Ball mill is the key equipment for crushing after the material is broken.Ball mill is one of the high fine grinding machines widely used in industrial production.There are many kinds of ball mill, such as hand ball mill, horizontal ball mill, ceramic ball mill, ball mill bearing bush, energy saving ball mill, energy ball mill enamel ball mill.
How to operate the ball mill correctly is an important problem in the dressing process.
At present, mining industry development is hot and skilled workers are relatively scarce. Many of them take up their posts without long-term formal training, thus causing great economic losses to mining enterprises.In addition, the operation of grinding belongs to the actual production experience technology, many engineers and technicians do not understand, and the technical experience in this area can not be found in all kinds of books.Therefore, according to the author many years in the production debugging instruction experience and the theory technology union foundation, carries on the detailed elaboration to the mill operation.
As ball grinder operation, relatively fixed without adjustment factors include: ore mineral hardness, crushing, lattice screen mesh size, ball mill type, quality of steel ball, steel ball, steel ball size proportion, ball mill, classifier impeller rotational speed, classifier of spacing, classifier main shaft hoisting height, grader blade wear, classifier overflow weir height, classifier under opening under high and low, classifier opening size, opening grading machine, grading machine opening size.This part of the factors for the design and process of the early development.Of course, now many concentrator design is not reasonable, equipment installation or equipment quality problems.First of all, this part of the factors.
Selection of ball mill model: different ball mill models can meet different technical requirements. This factor must be reasonably selected in the design. For details, please refer to the selection and calculation of ball mill.
Ball mill according to the installation of different centers, size gear meshing deviation and other issues.
The gear of the reducer of the transmission part of the ball mill has sand holes.
The following focuses on the important parameters for the daily adjustment of the ball grinder, which is also a direct reflection of the ball grinder operation level, grinding utilization rate of the important content.There are: ball mill feed water size, ball mill discharge mouth at the size of water, feed size.
For ball mill bulging belly aura several aspects can cause attention, the first is whether ball mill feeding mouth spit expected, the second is to listen to the ball mill, ball mill bulging belly, smaller and boring, the third is to look at the ball mill current control cabinet, particularly want to stress is that if the ball mill bulging belly, its current value smaller, and many operators and engineers believe that the contrary, they think ore in the ball mill bulging belly because of ball mill is larger, the current value is bigger, this is wrong point of view.Its principle is: ball mill bulging belly, because the amount of ore in the ball mill is more, and the ball mill ore is large, steel ball, ore is run with ball mill barrel, ball mill row ore mouth ore granularity coarsens, at this time, the ball mill work become smaller, smaller by the electrical energy into kinetic energy, electrical energy is smaller, under a certain voltage, electricity to smaller and smaller cause changes is the current value.
How to effectively improve the fineness of grinding is one of the important links in the dressing process.
Because the cost of grinding operation is a higher part of the concentrator, how to effectively and reasonably control the fineness of grinding is an important factor to directly reduce the cost of dressing and improve the economic benefits of the concentrator.Grinding fineness is one of the many factors that affect the mineral processing index.Therefore, the ball grinder's technical operation is extremely important.
First of all, it is necessary to fully understand the influencing factors of grinding fineness.Sum up, the factors affecting grinding fineness are: ore hardness, crushing, lattice screen mesh size, feed amount and proportion of ball mill type, number of steel ball, steel ball size, ball mill liner wear and ball mill, classifier spindle rotational speed, classifier of hoisting height, grader blade wear, classifier overflow weir height, classifier under opening under high and low, classifier opening size, opening grading machine, sizing machine, sand return water size, opening size ball mill, ball mill feed size row ore mouth water size, etc.
Knowing all these influencing factors, we need to search item by item in the production operation to find the best regulating factors.
Hardness of raw ore: the hardness of different ores is not the same. This factor is fixed relative to the same ore and cannot be adjusted.However, in the production, under the precondition of mineral processing technology requirements, reasonable ore blending can be carried out to make the ore size as uniform as possible, and the proportion of lump and powder is reasonable and stable.In addition, in the belt feeding place of the ball mill, the belt may leak due to wear for a long time, and most of the leakage is powder. This part of the leakage must be added to the ball mill as soon as possible.Especially difficult mineral separation, often powder mineral and block mineral properties are not the same.
Spindle hoisting height of classifier is also an important factor affecting the amount of sand return and grinding fineness.Normal production requires the classifier spindle in place.Some concentrator ball grinder in the equipment overhaul, because the ore in the classifier is not clean, in a long time to sink under the collection, the mud sink is more solid, in the lower the classifier spindle, due to careless, not put the spindle down completely, resulting in less sand return than normal.In addition, the spindle did not put down may also be because the spindle for a long time did not clean oil, so in the process of operation to pay attention to.
The adjustment of the crushing particle size, mesh mesh mesh is closed, the ball grinder must be on the crushing system supervision, if in the production of the ball mill feeding particle size changes, must immediately reflect to the crushing workshop.Finally, the finer the crushing particle size, the better.
Classifier blade wear: after blade wear, relative to the amount of sand return reduced, resulting in grinding fineness coarser, in addition, if the blade wear, will affect the classifier life, so in the work of timely inspection of blade wear, timely replacement of worn blade.Ball mill speed, classifier speed, classifier impeller spacing: set in the purchase of the ball mill, pay attention to the purchase of view consulting.
Classifier overflow weir height, size affects the precipitation of ore area, in production, we can according to the requirement of the grinding fineness, appropriate of classifier overflow weir height adjustment, if you want the grinding fineness and welding a certain height in the classifier two edge Angle, pull the plug wood with method to adjust the classifier overflow weir height, sometimes through the slime long-term accumulation, can raise the height of the overflow dam nature.
Classifier under opening under high and low, classifier opening size, opening grading machine, grading machine opening size was produced during the equipment installation on-site, in many plants, because in equipment installation classifier to adjust the opening size has no good, and the workers also don't pay attention to in the process of operation, intangible is also affected the grinding operation.Classifier under low opening, relative area ore deposits is big, so the sand return quantity will be big, grinding fineness is relatively thin, classifier under open big, relative area is ore precipitation, water is relatively flat, so the sand return quantity will be big, grinding fineness is relatively thin, the grading machine low opening, sand return quantity is relatively large, the grinding fineness and relatively grading machine open big, relative return sand amount is relatively large, relative to fine grinding fineness.Otherwise the opposite is true.
First of all, we should assume that all other factors are normal, the principle is: in the case of a certain grinding fineness, we want to maximize the processing capacity, so as to effectively improve the production efficiency.Relatively speaking, the finer the grinding fineness is, the more sufficient the dissociation of useful minerals and gangue minerals will be, which is beneficial to improve the metal recovery rate. Therefore, the grinding fineness can be improved as much as possible under the condition of a certain amount of ore processed.In addition, grinding is the first step of the mineral processing technology, in order to ensure the stability of production, grinding to ensure the stability of as far as possible.
In case, to the ore must be row ore mouth water size, feed quantity size directly affect the fineness of grinding thickness, in the domestic many mines are no grinding automation, the size of the water, directly by the manual regulation ball grinder, because the two currents is bigger, increase and decrease it's hard to see, so you must require careful observation and finely adjusted.First of all, we understand that the mill feed water increases, grinding concentration becomes thin, grinding fineness will become coarse, on the contrary, the mill feed water decreases, grinding concentration increases, grinding fineness will become fine.The flushing water at the discharge port of the ball mill becomes larger, the overflow becomes thinner and the overflow fineness becomes finer.On the contrary, the flushing water at the discharge port of the ball mill becomes smaller, the overflow thickens and the overflow fineness becomes coarser.Therefore, under the condition of other conditions including constant ore content, the feed water of the ball mill can be reduced and the flushing water at the ore discharge port of the ball mill can be increased to improve the fineness of grinding. It is better to adjust the two conditions at the same time to ensure that the fluctuation of flotation caused by the change of ore mass caused by the adjustment of grinding fineness can be reduced as far as possible.In many dressing plants, because of the ball grinder's operation, the amount of ore pulp changes greatly, resulting in unstable flotation liquid level, if the flotation workers did not timely treatment, resulting in the change of metal recovery rate and grade.If the grinding fineness coarse adjustment is opposite.
On the premise of ensuring the fineness of grinding, the feed amount of the ball mill can be increased.The size of the ore feed, in order to achieve the grinding fineness requirements at the same time, and the ball mill does not bulge to.The whole process must be carried out in each link of the delicate operation.
Three, grinding fineness in addition to the above links, but also add steel ball size ratio.
How to add steel balls in proportion to the ball size depends on factors such as the diameter of the ball mill, the hardness of the ore, the grain size of the ore into the ball mill, the hardness (quality) of the ball, and the speed of the ball mill.
When the type of the ball mill is determined, the speed of the ball mill is also set.The hardness of the ore is measurable.The ore size of the ball mill is determined by changing the size of the grizzly.How to add steel balls to the ball mill in proportion to their size?The present author summarizes the perennial practice and theoretical experience as follows:
Normally, new according to the loading of ball mill has a run-in period, in the process of running in, steel ball quantity for the first time to add, account for 80% of the maximum loading ball of ball mill, add the proportion of steel ball can be according to the size of steel ball (Φ 120 mm, 100 mm, 80 mm Φ Φ, Φ 60 mm, Φ 40 mm) size.
Steel ball addition: the total amount of ball is different for different types of ball mill.For example, MQG1500 3000 ball mill (processing capacity 100-150 tons) has a maximum loading capacity of 9.5 ~ 10 tons.First add steel ball (120 mm and 100 mm Ø Ø) accounted for 30% ~ 40% and 40% ~ 30%, the ball ball in 80 mm (Ø 60 and 40 mm Ø) accounted for 30%.Why in the process of ball mill in the steel ball only add 80%, because after installation of ball mill, ball mill tooth need to mesh size, capacity (ore) are to be gradually increased, for normal operation in two or three days in a row, ball mill stop ball mill pick up to check the size of the gear meshing, for everything is normal, open the add the remaining 20% steel ball mill manhole covers the second.
Ball mill boot after running normally, each class to add press 3, 4, 3 (Ø 120 mm for 3, 100 mm is 4, 80 mm Ø Ø for 3) added.Note: the addition of small steel ball is only the first time.Because, ball mill normal operation of the ball and ball, ball and ore, ball and ball mill lining board between the reasonable grinding, will increase the wear, so that the large ball grinding small (grinding for the ball), ball grinding for the ball.So usually under normal circumstances, do not need to add the ball.In the case of adding small balls, there is no monomer dissociation in the useful mineral particle size. When the fineness of the grinding machine fails to meet the requirements of flotation, an appropriate amount of small balls can be added.
The steel ball in the ball mill wears away constantly in the process of running.
------ -- Weifang Guote Mining Equipment Company
