patio process

or Mexican process

Method of isolating silver from its ore, apparently dating from pre-Columbian times.

The ore was crushed and ground by mule power in arrastras, reducing it to a fine mud. This was then spread over a courtyard or patio, sprinkled with mercury, salt, and copper sulfate, and mixed by driving mules over it. Chemical reactions caused the silver to dissolve in the mercury. When the amalgamation was complete, the material was agitated with water in large tubs and the mud run off. The amalgam at the bottom was collected and heated to drive off the mercury. Used for much of the world's silver production for 350 years, the process was replaced by the cyanide process early in the 20th century.

* * *

also called  Mexican process 

      method of isolating silver (silver processing) from its ore that was used from the 16th to early in the 20th century; the process was apparently commonly used by Indians in America before the arrival of the Europeans.

      The silver ore was crushed and ground by mule power in arrastras (arrastra), shallow circular pits paved with stone. Large blocks of stone attached by beams to a central rotating post were dragged around the arrastra, reducing the ore to a fine mud. This was then spread over a courtyard or patio, sprinkled with mercury, salt, and copper sulfate, and mixed by repeatedly driving mules over it. Chemical reactions freed the silver from its compounds and caused it to dissolve in the mercury. When the amalgamation was complete, the material was agitated with water in large tubs and the mud run off. The amalgam remaining at the bottom was collected and heated to drive off the mercury. The process, especially suitable for the silver ores of the dry, barren areas of Mexico, was responsible for a large proportion of the world's silver production for 350 years; it was finally displaced by the cyanide process early in the 20th century.

* * *


Universalium. 2010.

Look at other dictionaries:

  • Patio process — The patio process was a process used to extract silver from ore. It was developed by Bartolomé Medina in Pachuca, Hidalgo, Mexico in 1557 for the Pachuca Real del Monte mines. The patio process was the first process to use mercury amalgamation to …   Wikipedia

  • patio process — noun : an amalgamation process of reducing silver ore in which ore crushed to pulp is spread on the patio and mixed with salt, copper sulfate, and mercury by spading the mass and driving horses or mules through it …   Useful english dictionary

  • Patio — Pa ti*o (p[aum] t[ e]*[ o]), n. [Sp., a court] (Metal) A paved yard or floor where ores are cleaned and sorted, or where ore, salt, mercury, etc., are trampled by horses, to effect intermixture and amalgamation. [1913 Webster] Note: The patio… …   The Collaborative International Dictionary of English

  • process — processual /pro sesh ooh euhl/ or, esp. Brit, /proh /, adj. /pros es/; esp. Brit. /proh ses/, n., pl. processes /pros es iz, euh siz, euh seez / or, esp. Brit., /proh ses , proh seuh /, v., adj. n. 1. a systematic series of actions directed to… …   Universalium

  • Industrial process — Industrial processes are procedures involving chemical or mechanical steps to aid in the manufacture of an item or items, usually carried out on a very large scale.Industrial processes are the key components of heavy industry.Most processes make… …   Wikipedia

  • Pan amalgamation — The Pan amalgamation process is a method to extract silver from ore, using mercury. The process was widely used from 1609 through the 1800s; it is no longer used. The patio process had been used to extract silver from ore since its invention in… …   Wikipedia

  • silver processing — Introduction       preparation of the ore for use in various products.       Silver has long been valued for its white metallic lustre, its ability to be readily worked, and its resistance to the corrosive effects of moisture and oxygen. The… …   Universalium

  • Medina, Bartolomé de — ▪ Spanish theologian born 1528, Medina de Ríoseco, Spain died 1580, Salamanca       Spanish Dominican theologian who developed the patio process for extracting silver (silver processing) from ore.       Medina developed the patio process, an… …   Universalium

  • Mercury (element) — gold ← mercury → thallium Cd ↑ Hg ↓ Cn …   Wikipedia

  • Comstock Lode — Bonanza ore, Consolidated California and Virginia Mine, Comstock Lode The Comstock Lode was the first major U.S. discovery of silver ore, located under what is now Virginia City, Nevada, on the eastern slope of Mount Davidson, a peak in the… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.