Production practice of reducing return rate of 450m2 sintering m

1. To put it simply: after the iron ore powder is mixed and sintered by adding flux, the finished procts pass through four stages of screening (the screening level is not necessarily) which are large finished proct, small finished proct, bedding material and reverse ore (that is, the one with the least strength). The percentage of reverse ore amount in the total amount of finished sinter is the reverse ore rate.

2. The smoke, st, waste heat and resial humidity proced in heavy metal smelting process are purified by ventilation and st removal, so that the concentration of harmful substances can meet the health standards and emission standards. Most of the raw materials for heavy metal smelting are sulfide concentrate. The main harmful substance emitted in roasting, sintering, smelting, converting and other proction processes is SO2 flue gas, whose concentration is higher than 3%, which can be used to proce sulfuric acid. The concentration of SO2 flue gas escaping from the charging port of smelting furnace, matte (matte) port, slag discharge port, Baozi room (closed chamber for conveying metallurgical melt steel container) and converter secondary hood is relatively low, and the flue gas is generally discharged into the atmosphere in a centralized or decentralized way for dilution. The basic contents of the design include: st removal in material preparation and drying workshop, ventilation and st removal in roasting and sintering workshop, ventilation and st removal in smelting workshop, ventilation and st removal in converting and refining workshop, ventilation and st removal in electrolysis workshop, etc. The material preparation and drying workshop includes concentrate warehouse, flux section, proportioning warehouse and drying section. The main st procing points of concentrate warehouse are from grab to receiving bin and from bin to belt conveyor. Generally, the st removal system is only designed at the st procing point from the silo to the belt conveyor. The inlet and outlet of flux crushing, screening and transfer points in flux section are equipped with st hood, which forms a st removal system. The upper part of the proportioning bin is provided with an exhaust and st removal system for maintaining the negative pressure of the ore bin; Each st procing point from the lower feeder to the belt conveyor is provided with a st removal cover, which forms a st removal system. The cleaning equipment of the above st removal system can select dry or wet st collectors according to the properties of st. Concentrate drying is carried out in a cylindrical drying kiln or a short drying kiln, a squirrel cage crusher and an air flow drying tube. The latter is operated in a fully closed negative pressure state, generally without a st removal system. At the end of the cylinder drying kiln, the temperature of the material is high and the moisture content is low. The ventilation, st removal, roasting and sintering belong to the pretreatment process before smelting. The fluidized bed furnace and multi chamber furnace for concentrate roasting usually adopt the methods of furnace body heat insulation and natural ventilation to eliminate the waste heat in the workshop. When calculating the natural ventilation of the workshop, the effective coefficient m of heat diffused into the working area is 0.3 for the fluidized bed furnace with heat shield, and 0.4 for the fluidized bed furnace without heat shield. The workshop of multi-storey roaster is generally a multi-storey workshop. In order to facilitate natural ventilation, the floors of each floor should be staggered in design. In the process of loading, unloading and transportation of materials before entering the fluidized bed furnace, st hood is generally set at the loading and unloading st procing points of ore bin, disc feeder and belt conveyor, and a st removal system is formed. In order to remove the st with a large amount of water vapor, a low suspended volume airtight cover is set up at the hot calcine discharging and wet ore flushing places, and the exhaust air volume is per meter. The liquid level of flushing chute is calculated as 600m3 / h. High efficiency and corrosion-resistant wet desting equipment is selected for desting system. When the materials are discharged into the dry layer of the top of the multi chamber baking furnace, although there is st emission, because it is difficult to seal the charging point on the top of the furnace, only a closed st chamber is set up there. The main harmful substances in the sintering process are st, SO2 flue gas and waste heat. The workshop should adopt comprehensive natural ventilation measures to eliminate waste heat and flue gas. The m value of natural ventilation in sintering plant is 0.33. Mechanical ventilation and st removal system is set at the head, tail and ignition furnace of sintering machine. For a 50m3 sintering machine, the exhaust air volume of its head should be 5000-7500m3 / h, that of its ignition grate should be 16000-20000m3 / h, and that of its tail should be 35000-45000m3 / h. The sintering return ore should be cooled by cylinder cooler, and the st with a large amount of water vapor will be emitted ring the cooling process. The st removal system should adopt the wet st removal equipment with high-efficiency anti-corrosion and not easy to block. Sound control 2500mm × The exhaust volume of 5000mm cylinder cooler should be 20000-30000m3 / h. According to the variety of heavy metals, concentrate composition and grade, the smelting furnace can adopt reverberatory furnace, electric furnace, closed blast furnace and flash furnace. Through the furnace wall, matte discharge and slag discharge process, a large amount of waste heat is released, accompanied by SO2 flue gas into the workshop. Usually, organized natural ventilation is used to remove waste heat and harmful gases. When smelting copper with electric furnace, m value is 0.6, and ventilation and st removal facilities are set at feeding and charging places. A rotatable smoke exhaust hood is arranged at the matte outlet, and a smoke guide and heat insulation hood is arranged on the chute to prevent radiation heat. There is a movable cover plate on the top of the baozi room, and the exhaust air volume is 18000-25000m3 / h. The slag discharge chute is provided with a lifting water jacket heat insulation cover. A closed exhaust hood is set on the water quenching slag pool, and the exhaust air volume is calculated according to the amount of slag and the amount of steam generated. Mobile fans are set in each operation post of smelting furnace. Horizontal converter is generally used for converting and refining heavy metals. The primary st content of converter is 3-15g / m3, containing S0. The concentration is 7% ～ 8%, and the treatment process is shown in the design of st collection facilities of heavy metal smelter and the design of sulphuric acid proction facilities with sulfur dioxide flue gas of heavy metal smelter. The converter is additionally provided with a rotating shroud and a secondary smoke exhaust hood on both sides of the furnace top. Taking the 100t converter as an example, the exhaust volume of the rotating shroud is 42000m3 / h, and the exhaust volume of both sides of the top is 42000m3 / h. Local air supply or mobile fan is set at the air hole behind the furnace. Copper pyrometallurgical refining is usually carried out in reverberatory furnace or rotary furnace with natural smoke hood at furnace mouth. The crude copper out of the refining furnace is cast into metal ingot or anode plate on the casting machine. A ventilation system is designed in the cooling section to discharge water vapor, and the exhaust air volume is 30000-50000m3 / h. Heavy metal electrolysis workshop belongs to high humidity workshop. The temperature of electrolyzer liquid is 35-65 ℃. The liquid surface of electrolyzer disperses water vapor and acid mist. Generally, comprehensive natural ventilation and mechanical ventilation are adopted. The ventilation volume can be calculated according to the amount of acid mist and resial humidity in different seasons, and the larger one can be determined according to the number of air changes. In the process of zinc electrolysis, H 2 and O 2 gas are separated out from the anode and cathode respectively, resulting in a large amount of acid mist. The total ventilation rate is calculated as 10-15 times / h, except that the process adds an inhibitory covering on the liquid surface of the electrolytic cell. The ventilation rate of copper and nickel electrolysis is calculated as 5 ~ 10 times / h. The ventilation rate of lead electrolysis is calculated as 3 ~ 5 times / h. When the electrolyte is purified in various tanks, the sour water gas is proced. Generally, the corrosion-resistant natural exhaust pipe is set on the tank cover, and the exhaust air volume is related to the tank size, which can be 500-1200 m3 / h. There is chlorine escaping in the purification process of nickel electrolyte. The absorption purification exhaust system should be designed according to the discharge amount of chlorine. 2% - 4% alkali solution (NaOH solution) is used as the absorption solution. Sodium hypochlorite (NaOCl) with a certain concentration of circulating absorption solution can be returned to proction for reuse or export. In the purification system of copper electrolyte, the concentration of acid mist emitted by the de copper electrolytic cell is high, and it contains a certain amount of hydrogen arsenide gas. In addition to the process that the de copper electrolytic cell is configured in a separate room, the electrolytic cell should be equipped with a movable sealing cover plate, and the exhaust system should be equipped with a water washing purification device.

3. Today's economic research hotspots:
1,
supply side reform
2,
local debt research

3,
international economy

4,
overcapacity research
and so on

4. Ten Finns from Germany.

5.

The differences between "rent" and "rent" as past tense are: different meaning, different usage and different prototype

Rent means rent, crack, tear

Rent means to rent

Rend usage: the basic meaning is "tear" or "pull", which means to make something split (leaving a rough edge) or leave its attachment under the action of external force. It can be extended to "torture", "run", "walk away" and so on. It can also be used as intransitive verb. When it is used as a transitive verb, it can be followed by a noun or pronoun as the object, or sometimes an adjective or adverb as the compound object of a complement

2. Rented usage: when used as a noun, it means "rent", which is converted into a verb to refer to "rent", that is, the surplus house, land or other idle materials are lent to others in a paid way, and then recovered when needed. It can refer to renting in or renting out. It usually refers to renting land or house. In American English, it can also refer to renting a car, but it is not used to borrow money

3. Different prototypes

1. Rent prototype: the prototype verb of rent is rend

2. Rendered prototype: the prototype verb of rendered is rent

6. The difference between rent and lend is as follows:
1) in the sense of, Lend (lend...)
2) grammatical Collocation:
rent related phrases: rent sth from...
example: I lent it from factory / Jane

in a word, just remember that one is to rent and the other is to lend<

related development:

[rent]
~ + noun
rent a car
rent house
rent room
rent TV
~ + adverb
rent high rent
rent cheaply
rent out
~ + preposition
rent at (a certain price)
~ + Adverb />Rent from
rent to...

[lend]
~ + noun
lend a bike
lend a book
lend a flashlight
lend a helping hand
lend a place a Festival look to a place
lend money
lend money D money at high interest; Listen, Pay attention to the adverbs
~ + lend conditionally
lend conventionally and conveniently
lend gracefully and appropriately
lend gratuitously and gratuitously
lend grudgingly and reluctantly
lend innocently and unethically
lend willingly and willingly Lend out
lend out books
lend out the car
~ + preposition
lend colour to the streets
lend itself to, Easy to be
lent itself to dancing suitable for dancing
lent one self to agree to participate
lent one self to such a stupid plan submit to this stupid plan
lent truth to the story add authenticity to the story

7. Choose "rent
here" instead of "house"

8.

Rent control: return to scale

The change of returns to scale can be divided into three situations: increasing returns to scale, constant returns to scale and decreasing returns to scale

for example, suppose a factory with a monthly output of 100000 tons of chemical fertilizer uses 10 units of capital and 5 units of labor. Now, the proction scale of an enterprise will be doubled, that is, 20 units of capital and 10 units of labor will be used. Due to the change of proction scale, there may be three kinds of income changes as follows:

(1) the proportion of output increase is greater than that of proction factors, that is, the output is more than 20 tons, which is called increasing returns to scale

(2) the proportion of proction increase is less than that of proction factor increase, that is, the proction is less than 20 tons, which is called diminishing returns to scale

(3) the proportion of output increase is equal to the proportion of proction factor increase, that is, the output is 20 tons, which is called constant returns to scale

extended data:

the main feature of diminishing returns to scale is that when proction factors increase at the same time in the same proportion, the proportion of output increase is less than that of input factors. There are two main reasons for diminishing returns to scale. One is the limitation of availability of proction factors

with the graal expansion of the proction scale of manufacturers, e to the geographical location, raw material supply, labor market and other factors, the factor input that manufacturers need in proction may not be met. Second, the management efficiency of large-scale manufacturers will decline, such as the internal supervision and control mechanism, information transmission and so on. It is easy to miss the favorable decision-making opportunity and rece the proction efficiency