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Chromium-free alkaline brick for cement kiln and preparation thereof

A technology of cement kiln and alkaline brick, which is applied in the field of refractory materials, can solve the problem of high energy consumption, and achieve the effects of energy saving, high bulk density, good strength and toughness

Inactive Publication Date: 2009-07-08
WUHAN UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with the aforementioned methods, this patented process is simple, and the performance of the product is also good in all aspects, but it consumes a lot of energy due to high temperature firing

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] A chrome-free basic brick for cement kiln and its preparation method: first, 90-96wt% magnesia, 2-7wt% Al 2 o 3 It is mixed with 1-5wt% of Fe, and 3-4wt% of the above-mentioned water glass solution is added, and then kneaded, shaped and dried and hardened.

[0013] In embodiment 1: the particle gradation of magnesia is, 5~0.088mm is 60~63wt%, 0.088~0mm is 30~33wt%; Fe and Al 2 o 3 The particle size is 0.088~0mm; the pressure of machine pressing is 150~250MPa.

[0014] The main physical properties of the prepared chromium-free alkaline bricks are: the bulk density is 3.14g / cm 3 , The apparent porosity is 13-16%, and the compressive strength is 60-80MPa. After sintering at 1500°C for 3 hours and cooling naturally, the XRD test results showed that the main crystal phase was periclase, and FeAl was also detected 2 o 4 and MgFe 2 o 4 , MgAl 2 o 4 solid solution, and a small amount of Fe 2 o 3 and Fe 3 o 4 .

Embodiment 2

[0016] A chrome-free basic brick for cement kiln and its preparation method: firstly mix 85-90wt% magnesia, 2-7wt% Al 2 o 3 , 2~7wt% Fe and 2~6wt% Fe 2 o 3 Mixing, adding 3.5-4.5wt% sodium tripolyphosphate solution of the above-mentioned mixture, and then performing kneading, molding and drying hardening treatment.

[0017] In embodiment 2: magnesia particle gradation is, and 5~0.088mm is 58~61wt%, and 0.088~0mm is 27~29wt%; Fe, Fe 2 o 3 and Al 2 o 3 The particle size is 0.088 ~ 0mm; the pressure of machine pressing is 100 ~ 200MPa.

[0018] The main physical properties of the prepared chromium-free alkaline bricks are: the bulk density is 3.10g / cm 3 , The apparent porosity is 15-17%, and the compressive strength is 50-70MPa. After sintering at 1500°C for 3 hours and cooling naturally, the XRD test results showed that the main crystal phase was periclase, and FeAl was also detected 2 o 4 and MgFe 2 o 4 , MgAl 2 o 4 solid solution, and a small amount of Fe 2 o 3...

Embodiment 3

[0020] A chromium-free basic brick for cement kiln and its preparation method: firstly mix 80-85wt% magnesia, 7-12wt% Al 2 o 3 , 2-5wt% of Fe, 2-8wt% of iron-aluminum spinel and 2-4wt% of Fe 2 o 3 Mixing, adding 4.5-6wt% sodium hexametaphosphate solution of the above-mentioned mixture, and then performing kneading, molding and drying hardening treatment.

[0021] In the present embodiment 3: magnesia particle gradation is: 5~0.088mm is 55~58wt%, 0.088~0mm is 25~27wt%; Fe, Fe 2 o 3 and Al 2 o 3 The particle size of iron-aluminum spinel is 0.088-0mm; the particle size of iron-aluminum spinel is 0.088-0mm, and the pressure of machine pressing is 150-250MPa.

[0022] The main physical properties of the prepared chromium-free alkaline bricks are: the bulk density is 3.15g / cm 3 , The apparent porosity is 13-16%, and the compressive strength is 60-95MPa. After sintering at 1500°C for 3 hours and cooling naturally, the XRD test results showed that the main crystal phases were ...

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Abstract

The invention particularly relates to a chromium-free basic brick for a cement kiln and a preparation method thereof. The preparation method adopts the technical proposal that: firstly, mixing 45 to 96 weight percent of magnesia, 2 to 17 weight percent of Al2O3, 1 to 10 weight percent of iron, 0 to 40 weight percent of hercynite or magnesium aluminate spinel and 0 to 10 weight percent of Fe2O3, and adding a water glass solution or a sodium tripolyphosphate solution or a sodium hexametaphosphate solution which is 3 to 6 weight percent of mixed materials; and secondly, performing mixing, forming, roasting and hardening treatment. The preparation method utilizes a high-temperature environment at a temperature of 1,500 DEG C when products are used to generate the hercynite through in-site chemical reaction in the service process of unfired bricks, so that the chromium-free basic brick for the cement kiln has the superior characteristics of periclase-hercynite bricks. The preparation technology is simple, does not require high-temperature firing, and saves energy resources; and metallic combination is formed in green bricks through plastic phase transition of metallic phases under the action of forming pressure, and has the function of reinforcing and plasticizing the green bricks, so that the green bricks have large volume density, high strength and good thermal shock stability.

Description

technical field [0001] The invention belongs to the technical field of refractory materials, and in particular relates to a chrome-free basic brick for cement kilns and a preparation method thereof. Background technique [0002] In 2003, the German Refa Group found that introducing pre-synthesized iron-aluminum spinel into chromium-free basic bricks can significantly improve the adhesion of the kiln skin. The product has high refractoriness, good alkali resistance, Sulfur, chlorine and clinker etc. attack ability and thermal shock resistance. Therefore, periclase-aluminum spinel brick is the most promising material among the industrial alternative materials of magnesia-chrome brick. [0003] Cement rotary kilns have long used magnesia-chrome bricks as high-temperature kiln linings. In use, part of the chromium in the brick will change from Cr 3+ into highly toxic and carcinogenic Cr 6+ , thereby damaging the environment and threatening human health. With the continuous ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/66
Inventor 汪厚植冯运生顾华志王林俊范泳杨斌
Owner WUHAN UNIV OF SCI & TECH
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