This preclinical study from 1998 demonstrated the citric acid stabilizing and enhanced dialysability effect on other minerals calcium, magnesium, manganese and zinc.
References:
Walter A, Rimbach G, Most E, Pallauf J. Effect of citric acid supplements to a maize-soya diet on the in vitro availability of minerals, trace elements, and heavy metals. Zentralbl Veterinarmed A. 1998 Nov;45(9):517-24. doi: 10.1111/j.1439-0442.1998.tb00855.x. PMID: 9857829.