Process for producing transparent siliceous filling agent based on silica

Zp sob v²roby transparentn ho k°emi it ho plniva na b zi oxidu k°emi it ho spo v v tom, e se z°ed n sodn vodn sklo o koncentraci 5 a 14 % hmotn. SiO.sub.2.n. sr 5 a 14% H.sub.2.n.SO.sub.4.n. p°i teplot 50 a 99 .degree.C po dobu 90 a 240 minut. Rychlost d vkov n 5 a 14% H.sub.2.n.SO.sub.4.n. se ° d tak, aby k v²padu SiO.sub.2.n. doÜlo za 40 a 70 minut od po tku sr en , kter se ukon neutralizac Na.sub.2.n.O p°i pH 6 a 7. Po sr en se provede 1 a 10 hodinov teplotn stabilizace p°i 50 a 99 .degree.C, suspenze se ochlad a odfiltruje, kol se rozm ch s vodou na suspenzi a pH suspenze se uprav kyselinou s rovou. Suspenze se usuÜ a nebo znovu odfiltruje a kol se usuÜ a rozemele.\ In the present invention there is disclosed a process for producing silica-based transparent siliceous filling agent, which production process is characterized in that diluted sodium-silica glass with concentration of 5 to 14 percent by weight of sioi2 is precipitated with 5 to 14 percent sulfuric acid at a temperature ranging from 50 to 99 degC for a period of 90 to 240 minutes. Metering rate of the 5 to 14 percent sulfuric acid is controlled so that sioi2 discharge takes place after lapse of 40 to 70 minutes from the beginning of precipitation, which is then terminated by neutralization with nai2o when ph value ranging within 6 to 7 is achieved. After precipitation, 1 to 10 hour lasting thermal stabilization at a temperature ranging from 50 to 99 degC is carried out, the suspension is cooled down and filtered off, the cake is mixed with water to form a suspension, and ph value of the suspension is adjusted using sulfuric acid. Finally, the suspension is dried or filtered off again and the cake is dried and ground. The method of production of transparent silicone filler based on silicon oxide consists in the fact that diluted sodium water-glass with a concentration of 5 to 14 % by weight of SiO2 precipitates with 5 to 14% H2SO4 at a temperature of 50 to 99 degrees C for a period of 90 to 240 minutes. The rate of dosing of 5 to 14% H2SO4 is managed so that the breakdown of SiO2 occurs within 40 to 70 minutes from the start of precipitation, which is terminated by the neutralisation of Na2O at a pH of 6 to 7. After precipitation there is a 1 to 10 hour temperature stabilisation at 50 to 99 degrees C, the suspension is cooled and filtered off, the precipitate is mixed with water into a suspension and the pH of the suspension is modified by sulphuric acid. The suspension is dried and/or filter