Talk:Gold cyanidation

message: :Lime (calcium hydroxide) or soda (sodium hydroxide) is added to ensure that the pH during cyanidation is maintained over pH 10.5. 
why 10.5? Josh Parris # 03:35, 22 September 2005 (UTC)
replies: text: cause it's very low Klonimus 07:19, 19 September 2005 (UTC)
replies: text: The reason that the pH is maintained above 10.5 is because as the pH gets lower, cyanide in solution reacts to form hydrogen cyanide (HCN) gas!  10.5 is considered a safe pH for operating with a relatively comfortable margin, preventing the exposure of operators working around the leaching solution.  From memory, the leaching reactions forming the gold-cyanide complexes are actually favored at lower pH.  But operationally it's unsafe to go there.BSMet94 18:18, 12 January 2007 (UTC)
thread_title:  The Effect of pH 

message: From Cyanide: "Cyanide is highly reactive; it decomposes rapidly in sunlight." which gells with 61.68.199.162's entry of 
"While cyanide is toxic, it breaks down rapidly in nature. This fact has allowed its safe use over many decades at hundreds of mine sites without adverse side effects to workers at the mines."
Is there any reason why I shouldn't reinstate that text, perhaps reworked? Josh Parris # 03:44, 4 November 2005 (UTC)
thread_title:  Revert of  61.68.199.162 

message: That reference for "over 90 mines" is not definitive, as the figure is unsourced in the reference document.  If I had to guess, it's ultimately from some Inco SO2/Air sales literature, which means they've put in over 90 systems.  It doesn't necessarily mean that all of them are still operating, or operated well.  Also, no mention is made to the main competition for the SO2/Air process, which is the hydrogen peroxide based methods.  They're just as commonly used.  DeGussa is one supplier of this technology. Someone should come up with a more definitive source, and the article should not plug only one specific cyanide destruction technology (NPOV). BSMet94 20:07, 15 February 2007 (UTC)
thread_title:  Cyanide detoxification 

message: Is this article related to this one?--134.76.234.75 (talk) 15:13, 23 November 2007 (UTC)
thread_title: [[Bulk leach extractable gold]]

message: "It should be noted that destruction caused by such toxic releases cannot be easily washed away, and attempts to trivialize the environmental effects by citing the growth of plankton after two weeks are merely whitewashes by an industry tarnished by a horrendous environmental record."  —Preceding unsigned comment added by 70.73.53.88 (talk) 04:03, 24 March 2008 (UTC)
thread_title: Bias much?

message: The google patent  might be a good addition?--Stone (talk) 07:47, 18 April 2008 (UTC)
thread_title: Patent

message: Per End to anticianuro law, with promises of environmental care Josh Parris 02:49, 12 January 2012 (UTC)
thread_title: Gold Cyanidation no longer banned in Río Negro

message: To add ? Mention of alternatives to using Cyanide :
http://www.wired.co.uk/news/archive/2013-05/20/cornstarch-cyanide-gold
"chemistry postdoctoral fellow Zhichang Liu has discovered -- by accident -- a new method of extracting gold, using (of all things) corn starch instead of cyanide."  — Preceding unsigned comment added by 94.139.55.11 (talk) 23:49, 27 July 2013 (UTC)
replies: text: The idea of a section on alternatives is suitable.  The article you pointed to is probably too far from being even close to practical, pretty strongly hyped.  It relies on a super-duper expensive reagent and does not deliver an extract, much less a robust and biodegradable one like cyanide.  Let's look for secondary sources on the topic.--Smokefoot (talk) 05:22, 28 July 2013 (UTC)
thread_title:  Alternatives to Cyanide ? 

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thread_title:  External links modified 

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thread_title:  External links modified 

message: *Habashi, F. (1987) One Hundred Years of Cyanidation Historical Note. CIM Bulletin, 30, 108-114.
*
--Stone (talk) 15:28, 13 November 2018 (UTC)
thread_title:  History section