Patent TW-527233-B (TW)
Title: Water quenched converter slag powder wetting method for inhibiting re-expansion of fundamental filling material of converter
Inventor: WANG CHIN-CHUNG
IPC: B09B3/00
Filed: 2002-06-18
Granted: 2003-04-11
Abstract: This invention utilizes the characteristics of water quenched converter slag powder, by adding water to the slag to form a stable, thickening stable material, and selecting an appropriate amount of the stable material to wrap over the surface of the converter slag so as to obtain an re-expansion inhibited slag based fundamental filling material having the features of: (1) insulating external moisture from excessively invading into the converter slag; (2) filling up voids of the converter slag particles to reduce the compressibility and permeability thereof and enhance shear strength thereof; (3) densifying the converter slag particles by means of the hydrolysis reaction of the water quenched converter slag to from a continuous substrate; and (4) reducing f-CaO content by the decomposition of f-CaO into CaOH, thereby enhancing steadiness of the converter slag particles. Certificate test of the present invention is done by following CNS 14602 specification for re-expansion test to determine the effect of suppression of the re-expansion. In practice, converter slag having 6.8% f-CaO content (which is the highest f-CaO content for the time being) is selected and divided into (1) test group and (2) reference group. The reference group contains pure converter slag, while the test group contains converter slag that is wrapped with water quenched converter slag powders as the test material. Test bodies are solidified according to CNS 14602 specification and the solidified test bodies are dipped into water of 80±3 DEG C for 6 hours every day for ten days. The re-expansion amount is measured, which reveals that the re-expansion amount increases with the time of development. The pure converter slag of the reference group has the greatest increase in the re-expansion amount, which reaches 4.3% after ten days. On the contrary, the converter slag that has been wrapped with water quenched converter slag powder only has a re-expansion of 0.9% after the ten day test. This apparently shows that the water quenched converter slag powder wetting technique is effective in suppressing the re-expansion of the converter slag. Microscopic observation by means of scanning electronic microscopic shows that the converter slag is a porous material. The water quenched slag wrapped over the converter slag gradually grows into hydrolysis product due to the hydrolysis reaction of the quenched slag powder, the hydrolysis products eventually filling up the hydrolysis space, bonding the converter slag particles together as a continuous and solid substrate and thus reducing the re-expansion space available. This sufficiently proves that the water quenched converter slag powder wetting technique is effective in suppressing the re-expansion of the converter slag and the converter slag that is processed by the water quenched converter slag powder wetting technique is an excellent filling material with suppressed re-expansion, worth the use by industry.