Coating Ability and Corrosion Resistance of Basic Brick.pdf

May 12, 2018 | Author: sadatjafari | Category: Cement, Scanning Electron Microscope, Titanium Dioxide, Sintering, Refractory
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ournal of Medical and Bioengineering (JOMB) Vol. 1, No. 1, September 2012

Coating Ability and Corrosion Resistance of Basic Brick with TiO2 for Rotary Cement Kilns S. Ghanbarnezhad, M. Bavand-Vandchali, A. Nemati and R. Naghizadeh their eutectic of 2135 C is much higher than the burning temperature of cement (1450 C). Because of different thermal expansion coefficients between spinel and the magnesia matrix a microcrack system exists in the brick, which results the addition of alumina and titania(TiO2) to a magnesia composition and the spinel is formed during the brick firing  by an in-situreaction[5]. Magnesia-spinel bricks are highly thermal shock resistant (not sensitive against reducing /oxidizing conditions, but are attacked by thermal overload [6]. On the other hand, spinel forms low-melting low-melting phases with the result of a premature wear. To overcome this problem, latest development are directed at an increasing use of MgO-TiO2  products[7]. To use magnesia-spinel bricks, which were developed for transition zone,which the  beneficial property of non-adherence of cement clinker, in the burning zone, the properties of coating adherence and corrosion resistance must be improved.[8-9] In this paper reports the results for Cr-free brick used in focus area of rotary cement kilns, together with the development of an improved brick with lower thermal conductivity.

 Abstract  —The magnesia-chrome brick which have long been used in the burning zone of rotary cement kilns but the considerable amount of water soluble, hexavalent chromium ion has been reported for used this bricks. So, magnesia-chrome bricks are being replaced with chrome-free brick mainly of magnesia -spinel type. Due to the progress with Cr-free lining, together with the reduction of cement production,such problems as instability of the cement coating, corrosion resistance of brick and, etc., wich affect the stability of kiln operation, and require further improvement. In this research, the positive effect of TiO2  addition on the coating ability and corrosion resistance of basic brick is reported. Thus, 0, 2, 4, and 6 wt.%TiO2r  atios were used in the blend(grain size distribution in the blend was 1-4mm, 0-1mm and
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