Talk:Black copper

WP:PROD discussion

This page was recently flagged for WP:PROD, with the justification "This is a disambiguation page which has Tenorite, which never mention the name, and a non-existent page. Dismbigustions should only be when there are pages to differentiate, not non-existent ones or those of zero apparent relevance."

It had previously been a redirect to melaconite (from 2008), then tenorite (since 2012), which had been changed to a disambiguation page with the edit message "Convert redirect to disambiguation page - additional metallurgical meaning, neither appears to be primary - includes text adapted from wikt:black copper." As the author of this change, here's my review of the relevant background.

Disambiguation

The page has a single article-space backlink, to Chemetco#Refining_process, which uses the term in its metallurgical sense: "Copper-bearing material was smelted to produce black copper, containing impurities such as lead, tin and zinc. Black copper was refined using oxygen, producing 98% copper, along with a zinc oxide residue and a slag containing lead, tin, nickel and a number of heavy metals." Previously, this forward link was being redirected to tenorite, the wrong sense of the term, which led me to create this disambiguation page.

Wiktionary's black copper page lists both the mineralogical and metallurgical senses of the term, though its metallurgical definition mentions different impurities: "Copper with iron and sulfur impurities due to insufficient smelting." It also states that wikt:tenorite#English is a synonym, though this appears to be slightly incorrect: if tenorite is only a synonym of the mineralogical use of the term, it should be listed under that sense, as can e.g. be seen in the synonym list for wikt:unique#Adjective; I'll go fix this issue once the discussion here is resolved.

Merriam-Webster likewise provides two definitions, the first linking to melaconite, "an earthy black massive variety of tenorite", and the second describing a metallic copper product, typically of purity 70–99%, formed by smelting copper without an initial matte purification stage, or alternately by "remelting old or scrap copper and copper alloys." It does not mention specific impurities.

Inspecting the first 10 non-Wikipedia hits from this Google search, only Merriam-Webster covers both definitions, with 6 other webpages (including Collins) only using the term in its metallurgical sense, and 3 other webpages only using the word in its mineralogical sense. WP:PRIMARYTOPIC states a topic is primary w.r.t. usage "if it is highly likely—much more likely than any other single topic, and more likely than all the other topics combined—to be the topic sought when a reader searches for that term." A 7:4 ratio in favor of the metallurgical use is unlikely to satisfy this criterion. A Google Scholar search instead returns a 6:4 ratio in favor of the mineralogical use.

Based on this evidence, I view it as appropriate to change the page from a redirect to a disambiguation page, so that we can cover both senses of the term.

Redlinks

Regarding the concern raised about redlinked pages, our WP:PRIMARYRED editing guideline states "When a disambiguation page lists only one existing article by that name (all other suggested articles are red-linked), the normal rules for primary topic still apply. ... If there is no primary topic, then the disambiguation page should be the primary landing page. ... Please note, MOS:DABMENTION still applies: any red-linked entry should still have a blue link to an article that covers the redlinked topic."

At the time, I read this to imply it should be acceptable for DAB pages to contain redlinks, provided the redlink is followed by a bluelink to an article for which the DAB page's description of the topic is in scope. Upon review, this isn't the right interpretation: our MOS:DABMENTION guideline requires that the bluelinked article mention the redlinked term, i.e. it's not sufficient for the linked copper article to cover copper smelting and recycling, it must specifically mention black copper for this to be a valid bluelink.

MOS:DABRED explains how to remedy this: we should either link from the metallurgical section of the black copper DAB page to an existing article that "contain[s] some meaningful information about the term," redirect the black copper (metallurgy) redlink to an existing article, or start a new black copper (metallurgy) article "according to Wikipedia:Article creation practices." Deleting the DAB page isn't one of the main courses of action listed here, and as explained below, I think there are better alternatives.

Proposed edits to other articles

The sources I've seen almost exclusively mention metallurgical black copper in the context of copper recycling, suggesting that production via non-matte copper smelting is likely to be an outdated process of only historical relevance. Moreover, as explained by the European Copper Institute in their page on the substance (and confirmed in the corresponding ECHA page), black copper is an intermediate during the recycling process, meaning that it's unlikely to be of independent interest outside of this context. While copper extraction has its own long and comprehensive article, copper recycling redirects to Copper#Recycling, which only allocates two paragraphs to this section, despite recycling being a major worldwide source of copper, providing "35% of total worldwide copper usage [as of 2011]" (according to Copper extraction#Recycling). This may partly be because recycling information is scattered throughout the rest of copper, e.g. Copper#Methods:

A significant source of copper is from recycling. Recycling is facilitated because copper is usually deployed in its metallic state. In 2001, a typical automobile contained 20–30 kg of copper. Recycling usually begins with some melting process using a blast furnace.

This suggests to me that a reasonable short-term solution would be to rename Copper#Methods to Copper#Extraction and move information about recycling to the (immediately following) Copper#Recycling section. We could even reuse Ullmann's as a reference, as the 7th edition mentions black copper (listing its composition as "70–90% Cu, 2–4% Fe plus Zn, Sn, Ni"):

A significant source of copper is from recycling. Recycling is facilitated because copper is usually deployed in its metallic state. In 2001, a typical automobile contained 20–30 kg of copper. Recycling typically begins with the melting of scrap to produce black copper (70–90% pure, containing impurities such as iron, zinc, tin, and nickel), followed by oxidation of impurities in a converter to form blister copper (96–98% pure). This product may then be refined further using the same processes as for blister copper derived from copper ore.

Similarly, it would probably be a good idea to mention melaconite and black copper in tenorite, provided we agree they're relevant, though I'd prefer it if someone with more mineralogical experience was the one to make these changes. In any case, before going ahead with this proposal, I'll wait a few days to provide time for feedback from more experienced editors. Does anyone have an alternative they think might be better?

References

Preimage (talk) 04:45, 14 September 2024 (UTC)

So long as you make relevant changes to pages so this is not a disambig page to one that does not mention the topic, that is fine with me. I do have reservations about using dictionary definitions to support having the term -- standard Wikipedia:NOTADICTIONARY.

I like some variant of adding Black Copper to the Copper page as something from a paragraph to even a short section with a Figure. Then change the link Chemetco#Refining process to that and change also this to a redirect. Also add cross-linking/mention to the tenorite page. (I have not done the checking to see if the "black copper" slag is crystallographically different from Tenorite). I would prefer it if there is one location which explains what it is and then everything links to that, certainly for the slag.

If the slag and the minerallogical uses are really different, then it would be OK with me to keep the disambiguation page, now with the Copper page link. Then add "Black Copper Maran" as a link to Maran as this seems to be the most common usage!! Ldm1954 (talk) 12:43, 14 September 2024 (UTC)

Addendum, after doing a bit of searching over morning coffee. Based on https://reach-copper-consortium.eu/substances/black-copper/ it is a mixture of assorted materials, mainly copper. As such it has no connection to Tenorite, which is a well-defined oxide. I suggest editing the Tenorite page to say it is "sometimes called black copper", adding to the copper page and changing the redirect here. Ldm1954 (talk) 14:29, 14 September 2024 (UTC)

Problem is that "black copper" appears to also be used by mineralogists to refer to CuO and/or oxide-based black copper minerals, a separate usage to the metallurgical definition. E.g. the 8th Google Scholar hit, Extraction of Mn from Black Copper Using Iron Oxides from Tailings and Fe2+ as Reducing Agents in Acid Medium, uses "black copper ore" and "black copper" interchangeably. The 6th hit, Understanding Exotic-Cu Mineralisation: Part II - Characterisation of Black Copper (Cobre Negro) ore, is more consistent, referring to "black-copper ores" and "“black-copper” minerals". The 5th hit, Optical and microstructural analyses of a chemically converted textured black copper selective surface, uses the term to refer to a CuO surface layer over an underlying metallic copper substrate (presumably of high purity, hence not "black copper" in the metallurgical sense of the term). Preimage (talk) 15:03, 14 September 2024 (UTC)

Hmm, a more standard term for this appears to be "black copper oxide". So I think you're right, let's redirect black copper to a black copper anchor in copper, then add a WP:HATNOTE to copper(II) oxide, (which also describes some of the rarer copper oxide mineral variants, such as paramelaconite). (Oh heck, I see you've already done that—great!) Preimage (talk) 15:18, 14 September 2024 (UTC)

Agreed. We are not a dictionary, so I think we have to focus on providing useful information not the mess of names. (IMO we only need a mess of conflicting names when there are NPOV issues, I don't see any here.)

I will leave to you to do the refining linkages, otherwise we will be cross-editing. N.B., I also added to the Tenorite page; a hat might be better. Ldm1954 (talk) 15:20, 14 September 2024 (UTC)