公开(公告)号：US3843341A

公开(公告)日：1974-10-22

申请号：US31119172

申请日：1972-12-01

Applicant: PPG INDUSTRIES INC

Inventor： HAMMEL J ,  ALLERSMA T

IPC: C03B8/00 ,  B01D39/06 ,  B01D53/86 ,  B01J20/00 ,  B01J20/32 ,  B01J21/08 ,  B01J21/12 ,  B01J37/06 ,  C02F1/68 ,  C03B20/00 ,  C03C3/04 ,  C03C3/06 ,  C03C3/064 ,  C03C3/089 ,  C03C3/091 ,  C03C4/00 ,  C03C11/00 ,  C03C12/00 ,  C03C15/00 ,  C03C23/00

CPC classification number: B01D71/04 ,  B01D39/06 ,  B01D53/86 ,  B01D67/0058 ,  B01J21/08 ,  B01J37/06 ,  C02F1/681 ,  C03C3/06 ,  C03C3/064 ,  C03C3/089 ,  C03C3/091 ,  C03C11/005 ,  C03C15/00 ,  C03C23/008 ,  C03C2201/10 ,  C03C2201/32 ,  C03C2201/50 ,  C03C2201/80 ,  C03C2203/10 ,  C03C2203/50 ,  Y10T428/31 ,  Y10T428/315

Abstract: 1. A METHOD FOR MAKING A LOW ALKALI-CONTAINING POROUS GLASS ARTICLE HAVING A HIGH THERMAL STABILITY COMPRISING: (A) HEATING A PHASE-SEPARABLE ALKALI-BOROSILICATE GLASSS TO A TEMPERATURE SUFFFICIENT TO SEPARATE THE GLASS INTO TWO PHASES, ONE OF WHICH IS A BORATE-RICH PHASE AND IS SOLUBLE IN AN AQUEOUS SOLUTION, (B) A FIRST LEACHING OF THE PHASE-SEPARATED GLASS WITH WATER FOR A TIME AND AT A TEMPERATURE SUFFICIENT TO REMOVE A MAJOR PORTION OF THE BORATE-RICH PHASE TO FORM A POROUS GLASS HIGH IN SILICA, (C) A SUBSEQUENT LEACHING OF THE PREVIOUSLY LEACHED POROUS GLASS WITH AN ACID FOR A TIME AND AT A TEM-

PERATURE SUFFICIENT TO REMOVE SUFFICIENT ALKALI AND BORATE NOT REMOVAL IN THE FIRST LEACHING TO PROVIDE A LOW ALKALI-BORATE CONTAINING MICROPOROUS GLASS STRUCTURE HAVING A HIGH THERMAL STABILITY.