| 摘要 |
<p>A process for the manufacture of Zeolite-A useful as a detergent builder, which comprises: i) dilution of sodium aluminate liquor obtained as a pregnant liquor from Bayers process and having a concentration of at least 140 gpl of alumina therein and adjusting Al2O3-Na2O molar ratio to 0.5±0.01, ii) throroughly mixing alkali, water and sodium silicate to obtain a mixture with molar ratios SiO2-Na2O in the range of 1.25-1.66 and H2O-Na2O in the range of 35-45, iii) dosing hot sodium aluminate solution at a temperature in the range of 50-60 °C to the sodium silicate solution at ambient temperature with continuous mixing to obtain a synthesis mixture/crystallization bath having molar ratios: SiO2-Al2O3 in the range of 1.6-2.0, Na2O-SiO2 in the range og 1.6-2.0, H2O-Na2O in the range of 30-40, iv) heating the crystalisation bath at a temperature in the range of ambient to 95 °C for a period in the range of 45 to 75 minutes under condinuous strirring, v) recovering Zeolite-A by filtration and washing followed by drying and pulverising.</p> |
