(1. Department of Materials Science and Engineering, Tsinghua University; Beijing100084; 2. Inner Mongolia Baotou Jingyuan Graphite Co., Ltd. 0 14030)
This project is a technical achievement jointly developed by Tsinghua University Department of Materials Science and Engineering and Baotou Jingyuan Graphite Co., Ltd. after four years of careful research and development, and during the Tenth Five-Year Plan period, the "863" project was combined with the Tenth Five-Year Plan project and Industry-University-Research.
First, the content introduction
Industrial production technology of (1) high-quality expandable graphite
High quality expandable graphite is the raw material for producing high quality flexible graphite. In this project, the technology of preparing high-quality expandable graphite by chemical method with environmentally friendly hydrogen peroxide as oxidant was developed and trial-produced. Expansion volume ≥ 160 mL/g, and sulfur content after expansion ≤ 800× 10-6. At present, there is no similar technical report, and China has applied for a patent for invention (patent application number: 2004 10090866.2 "Method for manufacturing low-sulfur expandable graphite with hydrogen peroxide sulfate"). According to this technology, Baotou Jingyuan Graphite Company completed the transformation of the production line with an annual output of 2000 t of high-quality expandable graphite according to the key plan (see P527).
(2) Preparation technology and products of porous graphite.
Porous graphite (expanded graphite) has super-high adsorption capacity for oil, which can effectively control oil pollution in water. It is the international leading research achievement in Tsinghua University, and the adsorption capacity of loose expanded graphite for heavy oil is more than or equal to 80 g/g. The technology and products for preparing low-density porous graphite plates with expanded graphite have been developed, and the invention patent has been declared (application number: 2004 10037978. 1, a method for preparing and recycling polluted adsorbents). For the low-density board with the density of 0.02 ~ 0.08g/cm3, in the water lubricating oil system, more than 90% of the adsorbed substances are lubricating oil, and the adsorption capacity is ≥ 10g/g ... It also has a good removal effect on COD pollution in printing and dyeing wastewater. It has been used in the treatment of oily cooling water in rolling mills and sewage in wool mills. Porous graphite is developed for the graphite market of high-energy batteries. Based on this, Baotou Jingyuan Graphite Company expanded the index of building a 50t/a pilot production line of porous graphite proposed in the research task book to a 300t/a production line (see P528).
(3) high purity graphite micropowder production technology.
High purity graphite micropowder is an important raw material of graphite and nuclear graphite for high-energy batteries. This project has developed the industrial production technology of high purity graphite micropowder. Using medium-carbon graphite with carbon content of 92% ~ 94% as raw material, the (c) was purified to high purity graphite ≥99.9 by soaking in molten alkali and compound acid, and then the fine powder with d50 = 8 ~ 20μ m was made by airflow crushing technology. A classifier for silicon nitride ceramic impeller was developed, which can prevent metal pollution. Impurities are less than 50× 10-6 Fe, 2× 10-6 Cr, 5× 10-6 Ni, 3× 10-6 Cu and16 Mo. Tsinghua University has obtained a utility model patent (ZL200420084694.3) "A silicon nitride ceramic grading blade for grading high-purity powder", and Baotou Jingyuan Company has applied for an invention patent: application number (2004 10009068.2) "Processing technology and system of high-purity fine powder flake graphite". According to the market demand, the original 300t/a production line was expanded to build 1500t/a high purity graphite fine powder production line.
(4) Preparation technology of flexible graphite bipolar plate
Using the high-quality expandable graphite of Baotou Crystal Graphite Company as raw material, the expanded graphite with high expansion rate was made and directly molded into flexible graphite bipolar plate. Electrical conductivity ≥ 105S/m, thermal conductivity ≥100 w/(m k), and air permeability ≤ 10-6μm2, all of which are superior to bipolar plates processed by artificial graphite. The proton exchange membrane fuel cell of Beijing Feichi Green Energy Power Technology Co., Ltd. has been running for more than 100 h, and its performance is the same as that of imported artificial graphite bipolar battery. This technology has been patented and authorized (patent number ZL2004 1000846 1. X) "Preparation method of flexible graphite bipolar plate".
Second, popularization and application
The industrialization part of the technical achievements of this project has achieved obvious economic and social benefits. Relying on the industrialization of project achievements, Baotou Jingyuan Company increased its output value by 55% and profits and taxes by 68% from 200/kloc-0 to 2003. The graphite micropowder used in domestic high-energy battery factories has been changed from imported to supplied by Crystal Company. High purity graphite micropowder of Jingyuan Company has the first-class technical index of international battery graphite, and more than 80% of high-quality expandable graphite is exported. Jingyuan Company has established good business cooperation with Duracell, the world's largest battery production group, Temico Company of Switzerland, Roland Company of France and SGL multinational group, and the market will be further expanded. At the same time, Jingyuan Company won the Outstanding Contribution Award of High-tech Industrialization in Baotou Rare Earth Emerging Industry Development Zone in February 2003.
Three. Identification, awards and patents
Four invention patents have been applied for this project, including 1, and utility model patents 1 have been applied for and authorized, and a number of internationally leading or advanced scientific and technological achievements with independent intellectual property rights have been achieved in the field of deep processing of natural graphite. During the project, * * * published more than 20 papers, 8 of which were included in SCI.