CN1093616A - Coal cleaning process - Google Patents

Abstract

Selected fine particulate coal in the heavy medium cyclone of the particular design of improving particle acceleration and reinforcement separative efficiency.Original coal charging screening earlier is to shift out the duff particle.Raw granulate fraction is divided into clean coal, intermediate coal and ore dressing slag then.The middle rank coal is pulverized and and carefully part is selected together.Carefully part demineralization mud in adverse current cyclone loop is divided into many parts by the different grain size specification then in heavy medium cyclone.This dense media contains the ultra-fine magnet grains of narrow size distribution, and narrow size distribution helps to separate and improves magnet and reclaim.Magnet reclaims respectively from each separated portions.

Description

Coal cleaning process

The present invention generally is about the coal cleaning process field, specifically about by removing the ore dressing slag in the fine breeze, as contains sulfur mineral.

In the U.S. and the whole world, coal is widely, but is used as the fuel in power plant limitedly.But when burning, coal can send a large amount of dirts that influence environment.Nineteen ninety, the regulations amendment that purifies air enumerated environmental concerns, proposition is to come into force in nineteen ninety-five to coal, per 1,000,000 BTU(kilowatts/hour) produce the new restriction of 2.5 pounds of sulfur dioxide, and came into force in 2000, per 1,000,000 BTU produce the restriction of 1.2 pounds of sulfur dioxide.

The public public institution of current combustion sulphur coal or the selection low-sulfur coal of migrating, or select for use washing flue gas to remove sulfur dioxide.Washing sulfur dioxide needs great amount of investment and operation costliness.To many public public institutions and since by the freight charges of remote coal source fortune coal and with to reconstruct the relevant investment of factory building for adapting to different ignition quality coals, it is very expensive that the low-sulfur coal of migrating is become.Many power plants store a large amount of sulphur coal at present.Therefore be necessary to improve before burning by removing sulphur in this coal, do not produce excessive contaminants so that they can use effectively.

The selected of coal is meant by removing non-coal material in the raw coal to produce the product of coal of suitable cleaning.Raw coal is made up of high-purity coal material and non-coal material.Non-coal material in coal generally is meant ash, generally includes pyrite, earth and other aluminosilicate material.A large amount of this grey materials exist in the combustion process and can have problems, as slagging scorification and obstruction.Sulphur exists with two kinds of forms in raw coal, organic sulfur and inorganic sulfur.Organic sulfur is that chemical bond becomes the coal body part.Inorganic sulfur is that full sulphur rather than chemical bond are in coal-based body.Pyritic sulfur is the principal mode of inorganic sulfur.Sulfate sulfur is the another kind of form of the inorganic sulfur relevant with becoming grey material.The selected inorganic sulfur of only removing effectively of physics.The method of separation coal has multiple, but generally uses dense media separation, jigging or froth flotation and by separating clean coal in the non-coal material.Because versatility, high efficiency and easy operating, it perhaps is preferred separation method that dense media separates.

In dense media separates, the raw coal introducing is had in the medium of proportion between coal and non-coal material.Dense media can be uniform liquid, but often is by water and magnetic-particle, such as ferromagnetic particle, forms.Magnet is the magnetic-particle of using always.Separation can or be carried out in cyclone in dense media bath or jar.When using cyclone, then coal generally shifts out as the overflow product, and the ore dressing slag becomes the underflow product.After separating coal and ore dressing slag, help by coal with by reclaiming magnetic-particle in the ore dressing slag so that re-use.

Former coal charge is commonly referred to be common coal, is that three kinds of compositions are organic materials, stone and pyritous mixture.In raw coal, some particle breaks away from, and means that they constitute pure relatively composition.Other particles are fixed, and mean that these particles contain in three kinds of compositions two or more and are fixed together.These fixing particles are called intermediate coal.

Each raw coal composition has the proportion of feature.In order to illustrate, the proportion of organic materials is about 1.25, and stone proportion is about 2.85, and pyrite proportion about 5.0.Former coal charge contains the particle that many proportions are arranged, because three kinds of independent components are different with the proportion of the combination component that is fixed together.

Because dense media is selected to coarsegrain coal charge particle, effective greater than those of about 0.5mm granularity, therefore general it be not used in coal particle than small grain size.In this respect, be unsatisfied to granule coal charge separative efficiency.Therefore, buckwheat coal often discards.

Be with the raw material crushing or pulverize raw material by improving one's methods of separation coal in the non-coal material so that in intermediate coal, tell high-purity coal and non-coal material.In general, the particle mean size of former coal charge is littler, then tells more coal and non-coal material, and the particle percentage of forming intermediate coal just reduces, and can reclaim more product of coal.Crushing and grinding coal charge does not have practical application with the method for telling with the fixing coal of non-coal material in intermediate coal, because do not have a kind of effectively by the processing fine powder method of separating coal in the non-coal material.Therefore, thus intermediate coal charge or drawn make clean coal and in coal fuel, introduce pyrite or other useless mineral or quilt and be can be regarded as the ore dressing slag and cause undesirable coal losses.But it is unpractiaca pulverizing a kind of coal charge completely and be expensive and industrial.The expense of pulverizing is big, thereby will require to be reduced to this.

As mentioned above, for by reclaiming coal in the intermediate coal, must pulverize intermediate coal, then by separating coal in the ore dressing slag to produce high-purity product of coal.If intermediate coal is no longer handled with further recovery coal, then a large amount of available coal in intermediate coal discards with non-coal material.Therefore, reclaim the clean coal product, main is to develop a kind of method for concentrating that is designed to handle the former coal charge of small grain size the biglyyest.

The United States Patent (USP) 4364822 of the Rich that announce December 21 nineteen eighty-two has been described a kind of coal cleaning method, and this method comprises that second cyclone separates, and it produces three kinds of products, clean coal, ore dressing slag and intermediate coal.Pulverize intermediate coal then and recycle the cyclone that stimulates the menstrual flow with former coal charge.But Rich particularly points out, and based on the problem that reclaims the magnetic particle is arranged, he breaks away from the dense media method of using the magnetic particle.

The United States Patent (USP) 3908912 of the Irons that on September 30th, 1975 announced has been described a kind of method, and according to this method, the ore dressing slag just separates when high density at first, then passes through more low-density separation to produce clean coal and intermediate coal.Pulverize intermediate coal then with further cleaning.But in the patent of Irons, can not isolate small-particle coal in by coal charge before initial high-density separation, this causes that other ore dressing slag is arranged in the clean coal product.Moreover Irons has disclosed cyclone, and to separate little coal dust be invalid, because particle usually misplaces.Like this, Irons points out, will use the secondary eddy flow to eliminate the ore dressing slag in the coal after flotation.

Carried out many trials to clean fine particulate coal, various result has been arranged.In the dense media eddy flow, when the coal charge particle separative efficiency that diminishes is just fallen.Particularly, when coal charge granularity during, clean quite difficulty of coal charge less than about 0.5mm.When the coal charge particle diminished, selected back was also more difficult by reclaiming the magnetic particle in the dense media.

Thereby needing a kind of effective method with selected coal charge particle less than about 0.5mm granularity, its separative efficiency is to be enough to make product of coal to have desired specification.The separative efficiency of coal washing process usually illustrates as distribution curve by known probability curve.These curve descriptions the given particle in raw material be the coal cleaned of inclination rather than the probability of waste residue.The slope measurement value of the vertical component of distribution curve is the probable error of separating, or Ep.The core that separates curve more then separates more effectively, and probable error is littler.

For fear of with clean the relevant difficulty of small size particle, manyly be used to handle duff particle method and before selected (generally be meant and remove sludge), discard the particle that is lower than the limit value granularity.Remove sludge is based on method for concentrating on convention restriction.For example, United States Patent (USP) 3794162 that announced on February 26th, 1974, people such as Miller discloses a kind of a kind of dense media method for concentrating that is used for low to 150 sieve apertures (0.105mm) particle.To before selected, sift out less than the particle of 150 sieve apertures by the dense media eddy flow.The United States Patent (USP) 4282088 that on August 4th, 1981 announced discloses a kind of method, wherein separates in the rotational flow sorting device less than the particle of 0.1mm, and discards by heavy medium cyclone before selected.When the particle that all is lower than 0.1mm or 0.105mm granularity is all removed, the pure coal of then little coal particle and the pure coal that is fixed in the little intermediate coal particle are also all removed.

The ability that removes sludge with screening or screening is to be limited to the used sieve and the structure of scalping.The material that screening or screening are lower than about 150 sieve aperture granularities in a large number is unpractiaca.Come the classifying cyclone of separating particles to be used to the coal raw material of classifying based on the variable grain sinking speed, but be invalid for the grain-size classification of 0.015mm coal charge.The just coal particle of minimum in former coal charge that abandons, and major issue has appearred on the 0.015mm grade or littler particle.Particle less than this granularity mainly is the slag that will abandon.

A size that parameter is a charging aperture of not too noting in cyclone design enters cyclone by this mouthful coal charge.(Krebbs Engincers 1976) Arterburn points out in a literary composition that is entitled as " size of hydrocyclone ", the area of charging aperture often cyclone material chamber area 6%～8% between.The improvement of charging aperture diameter does not determine it is the factor of improving the classifying cyclone separating power.

Be used for the classification of starch by the multistage classifying cyclone of adverse current circuit arrangement.The United States Patent (USP) 4282232 of the Best that on August 11st, 1981 announced has been described a kind of a kind of adverse current cyclone loop of washing starch and designing that is mainly.Known to the inventor, the counter-flow arrangement of classifying cyclone is also had no talent and was implemented in coal washing industry, and is not used in the particle that separates 0.015mm and littler grade.

In coal industry, once attempted getting rid of the steps necessary that removes sludge by improving dressing process.For example, on February 7th, 1989 was announced, and the United States Patent (USP) 4802976 of Miller discloses a kind of method, wherein, used froth flotation method to reclaim the coal particle underflow less than 28 sieve apertures (0.595mm) of heavy medium cyclone.But this method is not suitable for all coals.Former coal charge usually contain can not be floating oxidized coal.Pyrite also can be floating with clean coal, thereby polluted clean product of coal.Designing a method, to handle the duff grain of all types, and partly remove pyrite by minimum particle size effectively, is inconvenient.

With the selected cyclone that is used in combination of dense media various grain size parameters are arranged, and can run into various operating condition.In general, when cyclone was used for selected small size particle, it was not to move effectively.In small-particle coal was selected, the problem of using cyclone was to guarantee that particle correctly or equally with the ore dressing slag move towards underflow or equally with coal move towards overflow.Granule often misplaces, thereby has reduced efficiency of hydrocyclone.

A cyclone parameter is that former coal charge enters the inlet area that cyclone passes through.The United States Patent (USP) 2819795 of the Fontein that announced on January 14th, 1958 disclose a kind of cyclone design, and its inlet area calculating is equivalent to be used between 0.1～0.4 times of overfall area.Fontein also particularly points out, and cyclone diameter is 2～3 times of overflow diameter.Fontein does not discuss the relation of inlet diameter and cyclone diameter or particle speed.The United States Patent (USP) 4341382 of the Liller that announces July 27 nineteen eighty-two discloses the design of one 18 inch diameter cyclone, wherein the inlet tube diameter calculate be equivalent to cyclone diameter 0.25～0.35 between.

People's such as Fourie " with the selected duff grain of heavy medium cyclone " (Journal of South African Institute of Mining and Metallurgy, 357～361 pages, in October, 1980) disclose with the dense media rotational flow separation to use magnet grains in the selected negative 0.5mm coal grain, wherein at least 50% magnet is less than 10 microns (0.010mm).But the magnet granularity is littler, and then more difficulty, valency are higher by just reclaiming in the coal of cleaning and the ore dressing slag.Fourie discloses by the arrangement of roughly selecting device-washer-remover of wet drum magnetic separator and has reclaimed magnet, and has reported the serious problem of magnet loss.Thereby a method must be arranged, it uses the magnet that is small enough to effectively separate Bed for Fine Coal and ore dressing slag, and can fully reclaim magnet in selected back.

The used magnet of Fourie makes by grinding magnetic iron ore.But is very expensive with ore grinding to ultra-fine granularity, and grinds control that grain graininess is distributed seldom.Be used for that magnet that dense media separates also can produce by the red iron-stone of electronation.On March 13rd, 1984, United States Patent (USP) 4436681 that announce, Barczak separated a method, will be reduced to magnet by the red iron that spray roasting iron chloride prepares.But Barczak does not discuss the problem that the granularity of magnet does not recognize that the magnet removal process is run into after dense media separates yet.

The patent 4777031 of the Senecal that on October 11st, 1988 was announced discloses a method, and wherein magnet is to carry out pyrohydrolysis by iron chloride under the temperature between 1000 ℃～1600 ℃ to produce.Yet Senecal is direct production granularity to be 0.02～0.2 micron (magnet between the 0.00002mm～0.0002mm), it is applicable to adhesive system very much, as is used for magnetic recording medium.The method of Senecal makes magnet grains too thin, and the dense media that can not be used for coal effectively separates, and is in-problem because will reclaim so little particle after dense media separates.

Be used for the magnet that dense media separates, general regeneration reclaim be by at first on sieve by the medium of draining in the product that separates, then at the dillying product to remove the magnet that stays, then by telling magnet by magnetic in flushing water, the diluent media.But when washing fine granularity coal particle, sieve can not be effectively kept coal and washup slag here from medium of flowing through together and flushing water.These Bed for Fine Coal and non-coal material have stain dense media, and separate in being difficult in common magnetic drum separator by magnet.

Another difficult problem that reclaims the small magnet particle is to be difficult to separate by discrete magnets in the flushing water with magnetic.The United States Patent (USP) 4802976 of the Miller of on February 7th, 1989 bulletin has proposed by reclaiming magnet by hypostasis in the bubble cell, thereby has avoided the duff grain carried secretly by magnet in magnetic separates and the problem of non-coal grain.But the froth flotation system is complicated and is difficult to operation.Magnetic separator combines with high density gradient magnet and is applied in the basement rock design and can uses.But high density gradient magnet is expensive, and the basement rock separator is compared complicated operation with habitual magnetic drum separator.Thereby be necessary a kind of effective separation method, be easy to use the magnetic separator of operation and design that magnetic is separated more economical.

In order to satisfy public utilities burning needs, must dewater to reduce its water content by the selected clean product of coal that gets.Bed for Fine Coal is because its bigger surface area ratio more is difficult to dehydration than the coarsegrain coal.

According to top described, necessary to improving one's methods of selected Bed for Fine Coal is to make desired specification, as sulfur content, and can be gratifying.Described to hinder and carried out many problems that a kind of method produced like this, and these problems are difficult to deal with.Need a kind of method, it can make coal reclaim the expense that reaches maximum and do not pulverize whole coal charges.And, must improve based on the coal grain stage division of granularity, particularly use the method for classifying cyclone.In the high flow capacity heavy medium cyclone, require to improve the separative efficiency of Bed for Fine Coal.The magnetic grain that must have method to reclaim effectively after dense media separates in order to the ultra-fine granularity of regeneration separates the life-span with the dense media that improves Bed for Fine Coal.Improved method also must be produced the magnetic grain of suitable granularity and be separated so that reach good dense media when maximum reclaims the magnetic grain.

According to one embodiment of the invention, a kind of method is provided, selected Bed for Fine Coal is with the acceleration that improves particle and strengthen separating effect in the heavy medium cyclone of particular design.Former coal charge at first sieves and is rough coal and duff part.Rough coal partly is divided into clean coal, intermediate coal and ore dressing slag.The middle rank coal dust is broken to carry out selected with the duff part.The duff part removes sludge in counter-current fractionation eddy flow loop, be divided into many parts according to granularity then before the dense media rotational flow separation.

Dense media contains the ultrafine magnetic grain of narrow size distribution, and it helps to separate and the magnetic grain that improves subsequently reclaims.The magnetic grain is reclaimed respectively by clean coal and ore dressing slag part.It is to carry out in the recovery unit based on the particular design of granularity that the magnetic grain reclaims; this unit have the draining more generally that is applicable to thicker part and divides-and-purging method, and separate at last in the loop at the device-washer-remover of roughly selecting of the wet bulging magnetic separator that is combined with high strength rare earth magnet.Total coal treatment loop can be settled like this, goes in the loop so that the non magnetic effluent that comes in the magnet recovery system by the rough coal part that may contain some the thin magnet that does not reclaim finally flows to the device-washer-remover of roughly selecting of all thin magnet of effective recovery.

An advantage of the invention is that it constitutes a kind of effective ways that are used for selected less than the 0.5mm coal particle.The advantage of a scheme of the present invention is that it provides a method that is used for feed coal being removed before selected sludge, and it makes the coal amount that abandons as sludge drop to minimum and helps subsequently magnetic grain to reclaim and the dehydration of product of coal.

According to a scheme of the present invention, a method is provided, its use is a kind of to have the classifying cyclone of inlet area in particular range with the classification ultra-fine grain.In another program of the present invention, provide a kind of method by using the multistage classifying cyclone granule of classifying by particle size.Relate to by classifying cyclone and make particle be assigned to overflow and underflow, think that classification is according to subsidence velocity, and subsidence velocity is not only by particle size influences but also by other particle parameter, comprise the influence of particle proportion and shape as being described by granularity.Another program provides a method, is used for the magnetic particle of dense media rotational flow separation with recovery, comprises that screening and classification coal charge become the narrow granularity part that is used to handle.

According to a scheme of the present invention, a method that is used for selected very thin coal grain is provided, carry out dense media by the magnetic grain that uses a kind of specific particle and size distribution and separate.According to another program, magnet produces by red iron reduction, and this magnet has dense media to be separated desired character and improved the recovery after the separation.According to another program, a kind of method that dense media separates very thin coal grain in cyclone is provided, the size of its inlet area is within particular range.

According to another program of the present invention, provide a kind of dense media that is used for to separate the method that the magnetic grain is reclaimed in the back, to reclaim the non magnetic effluent that comes in the unit by the magnet of the big-particle-granularity coal part that contains not two kinds of the clean coal that reclaims and magnet sends in the loop of handling less-granularity coal part, this loop uses a kind of magnet of roughly selecting device-washer-remover to reclaim the loop, all magnet is captured almost in this loop effectively, also reclaims coal simultaneously.According to another program of the present invention, provide a kind of method of using the wet method drum magnetic separation of rare-earth magnet.Provide a kind of according to another program, be included in adding paper fiber in the coal the very thin coal grain dehydration and the method for agglomeration.

The accompanying drawing summary

Figure 1A and Figure 1B are the flow charts of a scheme of the inventive method.

Fig. 2 is the flow chart that the high density of the rough coal of three kinds of products of description generation is separated with low-density.

Fig. 3 describes coal charge based on the tripartite flow chart of size sieves.

Fig. 4 schematically describes the schematic flow sheet of dense media separation back to the magnet recovery loop of big-particle-granularity part of negative 0.5mm coal charge.

Fig. 5 schematically describes dense media to separate the schematic flow sheet of back to the magnet recovery loop of the less-particle-granularity part of negative 0.5mm coal charge.

Fig. 6 is the curve map of expression magnet types to the influence of magnet recovery.

Fig. 7 is the influence curve figure that explanation separates coal charge at the heavy medium cyclone medium velocity.

Fig. 8 is that explanation speed is to the influence curve figure by the next clean product of coal quality of dense media rotational flow separation.

Fig. 9 represents the distribution curve figure of the coal charge part classification of 28 sieve apertures * 150 sieve apertures.

Figure 10 is illustrated in the curve map of the influence that magnet grains size distribution in the heavy medium cyclone separates coal charge.

Figure 11 represents the influence curve figure of magnet grains size distribution to the clean product of coal quality that got by the dense media rotational flow separation.

The present invention relates to by using the method for the selected fine particulate coal of dense media separation method.Particularly, the present invention includes a kind of method that is used for selected less than about 0.5mm Paniculate coal particle.Method of the present invention produces a kind of unexpected clean product of coal, high calorific value, low ash content and low rate and inorganic sulphur content is arranged.The inventive method can be used for producing a kind of product of coal of cleaning, and it has desired radiation specification during burning.Found a kind of improved product of coal, it can be produced by using following one or more method, and each method below the most handy.

Tell

In a scheme of the present invention, before selected, by telling pure substantially coal and high grey ore dressing slag in the former coal charge.Rough coal (coal of 0.5mm granularity at least) is relatively to be easy to clean and gratifying coal washing method is known in industry.It is complicated cleaning duff (granularity is less than the coal of 0.5mm).For example, little beans separates much more difficult in the dense media eddy flow, because granule has high surface area and stands high sticking resistance, and because dense media did not design for this particle often being used to.Thereby remove clean rough coal earlier before being preferably in the separation coal fine powder.

A kind of method of handling the duff grain comprises thick intermediate coal dust broken so that to produce coal be favourable by dividing in the non-coal material.Owing to be to have improved to the care of environment and this necessity that requires of regulations recently.It is no that coal electricity factory when not having expensive cleaning of high sulfur content is arranged.But pulverizing is expensive, moreover cleaning the gained duff is that valency is high.Therefore to make to pulverize and reduce to minimum.

The inventive method provides a kind of valid approach with by telling especially clean coal grain in the rough coal material and not having the ore dressing slag of coal basically.After removing thick clean coal and ore dressing slag, have only intermediate coal partly need pulverize further to handle as Bed for Fine Coal.Like this, the advantage of method has the useful load that reduces on the Bed for Fine Coal separator, reduces cost and the duff amount of minimizing in final clean product of coal pulverized.

In the method for the present invention, by any suitable method, preferably use sieve method, former coal charge is divided into thick and thin part by granularity.Separating is to carry out between about 0.25mm～about 1.0mm in granularity preferably, more preferably between about 0.6mm～about 0.4mm, and preferably in the granularity of about 0.5mm.Coal on the sieve carries out the dense media separation then, preferably by the dense media rotational flow separation, makes especially clean product of coal tell as the overflow product at low-gravity.Best, the overflow product contains the coal at least about 95%.Preferably partition density is not more than 0.1 proportion unit above pure coal proportion to be processed.Partition density is meant the proportion of equal probabilities, and the material grain with the density that is equivalent to that proportion will turn towards overflow or underflow.For example, to the bituminous coal of 1.25 proportions, it is about 1.35 that partition density will be lower than, preferably about 1.30, and to the anthracite of 1.55 proportions, partition density will be lower than 1.65, and preferably about 1.60.

The underflow product that this initial stage separates preferably will carry out once other dense media separation, preferably by the dense media rotational flow separation, make non-coal material to remove as the underflow product in such high specific gravity.The separation proportion of this dense media separation for the second time surpasses about 0.5 the proportion unit of pure coal proportion at least, and surpasses the about 0.75 proportion unit of pure coal proportion better at least.This underflow product does not have coal basically and removes as the ore dressing slag.Preferably the underflow product contains and is less than about 25% coal.More preferably be less than about 15% coal.On the other hand, separate the back coal charge by low-gravity and can carry out a high specific gravity separation.

The overflow product that high specific gravity is separated comprises and contains coal and non-coal material, becomes the intermediate coal of the bond of grey mineral with other as pyrite.These coals and non-coal material are fixed in the intermediate product of coal together.To from the non-coal material of intermediate coal, divide and produce coal, must be broken, to grind or pulverize intermediate coal be the fine grained granularity, preferably less than the 0.5mm granularity.After the pulverizing, the intermediate coal after will telling is then handled with the Bed for Fine Coal of being come out by the preliminary screening of coarse component.

For guaranteeing do not have coarse grain, the intermediate coal of pulverizing can be recycled to former coal charge logistics so that the screening step of stimulating the menstrual flow preliminary again with passing through with the pulverizing middle rank coal that Bed for Fine Coal is handled.By the minus mesh of screening step, comprise the intermediate coal of pulverizing, in the separative element of particular design, handle with the processing Bed for Fine Coal.If any requiring, Coarse Coal can be divided into a plurality of parts by screening with before high proportion separates low, and these a plurality of parts carry out separately low with high density separation so that produce coal by dividing in the non-coal material.Owing to handle coarse grain and Bed for Fine Coal respectively, and owing to only pulverize intermediate coal, above mentioned advantage can realize.

As illustrated in fig. 2, clean coal and ore dressing slag are by telling in the former coal charge.Former coal charge 80 is the sieve screenings 82 at 0.5mm.Reclaim minus mesh 84 and deliver to the dense media rotational flow separation loop 85 that is used for little beans.The oversize of being made up of positive 0.5mm particle 86 carries out the dense media separation first time 88 at about 1.3 low-gravities.Clean coal 90 as the first time dense media separate 88 come-up product and shift out.Carry out the dense media separation second time 94 by the dense media separation first time 88 sinking products 92 that obtain in about 2.0 high specific weight.High specific gravity sinking product 100 is removed as the ore dressing slag.The come-up product 96 of dense media separation for the second time 94 will pulverize 98.Milling product 102 will carry out another screening 82 up to the granularity of whole coal charges less than about 0.5mm, thereby enters the dense media rotational flow separation loop 85 that is used for little beans.

Screening and classification

In another program of the present invention, before cleaning, the particulate coal charge is distributed into the different grain size part.Cleaning performance has improvement in the operation of separating based on proportion, as use the dense media rotational flow separation when handling the coal charge grain of narrow size distribution.Distinguishing the fine granularity coal is a kind of effective ways of a plurality of superfine granularity parts, can more effectively separate the fine granularity coal.

Before differentiation, coal charge is made the fine granularity coal.The fine granularity coal charge preferably sieves and is the granularity less than about 0.25mm～about 1mm, and is preferred less than about 0.4mm～about 0.6mm, and most preferably less than about 0.5mm; Preferably, coal charge is the above-mentioned undersize of telling operation.

In the method for the invention, coal is divided at least three granularity parts, and preferably is divided into three granularity parts so that magnet thereafter reclaims and improve the cleaning performance of cyclone.Particularly, coal is preferably in the grading of about 0.044mm～about 0.150mm, more preferably in about 0.085mm～about 0.125mm granularity, and most preferably at about 0.105mm(150 sieve aperture) granularity, can be by any suitable method classification, for example by using a kind of fine pore sieve, preferably a kind of Krebs Varisieve ^TMSieve classification.Less than above-mentioned granularity, most preferred coal less than about 0.105mm will can reclaim with the clean product of coal that causes improvement being convenient to further classification on the granularity that minimum particle size partly allows to discard.Classification is preferably carried out on about 0.037mm～about 0.005mm granularity, preferred at about 0.025mm～about 0.01mm, and, then often can remove sludge with above-mentioned classification most preferably at about 0.015mm, in clean product of coal, there is the sludge of capacity to be harmful to.

In the past, by removing some small size particles in the coal charge, this is because the limitation of method for example, has the loss of fine grained material during dense media eddy flow cleaning enforcement before selected.The minimum particle size part of removing comprises and has removed the particle of comparing with the present invention than coarsegrain.Have only the coal of minimum granularity part to discard in the present invention, for example, granularity is less than the sludge of 0.015mm.

In general, separate, be difficult to separate less than the sludge of about 0.015mm with dense media, and often in refining process conduct abandon product.Before dense media separates, remove these sludges and have in uncomplicated relatively technology and remove the advantage that contains high ash particle, the advantage that reduces useful load is arranged on the dense media separator simultaneously.In addition, sludge has odiously increased the hydropexis amount of clean coal, has hindered by reclaiming magnet in the dense media and causing slagging scorification in the boiler when the burning.

In the scheme of the present invention, remove in the duff material and finish by using classifying cyclone less than about 0.015mm particle.Preferably, the classification loop comprises a series of classifying cyclones, and more preferably, the classification loop is to flow back to the road by countercurrent liquid to arrange.The advantage of the inventive method is, remove minimum granularity particle by classification in classifying cyclone and can cause high productive capacity, it is peaceful with 10 that " diameter cyclone and the cyclone than minor diameter that need not usually use in the minimum granularity particle of classification are as the cyclone of 1 " or 2 " diameter.

When using a kind of classifying cyclone with the minimum granularity coal particle of classification, as the particle of 0.015mm granularity, great majority greater than the grain flow of partition size to the underflow product and most of smaller particles by and the same pro rate of fresh water (FW).When the multistage classifying cyclone of use, preferably at least three series connection, preferably, classifying cyclone is to settle by countercurrent liquid stream, so that fresh water (FW) is flowed by the rightabout that former coal particle advances.For example, the end liquid stream that contains the first order classifying cyclone of rough coal grain flows to second level classifying cyclone, and the second level classifying cyclone underflow that contains the rough coal grain flows to third level classifying cyclone.The overflow of the classifying cyclone of moisture and sludge is then opposite, the overflow that is third level classifying cyclone flows to second level classifying cyclone, the overflow of second level classifying cyclone flows to first order classifying cyclone, and the overflow of first order classifying cyclone is delivered to ore dressing slag thickener to discard.By this method, in containing the coal grading cyclone of minimum sludge, use the cleanest water, and use the dirtiest water to separate the heaviest sludge.

By illustrated in fig. 3, raw coal 110 is delivered to first VariSieve ^TM112 to sieve at 150 sieve apertures (0.105mm).First underflow 114 flows to first storage tank 116.First overflow 118 flows to second sieve 120 to sieve at 150 sieve apertures again.Second underflow 122 also flows to first storage tank 116 that now contains negative 150 sieve aperture raw coal.Second overflow 126 is reclaimed and is delivered to and is used for the dense media rotational flow separation loop 128 of big-particle-granularity coal.

The raw coal of bearing 150 sieve apertures by first storage tank 116 is delivered to first pump 130, and it pumps into first order classifying cyclone 134 with screening again on 15 microns (0.015mm) with first charging 132.Now contain the overflow 136 of the first order classifying cyclone 134 of sludge, discharge with the ore dressing slag.The underflow 138 of first order classifying cyclone 134 is delivered to second storage tank 140 by second level pump 142.Second level pump feed 144 is delivered to second level classifying cyclone 146, to sieve at 15 microns again.Second level classifying cyclone 146 is told overflow 148.Part and first order VariSieve ^TM112 overflow merges further to handle by second sieve 120.The remainder of second level overflow 148 is incorporated underflow 122 into, flows to first storage tank 116 therefrom.The end liquid 150 of second level classification eddy flow 146 is delivered to the 3rd storage tank 152 by the 3rd pump 154.Purify waste water and 156 be added to the 3rd storage tank 152.The 3rd pump feed 158 is delivered to third level classifying cyclone 160 further to sieve at 15 microns.

The overflow 162 of third level classifying cyclone 160 combines with further processing with first order classifying cyclone 134 underflows 138.Underflow 164 third level classifying cyclone 160, that take advantage of the particle of 150 sieve apertures to make by 15 micron granularities is reclaimed and delivers to the dense media rotational flow separation loop 166 that is used for less-particle-granularity coal.

The dense media rotational flow separation

A cyclone design parameter

According to the solution of the present invention, be selected in a heavy medium cyclone less than the coal of 0.5mm granularity, this cyclone has specific improvement to overcome and to clean the relevant problem of fine granularity coal particle to the design of cyclone.With the problem of common cyclone is to be that the acceleration of coal in the cyclone and ore dressing slag is too weak so that can not give fine-grained particles with suitable speed, the result, and this particle is the flow direction or underflow or overflow inadequately.Separation weakness in the cyclone of common usefulness is that less coal and the bigger particle of ore dressing solid impurity particle has bigger liquid resistance or hydraulics resistance.This problem also runs in the classification nano sized particles based on granularity in classifying cyclone.To suitably separate and increased the back wash effect of resistance must for to overcome a kind of bigger acceleration of particle.

Therefore, in the concrete scheme of the present invention, by having carried out improving one's methods of a kind of selected fine granularity coal in the dense media rotational flow separation.In this scheme, hydrocyclone structure, the inlet area especially for flowing into cyclone material chamber is modified as like this by common cyclone, to cause its about 0.01 times less than inner room diameter square.Preferably, make the inlet area of liquid stream be not more than 0.0096 times of the indoor footpath of cyclone material square, but be not less than 0.0048 times of the indoor footpath of cyclone material square.Reduce inlet diameter, the same flow velocity before keeping reducing inlet diameter then increases the entrance velocity of feed liquid, has increased the acceleration that the cyclone endoparticle stands successively.Be increased in the endocorpuscular acceleration of cyclone and just improved separative efficiency.In a preferred version, selected is to carry out in such cyclone: the internal diameter of cyclone material chamber is that about 10 inch and the inlet area that is used for liquid stream are not more than about 0.96 square of inch and also are not less than about 0.48 square of inch.

Found that similarity relation between liquid inflow entrance area and cyclone material chamber diameter improves based on the classification performance in the cyclone of the classification nano sized particles of granularity.When separating coal and non-coal material with dense media, the cyclone classification efficient that is used to separate the different grain size particle is when other parameter equates, it increases along with the increase of particle acceleration.

The froth flotation system that an advantage of the invention is use dense media method for concentrating and need not be difficult to keep can clean fine particulate coal effectively.Compare with froth flotation method, because be not that whole coals are all floating in froth flotation, the dense media rotational flow separation is the advantage that the separative efficiency aspect is arranged.In addition, pyrite can be floating with clean coal in froth flotation, thereby make the sulphur that is contained in the pyrite stain clean coal.

In general, increase the separating effect that particle quickens to improve little beans, still, the increase particle quickens and does not reduce inlet area and also can reduce the holdup time of particle in cyclone.The undue short holdup time can be reduced the effect of separation.In a preferred version of the present invention, entrance velocity was 30 Foot/seconds at least, was more preferably for 60 Foot/seconds, and most preferred be 90 Foot/seconds.Select the flow of cyclone will make it have enough holdup times to reach effective separation.Preferably, flow is the industrial design normal flow that is bordering on specific cyclone.In case suitable entrance velocity and flow are selected, then inlet area can determine with following relational expression: flow=inlet area * entrance velocity.It will be understood by those skilled in the art that at the real run duration of cyclone flow normally presses measurement to calculate with known relation based on liquid stream.

B uses ultra-fine magnet as dense media

In the dense media dressing process, being chosen in the material that is easy to after selected remove from coal or ore dressing slag is favourable as dense media.Like this, the dense media material can recycle and reuse repeatedly.If select the magnetic particle to be used for dense media, use the method for the advantage of utilizing its small grain size and magnetic susceptibility to reclaim in selected back and reuse these particles.Here used magnetic particle is those particles that the enough magnetic devices of energy effectively separate, and comprises ferromagnetic or ferrous magnetic particle, as magnet, ferrosilicon, the red iron of magnetic.

As noted, the dense media that is used for the dense media separating technology often contains the magnetic-particle that is suspended in water.The suspension of magnetic-particle makes that the solid that will separate is floating to be similar to uniform fluid, as long as the grain graininess that will separate is than much bigger at the magnetic particle of dense media.

The problem of cleaning small size particle with dense media is the ore dressing slag underflow that clean coal particle can flow to cyclone inadequately.This problem is because the granularity difference between coal particle that will separate and dense media particle reduces caused.When coal particle becomes the proportion media particle more hour, the coal particle that separate will be freed buoyancy thereby sinking.It is floating in the mode that is similar to uniform heavy-fluid body that dense media stops the particle that will separate.Like this, the dense media particle of ultra-fine granularity must be arranged from the ore dressing slag, to separate fine granularity coal grain effectively.

A beyond thought result of the present invention is, the size distribution by keeping ultra-fine magnet grains has also been improved dense media and separated Bed for Fine Coal in a narrow particle size range.The narrow distribution of this magnetic grain graininess also causes separating the recovery that the magnetic grain is strengthened in the back at dense media.

In the scheme of the present invention, dense media is by water and ultra-fine magnetic grain, and the suspension of preferred magnet grains is formed.Preferably, at least about 65%(weight) the granularity of magnetic grain be about 2 microns～about 10 microns, and be not more than about 10%(weight) the granularity of this magnetic grain less than about 2 microns.Preferred, at least about 75%(weight) the granularity of magnetic grain be about 2 microns～about 10 microns, and be not more than about 10%(weight) this magnetic grain granularity less than about 2 microns, be not more than about 25%(weight) magnetic grain granularity less than about 3 microns and also at least about 10%(weight) magnetic grain granularity greater than about 7 microns.

The production of the ultra-fine magnet of C

In the scheme of the present invention, be used for a kind of ultra-fine magnet that coal charge dense media method for concentrating produced and be less than about 0.5mm sized granules.The magnet of industrial preparation can not separate Bed for Fine Coal and ore dressing slag too greatly effectively.Will separate the low coal that reaches about 0.015mm effectively, the granularity of magnet grains preferably is less than about 0.010mm, and 50% the particle of preferably will having an appointment at least is less than about 0.005mm granularity.Find to produce a kind of high-quality magnet with the inventive method, most of particles are less than about 0.010mm, and preferably are lower than about 0.010mm at least about 90%.

Two kinds of methods that are used to produce ultra-fine magnet are:

(1) produce red iron by pyrohydrolysis spray roasting solution of ferrous chloride in air, then the red iron of electronation is magnet.The reaction of this method is:

(a) produce red iron by the pyrohydrolysis of iron chloride

(b) by using hydrogen or carbon monoxide, perhaps both and to reduce red iron be magnet:

(2) under the condition of limit air, directly make magnet by the solution of pyrohydrolysis spray roasting frerrous chloride.The chemical reaction of this technology is:

Preferably the concentration of product gas will be restricted to like this ratio of the concentration of reacting gas, makes red iron revert to magnet and be no more than magnet to ferrous oxide, FeO, or even metallic iron.

Preferably, by the reduction of red iron or direct heat hydrolysis to magnet and the production magnet grains is under reducing condition, comprise the crystal growth of controlling the magnet of producing and the holdup time and the temperature of appointment, gained magnet preferably has top B and saves described narrow granularity and distribute.

In the scheme of the present invention, by pyrohydrolysis, with frerrous chloride in air spray roasting to form red iron.Then will be with reverting to magnet during the temperature and time of red iron foot that spray roasting produced with the crystal growth of restriction magnet.Preferably, under about 900 ℃～about 1000 ℃ temperature, and more preferably about 980 ℃～about 1000 ℃ down magnet grains is in narrow size distribution and do not reduce the separative efficiency of the dense media separation method that uses magnet producing the magnet crystal growth reduction red iron a period of times.Preferred size distribution is listed in above B joint.

Any red iron of reduction that is applicable to is that the reactor of magnet can use, as the reacting in rotary kiln device.In a preferred version, the red iron of spray roasting carries out granulation before reverting to magnet.Granulation has avoided before reverting to magnet red iron to be blown the problem of reactor.

Preferably, is magnet with carbon monoxide and hydrogen to reduce red iron with the reduction air-flow that enters the red iron granule stream opposite course the reactor from the burner opposite, and when granule is flowed through reactor chamber, be heated to higher temperature, near the product discharging time, reach maximum temperature.Whole reactor preferably keeps reducing condition, is for example injecting other reducing gas near product discharging end.

In preferred version, the magnet granule is by broken or grind washing and pulverize obtaining the magnetic particle, and it has magnetite particle after a kind of reduction of natural grain particle size fraction.Be appreciated that, preferred size distribution to magnetic grain listed in the top B joint is the granularity of pulverized particles, and preferably pass through washing by for example countercurrent washing or during grinding washing, by removing any soluble chloride in the magnet, particularly nonvolatile alkaline earth metal chloride.

The magnet of producing by the inventive method is being used for that several advantages are arranged when the granule jet selects.Particularly the magnet of producing with the inventive method can reclaim with magnetic method easilier, thereby reduces selected cost because of reducing magnet loss and magnetic separating apparatus necessary amount.Owing to be easy to reclaim magnet, operating cost also reduces.In addition the magnetic grain of producing by the inventive method have narrow size distribution (grain graininess of the granularity of most of particle in the middle of approaching, and quite few particle basically less than or greater than the average grain granularity).This narrow particle size distribution causes improving separative efficiency in the dense media method for concentrating.

The recovery of magnet

In another program of the present invention, reclaim the magnetic grain in selected back respectively in by clean coal and ore dressing slag, preferably magnet.Best, use distinct methods to reclaim the magnetic grain to the clean part of forming by different grain size scope particle.

To the magnetic grain in the flushing water of-granularity coal big by containing or ore dressing solid impurity particle part (for example, contain less than about 0.4mm～about 0.6mm, and greater than about 0.085mm～about 0.125mm), use is discharged and the purging method recovery after magnetic separates.When this big-particle-granularity is partly flowed through sieve, preferably at least two sieve series connection and preferably three sieve series connection, most of magnet therefrom reclaim.Counter current system is preferably used with the flushing of cleaning technology water in the discharging back, and wherein the liquid stream of flushing water is the liquid stream that counters to coal or ore dressing solid impurity particle.Be preferably on the last vibratory sieve by removing other magnet and moisture content in the coal, afterwards by reclaiming magnetic material in dilution or the flushing liquor stream.Preferably will drain the coal of medium and ore dressing slag part by adding entry pulp again, deliver to next sieve then, the big water gaging that has a large amount of magnet here this sieve that stimulates the menstrual flow.The medium of being discharged by first sieve that contains magnet and water can directly be recycled to the dense media basin to be used as dense media in heavy medium cyclone.

-granularity-coal less or ore dressing solid impurity particle by containing, for example contain less than about 0.085mm～about 0.125mm with greater than the part of about 0.01mm～0.02mm particle, it is the comparison difficulty that the magnet grains less than about 0.01mm grain matter that obtains reclaims by draining and purging method, because the sieve and the filter screen that are used for carrying out in 0.01mm～0.07mm particle size range commercial scale particle size separation aspect generally are unavailable.

In a scheme of the present invention, by reclaiming the magnetic grain in the ore dressing slag of less-particle-granularity part and the coal, preferably magnet grains is to reclaim at a series of specific magnetic separators that are used for reclaiming ultra-fine magnetic grain.Think that this debit case is to roughly select device-washer-remover loop.Roughly selecting device is one or more wet method drum-type magnetic separators, preferably three series connection wet method drum separators that have such as the normal intensity magnetic of barium ferrite magnetic.

Coal or ore dressing slag at first flow to and comprise the magnetic separator of roughly selecting the device step.Best, entering coal or the ore dressing slag of roughly selecting the device step is the recirculated liquid diluted stream of using the non-magnetic particle that is come by the washer separator.Dilution has improved by reclaiming magnet in the less-particle of coal and ore dressing slag-granularity part.

The next non magnetic outflow liquid of magnetic particle recycling step by the big-grain graininess part that is used for coal and ore dressing slag still contains a small amount of coal and magnet grains; they can be by before magnetic reclaims; before being preferably in dense media and separating less-particle-granularity liquid stream, described outflow liquid is merged mutually with the process streams of less-particle-granularity and remove.

The magnetic concentrate dilute with water of being separated by the magnetic of roughly selecting the device section, deliver to the washer section then, this washer section is made up of the wet method drum-type magnetic separator that contains such as the ferritic normal intensity magnetic of baric.The magnetic concentrate recirculation of telling in the washer section will be used for the dense media that dense media separates to form.The non magnetic outflow liquid that exists in the washer section can be used as dilution water recirculation, delivers to the feed liquid of roughly selecting the device unit with dilution.

At last deliver to the remover section by the non-magnetic current fluid that contains coal and ore dressing solid impurity particle and still contain a small amount of magnetic particle of roughly selecting that device and washer section obtain.The remover section comprises the wet method drum-type magnetic separator that contains than being used to roughly select device and washer Duan Gengqiang magnetic.Best, the magnetic that is used for remover contains Rare-Earth Magnetic.Best, the drum by the channel narrows of magnetic separator being located the remover separator so that the magnetic grain near magnetic.

The advantage of magnet recovery method of the present invention is the recovery method that is that expense is economized most, promptly discharge and wash to be applied to the place that may use, and only uses the thinnest magnet in the more expensive device-washer-remover loop of roughly selecting.

A kind of magnet that Fig. 4 has described after dense media separates big-particle-granularity coal or ore dressing slag part reclaims the loop.For example, the coal of 0.5mm * 150 sieve apertures (0.105mm) or ore dressing slag part can be handled with this loop.This loop comprises serial washing screen, flows by the mode with coal or washup slag adverse current with fresh water (FW) between sieve.Referring to Fig. 4, the coal or the ore dressing slag part 200 of being come by the dense media rotational flow separation enter first sieve 202, the dense media of venting coal or ore dressing slag here.The medium 204 of discharging is got back to the dense media storage tank in order to using again.Coal on the sieve or ore dressing slag 206 enter storage tank groove 208, at this moment water make coal or ore dressing slag again pulp and with slurry 210 pumps that obtain to first washing screen 212, water and magnet grains 214 are by discharging in coal or the ore dressing slag here.Can comprise that also a kind of jet douche is to remove other magnet.The wet method drum-type magnetic separator 216 that water of discharging and magnet 214 flow to reclaims magnet concentrate 218 here and delivers to overweight agent reservoir to re-use.Still contain cleaning a small amount of magnet, that come by magnetic separator flow out liquid 220 can with less-particle-granularity coal charge part, mix mutually as 15 microns (0.015mm) * 150 sieve apertures (0.105mm) part, preferably enter the thickener (not shown), separate that part of with dense media then.Left magnet is partially recycled by less-particle-granularity.

By coal or the ore dressing slag 222 water pulp again in storage tank 224 of crossing coarsegrain of first washing screen 212, and with gained slurry 226 pumps to second washing screen 228, here water and magnet 230 are by discharging in coal or the washup slag.The water and the magnet 230 of discharging are used for pulp again in first storage tank 208.

The coal of crossing coarsegrain or ore dressing slag 232 by second washing screen 228 flow to storage tank 234 and use clean fresh water (FW) 236 pulp again, and with gained slurry 238 pumps to the three washing screens 240, here storage tank 224 conducts pulp liquid is again discharged and flow to magnet and water 242.

Coarsegrain coal excessively or ore dressing slag 243 by the 3rd washing screen 240 flow to dewatering screen 244, and here the fresh water (FW) 236 with cleaning is sprayed on the dewatering screen to remove and to rinse out remaining magnet.The flushing water 246 that will contain magnet then is used as the liquid of pulp again in the 3rd storage tank 234.Coal or ore dressing residue product 248 are by removing as crossing the coarsegrain refuse in the dewatering screen 244.

Fig. 5 explanation separates the coal of less-particle-granularity or the magnetic recovery loop after the ore dressing slag part at dense media.For example, the coal of 150 sieve apertures (0.105mm) * 15 micron (0.015mm) and ore dressing slag part can be handled in this loop.Referring to Fig. 5, the less-particle-granularity coal or the ore dressing slag 300 usefulness dilution waters 302 that are come by heavy medium cyclone dilute.Dilution water 302 can be produced by many sources, for example, is produced by the non magnetic outflow liquid 306 of the washer section 308 of this method or fresh water or recirculation water (not shown).

The overflow (coal) of the heavy medium cyclone of dilution or underflow (ore dressing slag) 310 enter to be roughly selected device section 312 or flows through three wet method drum separators 314,316,318.Preferred wet method drum separator has normal intensity magnet, for example barium ferrite.320 usefulness dilution waters, 322 dilutions of magnetic thing are also delivered to washer section 308 to handle by a wet method drum separator 324.Preferably this wet method drum separator contains the magnet of a normal intensity.Magnetic concentrate 326 is delivered to the overweight agent reservoir such as the pump of magnetic concentrate, and it can recycle use in next dense-media separator therefrom.As previously described, the non magnetic outflow liquid that is present in washer section 308 can be used as dilution water 302 in heavy medium cyclone overflow (coal) or underflow (ore dressing slag) 300.The unnecessary outflow liquid 332 that needn't be used to dilute can be with delivering to remover section 334 by the non magnetic outflow liquid of roughly selecting device section 312.In remover section 334, using has kicker magnet, as a kind of wet method drum separator 338 of rare-earth magnet with by isolating the magnetic thing 340 that stays in clean coal or the ore dressing slag 342.Magnetic thing 340 by remover section 334 can be recycled to 328 to be used for the dense media separation.Clean coal or ore dressing slag 342 can be delivered to thickener 344.

Dehydration and agglomeration

In another program of the present invention, behind the recovery magnet, this product of coal uses often is used to method, dewaters as centrifugal or vacuum filtration in by clean product of coal.Before coal combustion, dehydration is favourable with the water content that reduces coal.In preferred version, before clean coal partial dehydration, with the paper fiber, preferably the newsprint fiber is added in the slurry of coal and water.Be preferably in that the coal particle granularity is less than about 0.085～0.125mm and greater than about 0.010～0.020mm in this part.Add the paper fiber dehydration is had several improvement, particularly including: (1) increases the reduction of moisture content in dehydration, (2) the coal ball intensity of improvement by being produced with the binding agent agglomeration, or reduce binder amount and the coal ball still has equal strength, (3) improve igniting of coal, (4) increase BTU(British thermal unit (Btu)) and (5) owing to favourable use paper waste material and favourable to environment.

In another program of the present invention, clean product of coal, particularly less-particle-the granularity part, carry out agglomeration with suitable agglomeration technique.

Figure 1A and 1B have described the technological process of a scheme of the present invention.By sieve, sieve by filter screen or other proper method in first sieve unit 2 for former coal charge 1.Oversized particles 4, for example granularity surpasses those of 0.5mm, delivers to high specific gravity separative element 5, this unit comprise by winnowing with a dustpan analyse, the density separation of dense media or other proper method.The hypostasis that is got by high specific gravity separative element 5 discards as ore dressing slag 6.Buoyancy aid 7 flows to and carries out the low-density separative element 8 that dense media separates.Buoyancy aid is removed as clean product of coal 9, adds ultra-fine magnet 62 if necessary.The hypostasis that is got by low-gravity separative element 8 forms intermediate coal 10, it is delivered to pulverize unit 11, and intermediate there coal is broken, grinds or pulverizes, and the intermediate coal 71 that will pulverize merges to handle with former coal charge 1 again.

After low-gravity separates, reclaim magnet and the magnet and the water 12 that reclaim are delivered to thickener 13 by any appropriate method, water 14 is removed here.The magnet of thickening and some water 15 flow to dense media storage tank 16.

Deliver to second sieve unit of sieving particle with sieve, filter screen or other known method by the screenings 3 that first sieve unit 2 is come out.Screenings 20, for example negative 150 sieve apertures (0.0105mm) particle flows to and specifies in the ultra-fine grain granularity, for example, goes up the classification eddy flow loop 21 of classification at 15 microns (0.015mm).Sludge is discharged and is discarded as the ore dressing slag with overflow 22.Fresh water (FW) 23 is added to the classifying cyclone loop 21 of adverse current operation.Underflow 24 is delivered to thickener 13, underflow and by the magnet thickening together of low-density separative element 8.Thickening slurry 15 flows to dense media storage tank 16, can add ultra-fine magnet 61 if necessary here.Slurry 17 by heavy storage tank 16 flows to heavy medium cyclone 25 to be used for the dense media separation.The overflow 26 that contains clean coal flows to magnetic separative element 58, removes magnet in by the wet method drum-type magnetic separator of roughly selecting device-washer-remover arrangement, introduces rare-earth magnet and reclaim to add strong magnet in the remover separator.Clean coal 64 flows to dewatering unit 56, before with centrifuge dewatering, adds paper fiber 66 in coal.Dewatered coal 67 flows to agglomeration unit 68, if necessary, by means of binding agent 69 with the coal granulation.Clean coal ball 70 is discharged as final products.The underflow 27 by heavy medium cyclone 25 that contains the ore dressing slag flows to magnetic separative element 28, and the above-mentioned magnetic separative element 58 that is used for overflow of its operation is identical.Non-magnet ore dressing slag 29 is discharged from magnetic separative element 28 waiting and is discarded.

Merge into 60 and flow into overweight agent reservoir 46 by the concentrated magnet 30 and 59 of magnetic separative element 28 and 58.The dense media 47 of crossing that is got by overweight agent reservoir flows to dense media storage tank 31.Cross dense media 63 and also deliver to low-gravity separative element 8 and dense media storage tank 16 if necessary.

By the oversize 19 of second sieve unit 18, for example 0.5mm * 150 sieve apertures (0.105mm) particle flows to dense media storage tank 31, adds fresh water (FW) 72 and cross dense media 47 to form suitable slurry density in storage tank 31.Used magnet is the ultra-fine grain granularity in dense media storage tank 31, and the granularity of the particle above 60% is between 10 microns and 2 microns.

Slurry 32 by dense media storage tank 31 flows to heavy medium cyclone 33 to carry out the dense media separation.Overflow 34 is draining 36 on sieve at first, and the fresh water (FW) 40 that clean coal 37 usefulness of mistake coarsegrain add is in dillying 39.What come out by purge zone 39 is clean product of coal 41.

The flushing water 42 that will contain magnet grains is then handled in the magnetic separative element 43 that contains one or more wet method drum-type magnetic separators, and by telling magnet in the water.

Reclaim magnet similar method recovery with what just describe by overflow 34 by the magnet in the underflow 35 of heavy medium cyclone 33.Magnet and water is in 49 drainings, discharges liquid 55 and merges with discharge liquid by overflow 38, delivers to dense media storage tank 31 then.Cross 52 flushings 51 of coarsegrain ore dressing slag 50 usefulness fresh water (FW)s.Crossing coarsegrain ore dressing slag 53 discharges from flush loop waiting and discards.The flushing water that contains magnet 54 flows to the magnetic separative element 56 that contains one or more wet method drum-type magnetic separators.Water 58 and 45 from the magnetic separative element is discharged still contains a small amount of magnet, merges into 48 and flow to thickener 13, and the magnet that is come out by thickener continues to flow and reclaim at last by the above on stream.

Embodiment 1

Magnet is produced

Magnet reduces red iron and produces under two different temperatures in the kiln reactor.Red iron charge produces by sprinkling roasting iron chloride by the pyrohydrolysis reaction in advance.Red iron is sent into an end of kiln and obtained the magnet product from the end opposite of kiln.When red iron moves through kiln, heat red iron and reaching maximum near the outlet side temperature.In kiln, inject hydrogen or natural gas to guarantee the reducing environment of whole kiln.By crushing magnet is broken for natural grain granularity and grinds washing if necessary.Measure grain graininess then.

Magnet at first is to produce under the maximum temperature in about 750 ℃ reactor.Secondly, produce under the maximum temperature of magnet in about 1000 ℃ reactor.Table 1 has been listed the grain size analysis of two kinds of magnet products and has been compared.The magnet that produces under about 750 ℃ of temperature is designated as M1, and the magnet that produces under about 1000 ℃ of temperature is designated as M2.

Extremely odd, M2 contains much narrow particle size distribution, about 80%(weight) the granularity of magnet grains at about 2 microns～about 10 microns.M1 has much wide particle size distribution, and only about 50% magnet grains granularity is between 2 and 10 microns.Though the definite reason to this size distribution difference is not understood as yet fully, nor hope is subjected to the restriction of any theory, think that the restriction recrystallization of magnet is enough to make particle size distribution to narrow down in 1000 ℃ of reactions, but recrystallization does not proceed to such degree to produce excessive germination.

As shown in Example 4, in M2 magnet,, be to help heavy medium cyclone to separate relatively not greater than 10 microns particle with less than 2 microns particle.The narrow size distribution of M2 magnet also helps after dense media separates, and the magnet of strengthening separating by magnetic reclaims.Fig. 6 represents the curve map of magnet to the reaction of different magnetic field intensity.Curve shows that the magnet amount that reclaims is the function of electricity consumption stream by the represented magnetic intensity of electromagnet coils in David Tube separator.M2 magnet has bigger reaction to more low intensive magnetic field, thereby is easy to reclaim after dense media separates in magnetic separator.

Table 1

The distribution of magnet grains granularity

Granularity weight % less than

M1????M2

44.0 micron 99.9% 98.0

31.1????98.9????97.2

22.0????93.7????95.2

15.6????86.2????92.1

11.0????75.4????91.4

7.78????67.5????85.9

5.50????59.8????70.0

3.89????51.6????41.1

2.75????38.2????19.8

1.94????21.8????8.2

1.38????11.5????3.2

0.97????3.7????0.5

Embodiment 2

The performance of classifying cyclone

To bear sample classification in the cyclone of different inlet areas is arranged of the Sewickley Seam coal of 150 sieve apertures (0.105mm).Test is " to carry out in the cyclone of diameter 10.Inlet pressure is different to keep that each test is had almost equal charging rate.Charging rate is in the normal range (NR) of industrial design standard to specific cyclone design.The effect that increases acceleration like this on particle separation can be used as velocity function and measures, and the volume flow rate that specific cyclone increases is surpassed the industrial design standard.

The inlet area of being tested is 3.1 squares of inch, 0.96 square of inch and 0.48 square of inch, and corresponding speed respectively is about 16 Foot/seconds, 56 Foot/seconds and 104 Foot/seconds.Table 2 has shown the granularity of particle, and when this granularity, to each test, 50% of the particle of this granularity flows to overflow, and 50% flows to underflow.These test results show that when the constant volume charging rate, when the charging rate increase, then classification produces on littler granularity.

Table 2

The performance of classifying cyclone

Cyclone diameter inlet area entrance velocity partition size

(50% separation)

31.8 microns of 10 " 3.10 " 16 Foot/second

11.3 microns of 10 " 0.96 " 56 Foot/second

5.5 microns of 10 " 0.48 " 104 Foot/second

Embodiment 3

The performance of heavy medium cyclone

Carried out three tests with measure different inlet areas with thereby different entrance velocities, the influence that under almost constant volume flow rate, heavy medium cyclone is separated.Sewickley Seam coal in 150 sieve apertures (0.105mm) * 15 micron (0.015mm) screening " separates in the diameter cyclone 10.For keeping inlet feed liquid flow rate almost equal, change inlet pressure, inlet feed liquid speed is within the industrial design standard concerning specific cyclone, therefore, to Total Test, acceleration is measured the function that the influence that separates can be used as entrance velocity.The inlet area of test is 3.1 squares of inch, 0.96 square of inch and 0.48 square of inch, and its corresponding speed respectively is 20.6 Foot/seconds, 66.6 Foot/seconds and 133.2 Foot/seconds.The dense media that Total Test is contained the M2 magnet shown in the table 1.

Fig. 7 and Fig. 8 combine the result of test.Fig. 7 shows that the yield of clean product of coal is along with increase enters the entrance velocity of cyclone and obviously increase.Fig. 7 shows that also speed is higher, and the percentage that reclaims thermal capacity in the coal charge in clean product of coal is also bigger.Fig. 8 shows that in Total Test clean product of coal is high-quality.Like this, the volume feed rate is constant to increase then that entrance velocity causes increasing the yield of clean coal greatly and the quality of not damaging clean product of coal when keeping.

Carried out another test on the coal charge of 28 sieve apertures (0.596mm) * 150 sieve apertures (0.105mm), its inlet area is that 0.48 square of inch and entrance velocity were 133.2 Foot/seconds.Fig. 9 has shown the distribution curve of test and 0.032 possible error.Good separation coal and non-coal material in the volume feed rate causes by the duff material to the high entrance velocity of cyclone during in the industrial design standard.

Embodiment 4

The influence that magnet types is separated dense media

Use two kinds of dissimilar magnet, M1 and M2 have carried out two tests to measure its separating property.The particle size distribution of M1 and M2 magnet is shown in table 1.The Sewickley Seam coal that use is gone up screening at 150 sieve apertures (0.105mm) * 15 micron (0.015mm) carries out two tests.Two tests " are carried out in the cyclone 10 with almost equal feed rate.Figure 10 and 11 has summarized the result of test and has shown, improves separative efficiency with M2 magnet.The result that Figure 10 shows is yield and the BTU recovery that M2 magnet improves clean product of coal.Figure 11 shows, and is very surprised, uses M2 magnet to improve the quality of clean product of coal, reduces ash and sulfur content and increases the BTU content of clean product of coal.M2 magnet even than M1 bigger average grain granularity is arranged, also shows the improvement separative efficiency.Like this, the size distribution of magnet grains and just grain graininess both influenced the coal separative efficiency and also influenced organic efficiency.

Though described preferred scheme by explanation and embodiment, only one skilled in the art will appreciate that according to the claims qualification, can carry out many changes of the present invention and correction in the scope of the present invention.

Claims (186)

1, a kind of coal preparation method comprises:

A. the material coal is pressed the grain graininess separated into two parts;

B. from the first in two parts of step a (promptly contain big-granularity part), be divided into three one's share of expenses for a joint undertaking parts by density, wherein the subdivision of density minimum mainly contains coal, and the subdivision of density maximum mainly contains non-coal material, and density subdivision placed in the middle contains coal and non-coal material;

C. pulverize described density subdivision placed in the middle;

D. from the second portion in two parts of step a, promptly contain the particle of less-granularity, be divided into three parts at least by grain graininess;

E. from the first in the described part of steps d, promptly contain the part of smallest particles, discharge as the ore dressing slag;

F. remainder, in the dense media separative element, handle respectively,, become clean coal overflow layer and ore dressing slag bottom flow layer to separate each several part with the dense media that comprises liquid and suspended magnetic particles from steps d;

G. separating overflow layer and the bottom flow layer that obtains through dense media from the second portion in the described part of steps d, on filter screen or sieve, discharge water flushing then respectively, then from this flushing water, tell magnetic-particle with magnetic separation method, reclaim these magnetic-particles respectively, this second portion contains big-granularity particle of handling at step f; With

H. separating the overflow obtain and the magnetic-particle in the underflow from the third part in the described part of steps d through dense media, reclaim with magnetic separation method respectively, this third part contains less-granularity particle of handling at step f.

2, the process of claim 1 wherein that the density part of pulverizing through step c of giving placed in the middle further handles with the second portion of step a, this second portion contain than step a first littler-particle of granularity.

3, the process of claim 1 wherein that the subdivision of density minimum of step b comprises the weight at least about 85%() coal.

4, the process of claim 1 wherein that the subdivision of density minimum of step b comprises the weight at least about 90%() coal.

5, the process of claim 1 wherein that the subdivision of density minimum of step b comprises the weight at least about 95%() coal.

6, the process of claim 1 wherein the amount of the magnetic-particle that do not reclaim in step g, be lower than in the material of the magnetic-particle that g set by step per ton reclaims 4 pounds.

7, the process of claim 1 wherein the amount of the magnetic-particle that do not reclaim in step g, be lower than in the material of the magnetic-particle that g set by step per ton reclaims 10 pounds.

8, the process of claim 1 wherein the magnetic-particle total amount that step g and h reclaim, at least about 99%(weight).

9, the process of claim 1 wherein at least about 75%(weight) inorganic sulfur, from described coal charging, separate.

10, the process of claim 1 wherein at least about 85%(weight) inorganic sulfur, from described this coal charging, separate.

11, the process of claim 1 wherein that the clean product of coal of gained contains the gross calorific value at least about 65% described coal charging.

12, the process of claim 1 wherein that the clean product of coal of gained contains the gross calorific value at least about 80% described coal charging.

13, the process of claim 1 wherein that the magnetic of step g and h separates, and is made up of the separation in wet method drum-type magnetic separator basically.

14, the process of claim 1 wherein that feed coal is divided into described two parts at step a, the particle that wherein said first is contained, at least 90% greater than the 0.5mm granularity, and the particle that described second portion comprises, at least 90% less than the 0.5mm granularity.

15, the process of claim 1 wherein feed coal at step a separated into two parts, the particles contained granularity of described first greater than about 0.25mm～1mm, the particle that described second portion contains is less than the granularity of about 0.25mm～1mm.

16, the method for claim 1, wherein from the second portion of step a, be divided into two subdivisions by grain graininess, first subdivision in these two subdivisions contains the particle of big-granularity, and handle according to handling from the same way as of the described first of step a to step h with step b, second subdivision of described two subdivisions is handled according to handling from the same way as of the second portion of step a to step h with step b.

17, the method for claim 1, wherein from the described second portion of step a, be divided into two subdivisions by grain graininess, first subdivision of these two subdivisions contains particle greater than about 0.4mm～0.6mm, and second subdivision of described subdivision contains particle less than about 0.4mm～0.6mm.

18, the process of claim 1 wherein that the second portion from the described part of steps d contains the particle of big-granularity, according to handling with the same way as of handling from the first of step a, this first handles to step h with step b.

19, the process of claim 1 wherein that subdivision from the density minimum of step b comprises the overflow layer from density separation, produce when wherein this partition density is a proportion in about 0.1 proportion unit of the proportion of pending coal.

20, the process of claim 1 wherein that subdivision from the density minimum of step b comprises the overflow from density separation, wherein partition density is to be about generation in 1.2～1.4 o'clock at proportion.

21, the process of claim 1 wherein that subdivision from the density maximum of step b comprises the underflow from density separation, wherein this partition density proportion of surpassing pending coal at proportion takes place during at least about 0.5 proportion unit.

22, the process of claim 1 wherein that subdivision from the described density maximum of step b comprises the underflow from density separation, wherein partition density is in about 1.8～about 2.1 generations of proportion.

23, the process of claim 1 wherein that subdivision from the density maximum of step b comprises the underflow from density separation, wherein this partition density proportion of surpassing pending coal at proportion takes place during at least about 0.35 proportion unit.

24, the process of claim 1 wherein that feed coal comprises anthracite, and comprise underflow that wherein this partition density takes place at least when proportion surpasses described anthracite proportion 0.3 from density separation from the subdivision of the density maximum of step b.

25, the process of claim 1 wherein that the second portion from step a is divided into three parts in steps d according to grain graininess.

26, the process of claim 1 wherein that first from steps d comprises the overflow from classifying cyclone, this first discharges at step e.

27, the method for claim 1, wherein comprise overflow from classifying cyclone from the first of steps d, and the charging of described first is at least about per second 60 Foot at the average speed that particle enters the charging aperture place of cyclone material chamber, and this first discharges at step e.

28, the method for claim 1, wherein comprise overflow from classifying cyclone from the first of steps d, and the charging of described first enters the charging aperture place of cyclone feed space at particle average speed is per second 90 Foot at least, and this first discharges at step e.

29, the method for claim 1, wherein comprise overflow from classifying cyclone from the first of steps d, and the feed volume flow rate that wherein enters classifying cyclone to make must graded particie the time of staying, be enough to reach effective gradation, this first discharges at step e.

30, the method for claim 1, wherein comprise overflow from classifying cyclone from the first of steps d, and wherein entering the feed volume flow rate of classifying cyclone, is within the industrial design critical field to specific cyclone configuration, and this first discharges at step e.

31, the method for claim 1, wherein comprise overflow layer from classifying cyclone from the first of steps d, and comprising the classification of described first particle, is according to particle sinking speed classification in classifying cyclone, and this first discharges at step e.

32, the process of claim 1 wherein that first from steps d mainly comprises the particle less than about 0.01mm～about 0.025mm granularity, this first discharges at step e.

33, the method for claim 1, the second portion of the step a of wherein less-granularity particle from containing, be divided into three parts by grain graininess, the granularity of the largest particles of the first in these three parts is about 0.4mm～0.6mm, the smallest particles granularity is about 0.085mm～0.125mm, the granularity of the largest particles of the second portion of described part is about 0.085mm～0.125mm, the smallest particles granularity is about 0.01mm～0.025mm, and the granularity of the largest particles of the third part of described part is about 0.01mm～0.025mm.

34, the process of claim 1 wherein that the dense media separative element among the step f comprises heavy medium cyclone, and wherein the average speed of charging by the charging aperture of cyclone material chamber is 30 feet of per seconds at least.

35, the process of claim 1 wherein that the dense media separative element among the step f comprises heavy medium cyclone, and the average speed of charging by the charging aperture place of cyclone material chamber is 60 feet of per seconds at least.

36, the process of claim 1 wherein that the dense media among the step f separates, the unit comprises heavy medium cyclone, and the average speed of charging by the charging aperture place of cyclone feed space is 90 feet of per seconds at least.

37, the process of claim 1 wherein that the dense media separative element among the step f comprises heavy medium cyclone, and the volume flow rate that enters this heavy medium cyclone to make the time of staying of the particle that must separate, be enough to obtain effective particle separation.

38, the process of claim 1 wherein that the dense media separative element among the step f comprises heavy medium cyclone, and the volume flow rate that enters heavy medium cyclone is in the industrial design critical field of this concrete cyclone configuration.

39, the process of claim 1 wherein that the dense media among the step f comprises water and magnet grains.

40, the process of claim 1 wherein that the dense media among the step f comprises water and magnet grains, and at least about 60%(weight) the magnet grains granularity be about 2～10 microns.

41, the process of claim 1 wherein that this dense media among the step f comprises water and magnet grains, and at least about 75%(weight) the magnet grains granularity be about 2～10 microns.

42, the process of claim 1 wherein that the dense media among the step f comprises water and magnet grains, and be not more than 10%(weight) the granularity of magnet grains less than about 2 microns.

43, the process of claim 1 wherein that the dense media of step f comprises water and magnet grains, and be not more than 25%(weight) the granularity of magnet grains less than about 3 microns.

44, the process of claim 1 wherein that the dense media of step f comprises water and magnet grains, and at least about 10%(weight) the granularity of particle greater than 7 microns.

45, the process of claim 1 wherein that this dense media among the step f comprises water and magnet grains, and this magnet grains by the reduction red iron obtain, in this reduction process, the maximum temperature that red iron is in is about 900 ℃～1000 ℃.

46, the method for claim 1, wherein the dense media among the step f comprises water and magnet grains, and this magnet grains is obtained by the red iron of reduction, the temperature of wherein said reduction process and the time of staying are the crystal growths of wanting the magnet of limit production, make to produce at least about 60%(weight) the granularity of magnet grains be about 2～10 microns.

47, the method for claim 1, wherein the dense media among the step f comprises water and magnet grains, and this magnet grains is obtained by the red iron of reduction, the temperature of wherein said reduction process and the time of staying are the crystal growths of wanting the magnet of limit production, make to produce at least about 75%(weight) the granularity of magnet grains be about 2～10 microns.

48, the process of claim 1 wherein that the dense media that reclaims among the step f comprises water and magnet grains, and this magnet grains is to be about 900～1000 ℃ of following spray roasting ferric chloride in aqueous solution and to obtain in maximum temperature in reactor.

49, the method for claim 1, wherein the dense media among the step f comprises water and magnet grains, and this magnet grains is to be obtained by the spray roasting ferric chloride in aqueous solution, its temperature and the time of staying are the crystal growths of wanting the magnet grains of limit production, make to produce at least about 60%(weight) the granularity of magnet grains be about 2～10 microns.

50, the method for claim 1, wherein the dense media among the step f comprises water and magnet grains, and this magnet grains is to be obtained by the spray roasting ferric chloride in aqueous solution, its temperature and the time of staying are the crystal growths of wanting the magnet grains of limit production, the weight of 75%(at least that make to produce) the size of magnet grains be about 2～10 microns.

51, the method for claim 1, wherein the recovery of the dense media particle among the step h is to carry out with the Magnetic Isolation method in wet method drum-type magnetic separator, this separator is by the circuit type arrangement of roughly selecting device-washer-remover, and wherein this remover unit contains rare-earth magnet.

52, the process of claim 1 wherein this Magnetic Isolation in the step g, is at one or more wet method drum-type magnetic separators.

53, the process of claim 1 wherein and handle to produce clean product of coal by overflow at step h, use centrifugal dewatering from the third part of steps d, and in this clean product of coal of dehydration forward direction adding paper fiber.

54, the process of claim 1 wherein and handle to produce clean product of coal by overflow at step h, carry out agglomeration from the third part of steps d, and in agglomeration forward direction this clean product of coal adding paper fiber.

55, the method for claim 1, wherein the dense media separative element among the step f is a heavy medium cyclone, wherein heavy medium cyclone can separate the part of coal charging, this part coal charging comprises granularity less than about 0.4mm～about 0.6mm with greater than the particle of about 0.085mm～about 0.125mm, and its possible error is less than 0.05.

56, the method for claim 1, wherein the dense media separative element among the step f is a heavy medium cyclone, wherein heavy medium cyclone can separate the part of coal charging, this part coal charging comprises granularity less than about 0.4mm～about 0.6mm with greater than the particle of about 0.085mm～about 0.125mm, and its possible error is less than 0.035.

57, the method for claim 1, wherein the dense media separative element among the step f is a heavy medium cyclone, this heavy medium cyclone can separate the part of coal charging, this part coal charging comprises granularity less than about 0.085mm～about 0.125mm with greater than the particle of about 0.010mm～about 0.025mm, and its possible error is less than 0.08.

58, the method for claim 1, wherein the dense media separative element among the step f is a heavy medium cyclone, this medium cyclone can separate the part of coal charging, this part coal charging comprises granularity less than about 0.085mm～about 0.125mm with greater than the particle of about 0.010mm～about 0.025mm, and its possible error is less than 0.12.

59, the process of claim 1 wherein among the step h and to remove non magnetic outflow liquid behind the magnetic-particle, be used to the charging of step h with this Magnetic Isolation unit of dilution input with the Magnetic Isolation method.

60, the process of claim 1 wherein and remove clean outflow liquid behind the magnetic-particle in the step g that entering the second portion that is added to before step f handles in part described in the steps d, this second portion contains the larger particles of handling at step f.

61, a kind of coal preparation method comprises:

A. the coal charging is divided into three parts at least by grain graininess;

B. the first from the described part of step a, promptly the part of content minimum particle size particle is made the ore dressing slag and is discharged;

C. in the dense media separative element, handle remainder respectively from step a; Each part is divided into clean coal overflow and ore dressing slag underflow, and used dense media comprises liquid and magnetic-particle;

D. separate the overflow and underflow that obtains through dense media from second portion from step a, reclaim magnetic-particle respectively, this second portion contains big-granularity-particle of handling at step c, this recovery method is to discharge water flushing then on filter screen or sieve, then takes out the dense media magnetic-particle with Magnetic Isolation from this flushing water;

E. separate the overflow and underflow that obtains through dense media from the third part from step a, reclaim magnetic-particle respectively with the Magnetic Isolation method, this third part contains the less-granularity-particle of c processing in steps.

62, the method for claim 61 wherein in steps d, before flushing on filter screen or the sieve, after the discharging, adds water in from the second portion in the described part of step c on filter screen or sieve.

63, the method for claim 61, the amount of the magnetic-particle that does not reclaim in the steps d wherein is lower than steps d per ton and will reclaims 4 pounds of magnetic-particle material.

64, the method for claim 61, the magnetic-particle amount that does not reclaim in the steps d wherein is lower than steps d per ton and will reclaims 10 pounds of magnetic-particle material.

65, the method for claim 61, wherein the magnetic-particle total amount that reclaims among steps d and the step e is at least about 99%(weight).

66, the method for claim 61 is wherein at least about 75%(weight) inorganic sulfur from this coal charging, separate.

67, the method for claim 61 is wherein at least about 85%(weight) inorganic sulfur from this coal charging, separate.

68, the method for claim 61, wherein the clean product of coal of gained contains the gross calorific value of at least 65% this coal charging.

69, the method for claim 61, wherein the clean product of coal of gained contains the gross calorific value of at least 80% this coal charging.

70, the method for claim 61, wherein the Magnetic Isolation among steps d and the step e is substantially included in the Magnetic Isolation in the wet method drum-type magnetic separator.

71, the method for claim 61 wherein is divided into three parts from this coal charging among the step a by grain graininess.

72, the method for claim 61, wherein from the first of step a, promptly the part of discharging at step b comprises the overflow from classifying cyclone.

73, the method for claim 61, wherein from the first of step a, promptly the part of discharging at step b comprises the overflow from classifying cyclone, and the average speed at the charging aperture place of this first's charging by the cyclone feed space is 60 feet of per seconds at least.

74, the method for claim 61, wherein from the first of step a, promptly the part of discharging at step b comprises the overflow from classifying cyclone, and the average speed of this first's charging by the charging aperture place of cyclone feed space is 90 feet of per seconds at least.

75, the method for claim 61, wherein from the first of step a, i.e. part of discharging at step b, comprise overflow from classifying cyclone, and the feed volume flow rate that enters this classifying cyclone to make must classification particle enough time of staying are arranged, to obtain effective gradation.

76, the method for claim 61, wherein from the first of step a, promptly the part of discharging at step b comprises the overflow from classifying cyclone, and enter the feed volume flow rate of this classifying cyclone, within the industrial design critical field of concrete cyclone configuration.

77, the method for claim 61, wherein from this first of step a, promptly the part of discharging at step b comprises the overflow from classifying cyclone, and comprises the gradation of this first, is by particle sinking speed classification in this classifying cyclone.

78, the method for claim 61, wherein from the first of step a, promptly the part of discharging at step b mainly comprises the particle of granularity less than about 0.01mm～0.025mm.

79, the method for claim 61, wherein the coal charging is divided into three parts by grain graininess, first comprises the particle of the about 0.4mm of maximum particle size～about 0.6mm and the particle of the about 0.085mm of minimum particle size～about 0.125mm, second portion comprises the particle of the about 0.085mm of maximum particle size～about 0.125mm and the particle of the about 0.01mm of minimum particle size～about 0.025mm, and third part comprises the particle of the about 0.01mm of maximum particle size～about 0.025mm.

80, the method for claim 61, wherein the dense media separative element among the step c comprises heavy medium cyclone, and the charging average speed at the charging aperture place by the cyclone feed space 30 feet of per seconds at least.

81, the method for claim 61, wherein the dense media separative element among the step c comprises heavy medium cyclone, and passes through the charging average speed at the charging aperture place of cyclone feed space, per second is 60 feet at least.

82, the method for claim 61, wherein the dense media separative element among the step c comprises heavy medium cyclone, and passes through this charging average speed at the charging aperture place of cyclone feed space, per second is 90 feet at least.

83, the method for claim 61, wherein the dense media separative element among the step c comprises heavy medium cyclone, and enters the feed volume flow rate of heavy medium cyclone, make to have enough time of staying by separating particles, effectively to be separated.

84, the method for claim 61, wherein the dense media separative element among the step c comprises heavy medium cyclone, and enters the feed volume flow rate of this heavy medium cyclone, within the industrial design critical field of concrete cyclone configuration.

85, the method for claim 61, wherein the dense media among the step c comprises water and magnet grains.

86, the method for claim 61, wherein the dense media among the step c comprises water and magnet grains, and 60%(weight at least) the granularity of magnet grains be about 2～10 microns.

87, the method for claim 61, wherein the dense media among the step c comprises water and magnet grains, and 75%(weight at least) the granularity of magnet grains be about 2～10 microns.

88, the method for claim 61, wherein the dense media among the step c comprises water and magnet grains, and is not more than 10%(weight) the granularity of magnet grains be lower than about 2 microns.

89, the method for claim 61, wherein the dense media among the step c comprises water and magnet grains, and is not more than 25%(weight) the granularity of magnet grains less than about 3 microns.

90, the method for claim 61, wherein the dense media among the step c comprises water and magnet grains, at least about 10%(weight) the granularity of this particle greater than about 7 microns.

91, the method for claim 61, wherein this dense media among the step c comprises water and magnet grains, and this magnet grains by the reduction red iron obtain, in this reduction process, the maximum temperature that red iron is in is about 900 ℃～1000 ℃.

92, the method for claim 61, wherein this dense media among the step c comprises water and magnet grains, and this magnet grains is obtained by the red iron of reduction, the temperature of wherein said reduction process and the time of staying are the crystal growths of wanting the magnet of limit production, make to produce at least about 60%(weight) the granularity of magnet grains be about 2～10 microns.

93, the method for claim 61, wherein the dense media among the step c comprises water and magnet grains, and this magnet grains is obtained by the red iron of reduction, wherein the temperature of this reduction process and the time of staying are the crystal growths of wanting the magnet of limit production, make to produce at least about 75%(weight) the granularity of magnet grains be about 2～10 microns.

94, the method for claim 61, wherein the dense media among the step c comprises water and magnet grains, and this magnet grains is to be about 900～1000 ℃ of following spray roasting ferric chloride in aqueous solution and to obtain in maximum temperature in reactor.

95, the method for claim 61; wherein the recovery of the dense media particle among the step e is to carry out with the Magnetic Isolation method in wet method drum-type magnetic separator; this separator is by the circuit type arrangement of roughly selecting device-washer-remover, and wherein this remover unit contains rare-earth magnet.

96, the method for claim 61, wherein the coal charging of step a is partly formed by being ground into the middle suction coal that maximum particle size is about 0.4mm～0.6mm.

97, the method for claim 61 wherein from this third part of step a, is promptly handled with the part of producing clean product of coal, is used the whizzer separating and dehydrating as overflow in step e, and before this dehydration this clean product of coal of paper fiber adding.

98, the method for claim 61 wherein from this third part of step a, is promptly handled to produce the part of clean product of coal as overflow at step e, carries out agglomeration, and before this agglomeration the paper fiber is added this clean product of coal.

99, with the method for dense media partition method separate solid particles, wherein dense media comprises water and magnetic-particle, and is about 2～10 microns at least about the granularity of this magnetic-particle of 60%.

100, the method for claim 99, wherein this magnetic-particle comprises magnet.

101, the method for claim 99 is wherein at least about 75%(weight) the granularity of this magnetic-particle be about 2～10 microns.

102, the method for claim 99, wherein this dense media comprises water and magnet grains, is not more than about 10%(weight) the granularity of this magnet grains less than about 2 microns.

103, the method for claim 99 is wherein at least about 25%(weight) the granularity of this magnetic-particle less than about 3 microns.

104, the method for claim 99 is wherein at least about 10%(weight) this magnetic-particle greater than 7 microns.

105, the method for claim 99, wherein the solid particle that will separate comprises the coal feed particles of granularity less than about 0.4mm～0.6mm.

106, the method for claim 99, wherein this dense media comprises water and magnet grains, and this magnet grains by the reduction red iron obtain, in this reduction process, about 900～1000 ℃ of the maximum temperature that this red iron is subjected in reactor.

107, the method for claim 99, wherein dense media comprises water and magnet grains, and this magnet grains is obtained by the red iron of reduction, wherein the temperature of this reduction process and the time of staying are the crystal growths of wanting the magnet of limit production, make to produce at least about 60%(weight) the granularity of magnet grains be about 2～10 microns.

108, the method for claim 99, wherein dense media comprises water and magnet grains, and this magnet grains is obtained by the red iron of reduction, wherein the temperature of this reduction process and the time of staying are the crystal growths of wanting the magnet of limit production, make to produce at least about 75%(weight) the granularity of magnet grains be about 2～10 microns.

109, the method for claim 99, wherein dense media comprises water and magnet grains, and this magnet grains is to be about 900～1000 ℃ of following spray roasting ferric chloride in aqueous solution and to obtain in maximum temperature in reactor.

110, the method for claim 99, wherein this dense media comprises water and magnet grains, and this magnet grains is to be obtained by the spray roasting ferric chloride in aqueous solution, its temperature and the time of staying are the crystal growths of wanting the magnet grains of limit production, make to produce at least about 60%(weight) the granularity of magnet grains be about 2～10 microns.

111, the method for claim 99, wherein this dense media comprises water and magnet grains, and this magnet grains is to be obtained by the spray roasting ferric chloride in aqueous solution, its temperature and the time of staying are the crystal growths of wanting the magnet grains of limit production, the weight of 75%(at least that make to produce) the granularity of magnet grains be about 2～10 microns.

112, the method for claim 99, wherein dense media comprises water and magnet grains, this magnet grains is obtained by the red iron of reduction, and this reduction is carried out in the rotary kiln reactor, red iron is from an endfeed and magnet is discharged from opposite end, introduce burner flame at this reactor outlet side, restriction offers the oxygen of this burner, and injects natural gas to keep reducing environment to reactor in addition.

113, a kind of dense media recovery method that is used for after the solid particle dense media separates comprises:

A. adopt the dense media comprise water and magnetic-particle, wherein at least about 60%(weight) the granularity of this magnetic-particle be about 2～10 microns:

B. reclaim the unit with magnetic-particle and reclaim this dense media, this recovery unit comprises magnetic separator.

114, the method for claim 113, wherein this magnetic-particle comprises magnet.

115, the method for claim 113, wherein 75%(weight at least) this magnetic-particle granularity be about 2～10 microns.

116, the method for claim 113 wherein is no more than 10%(weight) this magnetic-particle granularity less than about 2 microns.

117, the method for claim 113 wherein is no more than about 25%(weight) this magnetic-particle granularity less than about 3 microns.

118, the method for claim 113 wherein is no more than about 10%(weight) this magnetic-particle granularity greater than about 7 microns.

119, the method for claim 113, wherein the dense media in the coal charging separates back recovery dense media magnetic particle, and this grain graininess maximum is about the particle of 0.4mm～0.6mm.

120; the method of claim 113; wherein this dense media among the step a is used for the dense media separation of coal; this coal charging is divided into two parts at least by grain graininess before dense media separates; from every part, reclaim magnetic-particle respectively; the part of wherein less-particle-granularity is before magnetic-particle reclaims; with diluting from handling this outflow liquid than the bodies for purifying fluids this magnetic-particle recovery unit of granule-granularity part; this magnetic-particle of big-particle-granularity part reclaims the outflow liquid of the bodies for purifying fluids of unit from handling; before the dense media of less-particle-granularity part separates, add this less-particle-granularity part.

121, the method for claim 113, wherein this dense media comprises water and magnet grains, and this magnet grains by the reduction red iron obtain, in this reduction process, the maximum temperature that red iron is in is about 900～1000 ℃.

122, the method for claim 113, wherein this dense media comprises water and magnet grains, and this magnet grains is obtained by the red iron of reduction, wherein the temperature of this reduction process and the time of staying are the crystal growths of wanting the magnet of limit production, make to produce at least about 60%(weight) the granularity of magnet grains be about 2～10 microns.

123, the method for claim 113, wherein this dense media comprises water and magnet grains, and this magnet grains is obtained by the red iron of reduction, wherein the temperature of this reduction process and the time of staying are the crystal growths of wanting the magnet of limit production, make to produce at least about 75%(weight) the granularity of magnet grains be about 2～10 microns.

124, the method for claim 113, wherein this dense media comprises water and magnet grains, and this magnet grains is to be about 900～1000 ℃ of following spray roasting ferric chloride in aqueous solution in the reactor maximum temperature to obtain.

125, the method for claim 113, wherein this dense media comprises water and magnet grains, this magnet grains is obtained by the red iron of reduction, this reduction is carried out in the rotary kiln reactor, red iron charge enters and the magnet product is discharged from opposite end from an end, introduce burner flame at this reactor outlet side, restriction offers the oxygen of this burner, and injects natural gas to keep reducing environment to reactor in addition.

126, a kind of method of producing magnet with the red iron of reduction comprises:

A. under reducing condition, in reactor, heat red iron;

B. in this reactor, red iron is placed under about 900～1000 ℃ of the maximum temperature.

127, the method for claim 126 wherein places this red iron under about 980 ℃～1000 ℃ of the maximum temperature in reaction.

128, the method for claim 126, wherein this red iron is produced with the spray roasting ferric chloride in aqueous solution down for about 900～1000 ℃ in maximum temperature.

129, the method for claim 126, wherein this red iron is produced with the iron chloride pyrohydrolysis.

130, the method for claim 126 wherein limits the oxygen of supply response device burner, and injects hydrogen or natural gas to this reactor in addition, to keep reducing environment.

131, the method for claim 126, wherein this reduction is carried out in tunnel type reactor, and red iron is from an endfeed of reactor, and magnet is discharged from the other end, this red iron just is heated about 900～1000 ℃ of the maximum temperature that this red iron places when mobile between upstream end and outlet side.

132, the method for claim 126 is wherein at least about 60%(weight) the granularity of this magnet grains be about 2～10 microns.

133, the method for claim 126 is wherein at least about 75%(weight) the granularity of magnet grains be about 2～10 microns.

134, the method for claim 126 wherein is no more than about 10%(weight) the granularity of magnet grains less than about 2 microns.

135, the method for claim 126 wherein is no more than about 25%(weight) the granularity of magnet grains less than 3 microns.

136, the method for claim 126 is wherein at least about 10%(weight) the granularity of magnet grains greater than about 7 microns.

137, press the method for particle sinking speed classifying solid particle, comprising:

A. prepare mud, this mud comprises solid particle and the water of wanting classification,

B. this mud is sent into classifying cyclone, the feed liquid average speed that mud enters the charging aperture place of this cyclone feed space is at least about 60 feet of per seconds.

138, the method for claim 137, the feed volume flow rate of wherein sending into this classifying cyclone will make solid particle that enough time of staying are arranged in this cyclone, to obtain effective solid classification.

139, the method for claim 137, the feed volume flow rate of wherein sending into this classifying cyclone is within the industrial design critical field of this concrete cyclone configuration.

140, the method for claim 137 wherein should want the solid particle of classification to comprise the coal feed particles.

141, the method for claim 137 wherein is somebody's turn to do the granularity of the solid particle that want classification less than about 0.4mm～about 0.6mm.

142, the method for claim 137 wherein is somebody's turn to do the granularity of the solid particle that want classification less than about 0.085mm～about 0.125mm.

143, the method for claim 137, wherein this solid particle is mainly pressed the grain graininess classification.

144, the method for claim 137, wherein this solid particle is in about 15 microns (0.015mm) granularities punishment level.

145, the method for claim 137, wherein at step b, the average inlet velocity of this charging that enters this cyclone feed space is at least 90 feet of about per seconds.

146, come the method for separate solid particles in one or more heavy medium cyclones by density, wherein the charging average speed at the charging aperture place by the cyclone feed space is at least about 30 feet of per seconds.

147, the method for claim 146, wherein this solid particle that will separate comprises the coal feed particles.

148, the method for claim 146, wherein this dense media comprises water and magnetizing mediums.

149, the method for claim 146, wherein this dense media comprises water and magnet.

150, the method for claim 146, wherein the charging average speed at this charging aperture place by this cyclone feed space is at least about 60 feet of per seconds.

151, the method for claim 146, wherein the charging average speed at the charging aperture place by this cyclone feed space is at least about 90 feet of per seconds.

152, the method for claim 146, wherein heavy medium cyclone can separate a part of feed coal, and this part feed coal comprises granularity less than about 0.4mm～about 0.6mm with greater than the particle of about 0.085mm～about 0.125mm, and possible error is less than 0.05.

153, the method for claim 146, wherein this heavy medium cyclone can separate a part of feed coal, and this part feed coal comprises granularity less than about 0.4mm～about 0.6mm with greater than the particle of about 0.085mm～about 0.125mm, and possible error is less than 0.035.

154, the method for claim 146, wherein this heavy medium cyclone can separate a part of feed coal, and this part feed coal comprises granularity less than about 0.085mm～about 0.125mm, and greater than the particle of about 0.010mm～about 0.025mm, possible error is less than 0.08.

155, the method for claim 146, wherein this heavy medium cyclone can separate the part of coal charging, and this part coal charging comprises granularity less than about 0.085mm～about 0.125mm, and greater than the particle of about 0.010mm～about 0.025mm, possible error is less than 0.12.

156, the method for claim 146, wherein this dense media comprises water and magnetic-particle, this magnetic-particle at least about 60% is about 2～10 microns.

157, the method for claim 146, wherein this dense media comprises water and magnetic-particle, this magnetic-particle at least about 75% is about 2～10 microns.

158, the method for claim 146, wherein dense media comprises water and magnetic-particle, is no more than this magnetic-particle of about 10% less than about 2 microns.

159, the method for claim 146, wherein this dense media comprises water and magnetic-particle, is no more than this magnetic-particle of about 25% approximately less than 3 microns.

160, the method for claim 146, wherein this dense media comprises water and magnetic-particle, the magnetic-particle at least about 10% is greater than about 7 microns.

161, a kind of method of coal separation comprises:

A. remove less than about 15 microns particle;

B. further selected remaining coal particle produces coal to separate from non-coal material.

162, the method for claim 161, wherein the removal of particle is to carry out in classifying cyclone among the step a.

163, the method for claim 161, wherein the selected of step b is to be undertaken by heavy medium cyclone.

164, the method for claim 161, wherein this solid particle that will separate comprises the coal particle of granularity less than about 0.4mm～0.6mm.

165, the method for claim 161, wherein the coal charging average speed at the charging aperture place by the cyclone feed space is at least about 60 feet of per seconds.

166, the method for claim 161, wherein the coal charging average speed at the charging aperture place by the cyclone feed space is at least about 90 feet of per seconds.

167, the method for claim 161, the coal charging average speed at the charging aperture place by the cyclone feed space wherein, make must classification particle enough time of staying are arranged, to obtain effectively this coal feed particles classification.

168, the method for claim 161, the feed volume flow rate that wherein enters classifying cyclone, make must classification particle enough time of staying are arranged, to obtain effectively this coal feed particles classification.

169, the method for claim 161, wherein this particle removal of step a is to carry out in classifying cyclone by particle sinking speed.

170, a kind of method of coal separation comprises:

A. the grain graininess separated into two parts is pressed in this coal charging;

B. the big-particle-granularity part from step a, be divided into three subdivisions by density, the subdivision of density minimum mainly comprises pure coal, and the subdivision of density maximum mainly comprises non-coal material, and density subdivision placed in the middle comprises the bond of coal and non-coal material;

C. pulverize this density subdivision placed in the middle from step b, and and from step a less-particle-granularity part further handles together.

171, the method for claim 170, wherein the subdivision from this density minimum of step b is obtained by density separation, and wherein the density of Fen Liing is within 0.1 proportion unit of this coal.

172, the method for claim 170 is wherein obtained by density separation from the minimum subdivision of the density of step b, and this partition density is about proportion 1.2～1.4.

173, the method for claim 170 is wherein obtained by density separation from the maximum subdivision of the density of step b, and this partition density is at least than the great 0.5 proportion unit of the ratio of this coal.

174, the method for claim 170 is wherein obtained by density separation from the maximum subdivision of this density of step b, and this partition density is about proportion 1.8～2.1.

175, the method for claim 170, wherein the separation of the dense media among the step b is to carry out in heavy medium cyclone.

176, the method for claim 170, wherein the minimum subdivision of this density among the step b comprises 90%(weight at least) coal.

177, the method for claim 170, wherein the minimum subdivision of this density among the step b comprises the weight at least about 95%() coal.

178, the method for claim 170, wherein the minimum subdivision of this density among the step b comprises the weight at least about 85%() coal.

179, a kind of method by the particle size separation coal particle comprises

A. form the mixture of coal charging and water,

B., the multistage classifying cyclone of settling by series connection is provided,

C. sending into the classification device of releasing from the overflow of the classifying cyclone that connects after directly with from the underflow of the cyclone that connects before directly, wherein the underflow from the overflow of first classifying cyclone in this series connection and last classifying cyclone of connecting from this comprises that this product that has separated flows.

180, the method for claim 179, wherein the coal that will separate comprises the particle less than about 0.5mm granularity.

181, a kind of method of coal dewatering comprises to this coal adding paper fiber, centrifugation coal and water then.

182, the method for claim 181, wherein this coal comprises the particle less than about 0.105 micron granularity.

183, the method for claim 181, wherein this paper fiber comprises the newsprint fiber.

184, a kind of method that makes the coal particle agglomeration comprises to this coal adding the paper fiber, and makes ball, briquetting or push this coal particle and the paper fiber is made agglomerating shape.

185, the method for claim 184, wherein this coal comprises the particle less than about 0.105 micron granularity.

186, the method for claim 184, wherein this paper fiber comprises the newsprint fiber.

Images