The steel ball is the grinding media of the gold ball mill. In the working process, the steel ball will directly affect the grinding efficiency of the gold ball mill and even the working efficiency and product quality of the whole concentrator.
Below, we will introduce the steel ball in detail from its specification and quantity, material, ratio and grading to help you choose and add the steel ball correctly, so as to improve the grinding efficiency of the gold ball mill.
Generally, the diameter of the steel ball is between 20mm and 125mm. Among them, the diameter of the small steel ball is generally 40mm and a 60mm, the diameter of the medium steel ball is generally 80mm, and the diameter of the large steel ball is 100mm or 120mm. The diameter of the super large steel ball is 130mm-150mm.
Theoretically, when the filling amount of steel ball in the ball mill is 40%, the ball mill can obtain the ideal output. But in the actual production, the filling rate of the steel ball in the ball mill is mostly about 35%, that is, the volume of the steel ball in the gold ball mill is kept slightly below the horizontal centerline of the ball mill.
As the "consumable" in the grinding operation, the wear degree of the steel ball is different due to the different material. At present, the mainstream steel balls of the gold ball mill on the market mainly include casting steel balls and forged steel balls.
Casting steel balls are mainly low chromium casting steel ball, medium chromium casting steel ball and high chromium casting steel ball, whose hardness, impact value and breakage rate are related to the metallographic structure of steel. The higher the chromium content, the better the wear resistance of the steel ball.
Forged steel gold ball mills mainly include low carbon alloy steel ball, medium carbon alloy steel ball, high manganese steel ball, rare earth chromium molybdenum alloy steel ball. The impact toughness of the forged steel ball is large, not easy to deform, but the crushing rate is low.
When first enabled, the gold ball mill needs the large, medium and small steel ball for matching, and the steel mill ball for the first time should be added to 80% of the amount limit that the ball mill manufacturer of ball mill suggests. Because the gears of the ball mill need mesh after the installation, and the processing capacity of the ball mill is increased gradually, then the ball mill operator needs to observe the condition of gear meshing in two or three days. If all is going well, the ball mill operator can open the hole cover to add the remaining 20% of steel ball.
Usually, the small steel balls are used only in the first addition. When the ball mill is running normally, there will be reasonable friction between the steel ball and the steel ball, the steel ball and the ore, the steel ball and the lining plate of the ball mill, which makes the wear increase. The large steel ball is ground into small, and the medium steel ball is ground into the small steel ball, so there is no need to add the small steel ball under normal circumstances. However, if the particle size of the useful mineral does not realize the monomer separation, and the grinding fineness of the ball mill cannot meet the separation requirements (especially the flotation separation requirements), the appropriate amount of small steel balls can be added into the gold ball mill.
In addition, the ball mill steel ball is constantly worn in the operation, the ball mill operator must regularly make up the steel ball and maintain the load filling rate of the steel ball and reasonable ratio.
Determine the grading scheme of the steel ball usually starts from the first warehouse (namely the coarse crushing warehouse). For the multi-bin ball mill, the grading of the first bin is particularly important. According to the cross-gradation principle, the minimum diameter of the steel ball in the previous bin determines the maximum diameter of the steel ball in the next bin. It can be seen that the grading of the steel ball in the first warehouse actually dominates the grading of the steel ball in the other warehouses.
The upper limit of the ball diameter is determined according to the upper limit of particle size of the grinding material. The average diameter of the steel ball is determined according to the average particle size of the grinding material.
The composition proportion of each specification steel ball is set according to the proportioned principle of "small at both ends and large in the middle" for the grinding body and the distribution characteristics of material size,.
Calculate the average ball diameter of the mixed steel ball, and compare with the original average ball diameter of the steel ball, add the steel ball according to the proportion of the ball size. If the deviation is large, it is necessary to set the composition proportion of various steel balls and rematch the balls until the deviation is small.
The secondary grading method means to only select two different diameters of ball mill steel balls for grading. The diameter of the large steel ball depends on the particle size of the grinding material, and the diameter of the small steel ball depends on the size of the space between the large steel balls.
Usually, the diameter of small steel ball should be 13%-33% of the diameter of large steel ball. Generally, the small steel ball accounted for 3%-5% of the mass of large steel ball, and the incorporation amount of small steel ball shouldnt affect the filling rate of large steel ball in principle.
These are the main aspects of the steel ball involved in the grinding process: specifications and quantity, material, ratio and grading. For the concentrator, the selection and application of the steel ball involve many technical problems, it is suggested that the mine owners carefully analyze their own actual situation, determine the suitable steel ball for the concentrator through consulting the professional gold ball mill manufacturers, thus avoiding the unnecessary economic losses.
Capacity 0.65~130 t/h Feeding size 20-25mm Discharge size 0.074-0.89mm Grinding ball 1.5-338t Application gold ore and other ores grinding Advantages Rolling bearing has little friction and low consumption; Reasonable sealing, low failure; Little dust, low noise, energy-saving; Special design, good grinding effect, 60s manual response, 24hrs quotation. More ball mill model details
Since most of the gold mines contain impurities, we only can obtain the gold concentrate after a series of steps such as crushing, grinding, and sieving. The ball mill plays an important role in the gold ore grinding process, as a kind of high-efficiency fine grinding equipment, it has been widely used in fine grinding and ultra-fine grinding operations in mining, chemical, new materials, building materials and other fields. In the gold mining plant, the ball mill usually set after the jaw crusher, in a second-stage grinding, process sulfur-containing arsenic-containing refractory gold ore, and tailings treatment. The outstanding advantages of gold ball mill are low energy consumption, ultra-fine grinding, simple foundation, low noise and vibration, and has been regarded as an efficient new fine grinding equipment.
The main parts of the gold ore ball mill includes the feeding, the supporting device, the rotating part, the unloading device and the transmission device. Working principle: gold ore ball mill is a low-speed rotary cylinder horizontally mounted on the bearing. In the rotary cylinder, there are heavy steel balls. Along the motor and gear rotates the cylinder, generating centrifugal force to bring the steel ball to a certain height and then falling. The ore material are gradually crushed and ground by the steel ball impact force. The material is subjected to impact crushing and grinding, and the material is slowly flowed from the feeding end to the discharging end by the material level difference, until the material is discharged. That is the overflow ball mill.
Gold ore ball mill is especially suitable for two-stage grinding or ultra-fine grinding because of its advantages of ultra-fine grinding, high efficiency and energy-saving, low installation cost and low wear.
A gold mine used the JXSC gold ore ball mill for the second stage grinding to technically transform the original process, and achieved good results. After the transformation, the production capacity reached 130~140t/d. The production results show that the JXSC gold mine ball mill has low electromechanical consumption, high grinding efficiency, low wear of wearing parts and vibration noise less than 85dB.
There are rich sulfur-bearing and arsenic-containing refractory gold ore resources, but due to the lack of practical technology, these gold resources are not fully utilized. The JXSC Gold Mining Ball Mill has two basic characteristics of ultra-fine grinding and enhanced chemical leaching. The use of ultra-fine grinding of the JXSC gold ore ball mill can strengthen the alkali leaching, which may provide a technically feasible and economically reasonable treatment process for some sulfur-containing and arsenic-containing refractory gold ores.
Ball mill superfine grinding for secondary utilization of gold-bearing tailings in which gold was not fully recovered in the old days due to the technique limitation. In some gold tailings, the gold content is as high as 2~8g/t, if using the JXSC gold ore ball mill to retreat and recover gold, its potential economic benefits are huge.
The ball mill price are determined by many factors, such as machine weight, cylinder material, steel ball material, motor brand, lined plate thickness and material, etc. A professional and reasonable quotation made on your mine conditions, mine minerals, capacity, rock hardness, clay, etc. We are here to help.
JXSC is a 35 years Chinese mining equipment manufacturer, has great quality & price advantages in the ball mill, jaw crusher, trommel scrubber, shaker table and so on. Contact us for a 12hrs quotation.
A mill is a grinder used to grind and blend solid or hard materials into smaller pieces by means of shear, impact and compression methods. Grinding mill machine is an essential part of many industrial processes, there are mainly five types of mills to cover more than 90% materials size-reduction applications.
Do you the difference between the ball mill, rod mills, SAG mill, tube mill, pebble mill? In the previous article, I made a comparison of ball mill and rod mill. Today, we will learn about the difference between SAG mill vs ball mill.
AG/SAG is short for autogenous mill and semi-autogenous mill, it combines with two functions of crushing and grinding, uses the ground material itself as the grinding media, through the mutual impact and grinding action to gradually reduce the material size. SAG mill is usually used to grind large pieces into small pieces, especially for the pre-processing of grinding circuits, thus also known as primary stage grinding machine. Based on the high throughput and coarse grind, AG mills produce coarse grinds often classify mill discharge with screens and trommel. SAG mills grinding media includes some large and hard rocks, filled rate of 9% 20%. SAG mill grind ores through impact, attrition, abrasion forces. In practice, for a given ore and equal processing conditions, the AG milling has a finer grind than SAG mills.
The working principle of the self-grinding machine is basically the same as the ball mill, the biggest difference is that the sag grinding machine uses the crushed material inside the cylinder as the grinding medium, the material constantly impacts and grinding to gradually pulverize. Sometimes, in order to improve the processing capacity of the mill, a small amount of steel balls be added appropriately, usually occupying 2-3% of the volume of the mill (that is semi-autogenous grinding).
High capacity Ability to grind multiple types of ore in various circuit configurations, reduces the complexity of maintenance and coordination. Compared with the traditional tumbling mill, the autogenous mill reduces the consumption of lining plates and grinding media, thus have a lower operation cost. The self-grinding machine can grind the material to 0.074mm in one time, and its content accounts for 20% ~ 50% of the total amount of the product. Grinding ratio can reach 4000 ~ 5000, more than ten times higher than ball, rod mill.
Ball mills are fine grinders, have horizontal ball mill and vertical ball mill, their cylinders are partially filled with steel balls, manganese balls, or ceramic balls. The material is ground to the required fineness by rotating the cylinder causing friction and impact. The internal machinery of the ball mill grinds the material into powder and continues to rotate if extremely high precision and precision is required.
The ball mill can be applied in the cement production plants, mineral processing plants and where the fine grinding of raw material is required. From the volume, the ball mill divide into industrial ball mill and laboratory use the small ball mill, sample grinding test. In addition, these mills also play an important role in cold welding, alloy production, and thermal power plant power production.
The biggest characteristic of the sag mill is that the crushing ratio is large. The particle size of the materials to be ground is 300 ~ 400mm, sometimes even larger, and the minimum particle size of the materials to be discharged can reach 0.1 mm. The calculation shows that the crushing ratio can reach 3000 ~ 4000, while the ball mills crushing ratio is smaller. The feed size is usually between 20-30mm and the product size is 0-3mm.
Both the autogenous grinding mill and the ball mill feed parts are welded with groove and embedded inner wear-resistant lining plate. As the sag mill does not contain grinding medium, the abrasion and impact on the equipment are relatively small.
The feed of the ball mill contains grinding balls. In order to effectively reduce the direct impact of materials on the ball mill feed bushing and improve the service life of the ball mill feed bushing, the feeding point of the groove in the feeding part of the ball mill must be as close to the side of the mill barrel as possible. And because the ball mill feed grain size is larger, ball mill feeding groove must have a larger slope and height, so that feed smooth.
Since the power of the autogenous tumbling mill is relatively small, it is appropriate to choose dynamic and static pressure bearing. The ball bearing liner is made of lead-based bearing alloy, and the back of the bearing is formed with a waist drum to form a contact centering structure, with the advantages of flexible movement. The bearing housing is lubricated by high pressure during start-up and stop-up, and the oil film is formed by static pressure. The journal is lifted up to prevent dry friction on the sliding surface, and the starting energy moment is reduced. The bearing lining is provided with a snake-shaped cooling water pipe, which can supply cooling water when necessary to reduce the temperature of the bearing bush. The cooling water pipe is made of red copper which has certain corrosion resistance.
Ball mill power is relatively large, the appropriate choice of hydrostatic sliding bearing. The main bearing bush is lined with babbitt alloy bush, each bush has two high-pressure oil chambers, high-pressure oil has been supplied to the oil chamber before and during the operation of the mill, the high-pressure oil enters the oil chamber through the shunting motor, and the static pressure oil film is compensated automatically to ensure the same oil film thickness To provide a continuous static pressure oil film for mill operation, to ensure that the journal and the bearing Bush are completely out of contact, thus greatly reducing the mill start-up load, and can reduce the impact on the mill transmission part, but also can avoid the abrasion of the bearing Bush, the service life of the bearing Bush is prolonged. The pressure indication of the high pressure oil circuit can be used to reflect the load of the mill indirectly. When the mill stops running, the high pressure oil will float the Journal, and the Journal will stop gradually in the bush, so that the Bush will not be abraded. Each main bearing is equipped with two temperature probe, dynamic monitoring of the bearing Bush temperature, when the temperature is greater than the specified temperature value, it can automatically alarm and stop grinding. In order to compensate for the change of the mill length due to temperature, there is a gap between the hollow journal at the feeding end and the bearing Bush width, which allows the journal to move axially on the bearing Bush. The two ends of the main bearing are sealed in an annular way and filled with grease through the lubricating oil pipe to prevent the leakage of the lubricating oil and the entry of dust.
The end cover of the autogenous mill is made of steel plate and welded into one body; the structure is simple, but the rigidity and strength are low; the liner of the autogenous mill is made of high manganese steel.
The end cover and the hollow shaft can be made into an integral or split type according to the actual situation of the project. No matter the integral or split type structure, the end cover and the hollow shaft are all made of Casting After rough machining, the key parts are detected by ultrasonic, and after finishing, the surface is detected by magnetic particle. The surface of the hollow shaft journal is Polished after machining. The end cover and the cylinder body are all connected by high-strength bolts. Strict process measures to control the machining accuracy of the joint surface stop, to ensure reliable connection and the concentricity of the two end journal after final assembly. According to the actual situation of the project, the cylinder can be made as a whole or divided, with a flanged connection and stop positioning. All welds are penetration welds, and all welds are inspected by ultrasonic nondestructive testing After welding, the whole Shell is returned to the furnace for tempering stress relief treatment, and after heat treatment, the shell surface is shot-peened. The lining plate of the ball mill is usually made of alloy material.
The transmission part comprises a gear and a gear, a gear housing, a gear housing and an accessory thereof. The big gear of the transmission part of the self-grinding machine fits on the hollow shaft of the discharge material, which is smaller in size, but the seal of the gear cover is not good, and the ore slurry easily enters the hollow shaft of the discharge material, causing the hollow shaft to wear.
The big gear of the ball mill fits on the mill shell, the size is bigger, the big gear is divided into half structure, the radial and axial run-out of the big gear are controlled within the national standard, the aging treatment is up to the standard, and the stress and deformation after processing are prevented. The big gear seal adopts the radial seal and the reinforced big gear shield. It is welded and manufactured in the workshop. The geometric size is controlled, the deformation is prevented and the sealing effect is ensured. The small gear transmission device adopts the cast iron base, the bearing base and the bearing cap are processed at the same time to reduce the vibration in operation. Large and small gear lubrication: The use of spray lubrication device timing quantitative forced spray lubrication, automatic control, no manual operation. The gear cover is welded by profile steel and high-quality steel plate. In order to enhance the stiffness of the gear cover, the finite element analysis is carried out, and the supporting structure is added in the weak part according to the analysis results.
The self-mill adopts the self-return device to realize the discharge of the mill. The self-returning device is located in the revolving part of the mill, and the material forms a self-circulation in the revolving part of the mill through the self-returning device, discharging the qualified material from the mill, leading the unqualified material back into the revolving part to participate in the grinding operation.
The ball mill adopts a discharge screen similar to the ball mill, and the function of blocking the internal medium of the overflow ball mill is accomplished inside the rotary part of the ball mill. The discharge screen is only responsible for forcing out a small amount of the medium that overflows into the discharge screen through the internal welding reverse spiral, to achieve forced discharge mill.
The slow drive consists of a brake motor, a coupling, a planetary reducer and a claw-type clutch. The device is connected to a pinion shaft and is used for mill maintenance and replacement of liners. In addition, after the mill is shut down for a long time, the slow-speed transmission device before starting the main motor can eliminate the eccentric load of the steel ball, loosen the consolidation of the steel ball and materials, ensure safe start, avoid overloading of the air clutch, and play a protective role. The slow-speed transmission device can realize the point-to-point reverse in the electronic control design. When connecting the main motor drive, the claw-type Clutch automatically disengages, the maintenance personnel should pay attention to the safety.
The slow drive device of the ball mill is provided with a rack and pinion structure, and the operating handle is moved to the side away from the cylinder body The utility model not only reduces the labor intensity but also ensures the safety of the operators.
Ball mill is the key equipment for grinding materials. those grinding mills are widely used in the mining process, and it has a wide range of usage in grinding mineral or material into fine powder, such as gold, ironzinc ore, copper, etc.
JXSC Mining produce reliable effective ball mill for long life and minimum maintenance, incorporate many of the qualities which have made us being professional in the mineral processing industry since 1985. Various types of ball mill designs are available to suit different applications. These could include but not be restricted to coal mining grate discharge, dry type grinding, wet mineral grinding, high-temperature milling operations, stone & pebble milling.
A ball mill grinds ores to an end product size of thirty-five mesh or finer. The feeding material to a ball mill is treated by: Single or multistage crushing and screening Crushing, screening, and/or rod milling Primary crushing and autogenous/semi-autogenous grinding.
Normal feed sizes: eighty percent of six millimeters or finer for hard rocker eighty percent of twenty-five millimeters or finer for fragile rocks (Larger feed sizes can be tolerated depending on the requirements).
The ratio of machine length to the cylinder diameter of cylindrical type ball mills range from one to three through three to one. When the length to diameter ratio is two to one or even bigger, we should better choose the mill of a Tube Mill.
Grinding circuit design Grinding circuit design is available, we experienced engineers expect the chance to help you with ore material grinding mill plant of grinding circuit design, installation, operation, and optimization. The automatic operation has the advantage of saving energy consumption, grinding media, and reducing body liner wear while increasing grinding capacity. In addition, by using a software system to control the ore grinding process meet the requirements of different ore milling task.
The ball mill is a typical material grinder machine which widely used in the mineral processing plant, ball mill performs well in different material conditions either wet type grinding or dry type, and to grind the ores to a fine size.
Main ball mill components: cylinder, motor drive, grinding medium, shaft. The cylinder cavity is partial filling with the material to be ground and the metal grinding balls. When the large cylinder rotating and creating centrifugal force, the inner metal grinding mediums will be lifted to the predetermined height and then fall, the rock material will be ground under the gravity force and squeeze force of moving mediums. Feed material to be ground enters the cylinder through a hopper feeder on one end and after being crushed by the grinding medium is discharged at the other end.
Mining Equipment Manufacturers, Our Main Products: Gold Trommel, Gold Wash Plant, Dense Media Separation System, CIP, CIL, Ball Mill, Trommel Scrubber, Shaker Table, Jig Concentrator, Spiral Separator, Slurry Pump, Trommel Screen.