·Yellow phosphorus production enterprises are subject to strict supervision by government regulatory authorities, and the overall production of yellow phosphorus is classified as a restricted process.
·Yunnan Brent Chemical Co., Ltd., as a technology-based enterprise specializing in technical services for the entire phosphorus chemical industry chain, focuses on the difficulties and pain points of yellow phosphorus enterprises, and explores the path of transformation and upgrading of yellow phosphorus enterprises.
·On this platform today, I would like to share with you the following new technologies and achievements:
·Raw material pretreatment: sintering of phosphate ore pellets, brick making from fine ore
·New low-cost purification process for phosphorus furnace gas: cyclone dust removal, partition condensation, alkali fluorine removal, jet washing, product classification purification, etc.
·Harmless Treatment of Mud Phosphorus: Stacked Screw Dehydration, Low Temperature Phosphorus Steaming, High Temperature Phosphorus Steaming, Efficient Phosphorus Harvesting
·Integrated slag removal: closed quenching slag, scraper slag conveying, waste gas whitening
1. New sintering process for phosphate ore pellets
·Current situation: The comprehensive utilization technology of fine ore is widely adopted by most yellow phosphorus enterprises, which is to use the yellow phosphorus tail gas for drying after pressing the ball.
·Problem: After drying, the pellet still has issues such as insufficient strength and low addition amount.
·The amount of pellet ore added usually accounts for about 30% of the total amount of ore fed into the furnace
New technology:
·The pressed pellets are directly put into a vertical calcination kiln without going through a drying furnace. The pellets are heated to around 1100 ℃ using yellow phosphorus tail gas as fuel for calcination, resulting in high strength and anti drop of the calcined phosphate ore pellets. They do not pulverize or burst before melting in the yellow phosphorus electric furnace, achieving 100% pellet production.
Key equipment: vertical calcination kiln
Pilot test results: Phosphate ore powder with a P2O5 content of 26.82% was calcined, and the P2O5 content increased to 29.26%, an increase of 2.44%. Both CO2 and S were not detected.
2. Sintering process of phosphate ore brick making tunnel kiln
·This process can produce 450t/d sintered blocks, meeting the material requirements of the current 12.5kt/a phosphorus furnace.
·This process does not use binders, and the cost of binders saved per ton of sintered blocks is about 50-80 yuan/ton compared to pellet ore. The economic benefits are considerable
·From the obtained sintered blocks, the quality can rival that of Russian coke powder sintered materials.
Sintered sample
Analysis and Comparison
1. Cyclone dust removal
·The phosphorus furnace gas coming out of the phosphorus furnace duct is not directly sent to the condensing tower for phosphorus
collection, but first enters the cyclone dust collector to separate large particle raw materials and arsenic from the airflow.
·The latest research shows that at a temperature of 200 ℃, elemental arsenic exists in the form of a powdery solid, and dry dust removal can
remove most of the arsenic impurities.
·The removal of raw material particles can reduce the formation of sludge phosphorus during the gas condensation stage of the phosphorus
furnace, thereby reducing the output of sludge phosphorus.
2. Inter wall condensation
·The phosphorus furnace gas after cyclone dust removal enters the partition condenser (tubular heat exchanger).
·The phosphorus furnace gas is introduced from the top of the tower and flows through the tube. The condensed liquid yellow phosphorus
flows from the tube wall to the bottom of the tower and enters the yellow phosphorus collection tank;
·The cooling water flows through the shell side and is supplied by the circulating water cooling tower, reducing the temperature of the
phosphorus furnace gas to below 170 ℃ and causing the precipitation of liquid yellow phosphorus.
3. Alkali elution of fluoride
·The indirectly condensed phosphorus furnace gas enters the alkali washing fluorine process.
·Transport KF alkali solution to the jet scrubber and directly contact it with the phosphorus furnace gas. The KF reacts with SiF4 in the furnace
gas to produce potassium fluorosilicate precipitate, achieving the cooling and fluorine recovery functions of the phosphorus furnace gas.
·The removal of SiF4 can greatly reduce the formation of sludge phosphorus during subsequent water spray condensation.
4. Spray washing with clean water
·The phosphorus furnace gas after defluorination enters the clean water washing tower.
·The clean water is transported to the top of the clean water washing tower through a jet water circulation pump and directly contacts the
Venturi tube with the phosphorus furnace gas for heat exchange. This further condenses the gaseous yellow phosphorus in the phosphorus furnace gas into a solid state, which enters the clean water circulation tank along with the circulating water and settles at the bottom of the tank. The clear liquid in the upper part continues to be circulated for use.
5. Electrostatic dehazing of phosphorus furnace tail gas
·After washing with clean water, the phosphorus furnace gas becomes yellow phosphorus tail gas, which is sent to the wet electrostatic
precipitator for dust removal and then sent to the original tail gas pipeline system of the yellow phosphorus plant through the tail gas fan. The impurity content in the tail gas of the phosphorus furnace after alkali washing and water washing has been significantly reduced, and the scope of comprehensive utilization has been greatly expanded.
6. Yellow phosphorus classification purification
·The yellow phosphorus collected in the partition wall condensation yellow phosphorus collection tank is pumped to the yellow phosphorus
filter for filtration and sold as industrial yellow phosphorus.
·The yellow phosphorus collected in the fluorine liquid circulation tank and the clean water circulation tank is regularly pumped to the yellow
phosphorus filter for filtration and sold as high-purity yellow phosphorus.
7. Characteristics of the new process for purifying phosphorus furnace gas
·This process eliminates the commonly used three-stage/four stage condensing tower, significantly reducing the amount of circulating
washing water and also greatly reducing the amount of phosphorus containing wastewater treatment.
·By using dry dust removal and defluorination, the production of sludge phosphorus is significantly reduced, effectively alleviating the
pressure of subsequent sludge phosphorus treatment.
·Graded condensation can obtain low arsenic yellow phosphorus products, increasing the value of yellow phosphorus products.
1. Mud phosphorus closed dehydration
·The mud phosphorus from each section is collected in the mud phosphorus tank and transported to the stacked screw mud phosphorus
dewatering machine or plate and frame filter press through an underwater pump to reduce the moisture content of the mud phosphorus
from 50% to about 15%.
·Key equipment: Stacked screw mud phosphorus dewatering machine
·Sample of Stacked Screw Dehydrator
2. Low temperature phosphorus evaporation
The dehydrated mud phosphorus is sent to a hollow blade dryer through a closed screw conveyor. High temperature heat transfer oil
circulates in the hollow blades, heating the mud phosphorus to above 300 ℃. The moisture and most of the elemental phosphorus evaporate
and enter the phosphorus collection system from the top to condense and obtain yellow phosphorus products.
Key equipment: Hollow blade dryer
Hollow blade dryer
The drying principle of the hollow blade dryer is that wedge-shaped hollow blades are densely arranged on the hollow shaft, and the heat
medium flows through the blades through the hollow shaft to indirectly heat the sludge phosphorus. The wedge-shaped blade heat transfer surface has self-cleaning function and pushes the mud phosphorus forward during rotation.
3. High-temperature steam phosphorus
·After low-temperature phosphorus evaporation treatment, the mud phosphorus is mechanically pushed by the blade through the channel at
the lower part of the guide plate and transported to the closed screw conveyor for heating in the high-temperature heating evaporator.
·Mud phosphorus is continuously heated to above 500 ℃ in a high-temperature evaporator, and the elemental phosphorus content in the ash
residue is below 0.1%.
·The heat source of the high-temperature heating evaporator is provided by the direct combustion of yellow phosphorus tail gas.
Key equipment: High temperature heating evaporator
4. Efficient washing with phosphorus vapor
·By using a jet water circulation pump, clean water is transported to the top of the washing tower through a Venturi tube, where it
directly contacts and exchanges heat with phosphorus vapor. This causes the gaseous yellow phosphorus in the phosphorus vapor to
condense into liquid form, which enters the clean water circulation tank along with the circulating water and settles at the bottom of the tank. The clear liquid in the upper part continues to circulate and be used.
·By using a Venturi high-efficiency washing tower, complete collection of phosphorus vapor can be achieved in a single tower.
5. Characteristics of a new method for harmless treatment of mud phosphorus
·This method has the advantages of full system closed operation, continuous operation, small equipment footprint, low energy consumption,
high phosphorus extraction rate, no phosphorus by-products generated during the entire extraction process, and is safe and environmentally friendly. It is the preferred pollution-free and clean production solution for mud phosphorus extraction.
1. Closed quenching slag and automatic slag conveying process
·First, fill the enclosed structure of the slag quenching water tank with water. The molten liquid yellow phosphorus slag at 1400 ℃
automatically flows into the slag quenching water tank through the slag mouth, and the molten slag is rapidly cooled into fine particle slag.
·Transported by the scraper conveyor at the bottom of the slag quenching water tank to the bucket elevator, then lifted to the slag storage
hopper for temporary storage, and then transported by belt to the slag yard or truck for external transportation.
2. Exhaust gas collection and washing
·The large amount of water vapor generated during the slag quenching process is collected by the steam pipe and automatically enters the
washing tower. After being cooled and washed by low-temperature acidic water sprayed from the nozzle, it meets the standard for discharge.
3. Exhaust gas electrostatic defogging and whitening
·The yellow phosphorus production system generates a large amount of waste gas from slag and iron production, quenching slag, and crude
phosphorus refining system. Although the collection is carried out for washing and organized emission, the rolling white smoke still hinders
the appearance. The use of electrostatic defogging and whitening technology has a significant effect.
·The basic process principle is to collect and wash the exhaust gas and introduce it into the electrostatic defogger. Under the action of high
voltage, dust and mist particles are charged and move towards the anode, and accumulate on the anode plate. Regular flushing is carried
out to collect impurity particles, while the exhaust gas achieves the purpose of whitening.
Comparison diagram of whitening effect
1. The new process of raw material pretreatment has achieved the comprehensive utilization of low-grade phosphate ore powder.
2. The new low-cost purification process for phosphorus furnace tail gas not only produces low arsenic yellow phosphorus and recovers
fluorine resources, but also expands the utilization of tail gas, achieving multiple benefits in one fell swoop.
3. The two-stage automatic phosphorus evaporation method for mud phosphorus has achieved fully automatic harmless treatment of mud
phosphorus, which is safe and environmentally friendly, and obtains high-value yellow phosphorus products, meeting one of the "encouraged"
process conditions for yellow phosphorus.
4. The integrated clean slag removal process not only eliminates the need for a large concrete slag pool, slag grabbing crane, high-pressure
slag flushing water pump, and exhaust fan investment, but also greatly improves the external image of yellow phosphorus enterprises through
waste gas whitening treatment, meeting the second "encouraged" process condition for yellow phosphorus.
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