| 摘要 |
<p>Prod. is obtd. by pptn., and the metal (A) in the prod. is Pb, Zn, and/or an alkaline earth metal, where the molar ratio SiO2 : MO is min. 2:1 and pref. 3-5:1; and the prod. has a loss on ignition (LOI) above 500 degrees C of practically zero. The prod. is pref. made by mixing a soln. (I) of an alkali silicate with a soln. (II) of a salt of metal (M), so at least part of the alkali is replaced by metal (M) and the prod. is sepd. from the mother liq. An excess of soln. (II) is pref. used and the mother liq. and/or the wash water is recycled. The salt is soln. (II) is pref. a nitrate; and the prod. is pref. used in the mfr. of glass which can be rapidly refined and has a low m.pt. Used esp. for the mfr. of a prod. contg. Pb and a large amt. of SiO2.</p> |
