摘要 |
The preparation of a granular substrate comprises making a mixture of a bonding agent and kieselguhr in a proportion of from 70 to 50 parts by weight of bonding agent to from 30 to 50 parts by weight of kieselguhr, adding 50 parts by weight of water, with reference to the weight of the said mixture, to create a wet mixture, preparing grains or pellets from the wet mixture, drying the grain or pellets and heat treating the grains or pellets at temperatures of 750 DEG C or more for from 0.3 to 2 hours. The mixture can have added to it organic substances and the bonding agent may be clay and/or water- glass. The pellets are especially suitable for use as a hydroponics substrate. |