The advantages of recycling metallic zinc from the ... - Pyrotek

As one example of the zinc chemistry effects in the MZR, Table 1 provides an outline of the ICP
(Inductively Coupled Plasma) analysis of a representative processing run. Approximately
550kgs. (1210 lbs.) of top dross (skimmings) from a general galvanizing pot were heated for 3
hours with over 400kgs. (880 lbs.) metallic zinc extracted, resulting in a metal recovery in excess
of 70%. Furthermore, the zinc purity of the recovered metal was >99.6wt% Zn and was
analogous to the chemistry of the production galvanizing bath. Previous research [Ref. 21] has
indicated that controlled usage of secondary recycled zinc ingot in galvanizing operations can
provide a functional enhancement to primary zinc supply. Moreover, the zinc-depleted ash
(“residual ash”) from the MZR processing was still viable for sale at a reasonable rate due to the
induced purity of the retained ZnO and residual elemental Zn content.
TABLE 1: Identification of Zinc Chemistry for Input and
Output Products from a MZR System [Ref. 20]
Dross
Recovered
Metallic Residual
Analysis Zinc Ash
Zn: 87.37 99.66 74.86
Fe: 0.61 0.316 0.637
Al: 1.33 0.001 1.99
Si: 0.21