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=-0.8 required=5.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FROM,MAILING_LIST_MULTI, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 23913 invoked from network); 31 Jul 2023 21:20:18 -0000 Received: from minnie.tuhs.org (2600:3c01:e000:146::1) by inbox.vuxu.org with ESMTPUTF8; 31 Jul 2023 21:20:18 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id A43D940F7D; Tue, 1 Aug 2023 07:20:15 +1000 (AEST) Received: from mail-pf1-x42f.google.com (mail-pf1-x42f.google.com [IPv6:2607:f8b0:4864:20::42f]) by minnie.tuhs.org (Postfix) with ESMTPS id 52B3D40F7C for ; Tue, 1 Aug 2023 07:20:09 +1000 (AEST) Received: by mail-pf1-x42f.google.com with SMTP id d2e1a72fcca58-686f38692b3so4759010b3a.2 for ; Mon, 31 Jul 2023 14:20:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690838408; x=1691443208; h=to:subject:message-id:date:from:references:in-reply-to:mime-version :from:to:cc:subject:date:message-id:reply-to; bh=9geebSKtpLYLM9dvE3aClN4OQWPS47g6dXQVdEpgFOQ=; b=dAl8AxcvYSKMT+E3Ft+4KMJ5V9ZakHU6De89+ncqaRrhLO8vw9Cm1klDXyc9Lv7kPQ 8W6Kzl8RJOhOMDVpwKKA/JODO1hm7ozoRRLgkMt3tFIHirKNMUj2Sl+8UiozHFAVdeSz xJNHN4hYc+ynbFlb2Wujtq2fvztTrUkYt0O9d7GN0wFTrcZ+dFxcAIXGpoLqzKBSBSsf X6ml5whR11tFvOdXJO+G339/5hk/Wpbnh0FpWwFu8xO/j5b1NW55g84utMmYdXVHBusk v0RAqbjLf/ryu0K+G/+lGF7+Z2mx7WHNJk6JoPtwpGpGyZ/I8ZxzFtXzpfy7UxtdlSnX /ZVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690838408; x=1691443208; h=to:subject:message-id:date:from:references:in-reply-to:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=9geebSKtpLYLM9dvE3aClN4OQWPS47g6dXQVdEpgFOQ=; b=eZPhUl1hG77X+GsyxuIwA27vDkjGRai9gDPGibpBtGQzASqZntJKymQ65/nNbOmsSX QsBYbowbpSoAWzURW2YYH4gVu/gqY7Kss1C/+lZYueArTXt2tLqQCnddUo3RnRO95S5i dpd5q54YgdAsAX+fRvFOQbM3sH286cDX8Mp9FOyJKnO6dgSM64TtK0eUIb7D0xyCexNj AjmpASWq4WSRFHhWY8xxpMmLf65ZoQVYfEYf8a24rlHlQ1TxmR5YQG6RAd7QnceY0GZy alKTYKG7LV/8yT75xsVvc67YjFulXa0OnZRz9KfUA2Kw3teK1yGsvvYdErm7SbWnM3ib qWAg== X-Gm-Message-State: ABy/qLabbk4G4qK7T5QM48BHGSe4D8+DWAaBjd34P/XVcLJTyPFfjo6D HgpeZR4U8seuc+cEx57w7eZEio+pWovGmruPq7ky4Ty0 X-Google-Smtp-Source: APBJJlEySXfSAGAZ6no80wTlYloWJ4Bo7rmUk6599RXkkgMK+Ne+ySx5oNijPZJMseaGgVlV4BUDJcpT+B6zYpAcS/E= X-Received: by 2002:a05:6a20:2447:b0:134:1c06:19bb with SMTP id t7-20020a056a20244700b001341c0619bbmr13386712pzc.22.1690838408192; Mon, 31 Jul 2023 14:20:08 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a05:6a10:4404:b0:4c1:7ec0:eb04 with HTTP; Mon, 31 Jul 2023 14:20:07 -0700 (PDT) In-Reply-To: References: From: Paul Winalski Date: Mon, 31 Jul 2023 17:20:07 -0400 Message-ID: To: coff@tuhs.org Content-Type: text/plain; charset="UTF-8" Message-ID-Hash: YHSRBPDD5EKIRT364TTME37EQKYLDEDQ X-Message-ID-Hash: YHSRBPDD5EKIRT364TTME37EQKYLDEDQ X-MailFrom: paul.winalski@gmail.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 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: Brad Spencer is right about the resistance of gold to attack by acids makes using acids to attack the substrate an effective strategy. One other interesting property of gold is that it dissolves in liquid mercury. One old and primitive--but effective--way to extract gold is to grind the ore finely, mix it with liquid mercury, then allow the substrate to settle out. You then have liquid mercury with gold dissolved in it. You heat the mercury to evaporate it away and there's your gold. The problem with this method is of course the extreme toxicity and volatility of liquid mercury. It's difficult (and expensive) to handle it safely, and in those parts of the world where this method is still in use, it usually isn't handled safely. The mercury-contaminated waste left over after the extraction is also toxic and environmentally damaging to dispose of. -Paul W.