CEMENT PRODUCTION

Waipa Post, Volume 42, Issue 3305, 4 June 1931, Page 8

CEMENT PRODUCTION

f V TRIBUTE TO NEW ZEALAND l 5 ARTICLE. ■ •• V “I am certain that if the best ceA.ment is wanted for the best building i£ is quite unnecessary to go beyond Mrthe confines of New Zealand. The cement produced in this country is equal to - any similar product in the 'world,” said Mr C. G. Bryan-King | during the course of an address 01 cement at Timaru. wmz;c' early history. i'i There was a concrete thousands of

years ago, said the speaker, but it was j i vaflime concrete, and lime concrete was usjed'centuries farther back still. The tf. pyramids of Egypt, dating back some ■a . and a mortar was used upon them as 4. a cementing material. Thgseanae ap 5$ plied to the Parthenon of built .S, about 440 B.C. The dome''Bppfiq-Pan-f thenon at Rome, construcWfNmtrcely the concrete of that day, was still tflin a good state of preservation after :';#2000 years. In 1824 Joseph Aspdin, (tffii bricklayer of Leeds, found that b Bfe mixing in specified proportions finely,v pulverised chalk and clay, burning lllfhem at a high temperature, and I'Mgrinding the resulting clinker, he was " able to produce a hydraulic binding material far superior to any product fefknowh up to that time. As the colour f : ’ of'this material bore a real or fancied ; ilsemblance to that of Portland stone IpMspdin called the product “ Portland ” ' ■ .cement, the name under which it was . patehted, and the hamle by which this Ipjclass of cement had been known ever lllsinoe. The Portland cement of that produced by crude methods, and with comparatively little chemical knowledge, was not comparable with cement of to-day, the manufacture of which was a highlyv scientific process, in which highly- : .machinery was employed, carried, out by . skilled operators, and checked by expert chemists. .‘MODERN METHODS. » ,j the assistance of the different ;V ingredients of the finished product, plMr: Rryan-King went on to tell his . the modern methods used pi^hht>ih:up-to-date works the manufac- ; : ; ture was controlled at every stage, arid tesfel were carried out in the lau or at6r»? every hour, and often every jfßPP^lffur f day and night. Only in Biy could the reliable article, hey knew as Portland cement, luced. The component parts ent, he said, were limestone irl (a type of clay). The was taken from a tippler into ;r by an elevator to a bin havcapacity for 600 tons. The as sent to a washing mill conhorizontal arms, and with the l of a quantity of water, was ed into what was known as s||;ftur^iY. ! The marl was then pumped loli|into jblarge silo, while the lime was R the maw of a wet combina’by means of a belt conveyor rolving table. Simultaneously •y was mixed with the lime is of a large wheel of the ype. The combination mill en by a 450-h.p. engine, and ded into four compartments, l and steel balls were utilised rith the wet mash, which was ds pumped into three silos a capacity of 300 tons for poses of solidification. The cess was the bringing of the to the clinker stage by means uUge rotary kiln, which was Mned, and fed by coal pra%yiously dried and pulverised and ir fw hited by electricity. The pulverised preparation was necessary to ensure that no cinder or ash adulterated the clinker. This passed into an aircooled cylinder, and after being auto- .. : matically screened and weighed by ■process it was conveyed into the ge bins. The final crushing came .a shaker device fed the conveyor supplied the feeding tables with jr, which was fed into the finishdill in a similar manner as limestone was supplied to the wet combination mill. The finished product was then stored in large bins until vV- dealt with by the bagging machine, which automatically filled, weighed, and sewed the bags, preparatory to r; railing. p TESTS NECESSARY. V Mr Bryan-King mentioned that the f v. cement could not be marketed unti - extensive tests were carried out, so that the product reached the standard British specifications. The seven ! V; tests, which the speaker demonstrated, included fineness, chemical as per ?/ formula, and tests as to the cement’s . ■ strength and adhesive powers. New 8 Zealand cement, it had been proved, • was far ahead in quality of .the tests i'y required.:. •, - '■’ ■