From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 18845 invoked from network); 31 Jul 2023 18:40:24 -0000 Received: from minnie.tuhs.org (2600:3c01:e000:146::1) by inbox.vuxu.org with ESMTPUTF8; 31 Jul 2023 18:40:24 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 40B6E4110E; Tue, 1 Aug 2023 04:40:21 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tuhs.org; s=dkim; t=1690828821; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-owner:list-unsubscribe:list-subscribe:list-post; bh=RlsDYTEeZalIU4SEM5zjVI3Vr1kYccNFv+nB0th4Rps=; b=kUfr9ZRgXaq5J2dml2e87ulDMFTLreIpaAQjiUeMocwtuRZ76FCNmCCW6vLxx6xIcRDTJf mJeRGOmEdYm7jY3TTFFuqc8tguaCZqA9N6PDAjiSU4i80FzVQ0Z07PoawGLyW4f1JRz2eR u57Vqf5bRyzBM3gZyXTM7imWklg8Sd8= Received: from mail-40132.protonmail.ch (mail-40132.protonmail.ch [185.70.40.132]) by minnie.tuhs.org (Postfix) with ESMTPS id EBFD9410D7 for ; Tue, 1 Aug 2023 04:40:14 +1000 (AEST) Date: Mon, 31 Jul 2023 18:40:00 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1690828812; x=1691088012; bh=RlsDYTEeZalIU4SEM5zjVI3Vr1kYccNFv+nB0th4Rps=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=iOhdbcUGlnbTetZmj6ymkEBUCkpfZGodunEOUG8+PH6F5/i8EgCessAzg9lcboaRt ozXyfsSl9Sqqk2t7PGK09GEUfkb12T6N/DE26VzFAdwxGFpfqqP+3giVYLP3PgLY8v x5FMxr8p7EldYumeYxXrZ1I4fbi/gB20xxSjS2legP1igJA6x4daCVMoPGDWfth/Xj aRE1bC5G35YiIkccHarVwLusq0wUZdhDIdvgD3zmB+jz5ihPJKW/aR5QKPCqFcUyYB iwM73XP/pg7YRfGCXm3MTZx76+IfCBd/P+zRr0bXziu6n353T3qpEpa+D2JWOM9yEP q+rhzJ43R2PrQ== To: Brad Spencer Message-ID: In-Reply-To: References: Feedback-ID: 35591162:user:proton MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Message-ID-Hash: VK62RUPXVLPG7LHYA2CLVMVPZM4MVELL X-Message-ID-Hash: VK62RUPXVLPG7LHYA2CLVMVPZM4MVELL X-MailFrom: segaloco@protonmail.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: Paul Winalski , coff@tuhs.org X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [COFF] Re: Typical Fate of Older Hardware List-Id: Computer Old Farts Forum Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: segaloco via COFF Reply-To: segaloco > My understanding is the extraction of the gold from the contacts is more > often than not, more expensive to do then to mine new gold. If I recall > the details correctly, there are not a lot of ways to do that with gold > because it doesn't react with a lot of other elements so it ends up > being hard to reduce. > Brad Spencer Pardon the length, caught the chemist in me interested. Gold is famously difficult to attack with acids, which actually is a benefi= t moreso than a detriment. One strategy to free native gold from a substra= te is to instead attack that substrate. The main acidic mixture which will= actually attack gold is "aqua regia" which is typically a 1:1 nitric/hydro= chloric mix, and is "regia" in that it can attack "regal" metals like gold = and platinum. Nitric on its own is a very effective acid and oxidizer, and= can be used to knock out all sorts of other metals, up to and including si= lver. However, nitric alone won't make a significant impact on the gold wi= thout the HCl there too. One of the problems with HNO3 alone (can't recall= if this is why gold is unresponsive) is that its strong oxidizing potentia= l can, in some circumstances, actually prevent its acidic reactions by full= y oxidizing the exposed surface area of a metal before the acid can dissoci= ate it. This can be observed with copper and anhydrous nitric: the copper = will immediately oxidize on the surface and no further reaction occurs. Ad= d water to facilitate the dissolution of the iron nitrate being formed and = the reaction goes apoplectic. Still, this doesn't come into play as much s= imply in that anhydrous nitric is very uncommon, and it's hygroscopic so it= 'll sponge up enough water from the atmosphere if left to do so and then ov= ercome the otherwise insoluble oxidation. Long story short, you can extract all sorts of metals *from* gold given the= y present surface area to react with, while leaving much of the gold intact= , by successive baths in individual strong acids, taking care to not have H= NO3 and HCl in contact with the metal at the same time. This isn't 100%; p= latinum, for instance, will also survive this process I'm pretty sure, as w= ell as some minerals and other complexes, but its a good place to start. Y= ou can then take what's left and dissolve it in aqua regia, yielding a solu= tion containing gold, possibly platinum, but hopefully little if any other = metals. At that point, either electrolysis or precipitation reactions can = be used to further purify, either by depositing the gold or at least elimin= ating remaining impurities. Similar processes are used for preparing radio= active isotopes for analysis: several stages of precipitation reactions to = eliminate unwanted isotopes and then a final precip of the target species o= nto a planchet for alpha spectrometry or beta emission counting. For the c= urious, gamma is a different beast entirely, so this doesn't apply to parti= cularly high potency radioisotopes. That said, this all has to take into account the cost of the acids, safe ha= ndling vessels for actually performing the separation, disposal (or further= refinement) of the secondary metals from the process, etc. My hunch based= on experiences in the environmental market, is that these sorts of costs a= re more often than not the barrier than any amount of technical difficulty.= Mining operations have the game figured out on how to balance production = and environmental stuff (note balance doesn't necessarily mean accept and v= alue, industrial ops often budget for compliance violations and smaller fin= es.) Metal recycling operations likely have a lot more eyes on them, ironi= cally, than extractive measures, and that is a newer industry. So much of it too is informed by market volatility. When gold peeks above = a certain threshold, suddenly reclamation outweighs the costs, but then it = dips again and you're bleeding money on a formal operation. Mining, sadly,= has more history behind it, so will probably continue to be the most suppo= rted avenue for pursuing resources until either the chemical and disposal c= osts involved in reclamation come down or we run so low on resources the ta= cit, implied violence towards the communities these resources are extracted= from escalates into full blown war. Of course, the other option is the steady march towards new horizons in sem= iconductor research, quantum computing, all of these attempts to get away f= rom the current entrenched norms of IC implementation. One of the possible solutions to these issues, now that I've thought about = my chemistry and tech stuff in the same breath, is perhaps designing newer = substrates from which gold can be more easily reclaimed. If planned obsole= scence is already a thing, those same engineers could at the very least des= ign these frequently disposable devices with high turnover to have a recycl= ing potential higher than what we have currently. In other words, if thing= s are going to be made cheaply and to be discarded every couple of years to= keep a revolving customer base, at the very least, engineer processes to e= asily put those discarded resources right back into the pool, not into land= fills. Granted, I could go on for hours about that sort of humanistic engi= neering... - Matt G. P.S. You really awakend the chemist in me. Not often I get to dredge some = of those memories up talking tech. There's a metallurgist living somewhere= deep in my mind that enjoyed thinking about this at length.