Unshaped refractory for heat treatment furnace and lining structure of the furnace

Abstract

The invention provides an alkaline monolithic refractory used in a lithium composite oxide heat treatment furnace and an inner lining structure of a furnace using the same. The basic monolithic refractory used in a lithium composite oxide heat treatment furnace is not constructed After setting the refractory, during the sintering process, the densification of the joints and the intrusion of lithium vapor into the joints due to densification do not occur. An alkaline monolithic refractory used for lining joints of furnaces for heat treatment of lithium composite oxides, in the basic monolithic refractory containing refractory clay and refractory aggregates, as the refractory aggregates, Containing 96 to 99.5% by mass of magnesia raw material, as the refractory clay, clay with an alkali metal oxide content of 1 to 5% by mass, 95% by mass or more of the refractory aggregate has a particle size of 0.3mm or less, The normal temperature bending strength after heating is 1.0 MPa or more.

Description

technical field [0001] In particular, the present invention relates to a monolithic refractory for a heat treatment furnace suitable for heat treatment of a lithium composite oxide, and an inner lining structure of a furnace using the refractory. Background technique [0002] Lithium cobaltate (LiCoO 2 ), lithium manganate (LiMnO 2 ), lithium nickelate (LiNiO 2 ), lithium iron phosphate (LiFePO 4 ) and other lithium transition metals. As the currently used cathode material, lithium cobaltate is the mainstream. [0003] For example, making LiCoO 2 At the same time, the mixture of lithium hydroxide or lithium nitrate and cobalt oxide, cobalt hydroxide or cobalt carbonate is added into the container as a raw material, and fired in a fixed furnace or a tunnel furnace, or directly put into a rotary furnace for firing . This firing is performed in an oxygen atmosphere at a temperature around 1000°C. [0004] As the furnace material for the lining of the firing furnace for ...

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Problems solved by technology

[0005] However, using a firing furnace lined with a furnace material made of this heat-resistant ceramic material under the aforementioned firing temperature conditions produces LiCoO 2 At this time, the following phenomenon occurs: the lithium compound melts during the firing, and further, the lithium element derived from the compound evaporates under the high temperature condition in the furnace and invades into the lining material (hereinafter referred to as the furnace material) in the furnace.

Therefore, there is a problem that after repeated use of the firing furnace, cracks or peeling will occur in the furnace material, requiring frequent replacement of the furnace material.

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