Jbnkinson. — Manufacture of Iron and Steel in New Zealand 511 



The pig from Parapara ore offers a very difficult metallurgical problem 

 when used for steel-making, and one which has prevented the use of such 

 ores to any extent in other countries, as the solution involves a subsidiary 

 process which increases the cost of steel-production. As given, the white 

 pig contains 0-08 per cent, sulphur and 1 per cent, silica, both too high 

 for the basic open-hearth process. Either could easily be reduced in the 

 blast furnace, but only at the cost of increasing the other, so that the 

 attempted solutions fall under two main headings : (1) Making a high Si, 

 low S, pig, and desiliconizing by (a) blowing in a converter or [h) washing 

 in a bath of molten basic slag ; (2) making a low Si, high S, pig, and de- 

 sulphurizing by (a) using manganese-ores as a flux, (6) pouring the molten 

 pig on to nitrate of soda (Heaton process), or (c) using CaClo and CaFa 

 as a flux (Saniter process). All these operations require skill and add to the 

 cost. None of them have survived in practice, and all are of doubtful utility. 



However, assuming this difficulty was overcome by one of the pro- 

 cesses, an ingot steel would be obtainable costing £5 a ton in the ladle 

 (against £3 5s. in England), and suitable only for bar and rod trade, which 

 includes wire and gauge plates for galvanizing. New Zealand could absorb 

 50,000 tons a year of this material, but the selling-price of that manu- 

 factured in New Zealand would be at least £4 a ton above the imported. 

 Parapara steel would be quite unsuitable for rails, boiler-plate, and good 

 structural material, and the conclusion is inevitable that — (1) Parapara 

 ore presents a very difficult problem to the steel-maker ; (2) its content of 

 phosphorus and sulphur is such that it is economically unsuited for the 

 production of high-class steel, such as boiler-plate ; (3) the cost of fuel and 

 transport in New Zealand is at present prohibitive to the foundation of 

 a large iron and steel industry ; (4) the value of the ore is too low to 

 encourage the idea of exporting it. 



It may be pointed out here that the analysis given in Bulletin No. 3 

 of the Geological Survey of what is stated to be excellent pig iron made 

 from Parapara ore in Melbourne in 1873 proves that the metal in question 

 was a commercially useless steely product, probably made in a blacksmith's 

 fire. 



Taranaki Sands. 



This ore occurs as a very finely divided sand over a large stretch of sea- 

 €oast extending from Waitotara to the Awakino River, and forms workable 

 deposits at Patea, New Plymouth, Waitara, and Mokau at least. While 

 no useful estimate can yet be made of quantity, it is certain that millions 

 of tons of iron could be obtained. Earlier analysis made this ore appear 

 of remarkable purity, but lately this has been disproved, and it is virtually 

 cextain that the sand contains about 0-5 per cent, phosphorus, estimated 

 on the iron. Whether this percentage can be lessened by magnetic con- 

 centration is a moot point, but Mr. Donovan's valuable paper (see p. 503 

 in this volume), goes far to disprove the probability. Accepting his figures, 

 the average of the Patea and New Plymouth sands, after magnetic con- 

 centration, runs about 56 per cent. Fe, 10 per cent. TiOj, 0-25 per cent. Va, 

 which would give a pig running 0-5 per cent, phosphorus, suitable for heavy 

 foundry-work and for steel by the basic process. Certainly this is a purer 

 and (neglecting its form) more valuable ore than that of Parapara, but it 

 cannot be compared with Swedish or Styrian, and, indeed, would not be 

 accepted as a structural steel ore by the majority of English engineers. 



The titanium present might give some trouble in the blast furnace, 

 and neither it nor the vanadium add anything to the value of the ore, as 



