阅读说明：本技术 一种以石煤替代尾煤和硅质原料生产硅酸盐熟料的方法 (Method for producing silicate clinker by using stone coal instead of tail coal and siliceous raw material ) 是由 尹小林 张新策 于 2020-07-01 设计创作，主要内容包括：一种以石煤替代尾煤和硅质原料生产硅酸盐熟料的方法,包括如下步骤：(1)制粉；(2)预热、混合、分解；(3)调节尾煤用量、氧化煅烧。本发明解决了石煤烧制水泥影响窑系统工况及现有干法水泥生产中不能够根据烧成熟料的实际情况、即时调整硅酸盐熟料的率值和矿物组成的问题。本发明方法可根据烧成熟料的实际状况,通过调整“石煤粉”、“生料粉”两大组分料粉的用量比例,即时调整硅酸盐熟料的率值和矿物组成,以优化煅烧工况和熟料质量。(A method for producing silicate clinker by using stone coal instead of tail coal and siliceous raw materials comprises the following steps: (1) milling; (2) preheating, mixing and decomposing; (3) adjusting the use amount of the tail coal, and oxidizing and calcining. The invention solves the problems that the working condition of a kiln system is influenced by the cement fired by stone coal and the value of the silicate clinker and the mineral composition can not be immediately adjusted according to the actual condition of the fired clinker in the existing dry-process cement production. The method can instantly adjust the rate value and mineral composition of the silicate clinker by adjusting the dosage proportion of the two major component powders of the stone coal powder and the raw material powder according to the actual condition of the sintered clinker so as to optimize the calcining working condition and the clinker quality.)

1. A method for producing silicate clinker by using stone coal to replace tail coal and siliceous raw materials is characterized in that: the method comprises the following steps:

(1) milling: adding a modified sintering aid into stone coal, mixing and grinding the stone coal, and modifying the stone coal to prepare stone coal powder; mixing and grinding a calcareous raw material, a siliceous correcting material, an aluminous correcting material and an irony correcting material into raw material powder;

(2) preheating, mixing and decomposing: continuously feeding the stone coal powder and the raw material powder obtained in the step (1) into a preheater system of a dry cement clinker production line respectively according to the mass ratio of 3-20: 97-80 for preheating and mixing, feeding into a decomposing furnace for decomposition, and feeding into a rotary kiln of the dry cement clinker production line;

(3) adjusting the use amount of tail coal, oxidizing and calcining: calcining the material fed into the rotary kiln in the step (2) into silicate clinker by adopting a reinforced kiln head with one fire in an oxidizing atmosphere in the kiln; the tail coal dosage is dynamically increased or decreased according to the instant fluctuation state of the outlet temperature of the decomposing furnace and the fluctuation condition of the adjustment of the actual heat value or dosage proportion of the stone coal powder.

2. The method for producing the silicate clinker by using the stone coal instead of the tail coal and the siliceous raw material according to claim 1, wherein: in the step (1), the stone coal is various stone coal with the lower calorific value of 200 multiplied by 4.18KJ/Kg to 2500 multiplied by 4.18 KJ/Kg.

3. The method for producing silicate clinker by using stone coal instead of tailings and siliceous raw material according to claim 1 or 2, wherein: in the step (1), the stone coal is one or a mixture of more than two of block stone coal, granular stone coal, flaky stone coal and powdery stone coal.

4. A method for producing silicate clinker by using stone coal instead of tailings and siliceous raw material according to any of claims 1 to 3, characterized in that: in the step (1), according to the actual conditions of the stone coal, the siliceous correction material, the aluminum correction material, the iron correction material, the silicon-aluminum raw material and the calcareous raw material, the three rate values are controlled by selecting proper interval rate values in the ranges of lime saturation coefficient KH = 0.88-0.98, silicic acid rate SM = 2.2-3.2 and aluminum oxygen rate IM 1.3-1.9.

5. The method for producing the silicate clinker by using the coal gangue instead of the tail coal and the alumino-silica raw material according to one of the claims 1 to 4, wherein the method comprises the following steps: in the step (1), the modified sintering aid is a mixture of an oxidant and one or two of silica gel and alumina gel.

6. The method for producing the silicate clinker by using the coal gangue instead of the tail coal and the alumino-silica raw material according to one of the claims 1 to 5, wherein the method comprises the following steps: in the step (1), the fineness of the stone coal powder is 80 mu m, and the screen residue is less than or equal to 18 percent.

7. The method for producing silicate clinker by using coal gangue instead of tailings and alumino-silicate raw materials according to any one of claims 1 to 6, wherein the method comprises the following steps: in the step (1), the fineness of the raw material powder is 80 mu m, and the residue on sieve is less than or equal to 27%.

8. The method for producing silicate clinker by using stone coal instead of tailings and siliceous raw material according to any of claims 1 to 7, wherein: in the step (2), when the preheater system of the dry cement clinker production line is a five-stage cyclone preheater, the stone coal powder obtained in the step (1) is metered and continuously fed into an upstream air pipe of a C5 cyclone preheater of the five-stage preheater system of the dry cement production line; raw meal powder is fed from an upstream air pipe of a C2 cyclone preheater through continuous metering, is pulled into a C1 cyclone preheater along with air, is discharged into an upstream air pipe of a C3 cyclone preheater to be pulled into a C2 cyclone preheater, is discharged into an upstream air pipe of a C4 cyclone preheater from the C2 cyclone preheater to be pulled into a C3 cyclone preheater along with air, and is discharged into an upstream air pipe of a C5 cyclone preheater; stone coal powder fed into an upgoing air pipe of the C5 cyclone preheater and raw material powder discharged from a cone-shaped distillation pipe of the C3 cyclone preheater are continuously mixed and enter the C4 cyclone preheater along with pulling air; mixing the stone coal powder with the raw material powder through an upstream air pipe of the C5 cyclone preheater and the C4 cyclone preheater to form mixed raw material powder; the preheated mixed raw material powder is sent into a decomposing furnace through a conical distillation pipe of a C4 cyclone preheater, organic carbon combustible substances contained in stone coal powder particles in the preheated mixed raw material powder are burnt out in smokeless suspension combustion in the decomposing furnace, heat energy is supplied for decomposing calcium carbonate in the mixed raw material powder, and inorganic minerals of the stone coal powder particles are thermally decomposed into active oxides which are all components of raw materials; the mixed raw meal pre-decomposed in the decomposing furnace enters the C5 cyclone preheater along with the pulling wind, enters the kiln tail smoke chamber through the fractionating pipe at the cone part of the C5 cyclone preheater and is sent into the rotary kiln.

9. The method for producing silicate clinker by using stone coal instead of tailings and siliceous raw material according to any of claims 1 to 7, wherein: in the step (2), when the preheater system of the dry cement clinker production line is a six-stage cyclone preheater, the stone coal powder obtained in the step (1) is metered and continuously fed into an upstream air pipe of a C6 cyclone preheater of the six-stage preheater system of the dry cement production line; raw material powder is fed from an upstream air pipe of a C2 cyclone preheater through continuous metering, is pulled into a C1 cyclone preheater along with air, is discharged into an upstream air pipe of a C3 cyclone preheater to be pulled into a C2 cyclone preheater, is discharged into an upstream air pipe of a C4 cyclone preheater from the C2 cyclone preheater to be pulled into a C3 cyclone preheater along with air, is discharged into an upstream air pipe of a C5 cyclone preheater to be pulled into a C4 cyclone preheater along with air, and is discharged into an upstream air pipe of a C6 cyclone preheater from a C4 cyclone preheater to be pulled into a C5 cyclone preheater along with air; after stone coal powder fed into an upgoing air pipe of the C6 cyclone preheater and raw material powder from a cone-shaped distillation pipe of the C4 cyclone preheater are continuously mixed, the raw material powder enters the C5 cyclone preheater along with wind; the stone coal powder is mixed with the raw material powder through an upward air pipe of the C6 cyclone preheater and the C5 cyclone preheater to form mixed raw material powder, and the preheated mixed raw material powder is sent into the decomposing furnace through a conical distillation pipe of the C5 cyclone preheater; combustible substances such as organic carbon, sulfide and the like contained in stone coal dust particles in the preheated mixed raw material powder are burnt out in smokeless suspension combustion in a decomposing furnace, and heat energy is supplied for decomposing calcium carbonate in the mixed raw material powder; the inorganic mineral in the stone coal powder particles is thermally decomposed into active oxides which are all used as components of the raw material; the mixed raw meal pre-decomposed in the decomposing furnace enters the C6 cyclone preheater along with the drawing air, and enters the smoke chamber through the fractionating pipe at the cone part of the C6 cyclone preheater and is sent into the rotary kiln.

10. The method for producing silicate clinker by using stone coal instead of tailings and siliceous raw material according to any of claims 1 to 9, wherein: in the step (3), the temperature of the oxidizing atmosphere calcination is 1400-1500 ℃, preferably 1450 ℃; the instantaneous fluctuation range of the outlet temperature of the decomposing furnace is 860-890 ℃, and 875 +/-10 ℃ is preferred.

Technical Field

The invention relates to the technical field of production of silicate cement clinker, in particular to a method for producing silicate clinker by using stone coal to replace tail coal and siliceous raw materials.

Background

The stone coal is also called stone charcoal, silver charcoal, sand charcoal, slate coal, hemp coal and the like, and is a deposited combustible organic rock formed by transforming lower biological remains such as bacteria and algae in geological periods of early ancient times and early ancient times (about 4 hundred million to 5 hundred million years ago) through putrefaction and coalification in the environments of shallow sea, lagoon and gulf. Most of stone coal has the characteristics of high ash content (60-80%), high sulfur content (1.5-5%), low carbon content (10-25%), low calorific value (600 x 4.18-2500 x 4.18 kJ/kg) and high hardness, is a composite body consisting of organic carbon and inorganic mineral substances, is usually black, gray, brown and brown, and has a fibrous or granular structure. The fiber content of most stone coal with fibrous structure is generally 30-90% (30-90% of organic carbon, wherein humic acid is 10-60%), the calorific value is 1200 x 4.18-4000 x 4.18kJ/kg (the highest calorific value dry basis can reach 5000 x 4.18 kJ/kg), and the ash content is 10-70%. The high organic carbon content stone coal has more nitrogen, phosphorus and potassium contents, wherein the nitrogen content is 1 to 3 percent, and the potassium oxide content is 0.1 to 2 percent. The oil content of a small amount of stone coal mine can reach 2-10% due to oil and asphaltene contained by geological reasons, and the oil content of the stone coal mine can reach 12% if the stone coal mine is high in asphaltene.

The stone coal is a high-metamorphic sapropel coal or algae coal, and is also a multi-metal symbiotic ore with less carbon, low calorific value and low grade, the stone coal is associated with more metal elements, and the valuable metal elements which contain or are enriched comprise more than 60 elements such as molybdenum, nickel, uranium, nitrogen, phosphorus, potassium, silver, gold, zinc, copper, selenium, boron and the like besides vanadium. The main components of the stone coal are organic carbon, and the main chemical components of the inorganic mineral substances of the stone coal are silicon oxide, calcium oxide, iron oxide, aluminum oxide, magnesium oxide and the like, which are similar to siliceous raw materials of high-silicon clay or sandstone.

The traditional classification of the stone coal can be divided into common stone coal and high-quality stone coal according to ash content and heat productivity, wherein the ash content of the common stone coal is 40-90%, and the heat productivity is below 16.7 MJ/Kg; the ash content of the high-quality stone coal is 20% -40%, the heat productivity is 16.7-27.1 MJ/Kg, the heat value of a small amount of high-quality stone coal is as high as 32.2MJ/Kg, and the graphitized stone coal ore with high heat value is extremely difficult to ignite and burn; the high-quality stone coal with high carbon content is generally black, has semi-bright luster and less impurities, and has the relative density of 1.7-2.2; the stone coal with less carbon content is generally gray, dull and dull, is mixed with more pyrite, quartz veins and phosphorus-calcium nodules, and has the relative density of 2.2-2.8. Common stone coal is common stone coal, and most of the stone coal has a heat value of 800 multiplied by 4.18 to 2500 multiplied by 4.18KJ/Kg (3.35 to 10.45 MJ/Kg), ash of 60 to 80 percent, volatile matter of 5 to 15 percent, sulfur content of 1.5 to 5 percent and carbon content of 8 to 16 percent. Particularly, the storage amount of the stone coal with the calorific value of 1200 multiplied by 4.18KJ/Kg is the largest.

The stone coal can be divided into lump stone coal, granular stone coal, flaky stone coal and powdery stone coal according to the structural characteristics of minerals. The stone coal can be divided into siliceous stone coal, calcareous stone coal and the like according to main inorganic minerals contained in the stone coal.

As the inferior fuel, the combustion characteristics of the stone coal are different from those of other power coal in terms of the combustion characteristics of the stone coal, and the stone coal is about 4 to 5 million years ago, has higher coal rank than bituminous coal (about 1 to 2 million years ago) and anthracite coal (mainly 2 to 3 million years ago), has relatively deeper coal formation degree, and belongs to high-metamorphic inferior smokeless coal. From the analysis of the combustion reaction kinetics of the stone coal, the properties of the stone coal are much worse than those of the general anthracite coal.

China is one of few countries in the world with abundant stone coal resources, and the total reserve of stone coal is predicted to be about 1500 hundred million tons. More than 20 provinces such as the northwest of China, the southern Shaanxi, the northwest of Ebei, and the Hunan, the northwest of Henan and around the south of Yangtze river humps, Hubei, Anhui, Jiangxi, Zhejiang, Guangxi, Guizhou, etc., mainly distribute in the south of China, the stone coal resource advantage of the Hunan especially is obvious, the Huantiang, Yiyang, Hende and autonomous state of Hunan province (state) of Hunan have billions of tons of large-scale stone coal mines.

In the aspect of utilization of stone coal resources, the history of using stone coal to replace coal for lime burning and brick burning is long in China. Under the guidance of national policies, for decades, almost all scientific research institutes in China have the problems or achievements of comprehensive development and utilization of stone coal resources, and the existing stone coal resource development and utilization technology can be roughly summarized as follows:

1. the stone coal is used as fuel: once stone coal is used as poor fuel to burn lime and brick in earth kiln and mechanical kiln, and is used as fluidized bed furnacePoor fuel combustion heat supply and power generation of the fluidized bed furnace. Low combustion efficiency of post-combustion stone coal and SO in waste gas₂The environment-friendly emission standard is difficult to treat due to large pollutant emission amount, and most pollutants are wasted.

2. Roasting to extract vanadium and other elements: the stone coal slag after roasting stone coal with chloride salt is used for extracting vanadium pentoxide, molybdenum, nickel and other metal elements.

3. As filter aid materials and agricultural fertilizers: the stone coal is selected to be roasted, and the roasted stone coal slag is used as a filter aid or prepared into a multi-element fertilizer.

4. Manufacturing a building material: the blast induced coal is used for open-air stacking or mechanical kiln roasting to activate the stone coal, and the roasted stone coal slag is used as a blending material for cement production or is ground to be used as a raw material of carbonized bricks and clinker-free/less clinker cement.

5. And (3) firing cement: along with the whole development process of the cement production technology in China from a soil vertical kiln to a mechanical vertical kiln, a wet rotary kiln, a dry preheating kiln and a current dry cement (predecomposition kiln) production line, the exploration practice of the technology of using stone coal for firing cement makes a major effort on the technical workers in the cement industry and the first generation and the second generation of researchers in scientific research institutes, obtains uncommon performances and makes great contribution to cost reduction and efficiency improvement of cement enterprises. Currently, the technology of using stone coal for firing cement in a dry cement production line roughly includes the following two main categories:

the first kind is the application technology of stone coal as mixed fuel to replace partial raw coal as first coal fuel, first tail coal fuel or tail coal fuel in dry cement decomposing furnace. A large number of practices prove that the application conditions of the existing technology for replacing part of raw coal by stone coal cause cement plants to be very painful, one of the conditions is that the raw coal must be high-quality bituminous coal (high price and difficult to guarantee) with small internal water, low sulfur and good combustion performance, the other is that the sulfur content of the stone coal must be low, the calorific value of the stone coal must be as high as possible, the stone coal must be homogenized until the quality of the stone coal is stable (difficult to handle), the other is that the stone coal must be finely ground (energy consumption), and the fourth is that the components influencing the clinker rate value cannot be adjusted in time. And when the stone coal is directly used for replacing head coal, no matter how much the stone coal has influence on one fire at the head of the kiln, the stone coal has over-high effectOver 5 percent of stone coal can affect the stability of a kiln condition, the stone coal is directly used for replacing tailing coal, the influence on the smokeless combustion of the decomposing furnace is large, even if high-quality bituminous coal is used for the decomposing furnace, when the using amount of the stone coal powder is close to about 30 percent of the total amount of the tailing coal (not the replacing amount of the burning coal), the combustion condition in the decomposing furnace can be rapidly deteriorated, and the stability of a kiln system is seriously affected. In addition, SO in the exhaust gas₂The concentration of the contaminant increases.

The second kind is the application technology of stone coal in new dry cement decomposing furnace to replace siliceous material. For the production line of dry cement, the stone coal contains organic carbon, sulfide and the like, the waste gas desulfurization in the prior art needs to establish a costly wet desulfurization device to reach the emission standard, and the problem of crusting, sticking and blocking of a preheater kiln system is difficult to treat.

At present, the method only can be used for replacing siliceous raw materials by roasting stone coal slag or selecting stone coal with extremely low calorific value and low sulfur in a small proportion, and the problem of skinning needs to be treated in time.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects in the prior art and provide a method for producing silicate clinker by using stone coal instead of tail coal and siliceous raw materials, which reduces the coal consumption in cement production and the consumption of siliceous raw materials such as clay shale.

The technical scheme adopted by the invention for solving the technical problems is as follows: a method for producing silicate clinker by using stone coal instead of tail coal and siliceous raw materials comprises the following steps:

(1) milling: adding a modified sintering aid into stone coal, mixing and grinding the stone coal, and modifying the stone coal to prepare stone coal powder; mixing and grinding a calcareous raw material, a siliceous correcting material, an aluminous correcting material and an irony correcting material into raw material powder;

(2) preheating, mixing and decomposing: continuously feeding the stone coal powder and the raw material powder obtained in the step (1) into a preheater system of a dry cement clinker production line respectively according to the mass ratio of 3-20: 97-80 for preheating and mixing, feeding into a decomposing furnace for decomposition, and feeding into a rotary kiln of the dry cement clinker production line;

(3) adjusting the use amount of tail coal, oxidizing and calcining: calcining the material fed into the rotary kiln in the step (2) into silicate clinker by adopting a reinforced kiln head with one fire in an oxidizing atmosphere in the kiln; the amount of the tail coal is dynamically increased or decreased according to the timely fluctuation state of the outlet temperature of the decomposing furnace and the fluctuation condition of the adjustment of the actual heat value or the amount proportion of the stone coal powder.

The invention relates to a method for producing silicate clinker by using stone coal instead of tail coal and siliceous raw materials, which directly solves the problems that organic carbon, sulfide combustible, alkali sulfur and the like in stone coal particles are gradually heated, volatilized/reduced and decomposed in C1, C2, C3 and C4 grade preheaters of a multi-grade preheater, the reducibility and reducibility of raw materials are gradually increased, the reducibility and reducibility materials in the raw materials are further increased, the reducibility atmosphere in a decomposing furnace is further increased, the reducibility, crusting and blocking in the C5 grade preheater, a kiln tail smoke chamber, a throat and a rotary kiln are further increased in a linkage manner, the kiln condition, the energy consumption and the production quality of dry cement production are further seriously influenced (the heat consumption of reduction reaction, the crusting and blocking increase of heat consumption are both increased), the problems that the pollution of hydrocarbon volatile matters and sulfur dioxide caused by the application of the stone coal is greatly increased, the control difficulty is solved, and the combustion performance, the, Further leading to the problem that the operating condition of a kiln system is influenced by the skinning, and also solving the problems that the combustion condition of fuel in the decomposing furnace is deteriorated, the skinning is generated and SO in the flue gas is generated because the pulverized stone powder of the ultrafine grinding with higher heat value is selected to replace part of tail coal to be directly added into the decomposing furnace₂The concentration of pollutants is greatly increased and the kiln condition and the environmental protection are influenced to reach the standard.

Further, in the step (1), the stone coal is various stone coals with a low calorific value of 200 × 4.18KJ/Kg to 2500 × 4.18KJ/Kg, including but not limited to one or a mixture of more than two of lump stone coal, granular stone coal, flaky stone coal and powdered stone coal.

In the step (1), according to the actual conditions of the stone coal, the siliceous correction material, the aluminous correction material, the ferrous correction material, the silicoaluminous raw material and the calcareous raw material, the three values are controlled by selecting proper interval values in the ranges of lime saturation coefficient KH = 0.86-0.98, silicic acid rate SM = 2.2-3.2 and aluminum oxide rate IM 1.3-1.9. Wherein:

KH＝(CaO-1.65Al₂O₃-0.35Fe₂O₃-0.7SO₃)/2.8SiO₂，

SM＝SiO₂/(Al₂O₃+Fe₂O₃)

IM＝Al₂O₃/Fe₂O₃。

further, in the step (1), the modified sintering aid is a mixture of an oxidant and one or more than two of silica gel and alumina gel; the modified combustion aid is added to inhibit the reduction effect of organic carbon in the stone coal on iron oxide, sulfide and the like in raw material powder including stone coal powder, absorb and solidify alkali sulfur volatilized from thermal decomposition of the stone coal and promote the stone coal to be quickly burnt out in smokeless suspension combustion of a decomposing furnace, and is mainly a mixture of a strong oxidant, ferrate and the like and/or silica gel, alumina gel and the like, and can be added in liquid or powder.

Further, in the step (1), the fineness of the stone coal powder is 80 μm, and the screen residue is less than or equal to 18%.

Further, in the step (1), the fineness of the raw material powder is 80 mu m, and the screen residue is less than or equal to 27%.

Further, in the step (2), when the preheater system of the dry cement clinker production line is a five-stage cyclone preheater, the stone coal powder obtained in the step (1) is metered and continuously fed into an upstream air pipe of a C5 cyclone preheater of the five-stage preheater system of the dry cement production line; raw meal powder is fed from an upstream air pipe of a C2 cyclone preheater through continuous metering, is pulled into a C1 cyclone preheater along with air, is discharged into an upstream air pipe of a C3 cyclone preheater to be pulled into a C2 cyclone preheater, is discharged into an upstream air pipe of a C4 cyclone preheater from the C2 cyclone preheater to be pulled into a C3 cyclone preheater along with air, and is discharged into an upstream air pipe of a C5 cyclone preheater; stone coal powder fed into an upgoing air pipe of the C5 cyclone preheater and raw material powder discharged from a cone-shaped distillation pipe of the C3 cyclone preheater are continuously mixed and enter the C4 cyclone preheater along with pulling air; mixing the stone coal powder with the raw material powder through an upstream air pipe of the C5 cyclone preheater and the C4 cyclone preheater to form mixed raw material powder; the preheated mixed raw material powder is sent into a decomposing furnace through a conical distillation pipe of a C4 cyclone preheater, organic carbon combustible substances contained in stone coal powder particles in the preheated mixed raw material powder are burnt out in smokeless suspension combustion in the decomposing furnace, heat energy is supplied for decomposing calcium carbonate in the mixed raw material powder, and inorganic minerals of the stone coal powder particles are thermally decomposed into active oxides which are all components of raw materials; the mixed raw meal pre-decomposed in the decomposing furnace enters the C5 cyclone preheater along with the pulling wind, enters the kiln tail smoke chamber through the fractionating pipe at the cone part of the C5 cyclone preheater and is sent into the rotary kiln.

The stone coal powder is discharged into a decomposing furnace (taking about 8 seconds) to suspend along with pulling wind after being rapidly mixed and preheated by an upstream air pipe of a C5 cyclone preheater, a C4 cyclone preheater, hot raw material powder and hot air flow, namely the stone coal powder is rapidly heated to 680-780 ℃ from a normal temperature cold state in the powder environment of an upstream air pipe of an anoxic C5 cyclone preheater and a C4 cyclone preheater, and rapidly passes through the volatilization and cracking temperature (350-600 ℃) section of organic carbon in stone coal powder particles; the rapid temperature rise only comes to remove internal water and combined water which obstruct the temperature rise and ignition combustion in the stone coal, and the rapid oxidation combustion temperature range (680-800 ℃) of combustible materials such as organic carbon, sulfide and the like in stone coal particles is achieved; the combustion performance of the stone coal dust particles which are suspended in the straight-tube decomposing furnace along with the drawing of the air and are quickly preheated (dehydrated and puffed) is greatly superior to that of anthracite coal dust or semi-bituminous coal dust or bituminous coal containing water which enters the decomposing furnace in a cold state (various cold-state coal dust can be volatilized, cracked and oxidized and combusted after being subjected to temperature rise and dehydration at constant temperature in a period of time of temperature rise), and the modified combustion assistant has the modified combustion assisting effect on the stone coal dust particles, so that combustible substances such as organic carbon, sulfide and the like in the stone coal can be quickly burnt out in the decomposing furnace in a smokeless suspension combustion mode, and the released heat is directly supplied to the decomposition of calcium carbonate, thereby achieving the effect of effectively replacing tail coal fuel.

The aluminosilicate minerals in the stone coal are completely decomposed into active oxides in the decomposing furnace (the decomposition temperature of the aluminosilicate minerals in the stone coal is generally 580-820 ℃, and the aluminosilicate minerals in the stone coal do not have enough decomposition time in the C4 cyclone preheater). The sulfide (such as pyrite) in the stone coal is oxidized and decomposed intoSO₂/SO₃、Fe₂O₃Etc. (insufficient decomposition time in the C4 cyclone preheater), SO in a non-reducing atmosphere in the decomposing furnace₂/SO₃Combining with the newly generated high-activity CaO to generate calcium sulfate and fixing. The stone coal mixed raw material powder pre-decomposed in the decomposing furnace enters a C5 cyclone preheater along with the pulling wind, enters a smoke chamber through a rectifying pipe at the cone part of the C5 cyclone preheater and is sent into a rotary kiln, and the stone coal becomes a siliceous raw material for producing silicate clinker by dry cement.

Further, in the step (2), when the preheater system of the dry cement clinker production line is a six-stage cyclone preheater, the stone coal powder obtained in the step (1) is metered and continuously fed into an upstream air pipe of a C6 cyclone preheater of the six-stage preheater system of the dry cement production line; raw material powder is fed from an upstream air pipe of a C2 cyclone preheater through continuous metering, is pulled into a C1 cyclone preheater along with air, is discharged into an upstream air pipe of a C3 cyclone preheater to be pulled into a C2 cyclone preheater, is discharged into an upstream air pipe of a C4 cyclone preheater from the C2 cyclone preheater to be pulled into a C3 cyclone preheater along with air, is discharged into an upstream air pipe of a C5 cyclone preheater to be pulled into a C4 cyclone preheater along with air, and is discharged into an upstream air pipe of a C6 cyclone preheater from a C4 cyclone preheater to be pulled into a C5 cyclone preheater along with air; after stone coal powder fed into an upgoing air pipe of the C6 cyclone preheater and raw material powder from a cone-shaped distillation pipe of the C4 cyclone preheater are continuously mixed, the raw material powder enters the C5 cyclone preheater along with wind; the stone coal powder is mixed with the raw material powder through an upward air pipe of the C6 cyclone preheater and the C5 cyclone preheater to form mixed raw material powder, and the preheated mixed raw material powder is sent into the decomposing furnace through a conical distillation pipe of the C5 cyclone preheater; combustible substances such as organic carbon, sulfide and the like contained in stone coal dust particles in the preheated mixed raw material powder are burnt out in smokeless suspension combustion in a decomposing furnace, and heat energy is supplied for decomposing calcium carbonate in the mixed raw material powder; the inorganic mineral in the stone coal powder particles is thermally decomposed into active oxides which are all used as components of the raw material; the mixed raw meal pre-decomposed in the decomposing furnace enters the C6 cyclone preheater along with the drawing air, and enters the smoke chamber through the fractionating pipe at the cone part of the C6 cyclone preheater and is sent into the rotary kiln.

Further, in the step (3), the temperature of the oxidizing atmosphere calcination is 1400-1500 ℃, preferably 1450 ℃; the instantaneous fluctuation range of the outlet temperature of the decomposing furnace is 860-890 ℃, and the temperature is preferably 875 +/-10 ℃.

The invention has the following beneficial effects: 1) the method can effectively replace almost all clay siliceous raw materials and about 60 percent of fire coal (the tail coal consumption generally accounts for 60 to 70 percent of all fuels) which are required by the widely distributed dry-method cement production with huge capacity in China. A large amount of fire coal can be saved for cement enterprises, and the consumption of clay-like silicon-aluminum raw materials is greatly reduced; 2) aiming at the characteristics of technological equipment of a mature dry-process cement production line, the essence of firing of silicate clinker and the formation characteristics of physical and mechanical properties of silicate cementing materials, according to the premise that a cement production kiln is a set of high-temperature thermochemical reaction kiln system, on the premise of ensuring the firing quality of clinker and the working condition of the kiln system, the large interval fluctuation range of the components of reaction materials can be controlled, the preparation idea of a very mature and solidified raw material is broken through, the basic idea of stable control of a three-rate value is broken through, an interval range fluctuation method caused by the main body stability of the raw material, the component fluctuation or the dosage proportion adjustment of stone coal is adopted, a two-component preparation material powder and a three-rate value interval fluctuation control method are created, and the innovative development of a cement production technology is guided; 3) solves the problem that the value of the silicate clinker and the mineral composition can not be adjusted in time according to the actual condition of the clinker sintered by a kiln system in the prior dry-method cement production. The method can instantly adjust the rate value and mineral composition of the silicate clinker by adjusting the dosage proportion of the two major component powders of the stone coal powder and the raw material powder according to the actual condition of the sintered clinker so as to optimize the calcining working condition and the clinker quality; 4) aiming at the characteristics of stone coal and the characteristics of process equipment of a dry cement production line, the invention simply and directly solves the problems that combustible substances such as organic carbon, sulfide and the like in the stone coal are gradually volatilized/reductively decomposed and alkali sulfur and the like in a multi-stage preheater, the reducibility and the reducibility of raw materials are gradually increased, the reducing atmosphere in a decomposing furnace is further increased, the reducing skinning and blocking in a C5 stage preheater, a kiln tail smoke chamber, a throat and a rotary kiln are further increased in a linkage manner, the kiln condition, the energy consumption and the production quality of the dry cement production are further seriously influenced (the heat consumption is increased by the heat absorption of the reduction reaction, the skinning and blocking and the treatment thereof), and the pollution control difficulty of hydrocarbon volatile matters and sulfur dioxide caused by the application of the stone coal is solved. The method for modifying and quickly preheating the stone coal to the burning point (and removing water in the stone coal and combined water which obstruct the burning) to enter the decomposing furnace enables the stone coal to be effectively converted into the alternative fuel and the siliceous raw material which can be cleanly burnt, provides a brand new method for cement enterprises to utilize the combustible/sulfur-containing solid waste, and is beneficial to the energy conservation, emission reduction, cost reduction and efficiency improvement of the cement enterprises.

Detailed Description

The present invention will be further described with reference to the following examples.

The chemical reagents used in the examples of the present invention, unless otherwise specified, are commercially available in a conventional manner.

The modified sintering aid used in each example was a liquid sintering aid (Zc-R1 liquid sintering aid, mainly composed of a liquid mixture of an oxidant, a ferrate solution, liquid silica gel, and liquid alumina gel, produced by the minismy development of environmental energy science and technology ltd.