Sinter drum machine

1. Sintering is a method of heating powdery materials (such as fine ore and concentrate) at high temperature and sintering them into blocks under the condition of incomplete melting. The proct is called sinter, and its shape is irregular and porous. The heat energy required for sintering is provided by the combustion of the carbon in the sintering material and the excess air, so it is also called oxidation sintering. Sinter mainly depends on liquid phase bonding (also known as melting sintering), solid phase bonding only plays a secondary role
modern sintering proction is a process of exhaust sintering, in which the mixture (iron ore powder, fuel, flux and return ore) is mixed with an appropriate amount of water, mixed and granulated, and then spread on the grate of belt sintering machine. After ignition, a certain negative pressure is used to exhaust air, so that the sintering process can be carried out from top to bottom. The sinter is unloaded from the sintering trolley. After crushing, cooling, granulation and screening, the finished sinter, return ore and bedding material are separated< The typical sintering proction process can be divided into eight process systems:
1) the receiving process system mainly includes mper system, receiving tank, concentrate warehouse, flux warehouse, fire extinguishing warehouse, etc., which is responsible for the receiving, transportation and storage of incoming raw materials
2) raw material preparation process system includes neutralization of iron containing raw materials, crushing of fuel, crushing and screening of flux. Its task is to prepare raw materials, flux and fuel that meet proction requirements for batching process
3) batching process system, including ore trough, disc feeder, weighing facilities, etc; According to the specified sinter chemical composition and the type of raw materials used, through calculation, each raw material is fed according to the calculated weight, so as to ensure the stability of chemical composition of mixture and sinter and the adjustment of fuel quantity
4) mixing and granulating process system mainly includes cold and hot return plate and primary mixing; Mixture ore tank, secondary mixing and other processes. Its task is to add water and wet the mixture, then mix the mixture evenly with the primary mixer, and preheat the pellets with the secondary mixer
5) sintering process system includes bedding, distribution, ignition, sintering, etc. The main task is to sinter the mixture into qualified sinter
6) the ventilation system includes bellows, st collecting pipe, st collector and fan. Chimneys, etc
7) the finished proct processing system includes hot crushing, hot screening, cooling, cold crushing, cold screening and finished proct transportation system. The task of this process is to separate 5 ~ 50mm finished sinter, 10 ~ 20mm bottom material, less than 5mm cold return ore
8) the environmental protection st removal process system is mainly to use the electrostatic precipitator system to purify the waste gas from the st points of the sintering machine tail discharge, hot screen, cooling, ore return and whole grain system. After being purified by the precipitator, the waste gas is discharged into the atmosphere. After being wetted, the st is added into the sintering mixture for sintering. Its task is to protect the environment of sintering proction
in some sintering plants in our country, the process is not perfect, some of them have no cooling, cold crushing and cold screening operations (called hot ore plants); Some of them have cooling effect, but no cold breaking, cold screening and bedding effect. In the more advanced sintering process of Baosteel, the raw material receiving, flux crushing, screening and neutralization of iron bearing raw materials are carried out in the raw material yard, and the iron bearing raw materials are mixed into a single and stable mixture by the raw material yard and directly sent to the sintering batching tank.

2. 1. The concept of sintering

a series of physicochemical changes are made on the sintering equipment after mixing and pelletizing all kinds of powdery iron containing raw materials with appropriate amount of fuel and flux and adding appropriate amount of water< At present, the belt type suction sintering machine is widely used to proce sinter. The technological process of sintering proction is shown in Fig. 2-4. It mainly includes the preparation of sintering material, proportioning and mixing, sintering and proct treatment<
process flow of exhaust sintering

> preparation of sintering raw materials

① iron containing raw materials

high iron content, particle size & lt; 5mm ore powder, iron concentrate, blast furnace st, steel sheet, steel slag, etc

it is generally required that the raw material containing iron should have high grade, stable composition and less impurities

② flux

it requires high content of effective Cao, less impurities, stable composition, about 3% water content and more than 90% particle size less than 3mm in flux

adding a certain amount of dolomite into the sinter can make the sinter contain appropriate MgO, which has a good effect on the sintering process and can improve the quality of sinter

③ the fuel

is mainly coke powder and anthracite

the requirements for fuel are high fixed carbon content, low ash content, low volatile matter, low sulfur content, stable composition, water content less than 10%, and more than 95% of the particles with particle size less than 3mm

see table 2-2 for general requirements of raw materials for sintering<

General requirements of raw materials for sintering into the plant

● proportioning and mixing

① proportioning

proportioning purpose: to obtain sinter with stable chemical composition and physical properties to meet the requirements of blast furnace smelting

commonly used batching methods: Volume batching method and mass batching method

Volumetric Batching method is based on the condition that the bulk density of materials is constant and the mass of raw materials is proportional to the volume. The accuracy is poor

the quality batching method is based on the quality of raw materials. The specific volume proct method is accurate and easy to realize automation

② mixing

mixing purpose: to make the composition of sinter uniform, the moisture content appropriate, and easy to pelletize, so as to obtain the sinter mixture with good particle size composition, so as to ensure the quality of sinter and improve the output

mixing operation: wetting with water, blending and pelletizing

according to the different properties of raw materials, one mixing or two mixing processes can be used

the purpose of one-time mixing: wetting and mixing, and preheating the material when heating the return ore

the purpose of secondary mixing is to continue mixing and pelletizing, so as to improve the permeability of sinter layer

when sintering with rich ore powder with particle size of 10-omm, because its particle size has reached the requirement of pelletizing, one-time mixing is adopted, and the mixing time is about 50s

when fine grinding concentrate powder is used for sintering, because the particle size is too fine and the permeability of material bed is poor, in order to improve the permeability, pelletizing must be made in the mixing process, so the secondary mixing is adopted, and the mixing time is generally not less than 2.5 ~ 3min<

most sintering plants in China adopt secondary mixing< Sintering operation is the central link of sintering proction, which includes feeding, ignition, sintering and other main processes

① distribution

the operation of laying the bottom material and mixture on the sintering machine trolley

when the bedding material process is adopted, a layer of small sinter with particle size of 10-25 mm and thickness of 20-25 mm is laid as bedding material before the mixture is laid. The purpose is to protect the grate, rece the st removal load, prolong the service life of the fan rotor, and rece or eliminate the slag on the grate

after the bottom material is laid, the cloth is distributed. The size and chemical composition of the mixture should be evenly distributed along the vertical and horizontal direction of the trolley, with certain looseness and smooth surface

at present, the round roller distributor is widely used

② ignition

ignition operation is to ignite the material layer surface on the trolley and make it burn

sufficient ignition temperature, suitable high temperature holding time and uniform ignition along the trolley width are required for ignition

the ignition temperature depends on the melting temperature of sintering procts. It is usually controlled at 1250 ± 50℃ < The ignition time is usually 40-60s

ignition vacuum is 4-6kpa< The ignition depth is 10-20 mm

③ sintering

accurately control the air volume, vacuum degree, material layer thickness, machine speed and sintering end point

sintering air volume: the average air volume required per ton of sinter is 3200m3, which is (70-90) m3 / (cm2. Min) according to the sintering area

Vacuum Degree: it depends on the capacity of the fan, the resistance of the exhaust system, the permeability of the material layer and the air leakage loss

material layer thickness: appropriate material layer thickness should combine high yield with high quality. The thickness of material layer is 250-500mm

machine speed: the proper machine speed should ensure that the sinter is thoroughly burned at the predetermined sintering end point. In actual proction, the speed of the machine is generally controlled at 1.5 ~ 4 m / min

judgment and control of sintering end point: control the sintering end point, that is, control the position of the trolley when the sintering process is completed. The end point of small and medium sintering machine is generally controlled at the penultimate bellows, while that of large sintering machine is controlled at the penultimate bellows

the sintering process of belt sintering machine is carried out from top to bottom. The temperature change along the height of the material layer can be generally divided into five layers, and the reaction change in each layer is shown in Fig. 2-5. After ignition, sinter layer, combustion layer, preheating layer, drying layer and over wet layer appear successively. Then the last four layers disappear one after another, and finally only the sinter layer is left< After ignition at high temperature, the fuel in the sinter gives off a lot of heat, which makes the minerals in the sinter melt. With the combustion layer moving down and cold air passing through, the molten liquid phase is cooled and recrystallized (1000-1100 ℃) to solidify into sinter with mesh structure

the main change of this layer is the solidification of the melt, accompanied by crystallization and precipitation of new minerals, the cold air inhaled is preheated, and the sinter is cooled at the same time, and the low valent oxides may be reoxidized when contacting with the air

② combustion layer

the fuel burns in this layer, and the temperature is as high as 1350 ~ 1600 ℃, which makes the minerals soften, melt and bond into lumps

in addition to the combustion reaction, the melting, rection and oxidation of solid materials and the decomposition of limestone and sulfide occur in this layer

③ preheating layer

the mixture in the lower part is preheated to the ignition temperature quickly by the high temperature exhaust gas from the combustion layer, which is generally 400 ~ 800 ℃

solid state reaction begins in this layer, crystal water and part of carbonate and sulfate decompose, and magnetite is oxidized locally< (4) the drying layer is heated by the waste gas from the preheating layer, and the temperature of the drying layer quickly rises to above 100 ℃. A large amount of free water in the mixture evaporates, and the thickness of this layer is generally 10-30mm

in fact, it is difficult to separate the drying layer from the preheating layer, which can be collectively referred to as the drying preheating layer

the pellets in this layer are heated rapidly and dried rapidly, which is easy to be damaged and worsen the permeability of the layer

⑤ over wet layer

the hot waste gas from the dry layer contains a lot of water. When the material temperature is lower than the dew point temperature of the water vapor, the water vapor in the waste gas will re condense, which makes the water in the mixture increase greatly and form over wet layer

too much water in this layer will deteriorate the permeability of the material layer and rece the sintering speed

basic chemical reactions in sintering process

① combustion reaction of solid carbon

the combustion reaction of solid carbon is as follows:
after reaction, C0 and C02 are generated, and part of resial oxygen is proced, which provides oxidation-rection gas and heat for other reactions

the composition of the exhaust gas proced by combustion depends on the sintering raw material conditions, fuel consumption, the development of rection and oxidation reactions, and the composition of the gas pumped through the combustion layer

② decomposition and mineralization of carbonates

the carbonates in sinter are CaC03, mgc03, fec03, mnc03, etc., among which CaC03 is the main one. Under sintering conditions, CaC03 begins to decompose at about 720 ℃, and chemical boiling begins at 880 ℃. The decomposition temperature of other carbonates is lower

the decomposition proct Ca0 of calcium carbonate can react with other minerals in the sinter to form new compounds, which is mineralization. The reaction formula is:

CaCO3 + SiO2 = CaSiO3 + CO2

CaCO3 + Fe2O3 = Cao · Fe2O3 + CO2

if the mineralization is not complete, there will be resial free Ca0. During storage, it will digest with the water in the atmosphere:

CaO + H2O = Ca (OH) 2

make the volume of sinter expand and pulverize<

③ decomposition, rection and oxidation of iron and manganese oxides

under sintering conditions, Fe203 can decompose when the temperature is higher than 1300 ℃

Fe304 can decompose when the sintering temperature is lower than 1300 ℃

I don't know if it can meet your needs?

3. Heavy position means that in financial transactions, a high proportion of money in the financial account enters the financial market, while the proportion of the balance in the financial account is small
full position is a proper term for stock market. Position mainly refers to the proportion of funds used in the securities fund account, which can be divided into light position, half position, heavy position and full position according to different degrees. Full position operation generally means that all funds are bought into stocks, and the remaining funds are not enough to buy 100 current stocks
response time: February 4, 2021. Please refer to the official website of Ping An Bank for the latest business changes
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4. Fuzhou housing provident fund management center is directly under the Fuzhou Municipal People's government, rather than for the purpose of profit-making a quite positive agency<

under the leadership of Fuzhou housing provident fund management center, Fuzhou housing provident fund management committee performs the main responsibilities of the people's government entrusted by the "Regulations on the management of housing provident fund"& lt; Br / (1) to compile and implement the plan of collecting and using the housing provident fund
(b) responsible for recording the deposit, withdrawal and use of employees' housing provident fund
(c) is responsible for the accounting of housing provident fund< (4) examine and approve the withdrawal and use of housing provident fund< (5) responsible for maintaining the value of housing provident fund and restoration. BR /> 6 To prepare a report on the implementation of the housing provident fund collection plan< (7) other matters shall be handled by the housing provident fund management committee of the contractor< (1)
the unit responsible for coordination, supervision and inspection of management and business activities, and external liaison; Responsible for the official message processing and presentation draft review, responsible for the party, personnel, birth control, archives, confidentiality, security work; Responsible for property management, logistics services< (2) the planning and finance department is responsible for the
report and information disclosure of the preparation of the annual centralized use plan of the housing provident fund and the implementation of the plan; Is responsible for the center's financial management, financial analysis and accounting work to ensure the safety of capital hedging against inflation; To be responsible for the establishment, use and cancellation of the central fund account; Responsible for the bill handover and reconciliation work, responsible for the purchase of government bonds, custody and payment, responsible for the financial management of housing finance other than housing provident fund; Be responsible for statistics, report preparation, summary and report work; Responsible for the establishment of the center's internal financial rules and regulations and the training, guidance, guidance, supervision and inspection of accounting personnel, and managed by the Ministry of finance< (3) the loan management department is responsible for the collection and withdrawal of the housing provident fund, the preparation of the loan plan, and the enforcement of the housing provident fund, which involves a number of legal proceedings. It is responsible for the collection and withdrawal of the housing provident fund, the publicity, consultation and training of the loan policy, Audit and approve the housing provident fund held in low or increased deposit ratio applications, responsible for handling the bank's housing provident fund collection, withdrawal, loan supervision, inspection; Responsible for the guidance, training and inspection of housing provident fund business of the management department; Responsible for the statistical report and file management of the business department< (d) the supervision department of the general audit administration is responsible for the development of the internal control and supervision management system of the center; The Department responsible for auditing the financial revenues and expenditures of the internal audit center and its related economic activities is responsible for supervising the implementation of the loan recovery of the center. Under the leadership of the economic audit center, which is implemented by the audit and audit department, the business management center of the staff is responsible for the Central Discipline Inspection and supervision of the administrative efficiency and spiritual civilization construction< (E) responsible for the establishment, maintenance, upgrade and management of the central computer information management system in it to ensure the normal and safe operation of the system; The computer information management system of the management center for formulating rules and operating proceres is responsible for computer training, providing technical services, and each department of the center is responsible for the data inquiry of housing provident fund, the creation, update, maintenance and management of the supervision system; Responsible for the construction of housing provident fund website maintenance and information collection, the establishment of a central office automation system
(f) the business acceptance office is responsible for the collection, withdrawal and loan plan implementation of housing provident fund; Be responsible for the registration and reminder of the housing provident fund account, cancel the account, postpone the application of accepting the rection or increase of the deposit ratio of the housing provident fund, and withdraw the approval of the housing provident fund for employees; Responsible for the personal housing provident fund loan recipients, review, approval and issuance, responsible for the collection of loans and overe loans
the three institutions are directly under
& gt; Fuzhou housing provident fund management center under the Mawei, Fuqing, Changle, Minhou, Luoyuan, Minqing, Lianjiang, Yongtai, Pingtan management department, the specification is quite section level
the main responsibilities are: collection, use, implementation of formulated plans, implementation of municipal housing provident fund management center and compilation department plans, recording the deposit, withdrawal and use of employees' housing provident fund; Responsible for the withdrawal of housing provident fund account within the management department; Responsible for the examination and approval of housing provident fund; Housing fund and housing loan; Responsible for maintaining the value of the housing provident fund and compensation, preparing the submitted statistics and financial statements, preparing the internal management budget, and reporting the management department to the municipal housing provident fund management center for approval and implementation; Responsible for the management of the party department, namely health, safety and efficiency construction and other daily administrative work.

5. 3 / F, CCB urban sub branch, 295 Renmin Road, Xinxiang City

6. Introction: Xinxiang housing provident fund management center (hereinafter referred to as the center) is a deputy county-level public institution established in accordance with the spirit of the document "notice on the establishment of Xinxiang housing provident fund management center by Xinxiang organization committee" (No.55 [2002]). It is directly under the people's Government of Xinxiang City, with 44 authorized institutions and full budget management of funds. There are five departments in the city center, seven management departments in counties (cities) and districts, which are under the vertical management of the city center. The five departments are: office, accounting and finance department, collection department, supervision department and credit department. Vertical agencies: Weihui management station, Huixian management station, Yuanyang management station, Xinxiang management station, Fengqiu management station, Yanjin management station, Huojia management station
registered capital: RMB 29.3232 million

7. Inquiring about the information of indivial housing provident fund account, you can query the ID number of the other person according to the need. You can inquire through the following three ways:
1, login to the local housing provident fund website;
2
3. Call the housing provident fund hotline 12329.

8. In the three holes you went through before you went to Xuerou Town, you can find it in the lower position. Please take a walk