Cement kiln deals with in coordination the technology realized rubbish " decrease quantify, harmless change, resource is changed " deal with, obtained favorable social beneficial result, environment benefit and economic effect. But, because rubbish litter is medium existence is a large number of sulfur, alkaline, chloric wait for harmful composition, in rich market of the circulation inside system of cement kiln intake air heater, bring about firebrick to corrode easily, flake, mar. Current, area of low temperature of cement rotary kiln fastens a product to be like series silicon with aluminous silicon not brick, fight flake tall aluminous brick and new-style low aluminous Molaishi the brick, in raw material choice, manage turns the respect difference such as function apparent. In this job, to afore-mentioned different products fight alkaline aggressivity to be able to undertake contrast, combine micromechanism and analysis of substance appearance composition, judge its to fight alkaline aggressivity to be able to actor or actress bad, optimize cement kiln then fireproof material select material and configuration.
1, experiment 1) silicon of carry out of city of firebrick option option not brick 1680, silicon not brick 1550, fight flake JA of tall aluminous brick, low aluminous Molaishi bricky M55. The manage of appearance brick changes sexual visibility to express 1.
2) sample preparation and function detect use static crucible law to undertake fighting alkaline erode an experiment. The pattern that cuts next dimension to be 80mm of × of 80mm × 80mm from all kinds of brick piece, what get 40mm of φ 36mm × in central position is cylindrical groove makes crucible, cut again take thin plate of 30mm of × of 60mm × 60mm to make crucible top, undertake to crucible and crucible lid stoving is handled. Load pure K2CO3 of chemistry of 20g city carry out to the middle of each crucible, use fireclay general crucible between lid and crucible sealed. Whole crucible is in oven at electric stove of the park after 12h of 110 ℃ drying, and at 5h of 1100 ℃ heat preservation, wait for natural refrigeration. Fight alkaline aggressivity through observing what the exterior of sample evaluates sample can. The area after taking crucible bottom to erode undertakes micromechanism and substance appearance comprise an analysis, to bricky appearance bottom from crucible bottom every interval 5mm differentiates area (see a picture 1) , use EDS to analyse the K element content of every area. Use appearance of X ray diffraction to detect crucible bottom erodes composition of appearance of content of extent of degenerative layer 0~10mm.
2, result and discuss 1) the exterior after eroding an experiment analyses from 4 kinds of crucible alkaline discovery of photograph of the exterior after eroding: Silicon not brick 1680, silicon not brick 1550 with low aluminous Molaishi bricky M55 is flawless appear, fight alkaline aggressivity can admirable; And fight flake JA of tall aluminous brick has perforative sex great flaw to appear, fight alkaline function opposite poorer.
2) element of K of bottom of the crucible after eroding distributings to rely on each partition line closely to crucible bottom to undertake EDS face scans respectively, determine K element content is shown 2 times like the graph. Can see from the graph: The K element of different type brick distributings condition difference is very big, among them, silicon not brick 1680 with silicon not brick 1550 in curve of change of K element content is consistent, contain generous to be in crucible is bottom; As erode deepness to increase, k element content drops quickly, deepness arrives after 20mm, k element content is adjacent 1% (W) , and change no longer. Fight flake JA of tall aluminous brick and low aluminium not come in stone brick M55, distributinging curve of K element content is relatively similar. Fight flake JA of tall aluminous brick is in 0, the 5 K element content that are in with 10mm are higher; Low aluminous Molaishi in bricky M55, k element content is in bit higher 0 be in with 5mm. After element of the K in brick of these two kinds of appearance achieves high cost, as be far from ministry of crucible hole bottom, k element content drops quickly; Fight flake JA of tall aluminous brick is after 30mm, potassium element content is adjacent 1% (W) , and change no longer; Bricky M55 is in low aluminous Molaishi content of element of the Potassium after 20mm is adjacent 1% (W) , and change no longer. Silicon not of the brick fight alkaline aggressivity can with carborundum introduce reach silicon not apparent pore rate of the brick is concerned. The 2 oxidation silicon that the oxidation below carborundum high temperature makes generates vitreous photograph to form compact layer in firebrick surface and potassium carbonate reaction, can control K element effectively erode permeate, make K element is centered in bricky surface area. Fight flake the brick has tall aluminous brick and low aluminous Molaishi higher apparent pore rate, air hole was offerred for melt condition potassium carbonate permeate a passageway quickly. Stoma of potassium carbonate edge enters bricky interior, one part is alkaline nepheline or leucite are formed to wait with bricky reaction below high temperature mineral, of nepheline or leucite generate the volume with large generation to expand cause bricky body craze; Another part alkaline edge enrages interior of system of aperture development brick, reduce deposit along with temperature. Appear as a result of crackle when the surface outside bricky body when flaking, temperature of area of K element rich market is elevatory, produce reaction to continue to generate nepheline and leucite with fireproof material mineral, cause bricky system interior to produce crackle. Apparent pore rate is fought high flake tall aluminous brick is in the K2O content of same deepness relatively the low aluminous Molaishi with apparent pore low rate the brick is taller, and its K element is measured in exterior section rich volume bigger.
3) erode micromechanism of layer 0~10mm area and substance appearance composition to analyse silicon not brick 1680 graphs 3 for alkaline the silicon after eroding not brick 1680 erode layer 0~10mm area the SEM photograph below different multiple. From the graph 3 (A) observation discovery: The structure of crucible bottom surface layer that contacts K2CO3 is compact, occurrence crackle of section of section of big grain brim. From the graph 3 (B) observation sees: Aluminous grain brim corrodes in matrix apparent, carborundum does not have apparent change.
Graph 4 for silicon not brick the 1680 XRD a collection of illustrative plates that erode layer 0~10mm area. Can see: Composition of its substance appearance basically is corundum, Molaishi and carborundum, in photograph of glass of K element consist in. In the silicon below high temperature it is thus clear that Mo Zhuanji pledges in alumina is easy by alkaline erode, the 2 oxidation silicon that alumina and carborundum oxidation make and potassium reaction make fluid appearance, silicon of fluid photograph fill not bricky hole, close the stoma of firebrick and alkaline contact area and cranny, form compact layer, element of block up K is permeated further.
·Fight flake JA of tall aluminous brick is fought flake JA of tall aluminous brick is alkaline photograph of micromechanism of area of 0~10mm of bottom of the crucible after eroding sees a picture 5. From the graph 5 (A) observation discovery: Structure of crucible bottom surface layer becomes compact, aluminous grain corrodes the phenomenon is apparent, structure of the grain in matrix becomes not apparent. From the graph 5 (B) observation sees: Matrix grain brim becomes very ambiguous, the light color new look with crystal boundary stomatic or much fill. Fight flake apparent pore of JA of tall aluminous brick is led tall, stoma of potassium carbonate edge or crystal boundary enter bricky body to corrode sample interior, erode deepness big. Undertake to eating a layer substance appearance is analysed, discovery erodes a nepheline having potassium to generate (see a picture 6) . Of many Potassium nepheline generate cause bulk to expand, bring about fight flake tall aluminous brick produces great perforative flaw.
Graph 6: Fight the XRD a collection of illustrative plates that flakes JA of tall aluminous brick erodes layer 0~10mm area
Low aluminous Molaishi bricky M55 is alkaline photograph of micromechanism of area of 0~10mm of bottom of the crucible after eroding sees a picture 7. From the graph 7 (A) can see: Structure of surface layer of bottom of bricky M55 crucible also produces low aluminous Molaishi a few crackle, the structure also becomes compact, but with fight flake difference of tall aluminous brick is bigger. Fall times higher (see a picture 7 (B) ) observation, brim of grain of compact Mo Laishi also arises relatively apparent erode, visible potassium carbonate not comes to low aluminium the brick also forms stone to be eroded certainly with osmosis, but opposite Yu Kang flakes tall aluminous brick is improved apparently. In shooting a collection of illustrative plates by develop (see a picture 8) knowable: Erode a main thing appearance to be mixed for Molaishi a few did not produce changed andalusite, also exist at the same time a few potassium nepheline. The raw material that low aluminous Molaishi uses in bricky M55 is Molaishi all raw material of Shiwei of material He Gongzhu, not come composition of Shi Jun material is compact, the Gao Gui that contains certain amount is not brilliant photograph, the Potassium below high temperature blends in the photograph that be not brilliant to form photograph of tall viscosity glass; In the meantime, andalusite decomposes SiO2 of formation the condition that be not brilliant to absorb partial potassium carbonate to also make appearance of tall viscosity glass, close by its firebrick eats a layer, the osmosis of element of block up K. A few potassium carbonate and Mo Laishi reaction generate potassium nepheline, of potassium nepheline make an amount low, of generation expand can't destroy bricky system structure, accordingly, bricky M55 shows low aluminous Molaishi fight alkaline aggressivity goodly can.
3, conclusion (1) silicon not brick 1680, silicon not brick 1550 in because carborundum is joined,reach partial oxidation to become air hole of fill of 2 oxidation silicon, can reduce significantly erode alkalinely, fight alkaline aggressivity can admirable. Alkaline element of the K after eroding an experiment basically is in centrally erode area area, increase as the distance, k element content drops quickly.
(2) city carry out is fought flake the apparent pore of JA of tall aluminous brick is led tall, fight alkaline aggressivity to be able to be differred, alkaline erode deepness to achieve 10mm, content of element of the K in eating a layer (W) achieve 20%~25% , generate many potassium nepheline to bring about bricky body craze.
(3) bricky M55 apparent pore leads low aluminous Molaishi low, what use Molaishi all material and structure of andalusite raw material are compact, the photograph of a certain quantity of brilliant of tall silicon blame in matrix can be absorbed alkaline generate photograph of tall viscosity glass to close further stomatic, alkaline erode deepness to have 5mm only, alkaline erode make potassium nepheline amount opposite less, can't destroy bricky system structure, fight alkaline aggressivity opposite better.
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