The Rossi Retort

The Rossi Retort (HM25Z2)

Location: San Jose, CA 95120 Santa Clara County
Country: United States of America

N 37° 10.483', W 121° 50.659'

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This two-tube inclined retort, known as a "Rossi Retort," was named for Louis Rossi who came to New Almaden in the 1920s and built a reduction plant based on his patented design. This style of retort allowed rapid recovery of valuable mercury from high-grade ore.

In operation, the retort was charged with up to 400 pounds of crushed ore per cylinder, sealed, then heated for 8 to 24 house. The mercury sulfide vapors traveled up through the two condenser pipes, where the vapor cooled back to liquid mercury. The condenser pipes terminated into rubber buckets filled with water. Sulphur gases, a byproduct of the roasting process, were released through the chimney on top of the bucket cabinet.

Ore for the retort sat in the dump-truck bed above the retort. A knife gate mechanism regulated the ore feed and would only permit pieces less than 3 inches in size. Fresh ore was fed into the tubes by way of the triangular apron at the bottom of the truck bed.

The Rossi retort was unique because it used a perfect "angle of repose" to ensure the ore chambers were never completely full, thereby allowing freedom of gas movement and ready collection of the escaping mercury vapor.
HM NumberHM25Z2
Placed ByNew Almaden Quicksilver County Park Association and Santa Clara County Parks and Recreation. (Marker Number 2014.)
Marker ConditionNo reports yet
Date Added Tuesday, March 13th, 2018 at 10:01am PDT -07:00
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Locationbig map
UTM (WGS84 Datum)10S E 602594 N 4114879
Decimal Degrees37.17471667, -121.84431667
Degrees and Decimal MinutesN 37° 10.483', W 121° 50.659'
Degrees, Minutes and Seconds37° 10' 28.98" N, 121° 50' 39.54" W
Driving DirectionsGoogle Maps
Area Code(s)408
Closest Postal AddressAt or near Wood Rd Trail, San Jose CA 95120, US
Alternative Maps Google Maps, MapQuest, Bing Maps, Yahoo Maps, MSR Maps, OpenCycleMap, MyTopo Maps, OpenStreetMap

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