See the HF Acid Leach Process on page 290-291 (and in general the rest of Appendix 5E LMF Chemical Processing Sector, all outlined with an eye towards self-replicating lunar factories, from NASA under the Carter presidency): https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Farchive.org%2Fdetails%2FAd...
"[From the Intro] Mission complexity has increased enormously as instrumentation and scientific objectives have become more sophisticated. In the next two decades there is little doubt that NASA will shift its major focus from exploration to an increased emphasis on utilization of the space environment, including public service and industrial activities. The present study was sponsored by NASA because of an increasing realization that advanced automatic and robotic devices, using machine intelligence, will play a major role in all future space missions. Such systems will complement human activity in space, accomplishing tasks that people cannot do or that are too dangerous, too laborious, or too expensive. The opportunity to develop the powerful new merger of human intellect and machine intelligence is a result of the growing capacity of machines to accomplish significant tasks. Indeed, the growth in capability of onboard machine intelligence will make many missions technically or economically feasible. This study has investigated some of the ways this capacity may be used as well as a number of research and development efforts necessary in the years ahead if the promise of AI is to be fully realized. ...
[From Appendix 5E] Mining robots deliver raw lunar soil strip-mined from the pit to large input hoppers along the edge of the entry corridors into the chemical processing sector. The primary responsibility of the materials-processing subsystems is to accept lunar regolith, extract from it the necessary elemental and chemical substances required for system growth, replication, and production, and then return any wastes, unused materials, or slag to an output hopper to be transported back to the surrounding annular pit by mining robots for use as landfill.
It is possible to achieve qualitative materials closure (see sec. 5.3.6) - complete material self-sufficiency within the Lunar Manufacturing Facility (LMF) - by making certain that chemical processing machines are able to produce all of the 84 elements commonly used in industry in the United States and the global economy (Freitas, 1980). However, such a complete processing capability implies unacceptably long replication times T (on the order of 100-1000 years), because many of the elements are so rare in the lunar or asteroidal substrate that a vast quantity of raw soil must be processed to obtain even small amounts of them. By eliminating the need for many of these exotic elements in the SRS design, replication times can be cut by as much as three orders of magnitude with current or foreseeable materials processing technologies."
Whether that is "reasonable technology" in today's economic system is obviously debatable. I also did not see any of the critical minerals in the article (like Cobalt or Neodymium) on the list of the "Total of 18 elements" the study listed as key to build these systems in the box on page 282 on "TABLE 5.11. MINIMUM SEED ELEMENT AND PROCESS CHEMICAL REQUIREMENTS" . So maybe, as you suggest, they are harder to extract but the study participants knew of workarounds -- for example using Iron in a battery or to make electromagnets?
Anyway, I had a copy of the page with that HF Acid Leach process up on the wall in my office for many years as a symbol of hope and abundance -- even if in reality HF acid is nasty stuff best avoided (or left to automation in far-off places).
It would be ideal to find a better way on Earth like perhaps bacteria or plants or other organisms that concentrate specific materials... The short-story "The Skills of Xanadu" from 1956 by Theodore Sturgeon, for example, suggests breeding a shellfish that concentrates strontium in its shell...
https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fia601205.us.archive.or...
"At first, it seemed to Bril totally disorganized. These attractive people in their indecent garments came and went, mingling play and work and loafing, without apparent plan. But their play would take them through a flower garden just where the weeds were, and they would take the weeds along. There seemed to be a group of girls playing jacks right outside the place where they would suddenly be needed to sort some seeds.
Tanyne tried to explain it: "Say we have a shortage of something -- oh, strontium, for example. The shortage itself creates a sort of vacuum. People without anything special to do feel it; they think about strontium. They come, they gather it."
"But I have seen no mines," Bril said puzzledly. "And what about shipping? Suppose the shortage is here and the mines in another district?"
"That never happens any more. Where there are deposits, of course, there are no shortages. Where there are none, we find other ways, either to use something else, or to produce it without mines."
"Transmute it?"
"Too much trouble. No, we breed a freshwater shellfish with a strontium carbonate shell instead of calcium carbonate. The children gather them for us when we need it." ..."
For example, on Cobalt, maybe we could breed cows and their gut bacteria to concentrate it? See: https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2F...
"Cobalt is essential to the metabolism of all animals. It is a key constituent of cobalamin, also known as vitamin B12, the primary biological reservoir of cobalt as an ultratrace element. Bacteria in the stomachs of ruminant animals convert cobalt salts into vitamin B12, a compound which can only be produced by bacteria or archaea. A minimal presence of cobalt in soils therefore markedly improves the health of grazing animals, and an uptake of 0.20 mg/kg a day is recommended because they have no other source of vitamin B12."