21 
The first step in virtually all extraction techniques involves crushing 
the nodules. Nickel and copper are relatively easy to separate by 
chemical methods as these metals are associated with the manganese 
oxides. Leaching solutions can be developed to concentrate these metals 
and leave most of the others behind. Cobalt is found mostly with the 
iron minerals.!* Removing cobalt and other metals requires additional 
steps. The leaching method is carefully designed to optimize the yield 
of the particular metals which a company wishes to market (Table 4). 
TABLE 4.—COMPARISON OF 3 AND 4 METAL PRODUCTION FROM NODULES 
MANGANESE WILL BE THE MAJOR PRODUCT IF THE OCEAN IS MINED FOR 4 METALS * * * 
Annual 
output Estimated 
(millions of price (per § Gross value Percent of 
pounds) pound) (millions) gross value 
Manganesevieat 2th Libis oe. 22 esl oee teehee ce 500. 0 $0. 15 $75.0 58.8 
ING Kel eee Sa a se eee ee 25.0 1. 40 35.0 27.5 
Copper ten ee oS 20.0 56 11.2 8.8 
Goby] teeta otek 8 bee eyo 2 Soak he Soe 2 se 4.4 1. 40 6.2 4.9 
Ota meee enentnS Ol: eee ne ar Suc e h ke omens eae oe CRS ed SAREE Oe en 127.4 100. 0 
Nickel Skene Bee Sin oo esos ect eses sess 75.0 $1. 40 $105. 0 66.8 
Cop peleass sna oe ea Se oe 2 Eee 60.0 - 56 33.6 21.4 
(Cobia lit: eee Pee 8 be eee ee eee 13.2 1.40 18.5 11.8 
WOE see ee eS oe a ae ea 157.1 100. 0 
1 Assumes that high-purity manganese will be marketed rather than ferromanganese. 
Source: Chemical and Engineering news. Mar. 4, 1974, p. 25. 
HYDROCHLORINATION 
One leaching method being developed is the hydrogen chloride proc- 
ess of Deepsea Ventures. In this method hydrogen chloride reacts with 
the crushed nodules at elevated temperatures to dissolve essentially all 
the nodule material. Most of the metals except iron form soluble metal 
chlorides which are then leached with water and separated from the 
solid residue. The solid residue containing inert silicates, sulfates, and 
oxides (mainly iron oxides) is regarded as waste. Chlorine gas is re- 
covered as a by product and hydrogen chloride can be recovered from 
the leach liquor and recycled (Fig. 11). 
_“Tbid., p. 646. 
