CN110980785B - Sintering method of alumina clinker - Google Patents
Sintering method of alumina clinker Download PDFInfo
- Publication number
- CN110980785B CN110980785B CN201911130503.XA CN201911130503A CN110980785B CN 110980785 B CN110980785 B CN 110980785B CN 201911130503 A CN201911130503 A CN 201911130503A CN 110980785 B CN110980785 B CN 110980785B
- Authority
- CN
- China
- Prior art keywords
- sintering
- kiln
- clinker
- raw slurry
- flue gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/44—Dehydration of aluminium oxide or hydroxide, i.e. all conversions of one form into another involving a loss of water
- C01F7/441—Dehydration of aluminium oxide or hydroxide, i.e. all conversions of one form into another involving a loss of water by calcination
Abstract
The invention discloses a sintering method of alumina clinker, which specifically comprises the following steps: preparing raw slurry by using bauxite, and controlling the fixed carbon content of the raw slurry to 6.0-7.0 wt%; sintering the raw slurry in a clinker sintering rotary kiln according to a preset process to obtain clinker; preset ofThe process comprises reducing the oxygen content in the rotary sintering kiln during the sintering process. By the scheme, an effective reburning area is formed from the kiln tail lifting plate to the decomposition zone in the sintering rotary kiln, and nitrogen oxide formed in the kiln head burning zone is reduced in the reburning area, so that the content of nitrogen oxide in sintering flue gas discharged from the kiln tail is obviously reduced, and the NO of the sintering kiln flue gas is enabled to be in a range of x The content meets the requirement of the third peak section of environmental protection, the denitration efficiency can reach more than 50 percent, and the production flow is not stopped due to environmental protection.
Description
Technical Field
The application relates to the technical field of sintering of alumina clinker, in particular to a denitration method in a sintering furnace for sintering the alumina clinker by alkali-lime.
Background
To reduce NO X And (4) discharging, and enterprises generally need to denitrate the sintering flue gas. Tail gas denitration, also called flue gas purification technology, is to purify exhausted waste gas again and to remove NO X Reduction or adsorption oxidation. Compared with the traditional technology and the widely applied SCR denitration technology in the world, the technology is the tail gas denitration. The flue gas is treated with NH under the action of catalyst 3 As reducing agent, NO is reacted at a certain temperature x Reduction to N 2 The denitration efficiency is high and can reach 70% -95%, but the investment is large, the operating cost is high, and the effective denitration efficiency can be obtained only when the temperature of the flue gas is higher than 200 ℃ after the flue gas passes through the electric dust removal equipment. The prior flue gas denitration technology is applied to power plants and the cement industry, but has no success case on an alumina clinker sintering rotary kiln, because the temperature of sintering tail gas of the alumina clinker is only 140-180 ℃ after electric precipitation, the reaction temperature required in the traditional tail gas denitration technology can not be reached, and simultaneously, because the smoke dust of the alumina clinker kiln contains high-concentration alkali metalThe SCR denitration catalyst is poisoned due to the characteristics of ions, high flue gas humidity, easy moisture absorption and hardening and the like, so that NO in the flue gas cannot be treated x Effective removal is performed. With the continuous improvement of the current environmental protection requirement, NO of the clinker sintering kiln x The emission seriously threatens the continuous application prospect of the production process, and a method capable of effectively denitrifying flue gas generated after sintering alumina clinker must be found so as to meet the relevant requirements of national environmental protection.
Disclosure of Invention
The invention provides a sintering method of alumina clinker, which aims to solve or partially solve the technical problem that the existing sintering flue gas of the alumina clinker cannot be effectively denitrated.
In order to solve the technical problem, the invention provides a sintering method of alumina clinker, which comprises the following steps:
preparing raw slurry by using bauxite, and controlling the fixed carbon content of the raw slurry to 6.0-7.0 wt%;
sintering the raw slurry in a clinker sintering rotary kiln according to a preset process to obtain clinker; the preset process comprises the step of reducing the oxygen content in the sintering rotary kiln in the sintering process.
Alternatively, the bauxite may comprise gibbsite type bauxite.
Optionally, reducing the oxygen content in the rotary sintering kiln in the sintering process specifically includes:
and controlling the oxygen content of the flue gas at the feeding position of the kiln tail spray gun in the final equilibrium state to 1.0-2.0 wt.%.
Further, controlling the oxygen content of the flue gas at the feeding position of the kiln tail spray gun in a final equilibrium state to 1.0-2.0 wt.%, specifically comprising:
reducing the air quantity of secondary air, and adjusting the air quantity of primary air in a variable frequency manner to enable the oxygen content of flue gas at the feeding position of the kiln tail spray gun in a final balanced state to be 1.0-2.0 wt.%.
Further, the preset process further comprises:
the flue gas temperature of a kiln tail vertical flue of the clinker sintering rotary kiln is controlled to be more than or equal to 180 ℃.
According to the technical scheme, the fixed carbon content of the raw slurry is controlled to be 6.0-7.0 wt%, and the method specifically comprises the following steps:
in the process of preparing raw slurry by using bauxite, white coal is added into the raw slurry so that the fixed carbon content of the raw slurry is 6.0 wt.% to 7.0 wt.%.
According to the technical scheme, in the process of preparing raw slurry by using bauxite, the moisture content in the slurry is controlled to be less than or equal to 41 wt.%.
According to the technical scheme, the preset process further comprises the following steps: the iron-aluminum ratio of clinker is improved.
Further, the value range of the iron-aluminum ratio of the clinker is 0.085-0.11.
The invention also provides alumina, which is sintered by adopting the steps of any one of the methods in the clinker sintering process.
Through one or more technical schemes of the invention, the invention has the following beneficial effects or advantages:
the invention provides a sintering method of alumina clinker, which comprises the steps of increasing the fixed carbon content of raw slurry to 6.0-7.0 wt%; then the oxygen content in the sintering rotary kiln is reduced in the sintering process. Through higher fixed carbon content in the raw slurry, an effective reburning area is formed from the kiln tail lifting plate in the sintering rotary kiln to the decomposition zone, and CO, C and C are promoted to be accumulated in the reburning area n H m And waiting for the product to form a reducing atmosphere; the reduction of the oxygen content in the sintering rotary kiln is combined, so that the nitrogen oxide formed in the burning zone at the kiln head is reduced in the reburning zone, thereby obviously reducing the nitrogen oxide content of the sintering flue gas discharged from the kiln tail, and leading the NO of the sintering kiln flue gas to be NO x The content reaches the requirement of the third peak section of environmental protection (less than 300 mg/m) 3 ) The denitration efficiency can reach more than 50 percent, and the environmental protection emission standard required by the state is reached.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
Various additional advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
FIG. 1 shows a flow diagram of a method of sintering alumina clinker according to one embodiment of the present invention;
FIG. 2 illustrates environmental emission data for kiln No. 6 before modification according to one embodiment of the present invention;
FIG. 3 shows environmental emission data for kiln No. 6 after use of the improvement in the present invention, according to one embodiment of the present invention;
FIG. 4 illustrates environmental emission data for kiln No. 3 before modification according to one embodiment of the present invention;
figure 5 shows environmental emission data for kiln No. 3 after use of the improvement of the invention according to one embodiment of the invention.
Detailed Description
In order to make the present application more clearly understood by those skilled in the art to which the present application pertains, the following detailed description of the present application is made with reference to the accompanying drawings by way of specific embodiments.
As previously mentioned, due to the inherent characteristics of the alumina clinker sintering fumes: the flue gas temperature is low, the temperature requirement of effective tail gas denitration cannot be met, and high-concentration alkali metal ions in the sintering flue gas of the alumina clinker can cause the poisoning of a denitration catalyst, so that the denitration catalyst cannot remove nitrogen oxides, so that the sintering flue gas of the existing alumina clinker can only be directly discharged, but the treatment mode is difficult to continue in the current high environmental protection requirement. Based on the background, the inventor provides a brand-new method for sintering the clinker in the rotary sintering kiln and effectively denitrating the sintering flue gas according to the technical characteristics of sintering the alumina clinker, and the method comprises the following specific steps:
as shown in fig. 1, in an alternative embodiment, a method for sintering alumina clinker is disclosed, which specifically comprises:
s10: preparing raw slurry by using bauxite, and controlling the fixed carbon content of the raw slurry to 6.0-7.0 wt%;
s20: sintering the raw slurry in a clinker sintering rotary kiln according to a preset process to obtain clinker; the preset process comprises the step of reducing the oxygen content in the sintering rotary kiln in the sintering process.
The above percentages are mass percentages.
In general, according to the scheme, the fixed carbon content of the raw slurry is improved, the oxygen content of the sintering rotary kiln is reduced, when materials are injected from the kiln tail of the sintering rotary kiln and pass through a lifting blade at the kiln tail, coal in the raw slurry is contacted with high-temperature flue gas to form a reburning area of the sintering flue gas, and nitrogen oxide generated in a main burning area is reduced by utilizing a staged combustion mechanism and the reburning area, so that the aim of denitration in the sintering rotary kiln is fulfilled. The specific principle is detailed as follows:
as is well known, the kiln structure of the sintering rotary kiln can be divided into the following parts from the kiln tail to the kiln head according to the temperature and the physical and chemical change characteristics of materials along the length of the kiln: a drying zone, a preheating zone, a decomposing zone, a burning zone and a cooling zone. The raw slurry for producing the alumina clinker is sprayed from a feeding port at the tail of the kiln and moves towards the head of the kiln under the action of the inclination and autorotation of the rotary sintering kiln. Evaporating water in the raw slurry in a drying zone; dehydrating the hydroxide or hydrate in a preheating zone; the decomposition zone is mainly limestone thermal decomposition and initial part solid phase reaction; the chemical reaction of clinker mineral sintering is completed in the sintering zone; cooling the clinker in a cooling zone; the clinker is then discharged from the kiln head. The kiln head of the sintering rotary kiln is provided with a pulverized coal injection device to form sintering flame in the sintering rotary kiln, and the area covered by the flame is a burning zone. Sintering flue gas is generated in a burning zone, and enters a dust remover from a kiln mouth of the rotary kiln to be dedusted and then discharged after sequentially passing through a decomposing zone, a preheating zone and a drying zone.
Burning zone for generating nitrogen oxides NO x In the main region of fuel combustion, NO x According to different formation mechanisms, the method can be divided into the following steps: the fuel is a fuel, and the thermal type is formed by oxidizing nitrogen in air at a high temperature, the rapid type is formed by reacting nitrogen in air with hydrocarbon ion groups in fuel during combustion, and the combustion type is formed by thermally decomposing nitrogen compounds contained in fuel during combustion and then oxidizing the nitrogen compounds. Thermal NO x Influenced by the oxygen content in the high-temperature flame zone, the combustion temperature and the residence time in the high-temperature zone, the higher the oxygen content, the higher the temperature and the longer the residence time, and the thermal NO x The more production. Rapid NO x Is the impact of hydrocarbon radicals on N in the air during combustion 2 The molecules form intermediate products such as HCN, NH and CN, and the intermediate products are further oxidized to form NO x The temperature has little influence on the generation process, and the excessive oxygen content has great influence. Combustion type NO x The influence factors of the generation of (A) are more related to the combustion temperature and the excess oxygen content, and also related to the fuel properties, such as: the nitrogen content of the coal powder, the volatile component of the coal powder, the coke ratio, the fineness of the coal powder and the like. NO produced by thermal means during combustion of coal dust x Accounts for 20-30% of the total amount, accounts for 70-80% of the combustion type, and has a small proportion of the rapid type.
The scheme creatively introduces a fuel classification technology into the alumina clinker sintering rotary kiln for denitration. Generally, the common control method of fixed carbon is to add coal to raw materials before the sintering process, i.e. grinding a certain amount of coal dust during the preparation of raw slurry, and its main function is to remove sulfur (S) in the materials to eliminate the sulfur hazard during the sintering process of clinker. Sulfur and Na in the material 2 CO 3 Reaction to form Na 2 SO 4 The alkali consumption will increase. While the fixed carbon can form CO and Na in the kiln 2 SO 4 Conversion to Na 2 S, and a part of Fe 2 O 3 Reducing the FeO to FeO, and then reacting the FeO with Na 2 The S reacts to generate FeS, the FeS cannot enter a solution in a subsequent clinker dissolution process and is discharged from a system, and a specific reaction equation is as follows:
Na 2 SO 4 +4CO＝Na 2 S+4CO 2
Fe 2 O 3 +CO＝FeO+CO 2
FeO+Na 2 S+Al 2 O 3 ＝Na 2 O·Al 2 O 3 +FeO
through the reaction process, Na in the clinker is removed 2 SO 4 The control is below 2 percent, the alkali consumption can be reduced, and the yield is improved. Generally, for the purpose of controlling S, the fixed carbon content in the raw slurry in the prior art is usually about 3.5 wt.% to 4.5 wt.% based on the stoichiometric calculation.
After the inventor tests, if the fixed carbon in the raw meal is continuously increased to a certain content, the fixed carbon can be used as a secondary fuel of the sintering flue gas, so that a re-burning zone of the sintering flue gas is formed from the material raising plate of the rotary kiln to a decomposition zone area, and the burning zone at the moment is equivalent to a main burning zone, thereby forming staged combustion in the sintering rotary kiln. According to the fuel staged combustion mechanism, the primary fuel zone (main combustion zone, combustion zone) is oxidizing atmosphere, and N in the materials and coal in the main combustion zone can generate various nitrogen oxides NO x (ii) a The secondary fuel (fixed carbon) in the second combustion zone (reburning zone) forms a reducing atmosphere comprising excess carbon C, incomplete combustion products CO and C n H m The NO that has been generated can be used X Reduction to N 2 . In the original scheme, the addition amount of the fixed carbon is insufficient, the oxygen content in the sintering rotary kiln is high, and sufficient reducing gas cannot be generated, so that the effective reburning zone with sufficient length cannot be formed only by increasing the content of the fixed carbon, and the air excess coefficient in each combustion zone needs to be controlled. At present, the air excess coefficient at the kiln head is generally 1.35-1.50, the air excess coefficient is higher, namely the oxygen content is high, the reduction atmosphere generation in a reburning area is not facilitated, and more nitrogen oxides can be generated in a burning zone. Therefore, the oxygen content in the rotary kiln is reduced while the fixed carbon content in the raw meal is increased, and the raising plates are promoted to gather CO, C and C to the decomposition zone area n H m And the like, thereby forming an effective reburning area, reducing the nitrogen oxide generated at the kiln head again and obviously reducing NO of the sintering kiln smoke x The emission content and production data statistics show that the denitration efficiency can reach 50 percentThe above data are shown in FIGS. 2 to 5. In addition, the formation of the reburning area can disperse the heat energy provided by the kiln head in a centralized way, reduce the high temperature of the flame of the kiln head and reduce the generation of nitrogen oxides on the kiln head. According to the scheme, the combustor and other structures of the sintering rotary kiln do not need to be modified, or new denitration equipment is introduced, or new chemicals or a denitration agent is additionally added into the raw materials, only the preparation indexes of raw slurry are needed to be adjusted and sintering process parameters are needed to be controlled, the denitration effect of sintering flue gas can be achieved by staged combustion generated in the sintering rotary kiln, the applicability is good, the method can be applied to in-kiln denitration of the sintering rotary kiln in the aluminum industry and other similar fields, and considerable equipment cost is saved.
In order to form an effective reburning zone, it is necessary to accurately determine the range of fixed carbon content, and if the fixed carbon content is insufficient, a reducing atmosphere, such as CO and C, is generated n H m When the amount of the gas is insufficient, an effective reburning area cannot be formed; if the fixed carbon content added into the raw slurry is too high, the amount of coal which is added into the kiln head part and forms the sintering flame is reduced according to the principle that the total coal consumption is fixed, and the sintering quality of the material is reduced. Through a large number of tests, the content of fixed carbon is controlled to be generally 6.0-7.0 wt%, and the preferred value can be 6.5 wt%, so that the sintering quality of materials can be ensured, and an effective reburning area can be formed for NO at the same time x And (4) carrying out reduction.
On the other hand, the fixed carbon content of the raw slurry sprayed from the kiln tail and the index of the white coal composition are monitored, so that the effective range of the reburning area can be controlled while the sintering quality is ensured, and the denitration efficiency in the kiln is improved. Preferably, the denitration efficiency in the kiln is best when the coal content corresponding to the fixed carbon content (6.0 wt.% to 7.0 wt.%) in the raw meal accounts for 30 wt.% to 32 wt.% of the total coal consumption (coal in the raw meal + coal injected from the kiln head).
The embodiment provides a sintering method of alumina clinker, which comprises the steps of increasing the fixed carbon content of raw slurry to 6.0-7.0 wt%; then the oxygen content in the sintering rotary kiln is reduced in the sintering process. By means of higher fixed carbon content in raw slurry, kiln in rotary sintering kilnAn effective reburning zone is formed in the area from the tail raising plate to the decomposition zone, so that CO, C and C are accumulated in the reburning zone n H m And waiting for the product to form a reducing atmosphere; the content of nitrogen oxide formed in a burning zone at the head of the kiln is reduced in a reburning zone by combining with the reduction of the oxygen content in the sintering rotary kiln, so that the content of nitrogen oxide in sintering flue gas discharged from the tail of the kiln is obviously reduced, and NO in the sintering kiln flue gas is reduced x The content reaches the requirement of the third peak section of environmental protection (less than 300 mg/m) 3 ) The denitration efficiency can reach more than 50 percent, and the environmental protection emission standard required by the state is reached.
Based on the same inventive concept of the previous embodiments, in another alternative embodiment, the bauxite includes gibbsite type bauxite.
The domestic aluminium ore which takes diaspore type as the main form is adopted by the domestic enterprises producing alumina by the existing sintering method. Firstly, the gibbsite type bauxite is easy to react to generate a sodium aluminate material due to strong activity, and the reaction temperature is required to be lower than that of diaspore ore, so that the amount of coal powder sprayed into a kiln head can be reduced, the source of N is reduced, the reaction temperature is reduced, and the generation of nitrogen oxides is reduced in the two aspects; secondly, the gibbsite bauxite obviously reduces the combustion heat load of a clinker sintering kiln and also reduces the loss cost of sintering rotary kiln equipment; thirdly, the gibbsite type bauxite ore is lower in price, so that the mass production cost can be saved, and the annual production cost can be estimated to reach 3385 ten thousand yuan.
When gibbsite type bauxite is used, since the content of crystal water is significantly higher than that of diaspore type bauxite, a large amount of water needs to be evaporated, and the temperature of flue gas in a kiln tail drying zone is caused to decrease. In order to prevent the kiln tail from caking and ensure the safe operation of the rotary kiln, the necessary flue gas temperature of the kiln tail of the rotary kiln can be ensured by reducing the number of heat exchange elements in the sintering rotary kiln, and the flue gas temperature of a vertical flue at the kiln tail is controlled to be more than 180 ℃ in combination with the requirement of reducing atmosphere.
According to the same inventive concept and implementation principle as the previous embodiment, in another alternative embodiment, the fixed carbon content of the raw slurry is controlled to be 6.0 wt.% to 7.0 wt.%, specifically comprising:
in the process of preparing raw slurry by using bauxite, white coal is added into the raw slurry so that the fixed carbon content of the raw slurry is 6.0 wt.% to 7.0 wt.%. The white coal is anthracite and is added in an abrasive manner.
According to the same inventive concept and implementation principle as the previous embodiment, in another alternative embodiment, the step of reducing the oxygen content in the rotary sintering kiln during the sintering process specifically comprises: and controlling the oxygen content of the flue gas at the feeding position of the kiln tail spray gun in the final equilibrium state to 1.0-2.0 wt.%.
Specifically, if the oxygen content in the sintering kiln is high, the reducing gas is not easily generated, the reburning zone becomes narrow, and if the oxygen content is reduced, the reducing gas generation amount becomes larger, and the reburning zone becomes wide. The oxygen content cannot be too low, otherwise the sintering quality of the main combustion zone is affected. Before the scheme is applied, the oxygen content of the flue gas measured at the feeding position of a kiln tail spray gun is about 4.0 wt.%, an obvious reburning area is not observed in the kiln, and when the oxygen content of the flue gas is controlled to be 1.0 wt.% to 2.0 wt.%, an effective reburning area is formed from the material raising plate to the rear end of a decomposition zone.
Optionally, the method for controlling the oxygen content of the flue gas at the feeding position of the kiln tail spray gun in the final equilibrium state to 1.0 wt.% to 2.0 wt.% specifically comprises the following steps: reducing the air quantity of secondary air, and adjusting the air quantity of primary air in a variable frequency manner to enable the oxygen content of flue gas at the feeding position of the kiln tail spray gun in a final balanced state to be 1.0-2.0 wt.%. The specific air quantity of the front air and the rear air is determined according to the dynamic state of the oxygen content of the flue gas detected in the actual production.
Further, the preset process further comprises: the flue gas temperature of a kiln tail vertical flue of the clinker sintering rotary kiln is controlled to be more than or equal to 180 ℃. The method for controlling the flue gas temperature comprises controlling at least one of the air consumption of primary air and secondary air, the coal amount sprayed into the burning zone, the material amount sintered in the rotary sintering kiln, etc., to ensure that the raw material containing coal in the reburning zone is in a burning stateAnd the oxygen content of the flue gas at the feeding position of the kiln tail spray gun is controlled to be 1.0-2.0 wt.%. In the actual operation process, the measures are combined to prolong the reburning zone as far as possible so as to prolong the nitrogen oxides and CO, C and C n H m Etc. for a sufficient contact time with NO x And (4) carrying out reduction.
According to the same inventive concept and principle as the above-described embodiments, the moisture content in the slurry is controlled to be 41 wt.% or less in the process of preparing raw slurry using bauxite.
In the actual control process, the moisture content in the raw slurry should be controlled to be reduced as much as possible under the condition that the production liquid amount is balanced. The water evaporation of the slurry can take away about 40% of the heat energy of the sintering kiln, and the water is reduced, so that the heat load of the kiln can be reduced, the use amount of coal powder is reduced, and the generation of combustion type nitrogen oxides is reduced. In addition, due to the structural characteristics of the rotary kiln (the kiln head provides heat, and the kiln tail evaporates water), if the raw slurry in the kiln tail has high water, a large amount of heat energy needs to be provided by the kiln head to the kiln tail, the flame area of the kiln head is in a higher temperature state, and the output of thermal nitrogen oxides is obviously increased.
According to the same inventive concept and implementation principle as the above embodiments, in another alternative embodiment, the preset process further includes: the iron-aluminum ratio of clinker is improved.
Further, the value range of the iron-aluminum ratio of the clinker is 0.085-0.11.
The Fe in sintering is the main mineralizer in the process of sintering the clinker, and plays a role in reducing the sintering temperature and the clinker melting temperature, the sintering temperature of the raw meal is reduced along with the increase of the iron-aluminum ratio, so the increase of the iron-aluminum ratio can reduce the generation of nitrogen oxides, and the iron content in the ore is naturally higher when the gibbsite type bauxite is used. The iron-aluminum ratio cannot be too high, otherwise, the sintering temperature range is narrowed, and the normal operation of the sintering kiln is influenced. Production data show that the iron-aluminum ratio of the sintered clinker is improved to 0.085-0.11 from the original 0.075-0.095, and the sintered clinker has better effects, preferably 0.090, 0.095, 0.105 and the like.
Referring to the specific data, in an alternative embodiment, the denitration is performed in the kiln No. 6 by using the scheme, the process parameters and the monitoring result of the nitrogen oxides are shown in the table 1, and the process parameters not shown in the table are determined according to the existing control procedures. It can be seen that when raw slurry is prepared by using gibbsite type bauxite, the improved process can obviously reduce nitrogen oxides in sintering flue gas, and the denitration efficiency is 55.3% according to production data statistics.
Table 1: technological parameters and NO before and after No. 6 kiln improvement x Reduced concentration
In another alternative embodiment, the denitration in the kiln is carried out in the kiln No. 3 by adopting the scheme, the adopted process parameters and the monitoring results of the nitrogen oxides are as follows, the process parameters which are not referred to in the table are determined according to the existing control rules, and it can be seen that the nitrogen oxides in the sintering flue gas can be obviously reduced after the raw slurry is prepared by using the gibbsite type bauxite, and the denitration efficiency is 56% according to the statistics of production data.
Table 2: process parameters and NO before and after No. 3 kiln improvement x Reduced concentration
Based on the same inventive concept and implementation principle of the previous embodiment, in a further alternative embodiment, an alumina is further provided, and sintering is performed in a clinker sintering process by adopting the steps of the method in any one of the previous embodiments.
Through one or more embodiments of the present invention, the present invention has the following advantageous effects or advantages:
the invention provides a sintering method of alumina clinker, which comprises the steps of increasing the fixed carbon content of raw slurry to 6.0-7.0 wt%; then the oxygen content in the sintering rotary kiln is reduced in the sintering process. Through higher fixed carbon content in the raw slurry, an effective reburning area is formed from the kiln tail lifting plate in the sintering rotary kiln to the decomposition zone, and CO, C and C are promoted to be accumulated in the reburning area n H m And waiting for the product to form a reducing atmosphere; the reduction of the oxygen content in the sintering rotary kiln is combined, so that the nitrogen oxide formed in the burning zone at the kiln head is reduced in the reburning zone, thereby obviously reducing the nitrogen oxide content of the sintering flue gas discharged from the kiln tail, and leading the NO of the sintering kiln flue gas to be NO x The content reaches the requirement of the third peak section of environmental protection (less than 300 mg/m) 3 ) The denitration efficiency can reach more than 50 percent, and the environmental protection emission standard required by the state is reached.
Further, the invention uses gibbsite type bauxite to replace diasporite type bauxite for production; firstly, the gibbsite bauxite is more easy to react due to strong activity, and the reaction temperature is lower than that of diaspore ore, so that the amount of coal powder sprayed into a kiln head can be reduced, the source of N is reduced, the reaction temperature is reduced, and the generation of nitrogen oxides is reduced on the two aspects; secondly, the gibbsite bauxite obviously reduces the combustion heat load of a clinker sintering kiln and also reduces the loss cost of sintering rotary kiln equipment; thirdly, the gibbsite type bauxite ore is lower in price, and mass production cost can be saved.
While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.
Claims (5)
1. A method of sintering alumina clinker, the method comprising:
preparing raw slurry by using bauxite, and controlling the fixed carbon content of the raw slurry to 6.0-7.0 wt%; the bauxite comprises gibbsite type bauxite;
sintering the raw slurry in a clinker sintering rotary kiln according to a preset process to obtain clinker; the value range of the iron-aluminum ratio of the clinker is 0.090-0.105; the preset process comprises the steps of reducing the oxygen content in the sintering rotary kiln in the sintering process, and controlling the oxygen content of flue gas at the feeding position of a kiln tail spray gun in a final equilibrium state to be 1.0-2.0 wt.%.
2. The method as claimed in claim 1, wherein the controlling of the flue gas oxygen content at the kiln tail lance feed at the final equilibrium state to 1.0 wt.% to 2.0 wt.% comprises:
and reducing the air quantity of secondary air, and adjusting the air quantity of primary air in a variable frequency manner to enable the oxygen content of the flue gas at the feeding position of the kiln tail spray gun in the final balanced state to be 1.0-2.0 wt.%.
3. The method of claim 2, wherein the pre-conditioning process further comprises:
and controlling the flue gas temperature of a kiln tail vertical flue of the clinker sintering rotary kiln to be more than or equal to 180 ℃.
4. The method according to claim 1, wherein the controlling the fixed carbon content of the green slurry to be 6.0 wt.% to 7.0 wt.% comprises:
in the process of preparing raw slurry by using bauxite, white coal is added into the raw slurry so that the fixed carbon content of the raw slurry is 6.0-7.0 wt.%.
5. The method of claim 1, wherein the moisture content of the slurry is controlled to be 41 wt.% or less during the preparation of the raw slurry using bauxite.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911130503.XA CN110980785B (en) | 2019-11-19 | 2019-11-19 | Sintering method of alumina clinker |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911130503.XA CN110980785B (en) | 2019-11-19 | 2019-11-19 | Sintering method of alumina clinker |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110980785A CN110980785A (en) | 2020-04-10 |
| CN110980785B true CN110980785B (en) | 2022-08-05 |
Family
ID=70084779
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911130503.XA Active CN110980785B (en) | 2019-11-19 | 2019-11-19 | Sintering method of alumina clinker |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110980785B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113003600A (en) * | 2021-03-09 | 2021-06-22 | 淄博包钢灵芝稀土高科技股份有限公司 | Preparation method of rare earth oxide |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101413054B (en) * | 2008-12-09 | 2010-07-14 | 中南大学 | Technology for comprehensively utilizing high ferro aluminiferous material |
| CN102032565B (en) * | 2009-09-27 | 2012-07-04 | 烟台龙源电力技术股份有限公司 | Powdered-coal burner and rotary cement kiln using same |
| CN102718240A (en) * | 2012-06-21 | 2012-10-10 | 中国铝业股份有限公司 | Method for producing alumina through mineral containing aluminum |
| CN107233790A (en) * | 2016-03-29 | 2017-10-10 | 内蒙古大唐国际再生资源开发有限公司 | Rotary kiln denitration method for flue gas and system |
| CN109279633A (en) * | 2017-07-19 | 2019-01-29 | 陈湘清 | A kind of method of low-temperature bake bauxite production aluminium hydroxide |
| CN208038064U (en) * | 2018-01-31 | 2018-11-02 | 河南华诚轻金属科技有限公司 | A kind of alumina rotary kiln of low NOx drainage |
| CN109731465A (en) * | 2019-01-16 | 2019-05-10 | 北京清新环境技术股份有限公司 | A kind of alumina rotary kiln calcining flue gas denitrification system |
| CN110156356A (en) * | 2019-03-28 | 2019-08-23 | 福建鼎盛元环保科技有限公司 | A kind of production line and its technique preparing high alumina cement using white clay |
-
2019
- 2019-11-19 CN CN201911130503.XA patent/CN110980785B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN110980785A (en) | 2020-04-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101348743B (en) | Clean synergistic agent for coal-saving, devulcanizing and coke cleaning, and preparation technique thereof | |
| CN101343047B (en) | Improved preparation technique for preparing sulphuric acid and cement with gypsum | |
| US20170108275A1 (en) | Process and system for waste heat grading cyclic utilization and pollutant emission reduction of sintering flue gas | |
| JP6994579B2 (en) | Microwave sintering method for iron ore | |
| CN102061212B (en) | Fire coal efficient catalysis combustion-supporting agent and preparation method and use method thereof | |
| CN111233356B (en) | Method and system for preparing sulphoaluminate cement from all solid waste of aluminum ash pretreatment | |
| CN110075680B (en) | Desulfurization, denitrification, dust removal and ultralow emission process and system for producing cement from low-sulfur raw materials | |
| CN106800959B (en) | Combustion-supporting sulfur-fixing agent for coal | |
| CN107236580B (en) | High-efficiency sulfur fixation catalytic composition for coal | |
| CN102533387B (en) | Fire coal desulfurization and denitrification decoking additive and preparation process thereof | |
| CN110052141B (en) | Desulfurization, denitrification, dust removal and ultralow emission process and system for producing cement from high-sulfur raw materials | |
| CN102776309A (en) | Treatment method of zinc-bearing dust for steel works | |
| CN107442069A (en) | A kind of preparation method for sintering denitrating flue gas carbonaceous sorbing material | |
| CN108715930A (en) | A kind of discarded desulfurizing agent is applied to the processing method of sintering | |
| CN104174265A (en) | Method for reducing NOx in high-temperature calcination by SCR denitration technology adopting carbon-series reduction agent. | |
| CN108355488B (en) | Waste gas circulating denitration method for iron ore pellets | |
| CN107261826A (en) | A kind of cement kiln flue gas catalytically fixed sulphur pulvis | |
| CN110980785B (en) | Sintering method of alumina clinker | |
| CN107572844A (en) | The method that flue gas desulfurization and denitrification produces binder materials | |
| CN103725347A (en) | Desulfurizing, denitrifying and decoking synergic additive for fire coal and preparation method of additive | |
| JPH0541680B2 (en) | ||
| CN109012753A (en) | A kind of preparation method of denitration catalyst carrier | |
| CN102633237B (en) | Method for producing liquid sulfur dioxide by using gypsum (CaSO4) | |
| CN103566727B (en) | Method for desulfurization and denitrification of flue gas | |
| CN1239682C (en) | Sulfur-fixing coal saving agent |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20230913 Address after: No.1, wukm Road, Nanding Town, Zhangdian, Zibo City, Shandong Province Patentee after: China Aluminum Shandong New Material Co.,Ltd. Address before: 100082 No. 62 North Main Street, Haidian District, Beijing, Xizhimen Patentee before: ALUMINUM CORPORATION OF CHINA Ltd. |