阅读说明：本技术 一种利用半干法脱硫灰制备复合激发剂熟料的装置与方法及该熟料的应用 (Device and method for preparing composite exciting agent clinker by using semi-dry desulfurization ash and application of clinker ) 是由 樊传刚 郭小雨 李健生 樊鲁倩 樊曦 李家茂 于 2019-11-26 设计创作，主要内容包括：本发明公开了一种利用半干法脱硫灰制备复合激发剂熟料的装置与方法及该熟料的应用,属于冶金和烟气脱硫技术领域。本发明包括以下过程：将半干法脱硫灰、膨胀珍珠岩和水按照质量比进行配料后依次进行搅拌混合、造粒和干燥处理,得到脱硫灰生料颗粒,然后利用高温空气对干燥后的脱硫灰生料颗粒进行分段加热处理,使脱硫灰生料颗粒依次进行预热、干燥、CaSO<Sub>3</Sub>的氧化和Ca(OH)<Sub>2</Sub>的脱水活化反应,经充分反应和冷却后即得到主要组成为CaSO<Sub>4</Sub>、CaO和SiO<Sub>2</Sub>的复合激发剂熟料。采用本发明的技术方案能够使半干法脱硫灰中的CaSO<Sub>3</Sub>发生充分氧化,有效提高了氧化脱硫灰的利用效率和附加值,且该处理工艺简单、成本低。(The invention discloses a device and a method for preparing composite excitant clinker by using semi-dry desulfurized fly ash and application of the clinker, belonging to the technical field of metallurgy and flue gas desulfurization. The invention comprises the following processes: mixing semi-dry desulfurization ash, expanded perlite and water according to a mass ratio, sequentially stirring, mixing, granulating and drying to obtain desulfurization ash raw material particles, and performing segmented heating treatment on the dried desulfurization ash raw material particles by using high-temperature air to sequentially preheat, dry and CaSO 3 Oxidation and Ca (OH) 2 The main component of the reaction product is CaSO after full reaction and cooling 4 CaO and SiO 2 The compound excitant clinker. By adopting the technical scheme of the invention, CaSO in semidry desulfurization ash can be generated 3 Fully oxidized, effectively improves the utilization efficiency of the oxidized desulfurized ashThe rate and the added value are high, and the treatment process is simple and the cost is low.)

1. A device for preparing composite excitant clinker by using semi-dry desulfurized fly ash is characterized in that: including shaft furnace (1), this shaft furnace (1) is equipped with feed inlet (110) including shaft furnace body (11), the top of shaft furnace body (11), and its inside furnace includes preheating section (112), dehydration section (113), degree of depth oxidation section (114), calcium hydroxide activation section (115) and ejection of compact section (118) that top-down distributes in proper order, and the bottom of calcium hydroxide activation section (115) is equipped with air disperser (116), and this air disperser (116) links to each other with the high temperature air intake pipe.

2. The device for preparing the clinker with the composite excitant by using the semi-dry desulphurization ash as claimed in claim 1, wherein: the air disperser (116) is a conical structure with the cross-sectional radius gradually increasing from top to bottom.

3. The device for preparing the clinker with the composite excitant by using the semi-dry desulphurization ash as claimed in claim 2, wherein: a furnace bottom material blocking section (117) is also arranged between the calcium hydroxide activation section (115) and the discharging section (118), and the furnace bottom material blocking section (117) is processed into an inverted cone-shaped structure with the cross section radius gradually reduced from top to bottom.

4. The device for preparing the composite excitant clinker by utilizing the semi-dry desulphurization ash according to any one of claims 1 to 3, wherein: the temperature of the preheating section (112) and the dehydration section (113) is less than or equal to 300 ℃, the temperature of the deep oxidation section (114) is 300-600 ℃, and the temperature of the calcium hydroxide activation section (115) is 600-800 ℃.

5. The device for preparing the composite excitant clinker by utilizing the semi-dry desulphurization ash according to any one of claims 1 to 3, wherein: the discharge port of the discharge section (118) is connected with a hot clinker inlet (131) of the cooler (13), and a hot air outlet (134) of the cooler (13) is connected with the air disperser (116) through a hot blast stove (15) and a high-temperature air inlet pipe.

6. The device for preparing the composite excitant clinker by utilizing the semi-dry desulphurization ash according to any one of claims 1 to 3, wherein: the semi-dry desulfurization ash production device is characterized by also comprising a stirrer (2), an extrusion granulator (3) and a dryer (4), wherein the semi-dry desulfurization ash raw material is sequentially stirred, extruded, granulated and dried by the stirrer (2), the extrusion granulator (3) and the dryer (4) and then enters the shaft furnace (1) through a feeding hole (110); the top of the shaft furnace (1) is provided with a furnace cover (12) and a tail gas discharge port (111), the tail gas discharge port (111) is connected with the dryer (4) through a pipeline, and a waste gas outlet of the dryer (4) is connected with an induced draft fan through a dust removal device.

7. A method for preparing composite excitant clinker by using semi-dry desulfurized fly ash is characterized by comprising the following steps: mixing semi-dry desulfurization ash, expanded perlite and water according to a mass ratio, sequentially stirring, mixing, granulating, drying and dehydrating to obtain desulfurization ash raw material particles, and performing segmented heating treatment on the dried desulfurization ash raw material particles by using high-temperature air to sequentially perform preheating, dehydration and CaSO (calcium SO) treatment on the desulfurization ash raw material particles₃Oxidation and Ca (OH)₂The main component of the reaction product is CaSO after full reaction and cooling₄CaO and SiO₂The compound excitant clinker.

8. The method for preparing the clinker with the composite excitant by using the semi-dry desulfurized ash according to claim 7, wherein the clinker comprises the following steps: the addition amount of the expanded perlite accounts for 5-10% of the total mass of the expanded perlite and the semi-dry desulfurization ash, and the addition amount of water accounts for 50-60% of the addition amount of the semi-dry desulfurization ash.

9. The method for preparing the clinker with the composite excitant by using the semi-dry desulphurization ash as claimed in claim 7 or 8, wherein: the dried raw material particles of the desulfurized ash are placed in a muffle furnace with a programmed temperature control or are introduced into the shaft furnace of any one of claims 1 to 6 for a sectional heating treatment, when the shaft furnace of any one of claims 1 to 6 is used for heating, the raw material particles of the desulfurized ash are continuously discharged and fed from the top of the shaft furnace downwards, and form a material bed which slowly moves from top to bottom under the action of gravity, meanwhile, high-temperature air is blown upwards by an air disperser (116), the high-temperature air moves upwards along a channel formed by the accumulation of the raw material particles of the desulfurized ash, the preheating section (112), a dewatering section (113), a deep oxidation section (114) and a calcium hydroxide activation section (115) are sequentially used for preheating and dewatering the raw material particles of the desulfurized ash, and CaSO is sequentially carried out₃Oxidation and Ca (OH)₂The composite exciting agent clinker formed after full reaction is continuously discharged from a discharging section (118) at the bottom of the shaft furnace.

10. Use of the clinker of the composite excitant prepared by the method of any one of claims 7 to 9 in persulfate slag cement, plastering gypsum and soil solidification admixture.

Technical Field

The invention belongs to the technical field of metallurgy and coal-electricity flue gas desulfurization, and particularly relates to a device and a method for preparing composite excitant clinker by using semi-dry desulfurization ash generated by sintering, coal electricity and the like, and application of the clinker.

Background

In recent years, the Chinese economy has been rapidly developed, and the demand of the industry for coal has increased. Coal combustion typically produces large amounts of SO₂The greater the consumption of gas and coal, the more SO is produced₂The more the pollution is, the more serious the pollution of acid rain is, and the great harm is caused to the ecological balance and the economic and social development of human survival. Based on this, in recent years, the nation has increased SO for various large coal-fired enterprises₂The treatment of SO₂The emission rate reduction of (A) puts higher and higher demands, SO that most enterprises have SO₂The discharge is controlled to a certain degree, but simultaneously, the new problem that the discharge amount of the desulfurized ash is increased day by day is brought. SO discharged by iron and steel enterprises in China₂50% -70% of the flue gas is from the sintering process, and sintering flue gas desulfurization is carried out by adopting a semi-dry desulfurization technology, so that not only is the investment low, but also the desulfurization rate is high, but only a small part of the large amount of desulfurization ash generated in the semi-dry desulfurization process is utilized at home and abroad, and most of the desulfurization ash is discarded.

The semi-dry desulfurization ash has fine particle size and specific surface area of about 500m²/kg, its main component comprises CaSO₃·1/2H₂O 15～30wt％、CaSO₄·2H₂O21-50 wt% and Ca (OH)₂11-30 wt%, and the water content is about 1%. The treatment of the desulfurized fly ash has been an international problem for a long time, and most of the steel enterprises adopt a centralized accumulation mode to treat the desulfurized fly ash at present, so that the mode not only occupies a large amount of land, but also can form a new pollution source, and the treatment cost is continuously increased along with the time extension.In order to realize certain economic value while fully applying the desulfurization ash, many experts research the comprehensive utilization of the semi-dry desulfurization ash of the sinter flue gas. The current technique for treating and utilizing semi-dry desulfurized fly ash mainly comprises producing baking-free bricks, steam-cured bricks, cement retarders, cementing materials, dry-mixed mortar, roadbed materials, ceramics, gypsum products, panels for composite wallboards, building blocks, filling materials and other building materials, and finally, because CaSO is contained in the desulfurized fly ash₃The content is high and unstable, the actual mixing amount is small, and large-scale industrial production cannot be realized.

The research also utilizes the desulfurized fly ash to prepare acid (CN200910180052.0) after thermal decomposition, prepare gypsum (CN200910263921.6) by catalytic oxidation, prepare nano calcium carbonate (CN201110209483.2), prepare wet desulfurizer (CN200910194833.5), produce potassium-calcium-silicon-sulfur compound fertilizer (CN200610123966.X), and the like, but the process is only in the stages of concept design and laboratory research at present due to the reasons of high energy consumption, high production cost, large potential adverse effect on environment, complex product purification and the like. In order to obtain stable desulfurized fly ash, people begin to turn to pretreatment and oxidation of semi-dry sintered desulfurized fly ash to obtain desulfurized fly ash containing calcium sulfate dihydrate, such as CN201010606155, with the name: the application of the device and the method for preparing gypsum by sintering flue gas desulfurization byproducts by a semidry method adopts waste sulfuric acid as an oxidation reactant, so that calcium sulfite in the waste sulfuric acid is completely converted into calcium sulfate dihydrate; application No. CN201610077828, entitled: the application of the cement doped with the modified desulfurized fly ash and the rice hull ash comprises the steps of adding water into the desulfurized fly ash, standing for 10 days, hardening, and calcining, wherein the calcining condition of the modified desulfurized fly ash is 250 ℃ to 400 ℃ (calcining for 30-60min), so that calcium sulfite in the desulfurized fly ash is converted into calcium sulfate; the application number is CN201710123453, and the name is: the application of the method for modifying the acid oxidation of the desulfurized ash of the semi-dry method of the sintering flue gas is to adopt H₂O₂As an oxidant, the CaSO is introduced in the slurry state under the action of a catalyst₃Oxidized to CaSO₄(ii) a Publication number CN108118359A, name: the application of the electrochemical oxidation method and device for calcium sulfite in flue gas desulfurization ash applies an electrochemical method to react CaSO₃Oxidized to CaSO₄. However, the above method has the problems of high oxidation cost, large amount of water in the obtained product to be removed, high dehydration cost or secondary pollution in the dehydration process.

Meanwhile, some researches on the high-temperature oxidation treatment of semi-dry desulfurized fly ash are currently available, such as applications No. 201410380382.5 and No. 201410380659.4, which propose that calcium sulfite in desulfurized fly ash is oxidized by high-temperature oxygen in a rotary kiln, and although the effect of oxidizing the calcium sulfite into calcium sulfate is obtained, the calcining temperature is relatively low due to the fact that reversible reaction is easy to occur in the oxidation process at high temperature, and CaCO in desulfurized fly ash is enabled to be obtained₃、Ca(OH)₂Is not activated, so that the utilization efficiency and added value of the obtained oxidized desulfurized fly ash are not high; in addition, if high-temperature air is used, the calcium sulfite cannot be fully oxidized into calcium sulfate, so that the operation cost is high, and the difficulty of practical popularization is high. As another example, application No. 201610076883.3 discloses heating semi-dry desulfurized fly ash until calcium sulfite decomposes into calcium oxide and SO₂The subsequent desulfurization operation increases the desulfurization cost and also causes a problem that secondary desulfurization by-products are disposed of again. Application No. 201910279266.7 discloses a method and apparatus for accelerating the oxidation of calcium sulfite in desulfurized fly ash by using low-temperature exhaust gas, which comprises passing the low-temperature exhaust gas through desulfurized fly ash slurry, and oxidizing the calcium sulfite in the low-temperature exhaust gas by using oxygen in the low-temperature exhaust gas.

Therefore, the research of the desulfurization ash oxidation treatment process which has the advantages of low treatment cost, simple process and high utilization efficiency and added value has important significance for the comprehensive application of the semi-dry desulfurization ash.

Disclosure of Invention

1. Problems to be solved

The invention aims to overcome the defects of high treatment cost, relatively complex treatment process or relatively low utilization efficiency of desulfurized ash in the conventional oxidation treatment method of desulfurized ash by a semidry method, and provides a method for treating desulfurized ash by using a semidry methodA device and a method for preparing composite excitant clinker by using semi-dry desulfurization ash such as sintering, coal-electricity and the like and application of the clinker are provided. By adopting the technical scheme of the invention, CaSO in semidry desulfurization ash can be generated₃The full oxidation is carried out, the utilization efficiency and the added value of the oxidized desulfurized ash are effectively improved, the treatment process is simple, the cost is low, and the composite excitant clinker can be directly obtained after the treatment.

2. Technical scheme

In order to solve the problems, the technical scheme adopted by the invention is as follows:

the device for preparing the composite exciting agent clinker by using the semi-dry desulfurized fly ash comprises a shaft furnace, wherein the shaft furnace comprises a shaft furnace body, the top of the shaft furnace body is provided with a feeding hole, an internal hearth comprises a preheating section, a dehydration section, a deep oxidation section, a calcium hydroxide activation section and a discharging section which are sequentially distributed from top to bottom, and the bottom of the calcium hydroxide activation section is provided with an air disperser which is connected with a high-temperature air inlet pipe.

Further, the air disperser has a conical structure with a gradually increasing cross-sectional radius from top to bottom.

Furthermore, a furnace bottom material blocking section is arranged between the calcium hydroxide activation section and the discharging section, and the furnace bottom material blocking section is processed into an inverted cone-shaped structure with the cross section radius gradually reduced from top to bottom.

Furthermore, the temperature of the preheating section and the dehydration section is less than or equal to 300 ℃, the temperature of the deep oxidation section is 300-600 ℃, and the temperature of the calcium hydroxide activation section is 600-800 ℃.

Furthermore, a discharge port of the discharge section is connected with a hot clinker inlet of a cooler, and a hot air outlet of the cooler is connected with an air disperser through a hot blast stove and a high-temperature air inlet pipe.

The semi-dry desulfurization ash raw material is sequentially stirred, extruded, granulated and dried by the stirrer, the extrusion granulator and the dryer and then enters the shaft furnace from a feeding hole; the top of the shaft furnace is provided with a furnace cover and a tail gas discharge port, the tail gas discharge port is connected with a dryer through a pipeline, and a waste gas outlet of the dryer is connected with an induced draft fan through a dust removal device.

Secondly, the method for preparing the composite excitant clinker by using the semidry desulfurization ash comprises the following steps: mixing semi-dry desulfurization ash, expanded perlite and water according to a mass ratio, sequentially stirring, mixing, granulating and drying to obtain desulfurization ash raw material particles, and performing segmented heating treatment on the dried desulfurization ash raw material particles by using high-temperature air to sequentially preheat, dry and CaSO₃Oxidation and Ca (OH)₂The main component of the reaction product is CaSO after full reaction and cooling₄CaO and SiO₂The compound excitant clinker.

Furthermore, the addition amount of the expanded perlite accounts for 5-10% of the total mass of the expanded perlite and the semi-dry desulfurization ash, and the addition amount of water accounts for 50-60% of the addition amount of the semi-dry desulfurization ash.

Furthermore, the dried semi-dry desulfurized ash raw material particles are placed in a muffle furnace with program temperature control or are introduced into the shaft furnace for sectional heating treatment, when the shaft furnace is used for heating, the semi-dry desulfurized ash raw material particles are continuously discharged from the top of the shaft furnace downwards and fed into the shaft furnace, a material bed moving slowly from top to bottom is formed under the action of gravity, high-temperature air is blown upwards by an air disperser, the high-temperature air moves upwards along a channel formed by accumulation of the semi-dry desulfurized ash raw material particles, preheating and dehydration of the semi-dry desulfurized ash raw material particles are sequentially carried out in a preheating section, a dehydration section, a deep oxidation section and a calcium hydroxide activation section, and CaSO and the preheating and dehydration of the semi-dry desulfurized ash raw material particles₃Oxidation and Ca (OH)₂The composite excitant clinker formed after full reaction is continuously discharged from a discharging section at the bottom of the shaft furnace. Specifically, the following series of physical and chemical reaction processes are sequentially completed in the process that high-temperature air moves upwards in the shaft furnace: 1) the heat carried by the high temperature air first causes calcium hydroxide (Ca (OH)₂) Dehydrating to generate calcium oxide (CaO); 2) the high-temperature air moves upwards sequentially to permeate into the porous gaps of the expanded perlite in the semi-dry desulfurized fly ash particles and be exposed to the expansionCalcium sulfite (CaSO) on surface of perlite₃) Oxidation reaction to generate calcium sulfate (CaSO)₄) And calcium bisulfite (CaSO)₃·2H₂O) dehydration and oxidation to generate calcium sulfate (CaSO)₄) (ii) a 3) The high-temperature air continuously goes upwards and then sequentially completes the drying, dehydration and preheating processes of semi-dry desulfurization ash raw material particles. After the series of physical and chemical reaction processes of 1) to 3) above, the calcined desulfurized fly ash particles after leaving the shaft furnace are cooled by the process 4), namely, normal temperature air, so that the deeply oxidized desulfurized fly ash particles become the composite excitant clinker simultaneously containing calcium sulfate, calcium oxide and active silicon oxide.

Thirdly, the excitant clinker prepared by the method of the invention is applied to persulfate slag cement, plastering gypsum and soil solidification admixture.

3. Advantageous effects

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention relates to a device for preparing composite exciting agent clinker by using semi-dry desulfurized fly ash, which comprises a shaft furnace, wherein the shaft furnace comprises a shaft furnace body, an internal hearth of the shaft furnace body comprises a preheating section, a dehydrating section, a deep oxidation section, a calcium hydroxide activation section and a discharging section which are sequentially distributed from top to bottom, semi-dry desulfurized fly ash raw material particles are fed from a feed inlet, slowly move from top to bottom under the action of gravity and sequentially pass through the preheating section, the dehydrating section, the deep oxidation section and the calcium hydroxide activation section, high-temperature air is introduced from an air disperser and then moves from bottom to top through gaps among the raw material particles, and airflow with temperature step distribution is formed in the hearth under the heat transfer action between the high-temperature air and the raw material particles, so that the raw material particles in the hearth are sequentially preheated, dehydrated, subjected to calcium sulfite oxidation reaction and subjected to calcium hydroxide dehydration activation, therefore, the full oxidation of the semi-dry desulfurization ash can be effectively ensured, and the utilization efficiency and the additional value of the semi-dry desulfurization ash are improved.

(2) According to the device for preparing the composite exciting agent clinker by using the semi-dry desulfurization ash, the air disperser is of a conical structure with the cross section radius gradually increasing from top to bottom, the furnace bottom material blocking section is further arranged between the calcium hydroxide activation section and the discharge section, the furnace bottom material blocking section is processed into an inverted conical structure with the cross section radius gradually decreasing from top to bottom, high-temperature air is introduced into the shaft furnace through the air disperser, the shape of the air disperser is optimally designed, and the furnace bottom material blocking section is matched, so that the downward movement of the high-temperature air can be effectively prevented, and the upward movement of the high-temperature air entering the shaft furnace can be ensured.

(3) According to the device for preparing the composite exciting agent clinker by using the semi-dry desulfurization ash, the temperatures of the preheating section, the dehydration section, the deep oxidation section and the calcium hydroxide activation section are optimally controlled, so that the full progress of calcium sulfite oxidation and calcium hydroxide dehydration activation reactions in the sintered semi-dry desulfurization ash can be further ensured, and the utilization efficiency and the added value of the oxidized desulfurization ash are improved. Meanwhile, the activation process of calcium hydroxide and the oxidation process of calcium sulfite are completed in the same device and flow, the process has good connectivity, and the prepared excitant clinker has extremely strong pozzolan reactivity and excitability.

(4) According to the device for preparing the composite exciting agent clinker by using the semi-dry desulfurization ash, high-temperature air is used as an oxidation and heat transfer medium, and an oxidized object is obtained to be in a dry state, so that the problems of low oxidation efficiency and the need of drying and dehydrating powder when the desulfurization ash is oxidized in water at normal temperature in the prior art are solved; meanwhile, the hot blast stove is adopted to suck high-temperature air formed by cooling the composite exciting agent clinker into the hot blast stove, and the high-temperature air is heated by utilizing waste heat flue gas and then is introduced into the shaft furnace through the air disperser, so that the energy is saved, and the energy is recycled.

(5) The invention relates to a method for preparing composite excitant clinker by using semi-dry desulfurized fly ash, which comprises the steps of mixing and granulating semi-dry desulfurized fly ash, expanded perlite and water to obtain desulfurized fly ash raw material particles, and then directly heating the desulfurized fly ash raw material particles by using high-temperature air in a sectional manner, so that the oxidation efficiency of calcium sulfite in desulfurized fly ash can be effectively improved, calcium hydroxide in desulfurized fly ash is fully dehydrated and activated, and the prepared composite excitant clinker mainly comprising CaSO₄CaO and SiO₂The composite excitant clinker greatly improves the utilization efficiency and the added value of the semi-dry desulfurized fly ash. Meanwhile, compared with the existing semi-dry desulfurization ash oxidation treatment process, the method is simple to operate and low in cost.

(6) The invention relates to a method for preparing composite excitant clinker by utilizing semidry desulfurization ash, which skillfully completes the heat transfer and mass transfer processes required in the oxidation process of calcium sulfite in the desulfurization ash through an expanded perlite medium, oxygen in high-temperature air enters a honeycomb porous structure of the expanded perlite and is highly dispersed, so that the high-temperature air can be in contact with calcium sulfite particles to the maximum extent to generate oxidation reaction, meanwhile, the heat of the high-temperature air can be used for the oxidation reaction of the calcium sulfite to the maximum extent due to the heat insulation effect of the expanded perlite particles, and the oxidation efficiency of the reaction process is greatly improved.

(7) According to the method for preparing the composite excitant clinker by using the semi-dry desulfurized fly ash, the addition amount of the expanded perlite is optimally designed, so that the oxidation reaction efficiency of calcium sulfite and the yield of calcium sulfate can be effectively ensured, the strength of raw material particles of the obtained desulfurized fly ash can be effectively ensured, and the phenomenon that a large amount of powder blocks a reaction gas channel is prevented, so that the oxidation reaction efficiency of the calcium sulfite is influenced.

(8) The method for preparing the composite exciting agent clinker by using the semi-dry desulfurized fly ash comprises the step of oxidizing the semi-dry desulfurized fly ash by using the method, so that the composite exciting agent clinker containing active minerals such as active calcium oxide, silicon oxide, calcium sulfate and the like can be directly prepared, and the clinker can be directly ground to form products such as plastering gypsum, persulfate slag cement clinker, exciting agents of other soil curing agents (volcanic ash cement) and the like, so that the recycling way and channel of the semi-dry desulfurized fly ash are widened, and the problem of secondary pollution sources of the semi-dry desulfurized fly ash is thoroughly solved.

Drawings

FIG. 1 is a schematic structural diagram of a device for preparing composite excitant clinker by using semi-dry desulfurization ash;

FIG. 2 is a schematic structural view of a shaft furnace according to the present invention;

FIG. 3 is the mechanical properties of the persulfate slag cement obtained in example 3;

FIG. 4 shows the properties of the bottom stucco gypsum obtained in example 4 (JC/T517-2004 requires for the bottom stucco gypsum in parentheses);

FIG. 5 shows the properties of the soil cured with the soil curing admixture obtained in example 6 (in the figure, the cement is PO42.5 cement, the amount of the composite activator clinker in the soil curing admixture in the example is 33.3%, and the proportion of the clinker in the soil curing admixture is 18%).

The reference numbers in the figures illustrate:

1. a shaft furnace; 11. a shaft furnace body; 110. a feed inlet; 111. a tail gas discharge port; 112. a preheating section; 113. a dewatering section; 114. a deep oxidation section; 115. a calcium hydroxide activation stage; 116. an air disperser; 117. a furnace bottom material blocking section; 118. a discharging section; 12. a furnace cover; 13. a cooling machine; 131. a hot clinker inlet; 132. a cold air inlet; 133. a cold clinker outlet; 134. a hot air outlet; 14. an exhaust gas dust removal system; 15. a hot blast stove; 151. an air inlet; 152. an air outlet; 2. a blender; 3. an extrusion granulator; 4. and a dryer.

Detailed Description

The invention relates to a method for preparing composite excitant clinker by using semi-dry desulfurized fly ash, which comprises the following steps: mixing semi-dry desulfurization ash, expanded perlite and water according to a mass ratio, sequentially stirring, mixing, granulating, drying and dehydrating (drying or air drying) to obtain desulfurization ash raw material particles, and performing sectional heating treatment (100-200 ℃, 200-300 ℃, 300-600 ℃ and 600-800 ℃) on the dried desulfurization ash raw material particles by using high-temperature air to sequentially preheat, dehydrate and CaSO the desulfurization ash raw material particles₃Oxidation and Ca (OH)₂The dehydration activation reaction can effectively improve the oxidation efficiency of the calcium sulfite in the desulfurized fly ash, fully oxidize the calcium sulfite and fully dehydrate and activate the calcium hydroxide in the desulfurized fly ash, thereby solving the problem that the CaSO in the desulfurized fly ash is caused by low oxidation efficiency in the semi-dry desulfurization in the prior art₃The secondary oxidation is needed, the secondary oxidation is difficult under normal temperature conditions, and the high-temperature oxidation temperature is over high to causeCaSO₃Decomposed into SO again₂The problem of gas.

After full reaction and cooling, the main component of CaSO is obtained₄CaO and SiO₂The clinker of the composite excitant can be directly added into slag and ground to make the slag become high-performance persulfate slag cement; or grinding the clinker separately to obtain a plastering gypsum raw material; or directly becomes an excitant (soil curing admixture) of other volcanic ash raw materials, so that the volcanic ash raw materials become high-performance soil curing agents, thereby greatly improving the utilization efficiency and the added value of the semi-dry desulfurization ash and realizing the comprehensive recycling of the semi-dry desulfurization ash. In addition, since the invention uses oxygen in air as the most common oxidizing medium, CaSO₃The oxidation cost is greatly reduced, the obtained product does not need secondary dehydration, and the process is simpler.

The invention adds expanded perlite into semi-dry desulfurized fly ash to prepare desulfurized fly ash raw material particles, on one hand, the expanded perlite is used as heat and oxygen heat and mass transfer medium required in the oxidation process of calcium sulfite, and because the expanded perlite has a porous honeycomb structure, oxygen in high-temperature air is highly dispersed after entering the expanded perlite, thereby greatly increasing the oxygen in the high-temperature air entering the raw material and CaSO in the raw material₃The reaction area of the oxidation reaction is large, so that the calcium sulfite particles can fully generate the oxidation reaction, and the oxidation efficiency is effectively improved; meanwhile, due to the heat insulation effect of the expanded perlite particles, the heat of the high-temperature air can be maximally used for the oxidation reaction of the calcium sulfite, so that the oxidation efficiency of the reaction process is further improved. Meanwhile, the strength of the obtained raw material particles can be effectively improved by adding the expanded perlite, and the raw material particles are prevented from being pulverized or broken in the calcining process. The inventor optimizes the addition amount of the expanded perlite through a large number of experiments, controls the addition amount of the expanded perlite to be 5-10% of the total mass of the expanded perlite and the semi-dry desulfurization ash, and controls the addition amount of the water to be 50-60% of the addition amount of the semi-dry desulfurization ash, so that the oxidation reaction efficiency of calcium sulfite and the yield of calcium sulfate can be effectively ensured on one hand, and the oxidation reaction efficiency of the calcium sulfite and the yield of the calcium sulfate can be effectively ensured onThe strength of the obtained desulfurization ash raw material particles prevents a large amount of powder from being generated to block a reaction gas channel, thereby influencing the oxidation reaction efficiency of the calcium sulfite.

The present invention is further illustrated by the following specific examples.