CN85103743B - Method for pulverizing solid raw material - Google Patents

Abstract

The crushing method of the solid raw material comprises the following steps: crushing and crushing the solid raw material on a rotating circular grinding disc; conveying the generated fine powder to an air classifier located above a circular grinding disc by using an upward-spraying air flow, wherein the spraying speed of the air flow is enough to blow away and take away the powder and simultaneously make coarse particles fall off the circular disc; discharging fine powder having a predetermined fineness through an air classifier; returning the falling particles to the grinding disc; the jet velocity of the gas flow is controlled so that the ratio of the amount of the solid raw material falling from the circular grinding disk to the amount of the fine powder discharged is between 0.4 or more and less than 2.0.

Description

The breaking method of solid material

The present invention relates to a kind of method that solid material is efficiently pulverized.

The method of comminuted solids raw material had proposed several on the round mill of rotation, a kind of method wherein is such, solid material is input on the rotating grinding board, using grinding roller or ball to press pulverizes raw material, the attritive powder that produces is delivered in the air classifier by means of the air-flow that upwards sprays, and clasfficiator is installed in the top of rotating grinding board.Those powder-products with predetermined fineness then extract from this system in clasfficiator.

For example: the raw material of cement can adopt said method to pulverize, the raw material of input rotating grinding board is under mill rotatablely moves the centrifugal action that is produced in crushing process, to the circumferential edges motion of circle mill, in motion process, part of raw materials will be pulverized by grinding roller or ball.When crushed material arrived disk peripheral, they will be by by the gap that forms between circle mill and the hood around it wandering the dispelling of hot gas of ejection upwards, and move upward with gaseous blast.At this moment, molecule particularly fine powder is sent to an air classifier, and this air classifier is placed in the top of the mill coaxial with justifying mill.In air classifier, particle is had only those powder-products with regulation fineness row to be discharged to the outside of this system by classification, and all the other corase meals are carried again to get back on the disk and pulverized.Particularly thicker particle, promptly granular or blocky-shaped particle are transported to the mill center again and one of corase meal is pulverized again.

It is essential that the rotating to be of circle mill pulverized institute, and the required electric energy of its rotation is more much smaller than tubular type pulverizer, usually less than half of the required electric energy of tubular type pulverizer.Yet, huge by the gentle pressure consume of hot gas flow that spray in the space, drive the required electric energy of the blower fan that is used for spraying thermal current than making the required electric energy of round mill rotation big.Therefore, the required electric energy of whole system only is slightly smaller than the required electric energy of tubular type pulverizer.

Also disclose another method, in this method, the solid material that falls from the gap is by carry the centre of getting back to round mill such as bucket elevator.Yet, carry out according to the method, be difficult to pulverize, solid material is forced to and will stops for a long time in machine.This can cause the serious consume of grinding roller or ball and circle mill.Make when operating in this way, during for example mobile cement raw material, because the accumulation of powder can not continue operation, thereby to maintain machinery expense and improve operating efficiency and play negative interaction of reduction.Yet, the not mentioned problem that how to fall from the circle mill effectively to solid material of this method.State in the use in the machine of method, owing to following reason still needs a large amount of gas and keeps high gas flow rate.These reasons are: prevent that the solid material that falls from moving to above-mentioned gap, fine powder is sent to air classification and the raw material of coarse particle or not crushing are carried the round mill center of getting back to.The required electric energy of this machine almost with first kind of situation under described identical.

We study with the effect of the ratio (CF/P) of fine powder output (P) the quantity (CF) of the solid material that fallen by the rotational circle mill.Found that when ratio C F/P surpassed a certain numerical value, grindability reduced greatly, on the contrary, whole power consumption has but increased.We find that also although from the air-dry solid material this point that contains moisture, the output of fine powder is a key factor with the ratio of the throughput of injection, and CF/P ratio is a kind of definite grindability and the factor of determining the optimum range of required electric energy.

Therefore, the purpose of this invention is to provide a kind of breaking method that can overcome the solid material of each method shortcoming of prior art.

It is the economy breaking method of comminuted solids raw material effectively again that another object of the present invention provides a kind of.

Breaking method according to solid material provided by the present invention comprises, on the mill that is rotating, solid material is pulverized, by means of the air-flow that upwards sprays the fine powder that produces is sent to an air classifier, the speed of air-flow is enough to dispel fine powder and makes it to advance with air-flow, simultaneously, allow coarse granule fall, have the powder of regulation fineness and send the particle that falls back to round mill by the air classifier taking-up from the circle mill; To control the gas jet velocity, make the quantity of justifying the solid material that mill falls by oneself and discharge powder quantity ratio more than or equal to 0.4 and less than 2.0 between.Because be subjected to the circle mill caused action of centrifugal force that rotatablely moves, crushed material outwards moves, wherein, thinner particle is upwards taken away by air-flow, and thicker particle is shifted to shell wall, falls on the disk.Smalls through air classifier is discharged into the outside.Therefore, the electric energy and the pressure loss that blower fan consumes be can reduce, and equipment cost and maintenance cost reduced.

Fig. 1 is the partial sectional view of the pulverizer of use the present invention's method;

Fig. 2 is the cutaway view along A-A line among Fig. 1;

Fig. 3 represents W value and the P value graph of relation with respect to the CF/P value;

Fig. 4 represents P value and CF/P value and air-flow jet velocity graph of relation;

See also accompanying drawing, particularly consult numeral 1 representative in Fig. 1 and Fig. 2, the accompanying drawing and be used for making round nog plate or mill 2 drive unit in the horizontal plane rotation.Pulverizing drying chamber 3 is positioned at the top of drive unit 1.Granular or block material feeding skewed slot 4 is fixed in the chamber 3 by covering 6.Several grinding rollers that numeral 5 expressions are rotated around the axle 7 that passes cover 6 among the figure, grinding roller 5 is designed to do frictional rotation in company with the rotation of circle mill 2, and will deliver in the pulverizing drying chamber 3 the granular bedding raw material on the disk 2 and pulverize.The 8 confession circulations of air of an annular opening are arranged between justifying mill 2 and covering 6 and coarse granule is fallen from circle mill 2 at an easy rate.Row unload passage 9 just be placed in annular opening 8 below, to the hot cell 10 of annular opening 8 delivery airs also be positioned at round mill 2 around.

Settle an air classifier 13 above pulverizing drying chamber 3, under the drive of motor, the rotating vane 11 of air classifier becomes rotation coaxially with the circle mill.The gas discharge port 12 that has fine powder is positioned at the top of rotating vane.Numeral 14 expressions are unloaded the mechanical conveyor that passage 9 is connected with row.The bucket elevator of feed chute 4 is delivered to the coarse granule of conveyer 14 outputs in numeral 15 expressions.

In machine operation procedure, the gas of discharging with the suspension preheater (not expressing among the figure) of sintering furnace, blows into and pulverizes drying chamber 3 through hot gas chamber 10 and annular opening 8 by means of the effect of interior machine (not expressing among the figure).Under circle mill 2 rotatablely moved the action of centrifugal force that is produced, crushed particles was shifted to opening 8, and wherein, the air-flow that thinner particle is upwards sprayed is taken away.The particle that is pulled away enters air classifier 13, and in air classifier, the rotation owing to rotating vane is separated coarse granule, and the fine powder product is discharged outside the pulverizers from fine powder gas discharge port 12.

On the other hand, owing to be subjected to circle mill 2 institute that rotatablely moves to produce capable action of centrifugal force, granular or the block raw material of delivering to round mill 2 centres through feed chute 4 radially outwards moves, in moving process, granular or block raw material is broken between grinding roller 5 that grinds pressure downwards and circle mill 2 and pulverizes.Utilize the hot gas of necessary amount to dry, within the scope of 10 meters to 25 meters of per seconds, so just make in the crushed particles that moves on to opening 8 places and take away than the injected air-flow of fine grained in the gas jet speed at opening 8 places.As a result, the thinner injected gas of particle of a part blows away, and remaining is blown gets back on the round mill 2.

Meanwhile, falling from opening 8 that opening 8 is not blown away, unload passage 9 through row and deliver to conveyer 14 than coarse granule.As a result, the particle that falls enters feed chute 4 through bucket elevator 15.

Enter colliding of air classifier 13, thereby along with action of centrifugal force, the coarse granule that it is contained is separated, and throws the perisporium of cover 6 than fine grained and rotating vane 11.Coarse granule becomes the wall of back taper to fall back on the round mill 2 in gravity effect lower edge then.Discharge by the discharge port above the fine powder spinning blade of rotating vane 11, and be collected in the gatherer (not expressing among the figure) as powder-product.

For guaranteeing good economic benefit, to the cost of equipment, maintenance and operation are comprehensively considered, in the above-described embodiments, should control jet-stream wind, make CF/P ratio more than or equal to 0.4, less than 2.0 simultaneously.To this, will be explained in detail below.

For guaranteeing CF/P ratio less than 0.4, most of crushed particles that must will move on to opening 8 is blown the centre of getting back to round mill 2, perhaps takes it to air classifier 13 by jet-stream wind.This same with known machine needs a large amount of gas and very high flow velocity, thereby increases the consumption of the pressure loss and driving blower fan electric energy.

On the other hand, if CF/P ratio surpasses 2.0, then grindability reduces, thereby causes the increase of the required electric energy of machine running itself and the increase of dropping mass conveying capacity.Thereby opposite with people's hope, (except that the required electric energy of above-mentioned machine running itself, also comprising the blower fan required electric energy that turns round), the power consumption of whole power-equipment will increase inevitably.From Fig. 3, can be clear that this point.Among Fig. 3, P represents the quantity of fine powder product, and W represents entire equipment power consumption.

Below, analyze CF/P ratio greater than 2 disadvantageous reasons: the fine powder quantity that is transported to air classifier reduces.Therefore, fine powder repeats to flow in pulverizer and whereabouts ingredient conveyor for a long time; Along with the reduction of grindability, the solid material layer thickening on the circle mill 2.

Now, narrate gas in the jet velocity at opening 8 places.The gas jet velocity is one of principal element that influences CF/P ratio.Curve A can be seen from Fig. 4, when the gas jet velocity surpasses 40 meters of per seconds, almost do not have particle and fall, when gas jet velocity during less than 40 meters of per seconds, the quantity CF value that then falls particle with the gas jet velocity reduce and increase gradually.With regard to the quantity P value of fine powder product, when the gas jet velocity surpassed 25 meters of per seconds, the quantity P value of fine powder product did not have any variation, shown in Fig. 4 curve B.When the gas jet velocity was lower than 25 meters of per seconds, the P value reduced, and particularly when the gas jet velocity is lower than 10 meters of per seconds, the quantity of fine powder product drops sharply to below half of machine maximum productivity (being that the P coefficient is less than 0.5).In this case, fall the sharply increase of quantity CF value of particle, (seeing Fig. 4 A curve).When CF/P ratio less than 2 the time, entire equipment power consumption W value reduces, but when CF/P ratio more than or equal to 2 the time, entire equipment power consumption ability W value increase (see figure 3).

Will be noted that, for ease of being transported to air classifier and, should preferentially determining quantity and the ratio of gas weight, i.e. the P/G ratio of powder-product rightly than fine grained with its classification.When solid material was dried, P/G ratio should be determined according to the temperature of thermal current.Preferential definite P/G value is in view of above-mentioned needs.For saves energy, should reduce air mass flow as far as possible, increase the ratio of P/G.

Claims (4)

1, a kind of solid material breaking method comprises: on the round mill that is rotating solid material is carried out fragmentation and pulverizing; Utilize the air-flow that upwards sprays that the fine powder that produces is transported to air classifier, the air-flow jet velocity is enough to dispel and take away fine powder, simultaneously, allows coarse granule fall from the circle mill; The powder that will have predetermined fineness is discharged by air classifier, and the particle that falls is sent back to round mill; The invention is characterized in, the jet velocity of control air-flow, make from the ratio of the quantity of the powder of the quantity of the solid material that falls of circle mill and discharge more than or equal to 0.4 and less than 2.0 between.

2, in accordance with the method for claim 1, it is characterized in that the air-flow jet velocity is within the scope of 10 meters to 25 meters of per seconds.

3, in accordance with the method for claim 1, it is characterized in that gas sprays by the gap that forms between circle mill and its cover.

4, in accordance with the method for claim 1, it is characterized in that the particle of dishing out falls on the round mill in air classifier.

Images