CN114835412B - Preparation process of fine calcium oxide - Google Patents

Preparation process of fine calcium oxide Download PDF

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Publication number
CN114835412B
CN114835412B CN202210763356.5A CN202210763356A CN114835412B CN 114835412 B CN114835412 B CN 114835412B CN 202210763356 A CN202210763356 A CN 202210763356A CN 114835412 B CN114835412 B CN 114835412B
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kiln
limestone
zone
calcining
plate
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CN114835412A (en
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马元海
铁有录
马宇星
侯铟
刘启权
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Suzhou Keda Geotechnical Engineering Technology Co ltd
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Suzhou Keda Geotechnical Engineering Technology Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2/00—Lime, magnesia or dolomite
    • C04B2/10—Preheating, burning calcining or cooling
    • C04B2/108—Treatment or selection of the fuel therefor
    • 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
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/02—Oxides or hydroxides
    • C01F11/04—Oxides or hydroxides by thermal decomposition
    • C01F11/06—Oxides or hydroxides by thermal decomposition of carbonates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2/00—Lime, magnesia or dolomite
    • C04B2/10—Preheating, burning calcining or cooling
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
    • C01P2006/65—Chroma (C*)
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/40—Production or processing of lime, e.g. limestone regeneration of lime in pulp and sugar mills

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

The invention discloses a preparation process of fine calcium oxide, which comprises the following steps: (1) mixing raw materials; (2) distributing; (3) calcining; (4) and (7) discharging. The invention uses limestone and lump coal, and combines the combined action of the rotary distributor and the vertical lime kiln obtained by structural improvement of the kiln liner, so that the yield of the limestone is kept stable and reliable, and the particle size range of the prepared calcium oxide is smaller.

Description

Preparation process of fine calcium oxide
Technical Field
The invention relates to the technical field of calcium oxide preparation, in particular to a preparation process of fine calcium oxide.
Background
Lime is an air-hardening inorganic cementing material taking calcium oxide as a main component, is one of main raw materials for producing glass fiber, and is also widely applied to the industries of coating, papermaking, steelmaking and the like.
CN109455958B discloses a preparation method of fine calcium oxide, which comprises four steps of raw material crushing, raw material pretreatment, calcination and discharging, has a simple production process, solves the problem of limitation on the size of stone materials in the traditional preparation process, and cannot cause raw material waste, but the produced lime has low calcium oxide content, uneven granularity and overlarge granularity range. CN110963719A discloses a method for producing calcium oxide by calcining marble or granite waste in a tunnel kiln, and the prepared limestone has uniform particle size and regular structure, but has high impurity content, which affects the further application of lime.
At present, the calcium oxide is produced by calcining in China generally by a vertical lime kiln which generally adopts a rotary distributor with a rebound plate. The rotary distributor consists of a kiln top sealing gate valve, a receiving hopper, a distribution chute and a trapezoidal rebound plate, wherein materials are beaten on the trapezoidal rebound plate through the distribution chute, large limestone can rebound at the middle part of the kiln, and small limestone falls around the kiln, so that the 'kiln wall effect' of the shaft kiln is reduced. However, the following problems exist in the practical use of such a distributor: the lining on the upper part of the kiln is damaged prematurely, the materials around the kiln wall are slightly pressed and can not be used for fire at the side, the material distribution effect is not ideal, the corrosion prevention effect is good, but the impact resistance is not good, and the service life is less than one year.
Disclosure of Invention
In order to solve the above problems, an aspect of the present invention provides a preparation process of fine calcium oxide, the preparation process comprising the steps of:
(1) mixing raw materials;
(2) distributing;
(3) calcining;
(4) and (6) discharging.
The step (1) is to mix limestone in a limestone silo and lump coal in a fuel silo through a vibrating feeder, a weighing mechanism and a mixing mechanism to obtain a mixture 1;
the step (2) is that the mixture 1 falls into a closed electric vibration feeder, is transported to a hopper at the top of the furnace through a winch and is distributed into the furnace through a rotary distributor;
and the step (3) is to calcine the mixture 1 treated in the step (2) in a vertical lime kiln.
The raw materials include limestone and lump coal.
Further, the weight ratio of the limestone to the lump coal is (6-20): 1.
Further, the weight ratio of the limestone to the lump coal is (8-15): 1.
Further, the ash content of the lump coal is 5-10, and the volatile component is 30-35.
In a preferable scheme, the limestone is in a block shape; the ash content of the lump coal was 8 and the volatile matter was 32.
The massive limestone is purchased from Hubei and is a calcium industry Co Ltd; the lump coal is produced in Ordos and is named as Nemonto-Erjing coal.
Ash is a residue remaining after complete combustion of coal, and not only represents a residue after combustion of coal, but also affects the calorific value of coal. It is generally accepted that the lower the ash content of coal, the better. However, the applicant has found that in the compounding and processing system provided by the present invention, if the ash content is too low, the yield of CaO produced is improved, but a large amount of reducing pollutants is generated, which may be caused by the endothermic combustion of impurities doped in limestone during the exothermic combustion process. When the ash content is controlled to be in the range of 8-10, the generated ash content can also generate certain endothermic reaction, and the negative influence of limestone impurities is reduced, so that the COD content of the water after the produced calcium oxide and the water are mixed is reduced. Meanwhile, when the volatile component is 30-35, the coal has a specific coalification degree, and the stable calcination of the limestone is ensured. The above effect is particularly remarkable when the weight ratio of limestone to lump coal is (8-15): 1.
The rotary distributor comprises a trapezoid bounce plate, a distribution chute and a discharge port of a bottom plate of the distribution chute, the bottom of the distribution chute is connected with the upper bottom of the trapezoid bounce plate in a welding mode, and the lower bottom of the trapezoid bounce plate is connected with the discharge port of the bottom plate of the distribution chute in a welding mode. The trapezoid bounce plate is 300-350mm in length at the upper bottom, is 500-550mm in length at the lower bottom, is 180-220mm away from the kiln wall, is connected with the distribution chute at the upper bottom, has an inclination angle of 35 degrees, has a 100mm bevel shape at the discharge port of the distribution chute bottom plate, and is laid with an L70 angle steel along the blanking direction at the middle part of the distribution chute bottom plate to divide the material into two channels for material scattering, so that the distributed material surface is in a shape of a flat and continuous saddle.
Since the calcining process of the limestone is influenced by the ash content and volatile components of the lump coal, the problem that the limestone is unevenly heated and is easy to produce under-burnt lime or over-burnt lime is aggravated, and in order to solve the problem, the applicant improves the distributing device. A rotary distributor with a rebound plate is commonly adopted in domestic vertical limekilns. The materials are beaten on the trapezoidal rebounding plate through the distributing chute, the large limestone can rebound to the middle part of the kiln, and the small limestone falls around the kiln, so that the 'kiln wall effect' of the shaft kiln is reduced. In the practical use process, however, a small amount of materials directly impact the kiln wall without a rebound plate, so that the lining at the upper part of the kiln is damaged prematurely. In the invention, the trapezoid rebound plate of the rotary distributor is limited, the upper bottom of the trapezoid rebound plate is 350mm in length, the lower bottom of the trapezoid rebound plate is 550mm in length, and the inclination angle of the distribution chute is 35 degrees, so that the service life of the device is prolonged, the damage to the kiln is reduced, and the limestone is heated more uniformly in the calcining process. In addition, the applicant has found that such an improvement also surprisingly reduces the particle size range of the produced lime, making it more uniform in particle size. In order to further reduce the production cost of lime and prolong the service life of the distributing device, the distributing chute and the trapezoidal rebounding plate are made of stainless steel materials, however, due to the characteristics of the stainless steel materials, the impact resistance of the distributing chute and the trapezoidal rebounding plate is poor, based on the characteristics, the applicant finds through a large number of experiments that the discharge hole of the bottom plate of the distributing chute is improved, so that the impact resistance of the distributing device is remarkably improved, meanwhile, the excellent distributing effect is guaranteed, and the problem of material blockage is not easy to occur.
The outer diameter of the vertical lime kiln is phi 5.5-8m, and the effective height is as follows: 20-24m, effective kiln volume: 300m for transportation in 250 ℃ and kiln utilization coefficient: performing the high-speed crown planting at a speed of more than or equal to 0.65 t/m; the vertical lime kiln body is sequentially provided with a preheating zone, a calcining zone and a cooling zone from top to bottom; the inner diameter of the preheating zone kiln is as follows: phi is 3 to 3.5 m; the inner diameter of the calcining zone kiln is as follows: phi is 4.5-4.8 m; the inner diameter of the cooling zone kiln is as follows: phi is 3.5-4 m.
In a preferable scheme, the external diameter of the vertical lime kiln is phi 6.5m, and the effective height is as follows: 23m, effective kiln volume: 280m for carrying out dry distillation and kiln utilization coefficient: performing the high-speed crown planting at a speed of more than or equal to 0.75 t/m; the vertical lime kiln body is sequentially provided with a preheating zone, a calcining zone and a cooling zone from top to bottom; the inner diameter of the preheating zone kiln is as follows: phi is 3.4 m; the inner diameter of the calcining zone kiln is as follows: phi is 4.6 m; the inner diameter of the cooling zone kiln is as follows: phi is 3.8 m.
Further, the vertical lime kiln body is sequentially provided with a preheating zone (from top to bottom)<200 ℃, 60 min), a calcining zone (900-<100 ℃ C.), and along with the discharge of finished product ash, the furnace burden slowly moves downwards by the dead weight. Heat exchange is generated between the cold material in the preheating zone and high-temperature waste gas from the calcining zone, the high-temperature waste gas is cooled, and the cold material is preheated; in the calcining zone CaCO 3 Absorbing heat for decomposition, and supplementing heat by burning lump coal; in the cooling zone, the burnt high-temperature lime exchanges heat with cold air blown by a blast cap at the lower part of the furnace bottom, and the preheated air is used as combustion-supporting air for burning in the calcining zone. Waste gas and CaCO produced by combustion 3 CO produced by decomposition 2 It is discharged from the furnace top.
Further, the calcining zone kiln lining structure is respectively a phosphate high-alumina brick, a clay brick, a red brick and aluminum silicate refractory cellucotton from inside to outside.
Further, the preheating zone kiln lining structure is as follows from inside to outside respectively: clay brick, red brick, and aluminum silicate refractory fiber cotton.
Further, the cooling zone kiln lining structure is respectively as follows from inside to outside: clay brick, red brick, and aluminum silicate refractory fiber cotton.
Furthermore, the kiln lining is built by phosphate high-alumina bricks and refractory materials with good heat insulation performance.
The improvement of the distributor improves the impact property of the distributor, so that the kiln lining structure needs to be improved to bear larger impact property. The three belts of the kiln liner structure are made of specific structural layers, SO that the impact resistance of the inner kiln is improved, the service life of the kiln is prolonged, the yield of quick lime is improved, and SO in lime is reduced 3 、SiO 2 、MgO、Fe 2 O 3 The whiteness of the obtained lime is improved. The limestone passes through different temperature zones of the calcining zone, the preheating zone and the cooling zone, and the arranged specific heat insulation layers are arranged, so that the heat dissipation loss of a kiln body can be reduced, and meanwhile, the stable air supply effect of the inner kiln is ensured, so that the high impact resistance is ensured, and the yield of calcium oxide is improved. In addition, due to inherent weak acidity of the clay layer, the clay layer is combined with a specific heat insulation layer arrangement, can generate a specific number of protons at high temperature to participate in the calcining process of limestone, influence the calcining yield, and reduce SO in lime 3 、SiO 2 、MgO、Fe 2 O 3 The content of (a).
The weight ratio of limestone to lump coal is controlled to be (8-15): 1, lump coal with 5-10 ash and 30-35 volatile matter is selected, and the vertical lime kiln obtained by combining the structural improvement of a rotary distributor and a kiln liner is combined to act together, so that the yield of the limestone is kept stable and reliable, the particle size range of the prepared calcium oxide is smaller, the part exceeding the upper limit of the particle size of 40-70mm is not more than 5%, the part exceeding the lower limit is not more than 3%, the prepared calcium oxide has uniform particle size, and the whiteness of the obtained calcium oxide is excellent, thereby being beneficial to the further application of the calcium oxide in glass fibers. The preparation process is stable and controllable, the energy consumption is low, and the application value is high.
Has the advantages that:
1. the ash content of the added lump coal is 5-10, and the volatile component is 30-35, so that the limestone is heated more uniformly during calcination, the stable calcination of the limestone is ensured, and the COD content of water after the produced calcium oxide is mixed with the water is reduced.
2. The rotary distributor optimizes the structures of the trapezoidal rebound plate and the distribution chute, prolongs the service life of the device, reduces the damage to the internal kiln, and is beneficial to more uniform heating of limestone in the calcining process.
3. The three belts of the kiln liner structure are made of specific structural layers, so that the impact resistance of the inner kiln can be improved, the service life of the kiln can be prolonged, the yield of quick lime can be improved, the impurity content in the lime can be reduced, and the whiteness of the obtained lime can be improved.
4. The process of the invention fully utilizes the combustion heat, greatly improves the energy utilization rate and is green and environment-friendly.
5. The invention controls the weight ratio of limestone to lump coal to be (8-15): 1, selects lump coal with 5-10 ash and 30-35 volatile matter, and combines the combined action of the rotary distributor and the vertical lime kiln obtained by improving the kiln liner structure, so that the yield of the limestone is kept stable and reliable, and the particle size range of the prepared calcium oxide is smaller.
Detailed Description
Example 1
A preparation process of fine calcium oxide comprises the following steps:
(1) mixing raw materials: limestone in a limestone silo and lump coal in a fuel silo are weighed to be 1000kg of limestone and 125kg of lump coal through a vibrating feeder, and are mixed through a mixing mechanism to obtain a mixture 1.
(2) Material distribution: the mixture 1 falls into a closed electric vibration feeder, is transported to a hopper at the top of the furnace through a winch and is distributed into the furnace through a rotary distributor.
The rotary distributor comprises a trapezoidal rebound plate, a distribution chute and a discharge hole of a bottom plate of the distribution chute. The bottom of the distribution chute is connected with the upper bottom of the trapezoidal rebounding plate in a welding mode, and the lower bottom of the trapezoidal rebounding plate is connected with a discharge port of a distribution chute bottom plate in a welding mode.
The upper bottom length of the trapezoid rebound plate is 300mm, the lower bottom length is 500mm, the distance between the trapezoid rebound plate and the kiln wall is 180mm, the inclination angle of the distribution chute is 35 degrees, the discharge hole of the bottom plate of the distribution chute is in a 100mm bevel shape, and an L70 angle steel is laid in the middle of the bottom plate of the distribution chute along the feeding direction.
(3) And (3) calcining: calcining the mixture 1 treated in the step (2) in a vertical lime kiln.
The vertical lime kiln body is divided into three zones, namely a preheating zone (200 ℃, 60 min), a calcining zone (900 ℃, 20 min) and a cooling zone (100 ℃) from top to bottom in sequence, and furnace burden slowly moves downwards by means of dead weight along with the discharge of finished product ash. Heat exchange is generated between the cold material in the preheating zone and high-temperature waste gas from the calcining zone, the high-temperature waste gas is cooled, and the cold material is preheated; in the calcining zone CaCO 3 Absorbing heat for decomposition, and supplementing heat by burning lump coal; in the cooling zone, the burnt high-temperature lime exchanges heat with cold air blown by a blast cap at the lower part of the furnace bottom, and the preheated air is used as combustion-supporting air for burning in the calcining zone. Waste gas and CaCO produced by combustion 3 CO produced by decomposition 2 It is discharged from the furnace top.
The outer diameter of the vertical lime kiln is phi 6m, and the effective height is as follows: 20m, effective kiln volume: and (5) carrying out dry distillation at 250m and utilizing coefficient of the kiln: carrying out 0.65t/m flowering; the vertical lime kiln body is sequentially provided with a preheating zone, a calcining zone and a cooling zone from top to bottom; the inner diameter of the preheating zone kiln is as follows: phi is 3 m; the inner diameter of the calcining zone kiln is as follows: phi is 4.5 m; the inner diameter of the cooling zone kiln is as follows: phi is 3.5 m.
The calcining zone kiln lining structure is respectively a phosphate high-alumina brick, a clay brick, a red brick and aluminum silicate refractory cellucotton from inside to outside.
The preheating zone kiln lining structure is as follows from inside to outside respectively: clay brick, red brick, and aluminum silicate refractory fiber cotton.
The cooling zone kiln lining structure is as follows from inside to outside: clay brick, red brick, and aluminum silicate refractory fiber cotton.
(4) Discharging: the burnt lime is unloaded by an automatic lime unloading machine at the lower part of the furnace and is continuously discharged through a sealed star-shaped lime discharging valve, so that the lime is unloaded onto a finished product belt without stopping wind.
The limestone is in a block shape; the ash content of the lump coal was 5, and the volatile matter was 30.
The massive limestone is purchased from Hubei and is a calcium industry Co Ltd; the lump coal is produced in Ordos and is named as Nemonto-Erjing coal.
The phosphate high-alumina brick is purchased from Zhengzhou Jinhe-sourced refractory material Co., Ltd, and has the model of KQ-6.
The clay brick is purchased from Zhengzhou Fengyu refractory material Co., Ltd, and has the model number of N-1.
The red brick is purchased from Tangshan Baolong building materials Co., Ltd, grade A.
The alumina silicate refractory fiber cotton was purchased from the three gorges jinteng refractory company, ltd.
Example 2
A preparation process of fine calcium oxide comprises the following steps:
(1) mixing raw materials: limestone in a limestone silo and lump coal in a fuel silo are weighed to be 1000kg of limestone and 67kg of lump coal through a vibrating feeder, and are mixed through a mixing mechanism to obtain a mixture 1.
(2) Material distribution: the mixture 1 falls into a closed electric vibration feeder, is transported to a hopper at the top of the furnace through a winch and is distributed into the furnace through a rotary distributor.
The rotary distributor comprises a trapezoidal rebound plate, a distribution chute and a discharge hole of a bottom plate of the distribution chute. The bottom of the distribution chute is connected with the upper bottom of the trapezoidal rebounding plate in a welding mode, and the lower bottom of the trapezoidal rebounding plate is connected with a discharge port of a distribution chute bottom plate in a welding mode.
The upper bottom of the trapezoid bounce plate is 350mm in length, the lower bottom of the trapezoid bounce plate is 550mm in length, the distance between the trapezoid bounce plate and the kiln wall is 220mm, the inclination angle of the distribution chute is 35 degrees, the discharge hole of the bottom plate of the distribution chute is 100mm in shape of an inclined opening, and an L70 angle steel is laid in the middle of the bottom plate of the distribution chute along the feeding direction.
(3) And (3) calcining: calcining the mixture 1 treated in the step (2) in a vertical lime kiln.
The vertical lime kiln body is divided into three zones, namely a preheating zone (200 ℃, 60 min), a calcining zone (1100 ℃, 20 min) and a cooling zone (80 ℃) from top to bottom in sequence, and furnace burden slowly moves downwards by means of dead weight along with the discharge of finished product ash. Heat exchange is generated between the cold material in the preheating zone and high-temperature waste gas from the calcining zone, the high-temperature waste gas is cooled, and the cold material is preheated; in the calcining zone CaCO 3 Absorbing heat for decomposition, and supplementing heat by burning lump coal; in the cooling zone, the burnt high-temperature lime exchanges heat with cold air blown by a blast cap at the lower part of the furnace bottom, and the preheated air is used as combustion-supporting air for burning in the calcining zone. Waste gas and CaCO produced by combustion 3 CO produced by decomposition 2 It is discharged from the furnace top.
The outer diameter of the vertical lime kiln is phi 8m, and the effective height is as follows: 24m, effective kiln volume: 300m for carrying out dry distillation and kiln utilization coefficient: carrying out 0.75t/m flowering; the vertical lime kiln body is sequentially provided with a preheating zone, a calcining zone and a cooling zone from top to bottom; the inner diameter of the preheating zone kiln is as follows: phi is 3.5 m; the inner diameter of the calcining zone kiln is as follows: phi is 4.8 m; the inner diameter of the cooling zone kiln is as follows: phi 4 m.
The calcining zone kiln lining structure is respectively a phosphate high-alumina brick, a clay brick, a red brick and aluminum silicate refractory cellucotton from inside to outside.
The preheating zone kiln lining structure is as follows from inside to outside respectively: clay brick, red brick, and aluminum silicate refractory fiber cotton.
The cooling zone kiln lining structure is as follows from inside to outside: clay brick, red brick, and aluminum silicate refractory fiber cotton.
The phosphate high-alumina brick is purchased from Zhengzhou Jinhe-sourced refractory material Co., Ltd, and has the model of KQ-6.
(4) Discharging: the burnt lime is unloaded by an automatic lime unloading machine at the lower part of the furnace and is continuously discharged through a sealed star-shaped lime discharging valve, so that the lime is unloaded onto a finished product belt without stopping wind.
The limestone is in a block shape; the ash content of the lump coal was 10 and the volatile matter was 35.
The massive limestone is purchased from Hubei and is calcium industry Co., Ltd; the lump coal is produced in Ordos and is named as Nemonto-Erjing coal.
The clay brick is purchased from Zhengzhou Fengyu refractory material Co., Ltd, and has the model number of N-1.
The red brick is purchased from Tangshanbao Longe building materials Co., Ltd, grade A.
The alumina silicate refractory fiber cotton was purchased from the three gorges jinteng refractory company, ltd.
Example 3
A preparation process of fine calcium oxide comprises the following steps:
(1) mixing raw materials: limestone in a limestone silo and lump coal in a fuel silo are weighed to be 1000kg of limestone and 100kg of lump coal through a vibrating feeder, and are mixed through a mixing mechanism to obtain a mixture 1.
(2) Material distribution: the mixture 1 falls into a closed electric vibration feeder, is transported to a hopper at the top of the furnace through a winch and is distributed into the furnace through a rotary distributor.
The rotary distributor comprises a trapezoidal rebound plate, a distribution chute and a discharge hole of a bottom plate of the distribution chute. The bottom of the distribution chute is connected with the upper bottom of the trapezoidal rebounding plate in a welding mode, and the lower bottom of the trapezoidal rebounding plate is connected with a discharge port of a distribution chute bottom plate in a welding mode.
The length of the upper bottom of the trapezoidal rebound plate is 320mm, the length of the lower bottom of the trapezoidal rebound plate is 520mm, the distance between the trapezoidal rebound plate and the kiln wall is 200mm, the inclination angle of the distribution chute is 35 degrees, the discharge hole of the bottom plate of the distribution chute is in a 100mm bevel shape, and an L70 angle steel is laid in the middle of the bottom plate of the distribution chute along the feeding direction.
(3) And (3) calcining: calcining the mixture 1 treated in the step (2) in a vertical lime kiln.
The vertical lime kiln body is divided into three zones, namely a preheating zone (200 ℃, 60 min), a calcining zone (1100 ℃, 20 min) and a cooling zone (80 ℃) from top to bottom in sequence, and furnace burden slowly moves downwards by means of dead weight along with the discharge of finished product ash. Heat exchange is generated between the cold material in the preheating zone and high-temperature waste gas from the calcining zone, the high-temperature waste gas is cooled, and the cold material is preheated; in the calcining zone CaCO 3 Absorbing heatDecomposing, and combusting lump coal to supplement heat; in the cooling zone, the burnt high-temperature lime exchanges heat with cold air blown by a blast cap at the lower part of the furnace bottom, and the preheated air is used as combustion-supporting air for burning in the calcining zone. Waste gas and CaCO produced by combustion 3 CO produced by decomposition 2 It is discharged from the furnace top.
The outer diameter of the vertical lime kiln is phi 6.5m, and the effective height is as follows: 23m, effective kiln volume: 280m for carrying out dry distillation and kiln utilization coefficient: harvesting at 0.75 t/m; the vertical lime kiln body is sequentially provided with a preheating zone, a calcining zone and a cooling zone from top to bottom; the inner diameter of the preheating zone kiln is as follows: phi is 3.4 m; the inner diameter of the calcining zone kiln is as follows: phi 4.6 m; the inner diameter of the cooling zone kiln is as follows: phi is 3.8 m.
The calcining zone kiln lining structure is respectively a phosphate high-alumina brick, a clay brick, a red brick and aluminum silicate refractory cellucotton from inside to outside.
The preheating zone kiln lining structure is as follows from inside to outside respectively: clay brick, red brick, and aluminum silicate refractory fiber cotton.
The cooling zone kiln lining structure is as follows from inside to outside: clay brick, red brick, and aluminum silicate refractory fiber cotton.
(4) Discharging: the burnt lime is unloaded by an automatic lime unloading machine at the lower part of the furnace and is continuously discharged through a sealed star-shaped lime discharging valve, so that the lime is unloaded onto a finished product belt without stopping wind.
The limestone is in a block shape; the ash content of the lump coal was 8 and the volatile matter was 32.
The massive limestone is purchased from Hubei and is calcium industry Co., Ltd; the lump coal is produced in Ordos and is named as Nemonto-Erjing coal.
The phosphate high-alumina brick is purchased from Zhengzhou Jinhe-sourced refractory material Co., Ltd, and has the model of KQ-6.
The clay brick is purchased from Zhengzhou Fengyu refractory material Co., Ltd, and has the model number of N-1.
The red brick is purchased from Tangshan Baolong building materials Co., Ltd, grade A.
The alumina silicate refractory fiber cotton is available from the three gorges jinteng refractory ltd.
Comparative example 1
The lump coal was replaced with 200kg of lump coal purchased from Yongshengchang commerce and trade Co., Ltd, Yulin City, the ash content of the lump coal was less than 5, and the volatile matter was 40, as in example 3.
Comparative example 2
The vertical lime kiln is purchased from Zhengzhou City fixed star heavy equipment Co., Ltd, the external diameter of the vertical lime kiln body is phi 5m, the internal diameter of the kiln is phi 3.4m, and the effective height is as follows: 18.7m, effective kiln volume: 170m, as in example 3.
Comparative example 3
The rotary distributing device comprises a trapezoid rebound plate, a distribution chute and a discharge port of a distribution chute base plate. The bottom of the distribution chute is connected with the upper bottom of the trapezoidal rebounding plate in a welding mode, and the lower bottom of the trapezoidal rebounding plate is connected with a discharge port of a distribution chute bottom plate in a welding mode.
The length of the upper bottom of the trapezoidal rebound plate is 280mm, the length of the lower bottom of the trapezoidal rebound plate is 480mm, the distance between the trapezoidal rebound plate and the kiln wall is 300mm, the inclination angle of the distribution chute is 45 degrees, the discharge hole of the bottom plate of the distribution chute is in a straight-mouth shape, angle steel is not laid on the bottom plate of the distribution chute, and the rest is the same as that in embodiment 3.
Performance test
1. And (3) chemical composition testing: sampling according to GB/T2007.1, dividing into 100g samples from large sample, crushing with jaw crusher to particle size of 13mm, dividing into 25g samples by quartering method, grinding with sealed sampling machine until all the samples pass through square hole sieve with pore diameter of 0.08mm, mixing, adding into inserted sample bottle, and analyzing CaO and SO in the sample bottle 3 、SiO 2 、MgO、Fe 2 O 3 The test results are shown in the following table:
Figure 709042DEST_PATH_IMAGE001
2. and (3) whiteness testing: the lime whiteness according to examples 1-3, comparative examples 1-3 was tested according to JB/T9327-1999 using a whiteness meter, and the results are given in the following table:
Figure 688499DEST_PATH_IMAGE002
3. and (3) testing the COD content: according to the dichromate method for determining the chemical oxygen demand of water quality of HJ 828-2017, calcium oxide is mixed with water, the supernatant is taken, after the pH of the solution is adjusted to be strong acid, excessive potassium dichromate is added, ferrophos is used as an indicator, an ammonium ferrous sulfate standard solution is dripped back, and the chemical oxygen demand is calculated according to the consumed potassium dichromate standard solution, so that the content of reducing (mainly organic matters) substances in the calcium oxide is obtained. The COD content of the limes described in examples 1 to 3 and comparative examples 1 to 3 was tested and the results are given in the following table:
Figure 796132DEST_PATH_IMAGE003
。

Claims (3)

1. the preparation process of the fine calcium oxide is characterized by comprising the following steps of:
(1) mixing raw materials;
(2) distributing;
(3) calcining;
(4) discharging;
the step (1) is to mix limestone in a limestone silo and lump coal in a fuel silo through a vibrating feeder, a weighing mechanism and a mixing mechanism to obtain a mixture 1;
the step (2) is that the mixture 1 falls into a closed electric vibration feeder, is transported to a furnace top hopper through a winch and enters the furnace through a rotary distributor;
the step (3) is to calcine the mixture 1 treated in the step (2) in a vertical lime kiln;
the rotary distributor comprises a trapezoidal rebound plate, a distribution chute and a distribution chute bottom plate discharge hole;
the bottom of the distribution chute is connected with the upper bottom of the trapezoidal rebounding plate in a welding mode, and the lower bottom of the trapezoidal rebounding plate is connected with a discharge hole of a distribution chute bottom plate in a welding mode; the upper bottom of the trapezoid rebound plate is 300-350mm, and the lower bottom of the trapezoid rebound plate is 500-550 mm;
the raw materials comprise limestone and lump coal; the weight ratio of the limestone to the lump coal is (8-15) to 1; the ash content of the lump coal is 5-10, and the volatile component is 30-35;
the outer diameter of the vertical lime kiln body kiln is phi 6-7m, and the effective height is as follows: 20-24m, the effective capacity of the kiln is 250-;
the vertical lime kiln body is sequentially provided with a preheating zone, a calcining zone and a cooling zone from top to bottom; the calcining zone kiln lining structure is respectively a phosphate high-alumina brick, a clay brick, a red brick and aluminum silicate refractory cellucotton from inside to outside; the preheating zone kiln lining structure is as follows from inside to outside respectively: clay brick, red brick, aluminum silicate refractory fiber cotton; the cooling zone kiln lining structure is as follows from inside to outside: clay brick, red brick, and aluminum silicate refractory fiber cotton.
2. The process according to claim 1, wherein said limestone is in the form of blocks.
3. The manufacturing process according to claim 1, wherein the inside diameter of the preheating zone kiln is: phi is 3 to 3.5 m; the inner diameter of the calcining zone kiln is as follows: phi is 4.5-4.8 m; the inner diameter of the cooling zone kiln is as follows: phi is 3.5-4 m.
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