6 replies to this topic

Hi everybody, i'd like to ask some questions about ball mill. In this case, i'd like to ask about the factors which will effect the mass fraction :


1. what is the effect of the weight of the feed in ball mill for the held mass fraction and number of mesh in screening.

2. what is the effect of the duration of time in ball mill for the held mass fraction and number of mesh in screening.

3. what is the effect of the amount of stainless steel balls used for grinding in ball mill for the held mass fraction and number of mesh in screening.

I'm sorry for my bad English. I really thank you for helping me

Edited by NozzKiDZ, 20 August 2010 - 08:30 AM.

[Erwin APRIANDI]

Hi Nozzkidz

You forgetting something, soem introduction regarging to the use of ball mill in your case
so we could understand more clear regarding to the problem.

some flow sketch for the process are welcome

[sbmzhcn]

Hi Nozzkidz

You forgetting something, soem introduction regarging to the use of ball mill in your case
so we could understand more clear regarding to the problem.

some flow sketch for the process are welcome

Do you want to know about ball mill. how to ball mill works.let's me tell you,i also q chinese.my english is bad,but i also want to help you.


Ball mill is the material being broken, and then smash the key equipment . It is widely used in cement, silicate products, new building materials , refractory materials , fertilizer , black and non-ferrous mineral processing and manufacturing industries such as glass ceramics , of various ores and other materials can be carried out of dry ground or wet grinding . Applicable to all kinds of ball mill grinding ore and other materials , is widely used in mineral processing , building materials and chemical industry can be divided into two kinds of dry and wet grinding methods . According to Pai mine in different ways, can be divided into two grid -based and Overflow
Machine name
Ball Mill (ball grinding mill)
Ball is the material being broken, and then smash the key equipment .
Ball mill is widely used in industrial production of high- fine grinding machine .
Many of its species , such as hand ball mill , horizontal mill, ball mill , energy saving ball mill , overflow -type ball mill , ceramic ball mill , ball mill and other lattice .
Applicable to all kinds of ball mill grinding ore and other materials are widely used dressing , building materials and chemical industry can be divided into

Ball Mill Machine
Two for the dry and wet grinding methods . According to Pai mine in different ways, can be divided into two grid -based and Overflow .
Work
Ball in aerated Conceter Preparation of equipment is the most important ball , he used lime, plaste, sand , slag and other materials grinding . Only material to the required fineness of grinding , and only after full mixing interaction can make the product meet the strength , the production of aerated concrete grinding is an important process, grinding process of consumption powder Large , ball mill is usually aerated concrete factory in the largest electrical equipment capacity .
Ball is a simplified level , and out of the hollow shaft and grinding materials and other components , simplified for the long cylinder , cylinder with grinding media cylinder for the plate Manufacturing, with steel liner and simplified fixed , usually steel ball grinding media according to different tube diameters and a certain percentage of load , the steel grinding media can also be used in paragraph
According to the granularity of abrasive material to choose , the material from the mill feed end of the hollow shaft into the cylinder body , when the ball Simplified rotation when the grinding media due to inertia and centrifugal force, Fritco Role , it posts to be near the cylinder liner on the barrel away , when was taken to a certain height , because of its own gravity has been into the falling , falling as grinding media to drum like projectile body material To smash .

Material from the feed device into the compound by air evenly into the mill screw shaft first warehouse , the warehouse there are ladder liner or corrugated liner , built in different specification steel balls , steel ball cylinder rotation produces centrifugal force brought to a certain height After the fall , on the material produced Blow And abrasive . To coarse grinding of materials in the first position after the board by the single compartment into the second warehouse , the warehouse lined with flat lining , there Ball mill, the material to further grinding . Powder discharged through the discharge grate plate to complete the grinding operation .
Cylinder in the rotary process, the phenomenon of grinding media have fallen in the fall to the material in the process of grinding effect , for effective use of abrasive , size of material to teach a large general purpose Ground 20 times , the body tube mill Body board with a separate compartment for the Er Duan , becoming dual position , the material into the first position when the ball was crushed , the material into the second position when the steel side of the material for grinding , ground of qualified materials from the discharge end Discharge hollow shaft of a small feed particles were pulverized materials , such as when the 2nd slag sand , coarse fly ash, mill shell from time to set up Clapborad Into a single storage tube mill , grinding of steel section sizes can be .
The machine is a horizontal rotating device, outer gear , the two positions, lattice-type ball mill . Material from the feed device into the compound by air evenly into the mill screw shaft first warehouse , the warehouse there are ladder liner or corrugated liner , built in different specification steel balls , steel ball cylinder rotation produces centrifugal force brought to a certain height After the fall , produce severe impact on the material and abrasive . To coarse grinding of materials in the first position after the board by the single compartment into the second warehouse , the warehouse lined with flat lining , steel ball inside , the material to further grinding . Powder discharged through the discharge grate plate to complete the grinding operation .
Pemalinks: http://sbmzhcn.appsp.../26/138006.html
See Also
ball mill
ball mill

 Ball%20mill.jpg   91.07KB   4 downloads

[breizh]

Hi ,
A lot of informations are available on the net . I guess you did some Google work .

As an example : http://www.mine-engi...ng/ballmill.htm

Hope this helps

Breizh

[LuckyFGD]

Hi everybody, i'd like to ask some questions about ball mill. In this case, i'd like to ask about the factors which will effect the mass fraction :


1. what is the effect of the weight of the feed in ball mill for the held mass fraction and number of mesh in screening.

2. what is the effect of the duration of time in ball mill for the held mass fraction and number of mesh in screening.

3. what is the effect of the amount of stainless steel balls used for grinding in ball mill for the held mass fraction and number of mesh in screening.

I'm sorry for my bad English. I really thank you for helping me

My experience with ball mills is with crushing limestone into a slurry for wet FGD application. Our target grind is 95% passing 325 mesh and we start with 3/4" x 0 limestone gradation. I will answer your questions as though the scenarios applied to my ball mills, but generally speaking the grinding process should be similar to your application,

1) I think you're trying to say how does a change in feed rate of the raw material that is being ground in the mill affect the process. The simple answer is that it affects your recirculating load. What this means is that after a single pass through the mill, the grind slurry is pumped through a cyclone separator - the overflow is your product, and the underflow is returned to the mill for additional grinding, also known as recirculating load. Increased feed rate will increase your recirculating load, and vice versa. If you increase the feed rate beyond the size of the mill, you will not achieve the target grind mesh, in other words, your grind performance will suffer.

2) This doesn't make sense to me - the duration of time in the mill is set by the size of the mill.

3) This is critical. Having an insufficient ball charge in the mill will greatly diminsh mill performance. In my application, the ball charge should be maintained up to the trommel screen.

[kkala]

Hi everybody, i'd like to ask some questions about ball mill. In this case, i'd like to ask about the factors which will effect the mass fraction :
1. what is the effect of the weight of the feed in ball mill for the held mass fraction and number of mesh in screening.
2. what is the effect of the duration of time in ball mill for the held mass fraction and number of mesh in screening.
3. what is the effect of the amount of stainless steel balls used for grinding in ball mill for the held mass fraction and number of mesh in screening.
I'm sorry for my bad English. I really thank you for helping me

Having a brief look in the past (1990s) at bauxite wet grinding design, I would like to add following views to NozzKiDZ’s questions, in addition to the post of LuckyFGD (23-9-2010).
A given mill operating at constant rotations/min (RPM) and slope is supposed.

(Q2) ‘Duration of time’ (understood as residence time) is assumed as Tres = k*L/(N*D*S) (L=length, D=internal diameter, S=slope, N=RPM of the mill, k=constant), even though this may be a simplified rough approximation. The formula with k=0.19 is reported in Perry for rotary driers (5th ed, p 20-40, Solids-Drying Equipment), and I verified it for a pilot rotary kiln too (more complex formulae consider additional factors and material properties). A mill is also a rotating cylinder, but with balls in it, so k is expected to be different. At any case Tres can be assumed more or less independent of feed rate.
Hold up (understood as held mass fraction) in steady state is feed rate * residence time; thus hold up can be assumed proportional to residence time. Apparently longer residence time will result in thinner granulometry at the exit (all other parameters remaining same), but Tres is assumed to remain constant under supposed conditions as said (constant L, N, D, S).
(Q1) Higher feed rate will increase hold up while residence time will remain more or less same, so exit material will have a coarser granulometry (overfeeding can shut the mill down due to excessive hold up).
Note: In one case at least, mill capacity for a given exit granulometry was expressed as K*V*D^0.5/dp^0.25 ton/h (K=dimensional constant, V=mill int. volume=π*D^2*L/4, D= mill int diameter, L=mill length, dp=max (5% oversize) feed diameter).
(Q3) Concerning the balls, D. Liddel (Handbook of Chemical Engineering, McGraw-Hill, 1922, Chapter V ‘crushing and grinding’) advises that:
- Best results occur when the mill is loaded with balls between 3/10 and 4/10 full (personal interpretation: when balls in empty mill have a height = 0.3D – 0.4D).
- Mills operate between 0.6 (grinding by attrition) and 0.8 (grinding by impact) of the critical rotational speed.
- Balls size varies between 1-7 in, coarse feed needs big size; also hardness of material affects ball size.
Besides D Liddel’s advice, reduction of total ball weight (due to abrasion) is expected to result in coarser material at exit. So carbon steel balls are periodically replaced, which can be less often for stainless steel balls (being harder).

Hope above is helpful, comments welcomed.

Edited by kkala, 04 October 2010 - 02:40 AM.

[thaqrhys]

Dear sirs,

Discussing about the Ball Mill.

I have a reaction which involving Aluminium powder and Red Phosphorus powder. Since both of them are in solid state and the reaction needs to be well mixed. I'm considering using Ball Mill as the reactor.

While in the same time, this reaction needs to be heated until 500C approx. The heating system will use direct firing from the bottom.

My question is, is it possible to apply this kind of system on Ball Mill?

My concern with this system is that the heat will conduct to the gearbox and motor that will damage these two parts.

Thanks and looking forward to hearing any news from engineers here.

Attached Files

•  Reactor Design.pdf   39.43KB   26 downloads