| 摘要 |
<p>Glass fibres are disclosed for use as constituents in a substrate for soilless cultivation. Their composition consists essentially of the following components in the proportions indicated in % by weight : 55 - 70 % SiO2, 1 - 8 % Al2O3, 5 - 9 % CaO, 1,5 - 4 % MgO, 13 - 18,5 % Na2O, 0,5 - 10 % K2O, 0 - 4 % Fe2O3, 0 - 4 % ZnO, 0 - 4 % MnO, 0 - 4 % TiO2, 0 - 4 % P2O5, less than 1 % impurities. The total content of B2O3, Li2O and F does not exceed 1 %.</p> |
