In the accompanying book https://nap.nationalacademies.org/catalog/10026/dietary-reference-intakes-for-vitamin-a-vitamin-k-arsenic-boron-chromium-copper-iodine-iron-manganese-molybdenum-nickel-silicon-vanadium-and-zinc, significantly smaller amounts of iron are discussed. A daily iron intake of 6 mg for an adult male weighing approximately 75 kg maintains iron balance in the body. Note: not per kilogram of body weight. (Book page 340)
The average iron intake required to maintain iron balance in adults (EAR = Estimated Average Requirement, found on page 344 of the book) is:
And the recommended daily iron intake for adults (RDA = Recommended Dietary Allowances, page 344) are as follows:
The book also includes (on page 375) the UL = “Tolerable upper intake level,” which is a daily iron intake based on research that is unlikely to cause adverse effects in most individuals. That level is 45 mg per day.
I would by no means advise anyone to consume 20-60 mg per kilogram of body weight per day. For a 75 kg man, that would mean 1500-4500 mg of iron per day. Potentially a lethal dose! (edit: I’m not saying you advised this, but it’s very hard to believe that the information would be correct.)