Disposal cost. Storing, manifesting and shipping silver-bearing liquid waste is expensive.
- Customer expectations. Aerospace and energy customers audit their suppliers, and environmental controls are part of the picture.
How Metafix handles it
The MBX family uses our patented metallic-exchange media to capture silver as fixer and developer flow through the filter columns. No chemicals are added and no toxic sludge is produced, and the recovered silver goes to refining.
- Film chemistry. The MBX-1000 connects to up to 5 processors, treats 0.26 gal/min (1 L/min) and schedules filter changes from measured volume.
- Silver wash water. Where wash water needs treatment, the RT3 brings silver under 1 ppm and sends the effluent to drain by gravity, with zero hazardous sludge.
- Monitored 24/7. Metatrax tracks every system and emails your team when something needs attention.
Recovers 99.99% of the silver from the fixer and developer of up to 5 processors, with no chemicals and no toxic sludge.
Removes Cu, Cr, Ni and Ag to under 1 ppm, safely to drain, with zero hazardous sludge.
The bottom line
Every casting you X-ray leaves silver behind. Recovered, it is revenue and compliance. Ignored, it is a liability. With 38 years in silver recovery and more than 200 units in operation, Metafix helps investment casters close the loop on their inspection departments.