CN1034163C - Method for prodn. of ferric oxide by ultilizing steel rolling grease - Google Patents

Abstract

The present invention discloses a method for production of ferric oxide by utilizing steel rolling grease. The method is characterized in that oil sludge is burnt, and Fe3O4 in the oil sludge is oxidized to Fe2O3 by high temperature and oxidizing atmosphere, which are generated by incineration. The Fe2O3 with purity of larger than 98% can be generated through the processes of pulverization, classification, wet separation, chemical purification, etc. Because principal raw materials of the present invention are waste of a rolling mill, the manufacturing process is simple, no special equipment is needed, and the product cost is lower by 40 to 45% as compared with that of the traditional technology production. Simultaneously, the environment pollution is eliminated, and the present invention has good economical and social benefits.

Description

Utilize steel rolling greasy filth to produce the method for ferric oxide

The present invention relates to a kind of method of utilizing steel rolling greasy filth to produce ferric oxide, belong to the production method of industrial chemicals.

Di-iron trioxide claims again iron oxide red, is very widely industrial chemicals of a kind of purposes, can make colored construction material, is used as grinding agent in machinery industry, and the ferrite after specially treated can be used for video recording, audio tape and magnetic crack detection etc.In addition, red iron oxide is again a kind of crucial pigment.The method of producing iron oxide red is a lot, and according to Zhu Jiliang, Wu Shennian chief editor " pigment technology " introduced, and conventional method has two kinds of dry method and wet methods.Dry method be with industrial chemicals such as green vitriol iron oxide yellow or iron oxide blacks through calcining, generate di-iron trioxide after sloughing the crystallization water.Wet production is with sulfuric acid or nitric acid iron sheet and molysite to be processed generation hydroxide, and the oxidation of further dewatering of the hydroxide of iron can generate di-iron trioxide, more than the common characteristics of these methods be that raw materials technology is the chemical metallurgy product, the cost of material height.In order to overcome this shortcoming, must seek less expensive raw material.At Steel Mill's steel rolling greasy filth is a kind of oil-containing that produces in the production process and the waste of a large amount of brown iron oxides, and its quantity discharged is very big in Steel Mill, as about 1～20,000 ton of the various steel rolling greasy filth of the annual discharging of Wuhan Iron and Steel Plant.This greasy filth viscosity is big, should not make raw materials for sintering, can only so not only occupy a large amount of places as waste dump, but also can cause serious environmental pollution.

The objective of the invention is to utilize steel rolling greasy filth to produce ferric oxide, to reduce cost.

In order to realize this purpose, the invention discloses a kind of method of utilizing steel rolling greasy filth to produce ferric oxide, its principal feature is that greasy filth is burned, and utilizes the high temperature and the oxidizing atmosphere of burning generation to make the Z 250 in the greasy filth be oxidized to ferric oxide.Compare with conventional method, produce in this way di-iron trioxide, technology is simple, does not need special equipment, and cost can reduce by 40～50%, and can eliminate environmental pollution, saves the place of banking up, and obvious economic benefit and social benefit are arranged.

Below method of the present invention is described in detail.

Steel rolling greasy filth outward appearance is grey black, and slightly redly, greasy filth was paste when the oil-containing water yield was high, and it is block that the oil-containing water yield is when low.Cause is subjected to the composition fluctuation that affects greasy filth of steel rolling and water treatment technology bigger, and oil content is generally 4～7%, and its Main Ingredients and Appearance is iron oxide and a small amount of iron powder and other impurity, and FeO is and Fe in the iron oxide ₂O ₃Form Fe ₃O ₄Form exist, general all iron content is about 50%, make greasy filth become di-iron trioxide at first is exactly will be with Fe ₃O ₄Be oxidized to Fe ₂O ₃, secondly be exactly oil and other impurity of removing in the greasy filth.The key of concrete technology is that greasy filth is carried out burning disposal, burns 1 ton of greasy filth and can produce your heat of about 2,000,000 kilojoules, Fe per ton ₃O ₄All be oxidized to Fe ₂O ₃Need approximately your heat of 300,000 kilojoules, therefore, the heat that burns the greasy filth generation not only is enough to supply with Fe ₃O ₄Oxidation reaction, and remaining heat can also be used for other operation.

The product of greasy filth after incineration oxidation is powder granulous ferric oxide and a spot of silicon-dioxide, carbon dust and soda acid oxide impurity etc.Must from above-mentioned oxidation products, remove impurity.From analytical results as can be known, the initial size of iron oxide is less than 100 orders in the greasy filth, and wherein particle diameter accounts for 90% less than 320 purposes.SiO in greater than 320 purpose particles ₂Account for 3%, will can make SiO in the oxidation products greater than after the 320 purpose particle removals ₂Total amount reduce to below 0.25%.The proportion of carbon dust is little, can remove with fulling, and the soda acid oxide impurity can make it to become soluble-salt with chemical method, just can obtain the di-iron trioxide of satisfying the criteria and requiring through these steps.

The concrete technology that aforesaid method is used to produce is as follows:

The major equipment of handling greasy filth aborning is a far infrared indirect heating type rotary kiln, and rotary kiln is operated under negative pressure, and the Flow of Goods and Materials direction is opposite with the flow of flue gas direction in the kiln, and electric precipitator places feed end, and blower fan is contained in after the electric precipitator.Press the duty of rotary kiln, rotary kiln is divided into two parts, is combustion zone by feed end, is oxidized zone by discharge end, and combustion zone and oxidized zone Length Ratio are 2: 1, and combustion zone and oxidized zone can heat respectively.Must be with the combustion zone of rotary kiln and oxidized zone heating during blow-on, can charging when the barrel temperature of rotary kiln is heated to more than 400 ℃, the greasy filth behind the natural air drying is sent in the rotary kiln by batcher, start simultaneously blower fan, make to be negative pressure in the kiln.Greasy filth is met high temperature and is taken fire, and kiln temperature increases, and can close the heater of combustion zone when kiln temperature surpasses 400 ℃, and the heat that relies on the greasy filth burning to produce is kept kiln temperature, and greasy filth enters oxidized zone through behind the combustion zone, in order to make Fe ₃O ₄Fully oxidation, according to the content of FeO in the raw material, the temperature of oxidized zone will be controlled between 600-800 ℃, and the height of kiln temperature is relevant with the oil content of greasy filth, can not start the oxidized zone heater when requiring and adjusts when kiln temperature reaches.Greasy filth from enter rotary kiln through burning, be oxidized to out rotary kiln and last 70-80 minute approximately, the kiln discharge temperature of material is 350-400 ℃.Flue gas in the kiln purifies through electric precipitator, and the dustiness of flue gas is 5-10g/Nm ³, the dustiness after the purification is 20-60mg/Nm ³, funnel temperature is 250-300 ℃, flue gas after being purified is discharged into the back operation as drying source by high-temperature blower.The analysis of components result following (%) of greasy filth after burning and oxidation: Fe ₂O ₃FeO CaO SiO ₂MnO ₂C Al ₂O ₃Other is 94.58 1.63 0.56 0.52 0.41 1.42 0.25 0.21 a small amount of for MgO

Fe in the above-mentioned product ₂O ₃Exist with loose shape aggregation, the particle diameter of aggregation is greater than 320 orders, be unfavorable for adopting the mode desiliconization of grading, therefore, must carry out shot to above-mentioned product processes, soon 350～400 ℃ kiln discharge material is directly quenched in the agitator that is filled with water after loosing by disintegrating machine is broken, and aggregation is subjected to be burst behind the chilling, and is washed away, collides gradually dispersion with water movement.Agitator is opened turbine type with three hinged joints, and rotating speed is 500rpm, and every barrel of material concentration is controlled at 40% during stirring, stir after 50 minutes material is revolved to shake and sieves in sieving with being pumped into individual layer, screen cloth is 320 orders, and oversize is sent into reject chute, and minus mesh is delivered to rinsing bath with the flush away carbon dust.The turbine stirrer that open-type is arranged in the rinsing bath, rotating speed is 250rpm, minus mesh enters that thin up to material-water ratio is 1: 4 behind the rinsing bath, stirred 15 minutes, left standstill 30 minutes, and in the pond, slowly added water to Chi Kou then, the carbon dust that floats on the surface is overflowed, above-mentioned repeatedly rinse cycle 3-4 time is not till liquid level has carbon dust.It is 50% o'clock that the slip of rinsing bath is precipitated to concentration, discards upper clear supernate, slip is pumped into connect the reacting by heating jar always, add the solid NaoH that accounts for solid content 0.1-1% in slip, stir while adding, stirring velocity is 300rpm, feed steam simultaneously, when the pH value of slip is 9-10, stop to add NaoH, continued heated and stirred 40 minutes, added water washing then 10 minutes, wash concentration is 20%, and natural subsidence 30 minutes is discharged clear liquid.Repetitive scrubbing 3-4 time is to pH value 7-8.Adding concentration then in slip is the hydrochloric acid of 36-38%, and pH value is transferred to 2-3, and the limit adds sour limit heated and stirred, finishes the adjustment work of pH value in 15 minutes.Continued heated and stirred then 35 minutes, and added water washing at last, wash concentration 20% was washed 10 minutes, natural subsidence, and reject sinks clear liquid.The slip of post precipitation is pumped into a plate and frame(type)filter press, the water purification of 0.5～0.7MPa is pressed into filter cake cleans, scavenging period is 25 minutes, is 6-7 up to the scavenging solution pH value, and soluble salt just is removed basically.Ferric oxide filter cake moisture content after the filtration is about 20-25%, this filter cake is sent into drying cylinder carries out drying, thermal source promptly be in the rotary kiln through purified waste gas, drying cylinder adopts the direct heating mode.Water ratio is less than 0.5% after filtration cakes torrefaction 20-30 minute.Dried granular di-iron trioxide is ground through vibromill, inspection by sampling, quality index is (%): Fe ₂O ₃〉=98.0 SiO ₂≤ 0.25 C≤0.01 MnO ₂≤ 0.3Al ₂O ₃≤ 0.03 moisture content≤0.5 average grain diameter 2-2.5 μ m can pack after the assay was approved and dispatch from the factory.

Claims (1)

1, a kind of method of utilizing steel rolling greasy filth to produce ferric oxide, be that greasy filth is burned, utilize the high temperature and the oxidizing atmosphere of burning generation to make the Z 250 in the greasy filth be oxidized to ferric oxide, the oxidizing temperature that it is characterized in that greasy filth: 600-800 ℃, the useless flue gas that will burn the greasy filth generation simultaneously directly is used as the drying medium of ferric oxide.