NEW ZEALAND'S IRON POPULAR NOTIONS REVIEWED

Evening Post, Volume XC, Issue 92, 16 October 1915, Page 9

NEW ZEALAND'S IRON POPULAR NOTIONS REVIEWED

GOOD HOPE FOR IROU-SAND. No subject is more misunderstood among the public of New Zealand than the matter of iron-ore deposits. Who has not heard of the Parapara "mountain of iron" and the "billions of tons" of rich iron-sand along the beaches of Taranaki? Many Mahomets have gone to the mountain of Parapara, and they have prophesied an era of stupendous prosperity by the working of'' the iron measures, but, alas, they predicted "without the book." In a lecture to the Philosophic Institute on Wednesday evening, Mr. S. H. Jenkinson, who has been a close student of iron problems for some years, exposed several popular fallacies about the Parapara bodies of ore. The speaker referred to the meagreness of trustworthy metallurgical information about the quality of this ore, and he proved the incorrectness of certain statements commonly accepted. He marshalled facts and figures to lead up to a conclusion, which he stated thus : — "The Parapara iron ore presents a very difficult metallurgical problem to the steelmaker; its content of sulphur and phosphorus is such that it can hardly be hoped that high-class steel will be made from it; the prices of fuel and trans' port in New Zealand are at present prohibitive to the foundation of a large iron and steol industry; and the value of the ore is too low to encourage the idea that it will ever pay to export it." Turning to the iron-sand, Mr. Jenkin6on opened up an avenue of hope, by intelligent attention to the fact that a i finely-divided ore has to be treated. Discussing electrical processes, he remarked :—: — " Electrical heating is notoriously costly, except when very high temperature is reached, and it seems an obvioue improvement to utilise fuel for the greater part of the heating and reserve electricity for that field in which it really is economical — the giving of a final ' kick ' to the already high temperature of partially reduced and smelted ore. " Since Providence has obligingly powdered these ores for us, let us take advantage of the fact and use powdered fuel also, the cheapest form of fuel and the most economical method of using it. If highly preheated ore, powdered coal, and blast were introduced into the top of a furnace shaft, or into the end of a rotating kiln, the red hot sintered and partly reduced product would require very little electrical energy to be thoroughly melted, amd the electrical energy required could be easily provided from the combustion, of the waste furnace gases under a boiler. The necessity of maintaining a. reducing fame in the shaft means that the fuel must be burned to not morq than 1 part carbon dioxide to 2-2£ parts of carbon monoxide; hence the calorific value of the waste gas is just 50 per cent, of that of the original fuel. Now the blast furnace could smelt one ton of pig from a solid ore as pure as Taranaki concentrate for 15 cwt of fuel, and in this case, as in the above, only 50 per cent, of the heat value of that fujel is taken out of it. That means, that the total heat energy ©£ 7-jg cwfc ot coaX. *Ie- necessary in practice to smelt pure ore* I cannot believe that a. furnace such fts I have indicated— if the sensible heat was used for dry heating the blast, and if all the materials were highly preheated — would be so uneconomical that/ it would require over 30 cwt (four times as much) of powdered fuel. This fuel could be obtained for 20s a ton, dried and powdered, even in Taranaki, and even assuming that ten tons of sand have to be handled for one ton of pig, we would find the cost of the pig iron ppr ton to be :—: —

£4 9 6 Say £5 a ton for pig worth £5 16s to.b., Swedish ports., "But the beauty of 'this process is the fact that it can be applied in very small •units and at a very small cost, and further that the purity of the ore lends itself to the production of steel castings of the highest quality. We are thus in the happy position of making molten metal worth from £10 to £100 a ton, and labour and transport costs do not assume such a prohibitive aspect. Adding an electric refining furnace and assuming an output of 3000 tons of steel castings a, year, we could attain oar result on a capital of £25,000. Personally I believe that the ore could be found in commercial quantities much more rich in magnetite •than I have assumed, and p^ig, at under £4 a ton is, I think, in sight, even on such a small scale of working as this."

>re 10 tans (iriiniiig 2s 6d, drying 6d, concentrating Is 6d) ■Ttiel labour at furnace lepairs „.. [nterest £ s. d. 2 5 0 1 10 0 0 10- 0 0 2 0 0 2 6