CORRESPONDENCE.

Taranaki Daily News, Volume LVII, Issue 258, 10 April 1915, Page 5

CORRESPONDENCE.

TARANAKI BASIC SLAG. (To the Editor.) Sir, —Your esteemed correspondent J. B. Simpson asks for information as £o the method of making slag fertiliser. Tin: slag from blast furnaces was thrown away as useless for many years until Thomas and Gilchrist proved that slag from steel making furnaces had special fertilising properties. Further experiments with ordinary blast furnace slag proved that slag manure could (be produced l>y running tlie molten slag through a water-cooled tube, where it is transformed into a powder suitable either as a fertiliser or to jbe used as cement. My father made slag cement over forty years ago, and samples were placed on Mount Egmont and stooifthe intense cold, thereby proving its value. Cries and ijuid mines argues that we cannot produce slag with the required phosphatic contents. In answer to them I may say that tests have been made by competent judges with slag made lqcally, anil these tests have proved that there is no need to depend on any other country for basic slag. Mother Nature has bestowed on us all the necessary ingredients as well as having vast deposits of limestone to use i\s the'.most important factor in the manufacture of slag manures or slag cement. Please note, in the accompanying analysis I>\ the Mines Department of samples submitted by my father the phosphatie and sulphuric contents of our binding agents and fluxes, all recovered which would pay all the cost of producing iron and steel. Private enterprise seems unable to develop this all important industry. Why not tlie State, which has all the advantages?—! am, etc. J. 0. SMITH. (A copy of this interesting analysis accompanied Mr. Smith's letter, but is of a technical nature not lending itself to ready presentation of its contents and meanings.—Ed., D,N.)