Zheng Shuilin, Wang Guangyu, Li Yangjiang, Zhongqiang, Du Gaoxiang, Yang Hongcai, Liu Fulai, Wang Yanling, etc.
(School of Chemistry and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083)
1. Introduction
Using low-grade diatomite as raw material, we use physical purification, ultrafine and surface treatment, chemical methods (alkali dissolution, acid precipitation) and particle barrier technology to prepare ultrafine and nanometer silica. The main technical indicators of the product are as follows: ① Physical ultrafine silica: SiO2 content (dry basis) ≥90%, pH=6.5~7.5, specific surface area 50~100 m2/g, pore volume 0.2~0.6 mL/g; fine Degree d97≤2～3μm (average particle size≤1μm), oil absorption value (150±50) mL/100 g. ②Chemical ultrafine silica SiO2 content (dry basis) ≥99%, pH=5.5~7.0, specific surface area 300~450 m2/g, pore volume 0.6~2.0 mL/g, whiteness ≥92; average fineness Particle size (centrifugal sedimentation) 1 ~ 3μm, oil absorption value (280±50) mL/100 g. ③Nano silica: SiO2 content (dry basis) ≥99%, pH=5.5~7.0, specific surface area 400~700 m2/g, pore volume 0.4~1.5 mL/g, whiteness ≥92; particle size (transmission electron microscope) ) 10～60nm, oil absorption value (310±50) mL/100 g.
The project conducted an expanded test based on the meticulous preparation conditions and experiments in the laboratory, from a small comprehensive laboratory test to an enlarged test magnified 800 times. The results are generally better than the small laboratory test. During the expanded test, although the comparative surface area indicators were purposefully adjusted through the precipitation process and particle barrier agents, the whiteness and purity indicators of the samples were basically stable.
2. Promotion and application
A 3×104t/a ultrafine silica production line is under construction in Linjiang City, Jilin Province and has been partially put into production (the second batch of Northeastern old industrial bases in Jilin Province Adjustment and transformation of national debt projects).
The main target markets for the physical ultrafine silica in this project are rubber shoes and other light-colored rubber products except tires; the main target markets for the chemical ultrafine silica are "green tires", Paints, coatings and inks (thickeners and matting agents), functional plastics, silicone rubber, etc.; the main target markets of nano-silica are color inkjet paper, silicone rubber, paints, coatings and inks (matting agents), chemical fiber fillers, etc. These fields are closely related to modern high-tech and new material industries, with rapid development and good market prospects. The application of these materials is of great significance for comprehensive utilization of resources and environmental protection.
3. Appraisal, awards, and patent status
The achievement passed the technical achievement appraisal organized by the Jilin Provincial Department of Science and Technology on June 28, 2004.
The core technology of this project has passed the substantive review of the State Intellectual Property Office and has been authorized (Patent No.: ZL 02156764.6; authorization announcement date: July 27, 2005).