| 摘要 |
<p>Purified zirconium silicate is obtained from zircon ores by forming a melt of the ore with alkali metal bisulphate and charging the resulting melt into an extractor into which water is introduced at a rate sufficient to carry off the light mineral and precipitated impurities with the overflow. The residue may be subsequently agitated in the presence of water to separate further free silica &c., and this may be followed by a dry separation, for example by means of a controlled air blast. Zircon, preferably without previous milling or the like, is heated in a rotary furnace with 0,5 to 1,25 parts of nitre cake at 500--700 DEG C. for about 2--8 hours. The melt is cooled, crushed and extracted with water, impurities being removed by overflow washing. U.S.A. Specification 1,451,004 is referred to.</p> |
