WO2024060552A1 - 一种净化磷石膏动态焙烧制半水石膏粉的方法 - Google Patents

一种净化磷石膏动态焙烧制半水石膏粉的方法 Download PDF

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WO2024060552A1
WO2024060552A1 PCT/CN2023/082865 CN2023082865W WO2024060552A1 WO 2024060552 A1 WO2024060552 A1 WO 2024060552A1 CN 2023082865 W CN2023082865 W CN 2023082865W WO 2024060552 A1 WO2024060552 A1 WO 2024060552A1
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Prior art keywords
roasting
reaction section
phosphogypsum
reaction
cooling
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PCT/CN2023/082865
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English (en)
French (fr)
Inventor
肖聪
卢瑞
王致富
李长东
唐盛贺
王皓
Original Assignee
宜昌邦普循环科技有限公司
宜昌邦普时代新能源有限公司
广东邦普循环科技有限公司
湖南邦普循环科技有限公司
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Publication of WO2024060552A1 publication Critical patent/WO2024060552A1/zh

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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
    • C04B11/00—Calcium sulfate cements
    • C04B11/26—Calcium sulfate cements strating from chemical gypsum; starting from phosphogypsum or from waste, e.g. purification products of smoke
    • 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
    • C04B11/00—Calcium sulfate cements
    • C04B11/02—Methods and apparatus for dehydrating gypsum
    • C04B11/028—Devices therefor characterised by the type of calcining devices used therefor or by the type of hemihydrate obtained
    • C04B11/036—Devices therefor characterised by the type of calcining devices used therefor or by the type of hemihydrate obtained for the dry process, e.g. dehydrating in a fluidised bed or in a rotary kiln, i.e. to obtain beta-hemihydrate

Definitions

  • the present invention relates to the technical field of waste recycling, and specifically to a method for purifying phosphogypsum and dynamic roasting to produce semi-aqueous gypsum powder.
  • Phosphogypsum is a by-product produced during the production of phosphate fertilizer.
  • the main component is CaSO 4 ⁇ 2H 2 O, with a mass fraction of more than 80%. Since phosphogypsum contains a certain amount of SiO 2 , F, P and organic matter and other impurities, it affects the quality of phosphogypsum.
  • the rapid development of the phosphate fertilizer industry produces a large amount of phosphogypsum, but the resource utilization rate of phosphogypsum is low.
  • phosphogypsum is mainly treated by stockpiling, which takes up a lot of land and causes environmental pollution.
  • gypsum also known as plaster of paris
  • plaster of paris is a powdery cementing material with semi-hydrated gypsum as the main component. It is made from natural gypsum stone or industrial by-product gypsum (phosphogypsum), which is crushed and finely processed and calcined at low temperature.
  • phosphogypsum industrial by-product gypsum
  • traditional dehydration equipment such as rotary kilns have large internal temperature differences, making it difficult to accurately control thermal systems such as roasting temperature, resulting in semi-hydrated (anhydrous) gypsum produced with small crystals, low purity, and poor quality.
  • Some scholars also use fluidized roasting process to dehydrate dihydrate gypsum.
  • the dihydrate gypsum produced after impurity removal from phosphogypsum has a high water content. After entering the roasting furnace, it is easy to agglomerate, affecting the suspension state of the material. Moreover, the fluidized roasting speed is fast and has poor controllability. The produced semi-hydrated (without Water) gypsum has poor crystallization degree, smaller grains and low strength.
  • the purpose of the present invention is to provide a method for purifying phosphogypsum and dynamic roasting to produce semi-aqueous gypsum powder, which can establish a coordinated regulation mechanism for efficient drying and dehydration of phosphogypsum, reduce energy consumption, and increase the qualification rate of semi-aqueous gypsum products.
  • the invention can be implemented as follows:
  • the present invention provides a method for purifying phosphogypsum and dynamically roasting hemihydrate gypsum powder, which includes dynamic roasting using a dynamic roasting device.
  • the dynamic roasting device includes a furnace body and a center rotatably connected to the furnace body. Rotating shaft; the furnace body is provided with a plurality of furnace plates, and the plurality of furnace plates divide the furnace body into a multi-layer reaction chamber, and the furnace body is divided into a drying reaction section and a roasting reaction section from top to bottom.
  • the dry reaction section It includes 2-4 of the reaction chambers
  • the roasting reaction section includes 4-6 of the reaction chambers
  • the cooling reaction section includes 2-4 of the reaction chambers
  • the furnace plate includes a central blanking plate and An edge blanking tray is provided with a central blanking opening close to the central rotation axis, and an edge blanking opening is provided close to the inner wall of the furnace.
  • the center blanking disk and the edge blanking disk are arranged at intervals; a plurality of stirring parts are provided on the central rotating shaft, and the stirring parts extend into at least one of the reaction chambers for stirring materials; the furnace
  • the top of the furnace body is provided with a feed port, a preheated gas inlet and a waste gas outlet, and the bottom of the furnace body is provided with a discharge port; the side walls of the furnace body are provided with a feed port at positions corresponding to each of the reaction chambers.
  • Working gas inlet
  • the methods include:
  • the rotation speed of the central rotating shaft is 4-10 r/min.
  • both the central rotating shaft and the stirring member are provided with cooling air channels, the central rotating shaft is provided with a cooling air inlet, and the end of the stirring member is provided with a cooling air outlet. ;
  • the cooling air discharged from the cooling air outlet serves as the combustion-supporting air for the drying reaction section, the roasting reaction section and the cooling reaction section.
  • the central rotating shaft is provided with a wind shield, and the wind shield divides the central rotating shaft into a plurality of cooling sections, and the cooling sections are connected to the cooling air channel and have a One correspondence.
  • the stirring member includes a first stirring member and a second stirring member that are overlapped, the first stirring member is located above the second stirring member, and the third stirring member An end of an agitating member away from the central rotation axis is provided with an arc-shaped guide surface that is inclined downward toward the furnace body.
  • the dry reaction gas is gas combustion hot air
  • the roasting reaction gas is natural gas, coke oven gas, artificial coal gas or blast furnace gas with a calorific value of 3000-4000kJ/ Nm3 ;
  • the cooling reaction gas is provided by a Roots blower.
  • the dynamic roasting device is preheated by using a boiling furnace to burn raw coal to provide preheated gas. body.
  • the high-temperature exhaust gas discharged from the exhaust gas outlet of the dynamic roasting device is communicated with the boiling furnace for drying the raw coal.
  • the purified phosphogypsum is transported to the dynamic roasting device by pneumatic transport, and the pneumatic transport speed is 1-200 tons/hour.
  • the purified phosphogypsum is phosphogypsum that has undergone a decolorization, purification and flotation process.
  • the purified phosphogypsum has a moisture content of 15%-18%, a whiteness of 56%-62%, and CaSO 4 ⁇ 2H 2 O content is 95%-97%, SiO 2 content is 0.6%-1.0%.
  • the method for preparing semi-hydrated gypsum powder by dynamic roasting of purified phosphogypsum adopts a dynamic roasting device to realize dynamic roasting, wherein a combination of multiple reaction chambers is adopted to synchronously control main process parameters such as roasting temperature, time, atmosphere, etc.; the mineral powder tumbles and is evenly heated in the furnace body, the roasting time is shortened, and the roasting uniformity is greatly improved; the full-size mineral powder in the present application is directly roasted at medium and low temperatures; the present application adopts a step-by-step preheating-step reaction mode of the mineral powder, the reaction is relatively complete, the reduction rate can reach more than 90%, and the generation of block materials is avoided, thereby reducing the ore screening and grading and the grinding and batching ball making processes, and can be applicable to full-size mineral powder (0-15mm), and the raw material adaptability is strong; the temperature gradient in the furnace of the dynamic roasting device is obvious, dehydration, drying, preheating, roasting, and cooling are
  • FIG1 is a schematic structural diagram of a dynamic roasting device provided in an embodiment of the present invention.
  • Figure 2 is a schematic structural diagram of the edge blanking tray of the dynamic roasting device provided by an embodiment of the present invention
  • Figure 3 is a schematic flow chart of a method for purifying phosphogypsum and dynamic roasting to produce hemihydrate gypsum powder according to an embodiment of the present invention.
  • Icon 100-dynamic roasting device; 110-furnace body; 111-furnace plate; 1111-center blanking plate; 1112-edge blanking Disk; 1113-center blanking port; 1114-edge blanking port; 1115-baffle plate; 112-reaction chamber; 113-feed port; 114-preheated gas inlet; 115-waste gas outlet; 116-discharge port ; 117-working air inlet; 120-central rotating shaft; 121-stirring part; 1211-first stirring part; 1212-second stirring part; 1213-arc guide surface; 122-cooling air channel; 1221 - Cooling air inlet; 1222 - Cooling air outlet; 123 - Wind shield.
  • the present application provides a method for dynamically roasting purified phosphogypsum to produce semi-aqueous gypsum powder, which includes using a dynamic roasting device 100 to perform dynamic roasting.
  • a dynamic roasting device 100 to perform dynamic roasting.
  • this application first describes the specific structure of the dynamic roasting device 100.
  • the dynamic roasting device 100 includes a furnace body 110 and a central rotating shaft 120 rotatably connected to the furnace body 110 .
  • the furnace body 110 is used as a reaction chamber to realize drying, dehydration and roasting of materials (such as purified phosphogypsum). Burning and other operations.
  • the furnace body 110 has a vertical structure, with multiple furnace pans 111 provided inside.
  • the multiple furnace pans 111 divide the furnace body 110 into multi-layer reaction chambers 112.
  • the furnace body 110 The top of the furnace body 110 is provided with a feed port 113, a preheated gas inlet 114 and an exhaust gas outlet 115, and the bottom of the furnace body 110 is provided with a discharge port 116.
  • the material enters the furnace body 110 from the feed port 113, and performs preheating reaction, drying reaction, roasting reaction and cooling reaction layer by layer in the multi-layer reaction chamber 112.
  • the furnace body 110 is divided into a drying reaction section, a roasting reaction section and a cooling reaction section from top to bottom.
  • the drying reaction section includes 2-4 reaction chambers 112 and the roasting reaction section includes 4-6 reaction chambers. 112.
  • the cooling reaction section includes 2-4 reaction chambers 112.
  • the movement trajectory of the materials in this application is an "S" shape.
  • the furnace tray 111 includes a center drop tray 1111 and an edge drop tray.
  • the material tray 1112 and the center blanking tray 1111 are provided with a center blanking port 1113 close to the central rotation axis 120.
  • the edge blanking tray 1112 is provided with an edge blanking port 1114 close to the inner wall of the furnace body 110.
  • the center blanking tray 1111 and the edge blanking plate 1112 are arranged at intervals; in this application, the center blanking plate 1111 and the edge blanking plate 1112 are both inclined, and the side close to the central rotation axis 120 is higher than the side close to the inner wall of the furnace body 110.
  • the first layer of furnace trays 111 and the last layer of furnace trays 111 among the plurality of furnace trays 111 are both center blanking trays 1111.
  • the movement trajectory of the material is in an "S" shape.
  • the edge blanking tray 1112 in the present application is not directly connected to the central rotating shaft 120, in order to prevent materials from falling from the gap between the edge blanking tray 1112 and the central rotating shaft 120, the edge blanking in the present application
  • the side of the disk 1112 close to the central rotating shaft 120 is provided with a baffle plate 1115 to prevent materials from being discharged from the middle.
  • the setting of the baffle plate 1115 can prevent the material that should be discharged from the edge discharge port 1114 from being discharged from the middle, ensuring that the material movement trajectory.
  • the side wall of the furnace body 110 is provided with a working gas inlet 117 at a position corresponding to each reaction chamber 112.
  • the working gas can be, for example, natural gas, coke oven gas, artificial coal gas or a blast furnace with a low calorific value (3000-4000kJ/Nm 3 ).
  • Coal gas is used as a working gas for drying and roasting to achieve drying and roasting of raw materials.
  • the working gas can also be cold wind or normal temperature air to achieve air cooling of the raw materials in the bottom reaction chamber 112. Cold wind or normal temperature air can pass through the The blower is input into the reaction chamber 112.
  • each reaction chamber 112 by adjusting the working gas flowing into each reaction chamber 112, the temperature of each reaction chamber 112 can be adjusted, thereby realizing the operations of drying, roasting and air cooling in one furnace 110 in sequence.
  • the working gas inlet 117 corresponding to each reaction chamber 112 is independently equipped with a flow controller and a temperature control. device. The settings of the flow controller and the temperature controller can achieve better control of the temperature in the reaction chamber 112 .
  • the central rotating shaft 120 can rotate relative to the furnace body 110.
  • a plurality of stirring parts 121 are provided on the central rotating shaft 120.
  • the stirring parts 121 extend into at least one reaction chamber 112 for stirring materials; the materials are Driven by the stirring member 121, the turning movement can be realized, thereby achieving uniform heating in the reaction chamber 112, which is beneficial to shortening the roasting time.
  • the central rotating shaft 120 and the stirring member 121 are both provided with cooling air channels 122, the central rotating shaft 120 is provided with a cooling air inlet 1221, and the end of the stirring member 121 is provided with a cooling air outlet 1222.
  • the cooling air channel 122 By setting the cooling air channel 122, the temperature on the surface of the stirring element can be lowered to avoid agglomeration of raw materials.
  • the outlet of the cooling air is directly set on the stirring element 121.
  • the cooling air can be used as the dynamic furnace combustion-supporting air to fully Utilizes energy and reduces harmful gas emissions.
  • a wind shield 123 is provided in the central rotating shaft 120.
  • the wind shield 123 divides the central rotating shaft 120 into a plurality of mutually independent cooling sections. , the cooling section is connected with the cooling air channel 122 and corresponds one to one. This enables individual control of the cooling air in each cooling zone, with higher control accuracy.
  • the temperature in each reaction chamber 112 can be controlled cooperatively through the temperature and amount of the incoming reaction gas, the rotation speed of the central rotating shaft 120 and the temperature of the cooling air.
  • the roasting temperature can be controlled at 150-150°C. 850°C, the temperature field at each stage is uniform, the temperature and atmosphere at different stages are highly controllable and easy to regulate.
  • the stirring member 121 includes a first stirring member 1211 and a second stirring member 1212 arranged overlappingly.
  • the first stirring member 1211 is located above the second stirring member 1212, and the first stirring member 1211 is away from the center.
  • One end of the rotating shaft 120 is provided with an arc-shaped material guide surface 1213 that is inclined downward toward the furnace body 110 .
  • the movement time of the cooling air in the stirring part 121 can be extended, and it is beneficial to ensure that the materials in the upper or lower part of the reaction chamber 112 are Both can fully come into contact with the first stirring member 1211 and the second stirring member 1212 .
  • the design of the arc-shaped guide surface 1213 makes it easier for the material located on the upper surface of the first stirring member 1211 to slide downward along the surface of the first stirring member 1211, which is beneficial to controlling the movement trajectory of the material.
  • a stirrer 121 can be provided in each reaction chamber 112, or the stirrer 121 can be selectively provided in some reaction chambers 112 and not in the others.
  • the working principle of the dynamic roasting device 100 is: the preheating gas enters the furnace body from the preheating gas inlet 114 of the furnace body 110 110 preheats the furnace body 110 in advance. After the preheating is completed, the material enters the furnace body 110 from the feed port 113 of the furnace body 110, and falls into the first center dropping plate 1111 of the furnace body 110. At this time, the material is stirred. The material piece 121 drives the material to turn over to achieve uniform heating. At the same time, it drives the material to be dropped from the center blanking port 1113 of the center blanking tray 1111 to the edge blanking tray 1112 of the next layer. Since the edge blanking tray 1112 is tilted, The material moves toward the edge discharge port 1114 more easily.
  • the cooling air channel 122 provided on the stirring piece 121 in this application can not only cool the stirring piece 121, but also can pass the cooling air as combustion-supporting air, making full use of energy and reducing the emission of harmful gases. emission. It can be adjusted by adjusting the temperature and flow rate of the working gas introduced into each reaction chamber 112 of the dynamic roasting device 100, thereby adjusting the temperature of each reaction chamber 112, thereby realizing the transfer of materials from the reaction chamber 112 on the top to the reaction chamber 112 on the bottom. Reactions such as drying, roasting and cooling are carried out step by step, with simple operation and strong implementability.
  • the present application proposes a method for purifying phosphogypsum by dynamic roasting to produce semi-hydrated gypsum powder, as shown in FIG3 , which includes the following steps:
  • a boiling furnace is used to burn raw coal to provide preheating gas.
  • the boiling furnace is connected to the preheating gas inlet 114 to preheat the dynamic roasting device 100 .
  • the purified phosphogypsum is passed into the fully preheated dynamic roasting device 100 from the feed port 113; the purified phosphogypsum is pneumatically transported to the dynamic roasting device 100 using a feeder, and the pneumatic transport speed is 1-200 tons/hour.
  • Purified phosphogypsum is phosphogypsum that has undergone decolorization, purification and flotation technology.
  • the moisture content of purified phosphogypsum is 15%-18%, the whiteness is 56-62%, the CaSO 4 ⁇ 2H 2 O content is 95-97%, and SiO 2 Content is 0.6-1.0%.
  • the drying reaction section only needs to introduce cooling air into the central rotating shaft 120.
  • the cooling air introduced into the central rotating shaft 120 is mainly used to ensure that the stirring member 121 does not overheat.
  • the cooling air discharged from the cooling air outlet 1222 serves as the preheating air for the drying reaction section, which is beneficial to recovering heat energy and can adjust the drying reaction. segment temperature.
  • the flue gas in the drying reaction stage needs to be cooled and desulfurized before being discharged.
  • the roasting reaction gas is natural gas, coke oven gas, artificial gas or blast furnace gas with a calorific value of 3000-4000kJ/ Nm3 ; it has strong adaptability to fuels. Under a reasonable temperature system and air flow matching, the system resistance and the temperature of the exhaust gas out of the system are to achieve the best balance.
  • the rotation speed of the central rotating shaft 120 is 4-10 r/min.
  • the cooling air discharged from the cooling air outlet 1222 serves as the combustion-supporting air in the roasting reaction section, making full use of energy and reducing the emission of harmful gases; the comprehensive fuel consumption of the roasting system is less than 35kg standard coal/ton of raw ore, and there is no high-temperature exhaust gas emission in the whole process. It is an environmentally friendly new technology.
  • the temperature of the roasting reaction in this application is lower than the temperature in the drying stage.
  • the purpose of controlling the higher temperature in the drying stage is to allow the phosphogypsum to quickly remove external water, and the lower temperature in the roasting stage is to ensure that The semi-hydrated ignition loss of phosphogypsum gradually reduces the roasting temperature and also reduces the need for subsequent cooling reactions.
  • the hemihydrate gypsum content can reach 80.482%. If the temperature continues to rise to 140°C, the hemihydrate gypsum content will hardly change. At this time, the whiteness of the hemihydrate gypsum product is 72.75%.
  • the suitable conversion temperature range of hemihydrate gypsum in phosphogypsum flotation concentrate is 130-140°C. Therefore, the preferred roasting temperature in this application is 130-140°C.
  • the cooling reaction gas is provided by a Roots blower, which can pass air into the roasting reaction section to achieve roasting.
  • the materials in the burning reaction section are air-cooled.
  • the rotation speed of the central rotating shaft 120 is 4-10 r/min.
  • the cooling air discharged from the cooling air outlet 1222 serves as the auxiliary cooling air for the cooling reaction section, which can improve the cooling effect.
  • the high-temperature exhaust gas discharged from the exhaust gas outlet 115 of the dynamic roasting device 100 is connected to the boiling furnace for drying raw coal, which is beneficial to reducing high-temperature exhaust gas emissions, saving energy, and making it easy to adjust according to actual conditions.
  • the tail gas after drying the raw coal is processed by the desulfurization and denitrification device and then discharged to meet the standards, which is beneficial to protecting the environment and avoiding air pollution.
  • the dust collector is connected with the discharge port 116, and the dust collector is connected with the semi-hydrated gypsum silo through a bucket elevator.
  • the dust collector can collect the product, transport it through a bucket elevator, and finally transport it to a semi-hydrated gypsum silo for storage.
  • This embodiment provides a method for purifying phosphogypsum by dynamic roasting to produce semi-aqueous gypsum powder.
  • the Yichang purified gypsum is phosphogypsum that has undergone a decolorization, purification and flotation process.
  • the moisture content is 15%, and the CaSO4 ⁇ 2H 2 O content is 95.57%.
  • the whiteness of phosphogypsum is 59.45%
  • the SiO 2 content is 0.68%.
  • the dynamic roasting device 100 is preheated by the high-temperature flue gas generated by the boiling furnace. After the temperature reaches the set temperature of 220°C, the switch of the feed port 113 is opened, and the raw material purified phosphogypsum is pneumatically transported to the dynamic roasting device 100, allowing it to Slowly enter the furnace body 110.
  • the first section is the drying reaction section for removing free water. The drying temperature of the drying reaction section is 210°C and the drying time is 10 minutes.
  • the second section is the roasting reaction section for removing half of the crystal. Water, the roasting temperature of the roasting reaction section is 125°C, and the roasting time is 30 minutes; the third section is the cooling reaction section, which uses air cooling to reduce the temperature at the outlet of the cooling reaction section to 70°C and maintain it for 15 minutes.
  • the roasted samples were tested using a gypsum phase component analyzer.
  • the compressive strength and flexural strength of phosphogypsum were tested according to GB/T17669.3-1999 "Determination of Mechanical Properties of Building Gypsum”.
  • the semi-hydrated gypsum content of the product was 78.06%. , whiteness 70.01%, initial setting time 4min, final setting time 11min, 2h compressive strength 5.9Mpa, 2h flexural strength 2.8Mpa.
  • This embodiment provides a method for purifying phosphogypsum by dynamic roasting to produce semi-aqueous gypsum powder.
  • the Yichang purified gypsum is phosphogypsum that has undergone a decolorization, purification and flotation process.
  • the moisture content is 15%, and the CaSO 4 ⁇ 2H 2 O content is 95.57 %, the whiteness of phosphogypsum is 59.45%, and the SiO 2 content is 0.68%.
  • the process flow diagram is shown in Figure 3, including the following steps:
  • the dynamic roasting device 100 is preheated by the high-temperature flue gas generated by the boiling furnace. After the temperature reaches the set temperature of 200°C, the switch of the feed port 113 is opened, and the raw material purified phosphogypsum is pneumatically transported to the dynamic roasting device 100, allowing it to Slowly enter the furnace body 110.
  • the first section is the drying reaction section for removing free water. The drying temperature of the drying reaction section is 190°C and the drying time is 15 minutes.
  • the second section is the roasting reaction section for removing half of the crystal. Water, the roasting temperature of the roasting reaction section is 135°C, and the roasting time is 60 minutes; the third section is the cooling reaction section, which uses air cooling to reduce the temperature at the outlet of the cooling reaction section to 80°C and maintain it for 20 minutes.
  • the roasted samples were tested using a gypsum phase component analyzer.
  • the compressive strength and flexural strength of phosphogypsum were tested according to GB/T17669.3-1999 "Determination of Mechanical Properties of Building Gypsum”.
  • the semi-hydrated gypsum content of the product was 87.45%. , whiteness 74.04%, initial setting time 3min, final setting time 9min, 2h compressive strength 7.8Mpa, 2h flexural strength 3.5Mpa.
  • This embodiment provides a method for purifying phosphogypsum and dynamic roasting to produce semi-aqueous gypsum powder.
  • the Yichang purified gypsum is phosphogypsum that has undergone decolorization, purification and flotation.
  • the moisture content is 15%, and the CaSO 4 ⁇ 2H 2 O content is 95.57 %, the whiteness of phosphogypsum is 59.45%, and the SiO 2 content is 0.68%.
  • the process flow diagram is shown in Figure 3, including the following steps:
  • the dynamic roasting device 100 is preheated by the high-temperature flue gas generated by the boiling furnace. After the temperature reaches the set temperature of 180°C, the switch of the feed port 113 is opened, and the raw material purified phosphogypsum is pneumatically transported to the dynamic roasting device 100, allowing it to Slowly enter the furnace body 110.
  • the first section is the drying reaction section for removing free water.
  • the drying temperature of the drying reaction section is 170°C and the drying time is 20 minutes.
  • the second section is the roasting reaction section for removing half of the crystal water.
  • the roasting temperature of the roasting reaction section is between 145°C, and the roasting time is 90 minutes; the third section is the cooling reaction section, and air cooling is used to reduce the temperature at the outlet of the cooling reaction section to 65°C and maintain it for 20 minutes.
  • the roasted samples were tested using a gypsum phase component analyzer.
  • the compressive strength and flexural strength of phosphogypsum were tested according to GB/T17669.3-1999 "Determination of Mechanical Properties of Building Gypsum”.
  • the semi-hydrated gypsum content of the product was 81.47%. , whiteness 71.56%, initial setting time 3min, final setting time 10min, 2h compressive strength 6.6Mpa, 2h flexural strength 3.1Mpa.
  • Rotary kiln roasting was used to roast the purified gypsum in Example 1 (Yichang purified gypsum is phosphogypsum that has undergone decolorization, purification and flotation technology. The moisture content is 15%, the CaSO 4 ⁇ 2H 2 O content is 95.57%, and the whiteness of phosphogypsum is 59.45 %, SiO 2 content is 0.68%) is roasted to prepare hemihydrate gypsum.
  • the specific roasting process is to use a fluidized bed hot blast stove to heat the materials in the rotary kiln.
  • the hot blast temperature in the kiln is controlled between 180-220°C and the time is 90 minutes.
  • Gypsum powder is screened using bag dust collector and cyclone classifier.
  • the roasted samples were tested using a gypsum phase component analyzer.
  • the compressive strength and flexural strength of phosphogypsum were tested according to GB/T17669.3-1999 "Determination of Mechanical Properties of Building Gypsum".
  • the semi-hydrated gypsum content of the product was 75.62%. , Whiteness 69.01%, initial setting time 4min, final setting time 11min, 2h compressive strength 6.1Mpa, 2h flexural strength 3.1Mpa.
  • Example 1 By comparing Example 1 with Comparative Example 1, it can be seen that the total content of hemihydrate gypsum in the rotary kiln dried product is relatively low. There are two main reasons: First, there is material clustering in the rotary kiln, which requires cyclone classification and screening. The purity of the screened material is also lower than that of the dynamic roasting product; Second, the phosphogypsum entering the rotary kiln is not evenly contacted with the flue gas or the feed does not match, which will cause over-burning or under-burning of gypsum.
  • the purified gypsum in Example 1 (Yichang purified gypsum is phosphogypsum that has undergone decolorization, purification and flotation technology, the moisture content is 15%, the CaSO 4 ⁇ 2H 2 O content is 95.57%, and the phosphogypsum whiteness is 59.45%, SiO2 content is 0.68%) is roasted to prepare hemihydrate gypsum.
  • the fluidized roasting process generally uses the combustion hot air from the thermal oil central station to be sent to the primary crushing at 250-300°C to pre-dry the materials, and at the same time, the materials are broken up, broken, and homogenized.
  • the hot air fluidizes the crushed materials and brings them to the main drying device, where they are evenly heated indirectly through the introduced oil.
  • the heating temperature is controlled between 160-180°C, and then the dust is collected to produce qualified products.
  • the roasted samples were tested using a gypsum phase component analyzer.
  • the compressive strength and flexural strength of phosphogypsum were tested according to GB/T17669.3-1999 "Determination of Mechanical Properties of Building Gypsum”.
  • the semi-hydrated gypsum content of the product was 78.23%. , whiteness 70.12%, initial setting time 4min, final setting time 10min, 2h compressive strength 5.9Mpa, 2h flexural strength 2.8Mpa.
  • the method for purifying phosphogypsum and dynamically roasting semi-hydrated gypsum powder uses a dynamic roasting device 100 to achieve dynamic roasting, in which a combination of multiple reaction chambers 112 is used to synchronously control the roasting temperature, time, atmosphere, etc.
  • Main process parameters The tumbling and uniform heating of the ore powder in the furnace body 110 shortens the roasting time, overcoming the shortcomings of slow gas-solid heat and mass transfer in traditional roasting processes such as shaft furnaces, rotary kilns, and rotary hearth furnaces.
  • roasting The uniformity is greatly improved; it effectively avoids technical bottlenecks such as over-burning (over-reduction), under-burning (not burning through) and bonding that occur in other roasting processes. In practical production, there is no ringing and agglomeration throughout the year.
  • the dynamic roasting device 100 preheats and reacts the raw materials step by step, and uses the central axis cooling air as the combustion-supporting air of the dynamic furnace, making full use of energy and reducing the emission of harmful gases.
  • the gas generator is also a type of artificial gas equipment that has emerged in recent years and has a high ash burning rate.
  • the dynamic roasting device 100 is designed with a furnace cooling method to ensure waste heat recovery and reduce the total energy consumption of the process.
  • the whole-grain mineral powder in this application is directly roasted at medium and low temperatures; this application adopts the step-by-step preheating-step-by-step reaction method of the ore powder, so the reaction is relatively complete.
  • the reduction rate can reach more than 90%, avoiding the generation of lumpy materials, thus reducing the ore screening and classification, grinding, batching and pelletizing processes. It can be applied to full-size ore powder (0-15mm), and has strong raw material adaptability; dynamic
  • the temperature gradient in the furnace of the roasting device 100 is obvious. Dehydration, drying, preheating, roasting, and cooling are completed independently in one piece of equipment.
  • the roasting temperature can be controlled at 150-850°C.
  • the temperature field at each stage is uniform, and the temperature and atmosphere at different stages are controllable.
  • this application has strong stability and convenient control; this application has low energy consumption and good fuel adaptability; this application can use natural gas, coke oven gas, artificial coal gas or blast furnace gas with low calorific value (3000-4000kJ/Nm 3 ) as the roasting working gas, which is good for fuel It has strong adaptability.
  • the system resistance and the exhaust gas temperature of the system can reach an optimal balance; the exhaust gas discharged from the furnace top can be used to dry the raw ore, which not only reduces high-temperature exhaust gas emissions, but also saves energy and is convenient.
  • the semi-hydrated gypsum prepared by this application has stable quality and is easy to manage; the roasting device operates stably and reliably, is easy to operate and manage, has few wearable parts, and is simple to maintain.

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Abstract

本发明提供了一种净化磷石膏动态焙烧制半水石膏粉的方法，涉及废物回收技术领域，该方法采用动态焙烧装置进行动态焙烧，方法包括：将净化磷石膏从进料口通入预热完全的动态焙烧装置中；调节通入干燥反应段内的干燥反应气至干燥反应段的温度为180-220℃，反应10-30min以脱去游离水；调节通入焙烧反应段内的焙烧反应气至焙烧反应段的温度为120-160℃，反应30-60min以脱去半个结晶水；接着调节通入冷却反应段内的冷却反应气至冷却反应段的温度为60-120℃，反应15-30min以冷却石膏制得半水石膏粉。本发明能够建立磷石膏高效干燥脱水协同调控机制，减少能耗，增加半水石膏产品合格率。

Description

一种净化磷石膏动态焙烧制半水石膏粉的方法 技术领域
本发明涉及废物回收技术领域，具体而言，涉及一种净化磷石膏动态焙烧制半水石膏粉的方法。
背景技术
磷石膏是磷肥生产过程中产生的副产物，主要成分有CaSO4·2H2O，质量分数大于80％，由于磷石膏中含有一定量的SiO2、F、P和有机质等杂质，影响磷石膏的综合利用，磷肥工业的快速发展产排大量的磷石膏，而磷石膏的资源化利用率较低。目前磷石膏处理方法主要以堆存处理，占用了大量的土地，而且造成了环境污染。
建筑石膏又称熟石膏，是一种以半水石膏为主要成分的粉状胶结料，是由天然石膏石或工业副产石膏(磷石膏)在破碎磨细处理后经过低温煅烧制得的，但是传统的脱水设备如回转窑，内部温差较大，难以实现焙烧温度等热工制度精准调控，导致生产的半水(无水)石膏晶体小、纯度低、质量较差。也有学者采用流态化焙烧工艺将二水石膏进行脱水。但是，磷石膏经除杂后产生的二水石膏含水量大，在进入焙烧炉后，容易结块，影响物料悬浮状态，且流态化焙烧速度快，可控性差，生产的半水(无水)石膏结晶程度差，晶粒较小，强度低。
鉴于此，特提出本申请。
发明内容
本发明的目的在于提供了一种净化磷石膏动态焙烧制半水石膏粉的方法，其能够建立磷石膏高效干燥脱水协同调控机制，减少能耗，增加半水石膏产品合格率。
本发明可以这样实现：
第一方面，本发明提供一种净化磷石膏动态焙烧制半水石膏粉的方法，其包括采用动态焙烧装置进行动态焙烧，所述动态焙烧装置包括炉体和转动连接至所述炉体的中心转动轴；所述炉体内设置有多个炉盘，多个所述炉盘将所述炉体分为多层反应室，所述炉体从上至下依次分为干燥反应段、焙烧反应段和冷却反应段，其中，所述干燥反应段 包括2-4个所述反应室，所述焙烧反应段包括4-6个所述反应室，所述冷却反应段包括2-4个所述反应室；所述炉盘包括中心落料盘和边缘落料盘，所述中心落料盘靠近于所述中心转动轴的位置处设置有中心落料口，所述边缘落料盘靠近所述炉体内壁的位置设置有边缘落料口，所述中心落料盘和所述边缘落料盘间隔设置；所述中心转动轴上设置有多个搅料件，所述搅料件伸入至少一个所述反应室内用于搅拌物料；所述炉体的顶部设置有进料口、预热气进口和废气出口，所述炉体的底部设置有出料口；所述炉体的侧壁对应于每个所述反应室的位置处均设置有工作气进口；
所述方法包括：
将净化磷石膏从所述进料口通入预热完全的所述动态焙烧装置中；
调节通入所述干燥反应段内的干燥反应气至所述干燥反应段的温度为180-220℃，反应10-30min以脱去游离水；
调节通入所述焙烧反应段内的焙烧反应气至所述焙烧反应段的温度为120-160℃，反应30-60min以脱去半个结晶水；
接着调节通入所述冷却反应段内的冷却反应气至所述冷却反应段的出口温度为60-80℃，反应15-30min以冷却石膏制得半水石膏粉。
在可选的实施方式中，所述净化磷石膏通过所述干燥反应段、所述焙烧反应段和所述冷却反应段时，所述中心转动轴的转速为4-10r/min。
在可选的实施方式中，所述中心转动轴和所述搅料件均设置有冷却风通道，所述中心转动轴上设置有冷却风进口，所述搅料件的末端设置有冷却风出口；所述冷却风出口排出的冷却风作为所述干燥反应段、所述焙烧反应段和所述冷却反应段的助燃风。
在可选的实施方式中，所述中心转动轴设置有挡风板，所述挡风板将所述中心转动轴分为多个冷却区间，所述冷却区间与所述冷却风通道连通且一一对应。
在可选的实施方式中，所述搅料件包括重叠设置的第一搅料件和第二搅料件，所述第一搅料件位于所述第二搅料件的上方，所述第一搅料件远离所述中心转动轴的一端设置有朝着所述炉体倾斜向下的弧形导料面。
在可选的实施方式中，所述干燥反应气为燃气燃烧热空气；
优选地，所述焙烧反应气为天然气、焦炉煤气、人工煤气或热值为3000-4000kJ/Nm3的高炉煤气；
优选地，所述冷却反应气由罗茨风机提供。
在可选的实施方式中，所述动态焙烧装置的预热采用沸腾炉燃烧原煤以提供预热气 体。
在可选的实施方式中，从所述动态焙烧装置的所述废气出口排出的高温废气与所述沸腾炉连通以用于干燥所述原煤。
在可选的实施方式中，所述净化磷石膏采用气力输送至所述动态焙烧装置中，所述气力输送的速度为1-200吨/小时。
在可选的实施方式中，所述净化磷石膏为经过脱色提纯浮选工艺的磷石膏，所述净化磷石膏的含水率为15％-18％，白度为56％-62％，CaSO4·2H2O含量为95％-97％，SiO2含量为0.6％-1.0％。
本发明实施例的有益效果包括，例如：
本发明提供的净化磷石膏动态焙烧制半水石膏粉的方法采用动态焙烧装置来实现动态焙烧，其中，采用多个反应室组合来同步调控焙烧温度、时间、气氛等主要工艺参数；矿粉在炉体内的翻滚和均匀受热，焙烧时间缩短，焙烧均匀性大大得到改善；本申请中的全粒级矿粉直接中温、低温焙烧；本申请由于采用矿粉逐级预热——逐级反应的方式，反应较完全，还原率可达到90％以上，避免产生块状物料，因此减少了矿石筛分分级和磨矿、配料造球工序，可适用于全粒级矿粉(0-15mm)，原料适应性强；动态焙烧装置的炉内温度梯度明显，脱水干燥、预热、焙烧、冷却在一台设备内独立完成，焙烧温度可控制在150-850℃，各阶段温度场均匀，不同阶段温度、气氛可控性强，调控便捷；本申请能耗低、燃料适应性好；全流程无高温废气排放，属环境友好型新技术。本申请制备获得的半水石膏质量稳定、管理便捷；焙烧装置运行稳定可靠，操作管理方便，易磨易损部件少，维护维修简单。
附图说明
为了更清楚地说明本发明实施例的技术方案，下面将对实施例中所需要使用的附图作简单的介绍，应当理解，以下附图仅示出了本发明的某些实施例，因此不应被看作是对范围的限定，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他相关的附图。
图1为本发明实施例提供的动态焙烧装置的结构示意图；
图2为本发明实施例提供的动态焙烧装置的边缘落料盘的结构示意图；
图3为本发明实施例提供的净化磷石膏动态焙烧制半水石膏粉的方法的流程示意图。
图标：100-动态焙烧装置；110-炉体；111-炉盘；1111-中心落料盘；1112-边缘落料 盘；1113-中心落料口；1114-边缘落料口；1115-挡料板；112-反应室；113-进料口；114-预热气进口；115-废气出口；116-出料口；117-工作气进口；120-中心转动轴；121-搅料件；1211-第一搅料件；1212-第二搅料件；1213-弧形导料面；122-冷却风通道；1221-冷却风进口；1222-冷却风出口；123-挡风板。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。通常在此处附图中描述和示出的本发明实施例的组件可以以各种不同的配置来布置和设计。
因此，以下对在附图中提供的本发明的实施例的详细描述并非旨在限制要求保护的本发明的范围，而是仅仅表示本发明的选定实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
应注意到：相似的标号和字母在下面的附图中表示类似项，因此，一旦某一项在一个附图中被定义，则在随后的附图中不需要对其进行进一步定义和解释。
在本发明的描述中，需要说明的是，若出现术语“上”、“下”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，或者是该发明产品使用时惯常摆放的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。
此外，若出现术语“第一”、“第二”等仅用于区分描述，而不能理解为指示或暗示相对重要性。
需要说明的是，在不冲突的情况下，本发明的实施例中的特征可以相互结合。
本申请提供了一种净化磷石膏动态焙烧制半水石膏粉的方法，其包括采用动态焙烧装置100进行动态焙烧，为了便于后续对净化磷石膏动态焙烧制半水石膏粉的方法进行阐述，本申请先对动态焙烧装置100的具体结构进行阐述。
请参照图1和图2，动态焙烧装置100包括炉体110和转动连接至炉体110的中心转动轴120。
本申请中，炉体110作为反应的腔体实现物料(例如净化磷石膏)的干燥脱水和焙 烧等操作，具体来说，本申请中，炉体110为立式结构，其内部设置有多个炉盘111，多个炉盘111将炉体110分为多层反应室112，炉体110的顶部设置有进料口113、预热气进口114和废气出口115，炉体110的底部设置有出料口116。物料从进料口113进入炉体110内，在多层反应室112内逐层进行预热反应、干燥反应、焙烧反应和冷却反应。
具体来说，炉体110从上至下依次分为干燥反应段、焙烧反应段和冷却反应段，其中，干燥反应段包括2-4个反应室112，焙烧反应段包括4-6个反应室112，冷却反应段包括2-4个反应室112。
本申请中，为了加大物料在炉体110中的停留时间，本申请中物料的运动轨迹为“S”形，具体来说，本申请中，炉盘111包括中心落料盘1111和边缘落料盘1112，中心落料盘1111靠近于中心转动轴120的位置处设置有中心落料口1113，边缘落料盘1112靠近炉体110内壁的位置设置有边缘落料口1114，中心落料盘1111和边缘落料盘1112间隔设置；本申请中，中心落料盘1111和边缘落料盘1112均呈倾斜状，靠近中心转动轴120的一侧高于靠近炉体110内壁的一侧。多个炉盘111中的第一层炉盘111和最后一层炉盘111均为中心落料盘1111。通过上述结构的设置，使得物料从进料口113进入炉体110中，先从中心落料盘1111的中心落料口1113落至下一层的边缘落料盘1112上，接着从边缘落料盘1112的边缘落料口1114落料，此时物料的运动轨迹呈“S”形。进一步地，由于本申请中的边缘落料盘1112不直接与中心转动轴120连接，为了避免物料从边缘落料盘1112和中心转动轴120之间的间隙落料，因此，本申请边缘落料盘1112靠近于中心转动轴120的一侧设置有避免物料从中部下料的挡料板1115，挡料板1115的设置可以避免应该从边缘落料口1114落料的物料从中部落料，保证了物料的运动轨迹。
炉体110的侧壁对应于每个反应室112的位置处均设置有工作气进口117，工作气例如可以为天然气、焦炉煤气、人工煤气或低热值(3000-4000kJ/Nm3)的高炉煤气作为干燥和焙烧的工作气体，从而实现对原料进行干燥和焙烧，同时，工作气还可以为冷风或者常温空气，实现对底部反应室112内的原料进行风冷，冷风或者常温空气可以通过罗茨风机输入至反应室112内。
本申请中通过对每个反应室112内通入的工作气进行调节，可以实现对每个反应室112的温度进行调节，进而实现在一个炉体110中依次进行干燥、焙烧和风冷的操作。本申请中，每个反应室112对应的工作气进口117均单独设置有流量控制器和温度控制 器。流量控制器和温度控制器的设置可以实现对反应室112内温度进行更好的控制。
中心转动轴120能够相对于炉体110进行转动，本申请中，中心转动轴120上设置有多个搅料件121，搅料件121伸入至少一个反应室112内用于搅拌物料；物料在搅料件121的带动下可以实现翻转运动，进而实现在反应室112内均匀受热，有利于缩短焙烧时间。
进一步地，本申请中，中心转动轴120和搅料件121均设置有冷却风通道122，中心转动轴120上设置有冷却风进口1221，搅料件121的末端设置有冷却风出口1222。通过设置冷却风通道122，可以使搅拌件表面的温度较低，避免原料结块，同时，冷却风的出口直接设置在搅料件121上，此时可以利用冷却风作为动态炉助燃风，充分利用了能源，并减少了有害气体的排放。
为了更好地控制每个冷却风通道122的冷却温度，本申请中，在中心转动轴120内设置有挡风板123，挡风板123将中心转动轴120分为多个相互独立的冷却区间，冷却区间与冷却风通道122连通且一一对应。从而可以实现对每个冷却区间的冷却风进行单独控制，控制精度更高。本申请中每个反应室112内温度的控制可以通过通入的反应气温度和通入量、中心转动轴120的转动速度以及冷却风的温度等来协同进行控制，焙烧温度可控制在150-850℃，各阶段温度场均匀，不同阶段温度、气氛可控性强，调控便捷。
本申请中，搅料件121包括重叠设置的第一搅料件1211和第二搅料件1212，第一搅料件1211位于第二搅料件1212的上方，第一搅料件1211远离中心转动轴120的一端设置有朝着炉体110倾斜向下的弧形导料面1213。本申请中通过设置重叠的第一搅料件1211和第二搅料件1212可以实现延长冷却风在搅料件121内的运动时间，并且有利于保证在反应室112内的上部或者下部的物料均可充分与第一搅料件1211和第二搅料件1212进行接触。同时，弧形导料面1213的设计使得位于第一搅料件1211上表面的物料更容易沿着第一搅料件1211的表面向下滑落，有利于控制物料的运动轨迹。
本申请中，可以在每个反应室112内均设置一个搅料件121，也可以选择性地在某些反应室112内设置搅料件121，其余不设置。本申请优选在每个中心落料盘1111的上方均设置有一个搅料件121，边缘落料盘1112的上方未设搅料件121，这样设置的优势在于有利于保证中心落料盘1111上的物料在搅料件121的带动下从中心落料口1113排出，从而有利于控制物料的运动轨迹。
动态焙烧装置100的工作原理是：预热气体从炉体110的预热气进口114进入炉体 110预先对炉体110进行预热，预热完成后，物料从炉体110的进料口113进入炉体110，物料落入炉体110的第一个中心落料盘1111上，此时搅料件121带动物料翻转，实现均匀受热，同时带动物料从中心落料盘1111的中心落料口1113落料至下一层的边缘落料盘1112上，由于边缘落料盘1112倾斜设置，使得物料更容易向着边缘落料口1114运动。此外，本申请中搅料件121上开设的冷却风通道122不仅仅可以对搅料件121进行冷却，同时还可以将冷却风作为助燃风通入，充分利用了能源，并减少了有害气体的排放。可以通过调节动态焙烧装置100的每个反应室112通入的工作气的温度和流量进行调节，从而调节每个反应室112的温度，进而实现物料从顶层的反应室112至底部的反应室112逐步进行了干燥、焙烧和冷却等反应，操作简单，可实施性强。
基于上述动态焙烧装置100，本申请提出了一种净化磷石膏动态焙烧制半水石膏粉的方法，请参阅图3，其包括如下步骤：
S1、预热。
采用沸腾炉燃烧原煤以提供预热气体，沸腾炉与预热气进口114连通从而为动态焙烧装置100预热。
S2、进料。
将净化磷石膏从进料口113通入预热完全的动态焙烧装置100中；净化磷石膏采用喂料机进行气力输送至动态焙烧装置100中，气力输送的速度为1-200吨/小时。
净化磷石膏为经过脱色提纯浮选工艺的磷石膏，净化磷石膏的含水率为15％-18％，白度为56-62％，CaSO4·2H2O含量为95-97％，SiO2含量为0.6-1.0％。
S3、干燥反应。
调节通入干燥反应段内的干燥反应气至干燥反应段的温度为180-220℃，反应10-30min以脱去游离水；在干燥反应时，中心转动轴120的转速为4-10r/min。由于本申请中在进行干燥之前，预先通入了对动态焙烧装置100进行预热的风，因此干燥反应阶段没有升温的需求，干燥反应段只需要在中心转动轴120中通入冷却风即可，中心转动轴120中通入的冷却风主要用于保证搅料件121不超温，同时冷却风出口1222排出的冷却风作为干燥反应段的预热风，有利于回收热能，可以调节干燥反应段的温度。此外，干燥反应阶段的烟气需要经过降温脱硫处理后再行排出。
S4、焙烧反应。
调节通入焙烧反应段内的焙烧反应气至焙烧反应段的温度为120-160℃，反应30-60min以脱去半个结晶水。
焙烧反应气为天然气、焦炉煤气、人工煤气或热值为3000-4000kJ/Nm3的高炉煤气；对燃料适应性强，在合理的温度制度和风流匹配下，系统阻力和出系统尾气温度之间达到最佳平衡。
在焙烧反应时，中心转动轴120的转速为4-10r/min。冷却风出口1222排出的冷却风作为焙烧反应段的助燃风，充分利用了能源，并减少了有害气体的排放；焙烧系统综合燃耗低于35kg标煤/吨原矿，全流程无高温废气排放，属环境友好型新技术。
值得注意的是，本申请中的焙烧反应的温度低于干燥阶段的温度，本申请在干燥阶段控制温度较高是为了让磷石膏快速脱去外水，在焙烧阶段的较低温度是为了保证磷石膏的半水烧失量，将焙烧温度逐步降低，同时还降低了后续冷却反应的需求。
进一步的，本申请对不同焙烧温度焙烧90min进行了测试，测试结果如下：
从上表可以看出，在130℃时，半水石膏含量即可达到80.482％，继续升温至140℃，半水石膏含量几乎没有变化，此时，半水石膏产品白度为72.75％，该结果表明磷石膏浮选精矿的半水石膏适应转化温度区间为130-140℃。因此，本申请中优选焙烧温度为130-140℃，
S5、冷却反应。
接着调节通入冷却反应段内的冷却反应气至冷却反应段的出口温度为60-80℃，反应15-30min以冷却石膏制得半水石膏粉。
冷却反应气由罗茨风机提供，罗茨风机可以向焙烧反应段通入空气，以便实现对焙 烧反应段内的物料进行风冷。在冷却反应时，中心转动轴120的转速为4-10r/min，同时，冷却风出口1222排出的冷却风作为冷却反应段的辅助冷却风，可以提高冷却效果。
S6、废气排放。
另一方面，对于二水石膏的干燥和脱水而言，除了水分脱除外，磷石膏中部分易挥发杂质也会在干燥脱水过程中脱除，进入尾气，若焙烧装备无尾气净化处理，这些物质和微小石膏粉尘进入大气，极易造成空气污染。而本申请中从动态焙烧装置100的废气出口115排出的高温废气与沸腾炉连通以用于干燥原煤，有利于减少高温废气排放，又节约能源，同时也方便根据实际情况进行调节。干燥原煤后的尾气经过脱硫脱硝装置处理后达标排放，有利于保护环境，避免造成空气污染。
S7、产品收集。
收尘器与出料口116连通，收尘器与半水石膏仓通过斗提机连通。收尘器可以实现对产品的收集，并通过斗提机进行输送，最终输送至半水石膏仓内进行储存。
以下结合具体实施例进行具体阐述。
实施例1
本实施例提供了一种净化磷石膏动态焙烧制半水石膏粉的方法，其中宜昌净化石膏为经过脱色提纯浮选工艺的磷石膏，含水率为15％，CaSO4·2H2O含量为95.57％，磷石膏白度为59.45％，SiO2含量为0.68％。工艺流程图参见图3，包括以下步骤：
先通过沸腾炉产生的高温烟气对动态焙烧装置100进行预热，待温度达到设定温度220℃后，打开进料口113的开关，原料净化磷石膏采用气力输送到动态焙烧装置100，让其缓慢进入炉体110内，第一段为干燥反应段用于脱去游离水，干燥反应段的干燥温度为210℃，干燥时间为10min；第二段为焙烧反应段用于脱去半个结晶水，焙烧反应段的焙烧温度为125℃，焙烧时间为30min；第三段为冷却反应段，采用空气风冷至冷却反应段出口的温度降低至70℃，维持15min。
使用石膏相组分仪对焙烧后的样品进行检测，磷石膏抗压强度、抗折强度按GB/T17669.3—1999《建筑石膏力学性能的测定》进行试验，产品半水石膏含量为78.06％，白度70.01％，初凝时间4min，终凝时间11min，2h抗压强度5.9Mpa，2h抗折强度2.8Mpa。
实施例2
本实施例提供了一种净化磷石膏动态焙烧制半水石膏粉的方法，其中宜昌净化石膏为经过脱色提纯浮选工艺的磷石膏，含水率为15％，CaSO4·2H2O含量为95.57％，磷石膏白度为59.45％，SiO2含量为0.68％。工艺流程图参见图3，包括以下步骤：
先通过沸腾炉产生的高温烟气对动态焙烧装置100进行预热，待温度达到设定温度200℃后，打开进料口113的开关，原料净化磷石膏采用气力输送到动态焙烧装置100，让其缓慢进入炉体110内，第一段为干燥反应段用于脱去游离水，干燥反应段的干燥温度为190℃，干燥时间为15min；第二段为焙烧反应段用于脱去半个结晶水，焙烧反应段的焙烧温度为135℃，焙烧时间为60min；第三段为冷却反应段，采用空气风冷至冷却反应段出口的温度降低至80℃，维持20min。
使用石膏相组分仪对焙烧后的样品进行检测，磷石膏抗压强度、抗折强度按GB/T17669.3—1999《建筑石膏力学性能的测定》进行试验，产品半水石膏含量为87.45％，白度74.04％，初凝时间3min，终凝时间9min，2h抗压强度7.8Mpa，2h抗折强度3.5Mpa。
实施例3
本实施例提供了一种净化磷石膏动态焙烧制半水石膏粉的方法，其中宜昌净化石膏为经过脱色提纯浮选工艺的磷石膏，含水率为15％，CaSO4·2H2O含量为95.57％，磷石膏白度为59.45％，SiO2含量为0.68％。工艺流程图参见图3，包括以下步骤：
先通过沸腾炉产生的高温烟气对动态焙烧装置100进行预热，待温度达到设定温度180℃后，打开进料口113的开关，原料净化磷石膏采用气力输送到动态焙烧装置100，让其缓慢进入炉体110内，第一段为干燥反应段用于脱去游离水，干燥反应段的干燥温度为170℃，干燥时间20min；第二段为焙烧反应段用于脱去半个结晶水，焙烧反应段的焙烧温度为145℃之间，焙烧时间为90min；第三段为冷却反应段，采用空气风冷将冷却反应段出口的温度降低至65℃，维持20min。
使用石膏相组分仪对焙烧后的样品进行检测，磷石膏抗压强度、抗折强度按GB/T17669.3—1999《建筑石膏力学性能的测定》进行试验，产品半水石膏含量为81.47％，白度71.56％，初凝时间3min，终凝时间10min，2h抗压强度6.6Mpa，2h抗折强度3.1Mpa。
对比例1
采用回转窑焙烧对实施例1中的净化石膏(宜昌净化石膏为经过脱色提纯浮选工艺的磷石膏，含水率为15％，CaSO4·2H2O含量为95.57％，磷石膏白度为59.45％，SiO2含量为0.68％)进行焙烧以制备半水石膏。
具体焙烧工艺为采用流化床热风炉对回转窑内物料进行加热，窑内热风温度控制在180-220℃之间，时间90min。采用布袋除尘及旋风分级器对石膏粉进行筛选。
使用石膏相组分仪对焙烧后的样品进行检测，磷石膏抗压强度、抗折强度按GB/T17669.3—1999《建筑石膏力学性能的测定》进行试验，产品半水石膏含量为75.62％， 白度69.01％，初凝时间4min，终凝时间11min，2h抗压强度6.1Mpa，2h抗折强度3.1Mpa。
将实施例1和对比例1进行对比可以看出，回转窑干燥产品半水石膏总含量较低，主要有两点：一、回转窑内存在物料组团情况，需要进行旋风分级筛选，筛选后的物料纯度也较动态焙烧产品质量差；二、进回转窑磷石膏与烟气接触不均匀或进料不匹配，会造成石膏过烧或欠烧。
对比例2
采用流态化焙烧对实施例1中的净化石膏(宜昌净化石膏为经过脱色提纯浮选工艺的磷石膏，含水率为15％，CaSO4·2H2O含量为95.57％，磷石膏白度为59.45％，SiO2含量为0.68％)进行焙烧以制备半水石膏。
流态化焙烧工艺一般采用导热油中心站的燃烧热风在250-300℃之间送入初级破碎，对物料进行预干燥，同时对物料进行打散破碎，匀化处理。热风将破碎好的物料流态化带入主要干燥装置，经导入油间接均匀加热，加热温度控制在160-180℃之间，之后除尘收集产出合格产品。
使用石膏相组分仪对焙烧后的样品进行检测，磷石膏抗压强度、抗折强度按GB/T17669.3—1999《建筑石膏力学性能的测定》进行试验，产品半水石膏含量为78.23％，白度70.12％，初凝时间4min，终凝时间10min，2h抗压强度5.9Mpa，2h抗折强度2.8Mpa。
将实施例1和对比例2进行对比可以看出，流态化导热油加热工艺过程复杂，物料负荷受制于热风总量限制，各工艺参数控制过程中相互影响，无法实现动态调节，调节热风将影响系统投料量，热风过多则导入油易超温，产品质量控制较动态焙烧过程难以把控。
综上所述，本发明提供的净化磷石膏动态焙烧制半水石膏粉的方法采用动态焙烧装置100来实现动态焙烧，其中，采用多个反应室112组合来同步调控焙烧温度、时间、气氛等主要工艺参数；矿粉在炉体110内的翻滚和均匀受热，焙烧时间缩短，克服了竖炉、回转窑、转底炉等传统焙烧工艺堆积态气固传热传质速度慢的缺点，焙烧均匀性大大得到改善；有效地避免其他焙烧工艺中出现的过烧(过还原)、欠烧(烧不透)及粘结等技术瓶颈，实践生产中全年无结圈结块现象。且动态焙烧装置100将原料逐级预热、逐级反应，利用中心轴冷却风作为动态炉助燃风，充分利用了能源，并减少了有害气体的排放。煤气发生炉也是近年来兴起的一种人造煤气的设备，燃烬率高。动态焙烧装置100设计了炉内冷却方式，保证余热回收，降低了工艺总能耗。本申请中的全粒级矿粉直接中温、低温焙烧；本申请由于采用矿粉逐级预热——逐级反应的方式，反应较完全， 还原率可达到90％以上，避免产生块状物料，因此减少了矿石筛分分级和磨矿、配料造球工序，可适用于全粒级矿粉(0-15mm)，原料适应性强；动态焙烧装置100的炉内温度梯度明显，脱水干燥、预热、焙烧、冷却在一台设备内独立完成，焙烧温度可控制在150-850℃，各阶段温度场均匀，不同阶段温度、气氛可控性强，调控便捷；本申请能耗低、燃料适应性好；本申请可以使用天然气、焦炉煤气、人工煤气或低热值(3000-4000kJ/Nm3)的高炉煤气作为焙烧工作气，对燃料适应性强，在合理的温度制度和风流匹配下，系统阻力和出系统尾气温度之间达到最佳平衡；炉顶排出废气可用来干燥原矿，既减少高温废气排放，又节约能源，同时也方便根据实际情况进行调节；利用中心轴冷却风作为动态炉助燃风，充分利用了能源，并减少了有害气体的排放；焙烧系统综合燃耗低于35kg标煤/吨原矿，全流程无高温废气排放，属环境友好型新技术。本申请制备获得的半水石膏质量稳定、管理便捷；焙烧装置运行稳定可靠，操作管理方便，易磨易损部件少，维护维修简单。
以上所述，仅为本发明的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应以所述权利要求的保护范围为准。

Claims (10)

  1. 一种净化磷石膏动态焙烧制半水石膏粉的方法，其特征在于，包括采用动态焙烧装置进行动态焙烧，所述动态焙烧装置包括炉体和转动连接所述炉体的中心转动轴；所述炉体内设置有多个炉盘，多个所述炉盘将所述炉体分为多层反应室，所述炉体从上至下依次分为干燥反应段、焙烧反应段和冷却反应段，其中，所述干燥反应段包括2-4个所述反应室，所述焙烧反应段包括4-6个所述反应室，所述冷却反应段包括2-4个所述反应室；所述炉盘包括中心落料盘和边缘落料盘，所述中心落料盘靠近于所述中心转动轴的位置处设置有中心落料口，所述边缘落料盘靠近所述炉体内壁的位置设置有边缘落料口，所述中心落料盘和所述边缘落料盘间隔设置；所述中心转动轴上设置有多个搅料件，所述搅料件伸入至少一个所述反应室内用于搅拌物料；所述炉体的顶部设置有进料口、预热气进口和废气出口，所述炉体的底部设置有出料口；所述炉体的侧壁对应于每个所述反应室的位置处均设置有工作气进口；
    所述方法包括：
    将净化磷石膏从所述进料口通入预热完全的所述动态焙烧装置中；
    调节通入所述干燥反应段内的干燥反应气至所述干燥反应段的温度为180-220℃，反应10-30min以脱去游离水；
    调节通入所述焙烧反应段内的焙烧反应气至所述焙烧反应段的温度为120-160℃，反应30-60min以脱去半个结晶水；
    接着调节通入所述冷却反应段内的冷却反应气至所述冷却反应段的出口温度为60-80℃，反应15-30min以冷却石膏制得半水石膏粉。
  2. 根据权利要求1所述的净化磷石膏动态焙烧制半水石膏粉的方法，其特征在于，所述净化磷石膏通过所述干燥反应段、所述焙烧反应段和所述冷却反应段时，所述中心转动轴的转速为4-10r/min。
  3. 根据权利要求1所述的净化磷石膏动态焙烧制半水石膏粉的方法，其特征在于，所述中心转动轴和所述搅料件均设置有冷却风通道，所述中心转动轴上设置有冷却风进口，所述搅料件的末端设置有冷却风出口；所述冷却风出口排出的冷却风作为所述干燥反应段、所述焙烧反应段和所述冷却反应段的助燃风。
  4. 根据权利要求3所述的净化磷石膏动态焙烧制半水石膏粉的方法，其特征在于，所述中心转动轴设置有挡风板，所述挡风板将所述中心转动轴分为多个冷却区间，所述冷却区间与所述冷却风通道连通且一一对应。
  5. 根据权利要求3所述的净化磷石膏动态焙烧制半水石膏粉的方法，其特征在于，所述搅料件包括重叠设置的第一搅料件和第二搅料件，所述第一搅料件位于所述第二搅料件的上方，所述第一搅料件远离所述中心转动轴的一端设置有朝着所述炉体倾斜向下的弧形导料面。
  6. 根据权利要求1所述的净化磷石膏动态焙烧制半水石膏粉的方法，其特征在于，所述焙烧反应气为天然气、焦炉煤气、人工煤气或热值为3000-4000kJ/Nm3的高炉煤气；
    优选地，所述冷却反应气由罗茨风机提供。
  7. 根据权利要求1所述的净化磷石膏动态焙烧制半水石膏粉的方法，其特征在于，所述动态焙烧装置的预热采用沸腾炉燃烧原煤以提供预热气体。
  8. 根据权利要求7所述的净化磷石膏动态焙烧制半水石膏粉的方法，其特征在于，从所述动态焙烧装置的所述废气出口排出的高温废气与所述沸腾炉连通以用于干燥所述原煤。
  9. 根据权利要求1所述的净化磷石膏动态焙烧制半水石膏粉的方法，其特征在于，所述净化磷石膏采用气力输送至所述动态焙烧装置中，所述气力输送的速度为1-200吨/小时。
  10. 根据权利要求1-9任一项所述的净化磷石膏动态焙烧制半水石膏粉的方法，其特征在于，所述净化磷石膏为经过脱色提纯浮选工艺的磷石膏，所述净化磷石膏的含水率为15％-18％，白度为56％-62％，CaSO4·2H2O含量为95％-97％，SiO2含量为0.6％-1.0％。
PCT/CN2023/082865 2022-09-22 2023-03-21 一种净化磷石膏动态焙烧制半水石膏粉的方法 WO2024060552A1 (zh)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB994067A (en) * 1960-09-21 1965-06-02 Prerovske Strojirny Np A method of and apparatus for thermally treating pulverulent or finely granulated materials
JPH0238347A (ja) * 1988-07-28 1990-02-07 Mitsubishi Mining & Cement Co Ltd 石膏焼成装置の製御方法
RU2558569C1 (ru) * 2014-06-02 2015-08-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования Воронежский государственный университет инженерных технологий (ФГБОУ ВПО ВГУИТ) Установка для дегидратации альфа-гипса
CN111306934A (zh) * 2020-04-10 2020-06-19 绍兴合源环境科技有限公司 一种炉盘加热外热式多膛炉
CN112551925A (zh) * 2020-10-29 2021-03-26 中科院过程工程研究所南京绿色制造产业创新研究院 一种石膏原料综合利用的装置和方法
CN115448627A (zh) * 2022-09-22 2022-12-09 宜昌邦普循环科技有限公司 一种净化磷石膏动态焙烧制半水石膏粉的方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1386464A (fr) * 1963-12-12 1965-01-22 Lambert Freres & Cie Procédé de cuisson du gypse
US4569831A (en) * 1985-04-01 1986-02-11 Fuller Company Process and apparatus for calcining gypsum
CN114317945A (zh) * 2021-04-25 2022-04-12 赣州泽钰管理咨询有限公司 一种稀土废料或回收料氧化焙烧系统及工艺
CN114538801B (zh) * 2022-04-07 2023-02-17 广西大学 用于烧制氧化钙的生物燃料竖窑及烧制氧化钙的方法
CN114893960A (zh) * 2022-04-27 2022-08-12 河南郑矿机器有限公司 石膏煅烧回转窑生产线系统

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB994067A (en) * 1960-09-21 1965-06-02 Prerovske Strojirny Np A method of and apparatus for thermally treating pulverulent or finely granulated materials
JPH0238347A (ja) * 1988-07-28 1990-02-07 Mitsubishi Mining & Cement Co Ltd 石膏焼成装置の製御方法
RU2558569C1 (ru) * 2014-06-02 2015-08-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования Воронежский государственный университет инженерных технологий (ФГБОУ ВПО ВГУИТ) Установка для дегидратации альфа-гипса
CN111306934A (zh) * 2020-04-10 2020-06-19 绍兴合源环境科技有限公司 一种炉盘加热外热式多膛炉
CN112551925A (zh) * 2020-10-29 2021-03-26 中科院过程工程研究所南京绿色制造产业创新研究院 一种石膏原料综合利用的装置和方法
CN115448627A (zh) * 2022-09-22 2022-12-09 宜昌邦普循环科技有限公司 一种净化磷石膏动态焙烧制半水石膏粉的方法

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