CN105314992A - Chromium-free fireproof material used for cement rotary kiln and having excellent kiln coating adhering performance - Google Patents

Abstract

The invention relates to a chromium-free fireproof material used for a cement rotary kiln and having excellent kiln coating adhering performance. The chromium-free fireproof material is characterized in that first, periclase and magnesia-alumina spinel (material compositions are MgO and Al2O3 respectively) are taken as main raw materials to be crushed and then mixed in a powder form according to the ratio of 85% to 8% in a formula, and the powder is placed into a box of 1 cubic meter after being stirred evenly and transported to a tunnel kiln to be burned for 60 minutes into light-burned magnesia at the temperature of 800-850 DEG C, wherein the box is made of iron; cooling is performed until the indoor temperature is reached; additives are added into the light-burned magnesia. The chromium-free fireproof material has the advantages that application is convenient, the raw materials are saved, and the cost is lowered.

Description

For cement rotary kiln, there is the excellent Chrome free refractories sticking kliner coating performance

Technical field

The present invention relates to and be a kind ofly applicable to having of cement industry and excellently stick kliner coating performance, Chrome free refractories that corrosion resistance is strong.

Background technology

The development of cement industry derives from the progress of cement clinker calcining process, and the progress of cement kiln is depended on again in the progress of cement clinker calcining process, and cement kiln-progressive be that the progress of the refractory materials used in kiln is as prerequisite.The refractory materials used in present cement kiln become cement mill can for a long time, the key factor of Effec-tive Function, and the key in key is the refractory materials of cement kiln clinkering zone.The Direct bond magnesia-chrome brick that current China new type nonaqueous cement rotary kiln clinkering zone uses in a large number can bring Cr6+ public hazards after using, belong to the kind that must eliminate, and common Mg-Al spinel brick can not be competent at the use of cement rotary kiln clinkering zone completely, so the task of development of new chromium-free brick is extremely urgent.Refractory brick in order to obtain longer work-ing life in new type nonaqueous cement rotary kiln, suitable intensity, good thermal shock resistance must be had, good stick the performance such as kliner coating performance, resisting cement clinker erosion, wherein, sticking kliner coating performance is an important indicator in Novel fireproof brick triturating, because the quality that novel non-chrome brick sticks kliner coating performance directly affects its work-ing life in cement kiln.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind ofly has suitable intensity, the Chrome free refractories of good thermal shock resistance.

Technical characteristics of the present invention is:

(1) periclasite is first got and magnesium-aluminium spinel is that (material composition is respectively MgO, Al to main raw material ₂o ₃) pulverize, in the mixing of formula 85%: 8% ratio powder, put into irony 1 cubic metre of box, be transported to tunnel furnace after stirring, temperature control 800-850 DEG C is fired (60 minutes) and is become caustic-calcined magnesite; Cool to room temperature;

(2) in caustic-calcined magnesite, add additive, additive is difference SiO2ZrO2, La2O3, CaO, Fe2O3, and its additive is in proportion:

MgO: Al ₂o ₃: at room temperature environment with caustic-calcined magnesite mix at SiO2: ZrO2: La2O3: CaO: Fe2O3=85: 8: 1.2: 2: 1.5: 1.8: 0.5, after pulverizing, adds water and stir, and amount of water is by total compound: water=100: 20 proportionings;

(3) in 5T pressing machine extrusion forming (refractory brick), shaping rear drying (under ventilation booth 10 day time of seasoning or dry 36 hours at drying kiln 60-70 DEG C), refractory brick water content≤0.5% after dry;

(4) dry refractory brick calcines 48 hours, cool to room temperature at 1700-1850 DEG C of tunnel furnace, can obtain having excellent stick kliner coating performance without chromium firebrick.

Beneficial effect of the present invention is: convenient application, conservation, reduces cost.

Embodiment:

Below in conjunction with embodiment, the present invention is described in further detail

1, for cement rotary kiln, there is the excellent Chrome free refractories sticking kliner coating performance, it is characterized in that:

(1) periclasite is first got and magnesium-aluminium spinel is that (material composition is respectively MgO, Al to main raw material ₂o ₃) pulverize, in the mixing of formula 85%: 8% ratio powder, put into irony 1 cubic metre of box, be transported to tunnel furnace after stirring, temperature control 800-850 DEG C is fired (60 minutes) and is become caustic-calcined magnesite; Cool to room temperature;

(2) in caustic-calcined magnesite, add additive, additive is difference SiO2, ZrO2, La2O3, CaO, Fe2O3, and its additive is in proportion:

MgO:Al ₂o ₃: at room temperature environment with caustic-calcined magnesite mix at SiO2: ZrO2: La2O3: CaO: Fe2O3=85: 8: 1.2: 2: 1.5: 1.8: 0.5, after pulverizing, adds water and stir, and amount of water is by total compound: water=100: 20 proportionings;

(3) in 5T pressing machine extrusion forming (refractory brick), shaping rear drying (under ventilation booth 10 day time of seasoning or dry 36 hours at drying kiln 60-70 DEG C), refractory brick water content≤0.5% after dry;

(4) dry refractory brick calcines 48 hours, cool to room temperature at 1700-1850 DEG C of tunnel furnace, can obtain having excellent stick kliner coating performance without chromium firebrick.

Add additive La 2O3 and can generate zirconic acid lanthanum sosoloid (La2O32ZrO2) with ZrO2 reaction in refractory materials, containing a small amount of CaO in the zirconic acid lanthanum that reaction is formed, zirconic acid lanthanum is a kind of high melting compound, little on the high-temperature behavior impact of refractory materials.Therefore, zirconic acid lanthanum is that a kind of refractory brick that can significantly improve sticks the kliner coating performance not obvious refractory mineral affecting refractory brick high-temperature behavior again.

The main moiety of novel non-chrome refractory materials is periclasite and magnesium-aluminium spinel, and wherein periclasite accounts for the overwhelming majority, and the introducing of Spinel is the thermal shock resistance in order to improve refractory brick.The coefficient of linear expansion of periclasite and magnesium-aluminium spinel at high temperature differs larger, at the stress that Spinel generation alternate with periclasite is huge in sintering procedure, around some Spinel, generate a large amount of tiny crack, these reasons make novel non-chrome brick also have good thermal shock resistance.

Simultaneously in order to improve the thermal shock resistance of novel non-chrome material further, add zirconium white in novel non-chrome material, ZrO2 can undergo phase transition when temperature changes.During heating, ZrO2 (monoclinic phase) turns to ZrO2 (Tetragonal) at 1200 DEG C of left/right rotations, and volumetric shrinkage nearly 7%, during cooling, ZrO2 (Tetragonal) is converted into ZrO2 (monoclinic phase) at 1000 DEG C, volumetric expansion about 7%.In refractory brick matrix, four directions ZrO2 is high-temperature stable phase, monoclinic zro2 is cryostatic stabilization phase, lower than under transformation temperature condition, owing to being subject to the suppression of matrix, the unconverted cubic ZrO2 of a part is kept its steady state, once the restraint force of matrix weakens or disappears under the effect of external force, ZrO2 particle just can be converted into the monoclinic phase of low-energy state from the Tetragonal of high-energy state.

The tiny crack that ZrO2 produces in phase transition process can play the effect increasing refractory brick toughness.ZrO2 is evenly distributed on refractory brick inside, and the ZrO2 firing rear refractory brick inside is generally rendered as cubic Mass phase.Under the effect of temperature and stress, the phase transformation that Tetragonal transforms to monoclinic phase is just there is once meet thermodynamic (al) phase transition energy condition, correspondingly there is the tiny crack that volumetric expansion causes, no matter be the phase change induction tiny crack that ZrO2 material produces in process of cooling, or the tiny crack band that the Stress-induced transformation that formed in its tip region in expansion process of crackle causes, all will play a part the most advanced and sophisticated energy of dispersion lead crack, the tiny crack namely caused during phase transformation absorbs the energy required for some energy-crackle continuation expansion further.Thus the toughness that improve refractory brick in various degree.

Claims (1)

1. for cement rotary kiln, there is the excellent Chrome free refractories sticking kliner coating performance, it is characterized in that:

(1) periclasite is first got and magnesium-aluminium spinel is that (material composition is respectively MgO, Al to main raw material ₂o ₃) pulverize, in the mixing of formula 85%: 8% ratio powder, put into irony 1 cubic metre of box, be transported to tunnel furnace after stirring, temperature control 800-850 DEG C is fired (60 minutes) and is become caustic-calcined magnesite; Cool to room temperature;

(2) in caustic-calcined magnesite, add additive, additive is difference SiO2, ZrO2, La2O3, CaO, Fe2O3, and its additive is in proportion:

MgO: Al ₂o ₃: at room temperature environment with caustic-calcined magnesite mix at SiO2: ZrO2: La2O3: CaO: Fe2O3=85: 8: 1.2: 2: 1.5: 1.8: 0.5, after pulverizing, adds water and stir, and amount of water is by total compound: water=100: 20 proportionings;

(3) in 5T pressing machine extrusion forming (refractory brick), shaping rear drying (under ventilation booth 10 day time of seasoning or dry 36 hours at drying kiln 60-70 DEG C), refractory brick water content≤0.5% after dry;

(4) dry refractory brick calcines 48 hours, cool to room temperature at 1700-1850 DEG C of tunnel furnace, can obtain having excellent stick kliner coating performance without chromium firebrick.