Note 46 — BOOK IX.[1] (continued 2)

[Pg 407][46] The method of this paragraph involves two main objectives—first, the gradual enrichment of matte to blister copper; and, second, the creation of large cakes of copper-lead-silver alloy of suitable size and ratio of metals for liquation. This latter process is described in detail in Book XI. The following groupings show the circuit of the various products, the "lbs." being Roman librae:—

Charge.Products.

1stCrude ore5,400 lbs.Primary matte (1)600 lbs.

Lead slags3 cartloadsSilver-copper alloy (A)50 "

Schist1 cartloadSlags (B)

Flux20 lbs.

Concentrates from slags & accretionsSmall quantity

2ndPrimary matte (1)1,800 lbs.Secondary matte (2)1,800 lbs.

Hearth-lead & litharge1,200 "Silver-copper-lead alloy (liquation cakes) (A₂)1,200 "

Lead ore300 "Slags (B₂)

Rich hard cakes (A₄)500 "

Liquated cakes200 "

Slags (B)

Concentrates from accretions

3rdSecondary matte (2)1,800 lbs.Tertiary matte (3)1,300 lbs.

Hearth-lead & litharge1,200 "Silver-copper-lead alloy (liquation cakes) (A₃)1,100 "

Lead ore300 "Slags (B₃)

Rich hard cakes (A₄)500 "

Slags (B₂)

Concentrates from accretions

4thTertiary matte (3)11 cartloadsQuaternary hard cakes matte (4)2,000 lbs.

Poor hard cakes (A₅)3 "Rich hard cakes of matte (A₄)1,500 "

Slags (B₃)

Concentrates from accretions

5thRoasted quartzPoor hard cakes of matte (A₅)1,500 lbs.

Matte (4) (three times roasted)11 cartloadsFinal cakes of matte (5)

6thFinal matte three times roasted is smelted to blister copper.

The following would be a rough approximation of the value of the various products:—

(1.)Primary matte=158ounces troy per short ton.

(2.)Secondary matte=85 " " "

(3.)Tertiary matte=60 " " "

(4.)Quaternary matte=Indeterminate.

A.Copper-silver alloy=388ounces Troy per short ton.

A₂Copper-silver-lead alloy=145 " " "

A₃ " " "=109 " " "

A₄Rich hard cakes=97 " " "

A₅Poor hard cakes=Indeterminate.

Final blister copper=12ozs. Troy per short ton.