Method for compactly sintering chromium oxide aggregate

Abstract

The invention discloses a method for compactly sintering a chromium oxide aggregate. The method comprises the following steps: after pressing and forming pure Cr2O3 micro powder or Cr2O3 compound micro powder, putting into an electric heating kiln or a heater type kiln, keeping the total pressure in the kiln, controlling CO differential pressure in the kiln and reducing and sintering a Cr2O3 material in a CO atmosphere maintained by carbon; firstly, vacuumizing when sintering, then filling Ar gas or Ar+CO gas of a protective gas, sintering at the temperature of 1400-1600 DEG C, keeping the temperature for 2 hours at the temperature and obtaining the pure Cr2O3 aggregate which is compactly sintered. The method has low labor strength, convenient and controllable sintering, low sintering temperature, environmental protection and energy saving, is safer than a method adopting an H2 atmosphere for sintering and is a good method for compactly sintering the aggregate with high chromium.

Description

technical field [0001] The invention belongs to the technical field of sintering of high chromium refractories, and relates to a method for dense sintering of chromium oxide aggregates. The method adopts an electric heating method and is densely sintered in a lower sintering temperature and a CO reducing atmosphere to obtain pure chromium oxide aggregates. or high chromium aggregate. Background technique [0002] Texaco coal gasifier can use low-grade coal such as coal slime and lean coal produced by coal preparation to produce industrial gas such as fertilizers and city gas. It is a key equipment for comprehensive utilization of coal with high efficiency and low pollution. Alkali-free glass fiber is mainly used for fiber reinforced materials, which can improve my country's international competitiveness in the field of new materials. High-chromium refractories are irreplaceable high-grade refractories for coal gasifiers and alkali-free glass fiber tank kiln linings, but the...

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Problems solved by technology

[0007] 2. Controlled atmosphere sintering: P.D.Ownby and Junquist use controlled CO / CO 2 The ratio of the oxygen partial pressure of the sintering system is strictly controlled (in Cr 2 o 3 equilibrium oxygen partial pressure), so that pure Cr 2 o 3 The density after sintering reaches 98% of the relative density; however, the partial pressure of oxygen in the sintering process is difficult to control and can only be used in laboratory research, which is not conducive to industrial production

[0008] 3. Buried carbon sintering and composite buried layer sintering: Japan's Yamaguchi Akiyoshi and others adopted the method of buried carbon sintering, and sintered at a lower temperature to obtain dense Cr 2 o 3 -ZrO 2 Composite materials; however, after sintering, there is a dense, hard-to-remove carbide layer on the surface of the material, which affects the sintering of the product, and produces smoke pollution during the sintering process, consuming a large amount of carbon

This sintering method has a high sintering temperature and consumes a lot of energy during the sintering process;

[0011] 5. Geng Keming et al. adopted H 2 The atmosphere can be sintered to obtain dense chromium oxide materials, but with this sintering method, there is H 2 Explosive and other potential safety hazards, and H 2 The cost is also higher

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