Compsn. for controlled release of trace elements - into water, esp. for optimised nutrition of animals

摘要

Compsn. comprises a relatively insoluble trace-element cpd. (A), pref. together with a binder, such that addn. to water results in a controlled level of dissolved trace element. Pref. (A) is a cpd. of Cu, Co, Mg, Mn, Zn, Se, Fe, Ni, As, Cr, V, iodine or F, and the binder is a cpd. which (a) gives a compsn. with a different solubility prod. from (A) alone; (b) forms a mouldable, hardenable compsn.; and (c) is non-toxic and stable with respect to lime, heat and water; specifically calcium sulphate hemihydrate.S Opt. the compsn. also contains a blocking-complexing agent to prevent fixation of trace element onto impurities, e.g. in the case of copper, 0.75-1 wt.% hexametaphosphate. It can also include cpds. which retard (e.g. silicone or stearic acid) or accelerate (e.g. ligno-sulphonate, reducing sugar, ethylene glycol or a basic cpd.) dissolution of (A). Compsns. are esp. used to introduce trace elements to animals, drinking water and allow the content of trace metal to be maintained at a constant optimum level without risk of toxicity. Since Cu is toxic to mollusis and algae, the compsns. can also be used to kill snails and trematodes (e.g. in trout or oyster breeding) and to clear out algae from waterways.