How to throttle resources for ball mill

 Nowadays, with the continuous development of social productivity, green energy saving has become the theme of today's society, and various equipment has been continuously improved to save energy and reduce expenditure, especially in the heavy industry industry. It's easy to say, but for mining, power consumption is a big problem. Therefore, in response to similar problems, we propose two improvements, one is the equipment itself, and the other is to improve the operation of the process.

On the one hand, resource throttling of the ball mill is very important. First of all, when designing the ball mill, full consideration must be given to the accessories and devices to save power and reduce consumption. In the design of the ball mill, considering the purpose of energy saving and consumption reduction, a new type of transmission system is specially designed, and a planetary gear reducer is used for transmission, which changes the traditional transmission layout and greatly improves the working efficiency of the motor. This is one of them. Design advantages. In addition, when designing the ball mill, the bearing, drive mode, and liner of the ball mill also added innovations and played a great role.

Another aspect is the process operation. The process is continuously optimized. The three main aspects are the selection of the process flow, the topping method of the steel ball, and the stable and safe operation. Continuously optimize.

The above is what we need to improve. Starting from these aspects to improve equipment to save resources is also a direction we need to continue to develop.

The "hidden rules" of ball milling

 Corresponding proportioning of the ball mill, so that it can crush minerals to the greatest extent, and meet the requirements of mineral crushing and grinding. The quality of mineral crushing can directly affect the efficiency of milling, and ultimately affect the overflow output of the ball mill. The level of ball loading can directly affect the crushing effect. These parameters are mainly affected by the specifications of the ball mill, the internal structure of the ball mill, and the fineness of the product.

The ball must have sufficient impact force so that the ball has sufficient crushing capacity to handle the material, which is directly related to the diameter of the steel ball.

The number of impacts of loading the ball must be enough so that the ball can crush the material. The average ball diameter and filling rate are the main influencing factors. The amount of filling is fixed. In order to ensure sufficient impact force, the diameter of the sphere can be reduced and the number of spheres can be increased to increase the number of impacts on the mineral and improve the crushing efficiency.

To ensure sufficient time for the material to grind in the mill, the ball must have the ability to control the flow rate to ensure that the material is fully crushed.

The law of two-level ball allocation

The use of two spheres of different specifications for grading is called two-stage grading, but there is a requirement that the diameters of the two spheres differ greatly. Its main function is to improve the impact capacity and the number of impacts of the mill. In addition, the higher bulk density allows the material to be fully ground.

In the two-stage ball distribution rule, the large balls are mainly used to crush materials, and the small balls are mainly used to fill the gaps of the large balls to increase the bulk density of the balls, thereby controlling the flow rate of the flow, thereby increasing the grinding The second is the transfer of energy; the last is to squeeze the coarse-grained materials in the gap into the impact area of ​​the big ball.

See details：https://www.pizzerie-u-pepy.cz

What to do if the flotation effect is not good?

 In the flotation process, there are many processes that affect the flotation effect. There are not only non-adjustable factors of ore properties, but also adjustable factors such as pulp concentration, pulp temperature, pH, flotation time, grinding fineness, and reagents. Let's introduce them one by one below.

Ore properties refer to the chemical composition, mineral composition, structure, structure and element occurrence state of the ore. The oxidation degree of the ore has a great influence on the flotation effect, because oxidation will change the original mineral structure and make the mineral composition It is more complicated, thus changing the physical and chemical properties, and at the same time, oxidation will change the pH of the pulp, which will affect the use of chemicals.

There is a great relationship between pulp concentration and recovery rate. Generally speaking, there is a normal distribution between the slurry concentration and the recovery rate. Only when the optimal concentration is reached, the recovery rate also reaches its peak. In the flotation process, the slurry must maintain a certain concentration of reagent to obtain good results. When the slurry is thicker, the reagent concentration should be increased accordingly. When the slurry concentration increases, the flotation time and processing capacity of the flotation machine should also increase accordingly.

The temperature of the slurry is also an important factor affecting the flotation effect. Heating can accelerate the movement of molecules, accelerate the dispersion and hydrolysis of the reagent, and increase the interaction speed between the reagent and the mineral surface.

The pH of the pulp often affects the floatability of the mineral, but the critical pH will change with the change of flotation conditions. Under certain conditions, any mineral has a suitable pH value, and only under this value can a better flotation index be obtained.

Flotation time refers to the residence time of the slurry in the flotation tank. To determine the best flotation time, it should be determined in advance through the beneficiation test. When the floatability is good, the content of the minerals to be floated is low, the slurry concentration is small, the agent has a strong effect, and the flotation time is short. On the contrary, longer floating time is required.

The appropriate grinding fineness should be determined according to the particle size of the useful minerals, to dissociate the useful minerals from the gangue, and minimize the symbiosis between the minerals and the gangue. For single minerals, the fineness of grinding must be less than the upper limit of the floating particle size of the mineral.

However, it should be noted that the finely ground particle size of the ore will also have an adverse effect on the flotation effect, so the selection of the appropriate grinding particle size is of decisive significance for the final effect.

In the flotation process, the agent addition system is called the formula, which mainly refers to the type, quantity, order, addition point and preparation method of the agent. The type of medicament is mainly determined by the results of ore selectivity research, and the dosage of medicament is determined by the beneficiation test and practical experience. In the actual operation process, timely adjustments should be made according to changes in the situation. It is determined according to the dissolution rate and action time of the drug.

Every detail in the flotation process will affect the final flotation effect. It is recommended to conduct a beneficiation test before flotation, and determine the process parameters according to the beneficiation test results to achieve the best results.

How to determine the reasonable load of the grinding body of the ball mill

 The configuration of the grinding body of the ball mill will have a great influence on the output quality of the ball mill. If there is a gradation of the grinding body, then the conditions such as the load of the grinding body must be fully considered. The following briefly introduces the calculation method of the grinding body.

The first condition is the filling rate of the abrasive body. So what is the filling rate of the abrasive body? The percentage of the filling volume of the grinding body compared to the effective volume is called the filling rate of the grinding body. Generally speaking, if the filling rate of the grinding body is too high or too low, the grinding efficiency of the mill will be too low. For the grinding body filling rate greater than 32%, you can use the formula to calculate:

Φ0=113-126H/Di

Since there are many influencing factors of the grinding body, it is necessary to find a better filling rate in the production and adjust the equilibrium state according to the degree of change of the influencing factors.

Then we have to mention the loading capacity of the grinding body. What is the loading capacity of the grinding body? It is the quality of the grinding body loaded into the mill (or in the container), and the size of the load mainly depends on the filling rate of the mill. The calculation formula of the loading capacity of the grinding body:

G=VΦ0

                                                G=0.00785Di2LΦ0

It can be seen from the above that G——loading capacity (t), V——effective volume (m3), Di——effective diameter (m), L——effective length (m), Φ——filling rate (%), P ——Bulk density (t/m3)

How to choose economical and reasonable mining methods for different mines?

 Mining method is the core of mining. It can be said that the choice of mining method determines the operation of the entire mining system. The selection of a correct and reasonable method of mining for a mine plays a decisive role in the future production and operation of the mine. Inferiority determines the mining efficiency, production scale, ore recovery rate, and ore quality of the mine. The method of mining is restricted by many factors, such as the geographical location of the ore body, the stability of the ore rock, the type of ore, the taste of the ore, and the depth of burial.

Although the burial elements of mineral deposits vary widely, in general, some rules can be summarized for the selection of mining methods, which are mainly divided into the following four situations:

1. If the buried depth of the ore body is shallow, and the extension depth is also shallow, all deposits are mined in open pit.

2. If the buried depth of the ore body is very deep, underground mining is adopted for all deposits.

3. If the burial depth of the upper part of the ore body is shallow, and the extension depth is very deep, the upper part of the ore bed adopts open-pit mining and the lower part adopts underground mining. In this case, in the middle of production, a transition period from open-pit mining to underground mining is needed.

4. The upper part of the ore body has a deeper buried depth, and the extension depth is shallower, all of which may be open-pit mining or all underground mining.

Failure analysis of ZGMn13 liner of ball mill

 Through the macro inspection and the onlooker inspection, it can be found that the liner of the ball mill will occasionally show loose casting, oxides, and a large number of massive unmelted carbides and needle-like carbides.

    The ideal microstructure of high manganese molten steel after treatment is a single austenite, but due to the metallographic examination of the liner, there are a large number of unmelted massive carbides and precipitated needle-like carbides in the microstructure. This is because the heating temperature is too low during the water toughening treatment, or the holding time is too short, so that the carbides are not fully integrated into the austenite. In the subsequent quenching and cooling process, a large amount of precipitation may be due to insufficient cooling speed. Needle carbide. From the field investigation, the heating temperature of the heat treatment furnace will be lower than the temperature required by the process due to long-term neglect and maintenance; when the water toughening treatment is cooled, because the water tank is too small, the treated tonnage is too heavy. The water temperature after cooling cannot be kept below 60 degrees Celsius, which reduces the cooling rate; if the workpiece stays in the water for too long from the furnace to the water, these will make the microstructure after the water toughening treatment appear abnormal.

    The chipping of the liner of the ball mill is mainly due to the improper longevity of the heat treatment process, the defective structure and casting shrinkage, as well as the existence of coarse non-metallic debris, which reduces the strength and toughness of the liner. Under the action of this, it will lead to the early failure of the liner.

Specific details can be consulted：https://clactononseaessex.uk/

Movement form of hydrocyclone fluid

The hydrocyclone is a separation device that uses the principle of centrifugal sedimentation to separate or concentrate the slurry. Because of its simple structure, large workload, high separation efficiency, low cost, and low maintenance cost, it has been widely used in mineral processing, petroleum and chemical industries. The structure and size of the hydrocyclone are very important for separation. The diameter and underflow of the hydrocyclone are very important parameters that affect the working capacity and separation efficiency. For a larger cyclone diameter, the separation efficiency is low, but the working capacity is high. Therefore, if the separation efficiency of the large-diameter separator is satisfied, it is preferred. For solid-liquid hydrocyclones, increasing the underflow will increase the flow rate of the underflow. However, if the amount of underflow is too large, a large amount of water will flow out from the outlet of the underflow pipe, thus impairing the function of the underflow pipe. On the contrary, if the underflow diameter is too small, it may block solid particles, especially when the feed slurry is disturbed by a large concentration. Therefore, designing a proper hydrocyclone diameter and underflow pipe size is the key to improving the separation efficiency of the hydrocyclone.

                            

The structure of the hydrocyclone looks very simple, but the requirements for its structure, productivity, and grading effect are very high, and high matching degree can improve efficiency and productivity. Structural factors directly affect the flow form and movement mode of the fluid inside the cyclone. The fluid movement in the hydrocyclone mainly has the following forms: internal and external swirling flow, under-cover flow, balanced flow, and zero-speed envelope surface. The direction of rotation of the inner and outer swirling flow is the same, both clockwise or counterclockwise, but the direction of rotation of the swirling flow is opposite, the outer swirling flow is from top to bottom, and the inner swirling flow is from bottom to top. The underflow of the cover is also called short-circuit flow. It is due to the centrifugal force and the frictional force of the inner wall of the cylinder, a small part is suddenly released under the influence of the nozzle and pressure, first hits the top cover and then moves downward, and finally overflows with the overflow. The flow port is discharged, because this part of the slurry is directly mixed into the overflow without separation, so it directly affects the separation effect. The balance flow is two streams of two-phase fluid rotating inside and outside. Due to the different sizes of overflow ports and different insertion depths, there is no time for the slurry to be discharged from the upper and lower discharge ports, and the part of the slurry fluid that is not discharged is overflowing Between the tube and the cylinder, there is a balanced vortex movement up and down to form a balanced vortex. But this part of the exercise generally does not affect efficiency. The zero-speed envelope surface is due to the different movement directions of the inner and outer swirling flows. The inner swirling flow is formed by the movement of the outer swirling flow. Relatively speaking, there is a separation surface, that is, there is a fluid separation track with an axial velocity approaching zero. surface.

∅The realization of 4.5mx6m overflow ball mill electric control system

Overflow https://clactononseaessex.uk are widely used in cement, mining and thermal power generation industries due to their simple operation and low maintenance costs. With the development of society, the ball mill has made great progress in overall performance. The ball mill electrical control system is the central system of the entire ball mill, used to control various operating techniques.

  The control system mainly includes:

(1) Control of temperature measurement of bearings and stator windings;

Each mill has three temperature measurement points for the main bearing at the feed end, the main bearing at the discharge end and the stator winding of the main motor, and the pinion bearing and the main motor have two temperature measurement points. At the same time, the status value of each point can be displayed in real time on the man-machine interface connected to the PLC, and the alarm value and shutdown value of each measurement point can be given.

(2) Control of the main bearing high and low pressure lubrication station

   The main bearing high and low pressure lubrication station includes high pressure oil supply and low pressure lubrication. The high pressure oil supply system of each station supplies two high pressure pump motors. When any high pressure pump fails to work or the oil pressure is low, the backup pump will automatically replace the original work. The pump works and continues to supply oil to the main bearing.

(3) Pressure control

The high-pressure system of the lubrication station is equipped with four pressure sensors to detect the high-pressure oil supply system in real time. When the oil pressure is lower than the lower limit setting value, the sensor will send out an audible and visual alarm signal and limit the start of the host; when it is higher than the upper limit value When the sensor will send out an audible and visual alarm signal.

(4) Oil flow control

Install a flow switch in the low pressure oil supply system near the two main bearing oil supply points to continuously monitor the oil supply flow at each point.

(5) Oil temperature control

There is no electric heater or cooler on the lubrication station, and the oil temperature is given an obvious display signal by the bimetal thermometer through the electric control system to automatically turn on the electric heater or the cooling water valve.

(6) Control of slow drive motor

The slow-speed drive motor and the main motor are interlocked with each other, and they cannot work at the same time; when the slow-speed drive motor is working, the high-voltage oil supply system should be in a normal working state.

Choose a ball mill or a rod mill?

Grinding operation is very important in the entire beneficiation process, the cost is also quite large, the investment is huge and the energy consumption is high, therefore, choosing a suitable mill is very important for the entire beneficiation plant.

At present, ball mills and rod mills are widely used in concentrators. However, the difference in appearance between ball mills and rod mills is not very large, and it is not easy to distinguish. However, a careful comparison shows that the difference between the two is still very large. First of all, from the point of view of the name, the grinding medium of the ball mill is a steel ball, generally less than 100 mm in diameter, and the grinding medium of the rod mill is a steel rod, generally greater than 500 mm in length. The discharge methods of the two are also very different. The ball mill has two types of discharge methods: grid type and overflow type. Both have advantages and disadvantages. The rod mill has no grid plate, and mainly has overflow type and opening. Two types. Secondly, the filling rate of the grinding media is also different, that is, the percentage of the equipment volume occupied by the grinding media is different. If the filling rate is too high or too low, the final effect will be affected. Usually, the ball mill is 40%-50%, and the rod mill is 35%. -45% is the most ideal. The performance of the two equipment is also quite different. Due to the different media, the rod mill grinding media is in linear contact with the ore, which has a certain selective grinding effect, the product size is more uniform, and there is less over-grinding. The ball mill media and the ore are in point contact, which has impact and grinding power, and the product size is finer, but the over-grinding phenomenon is more serious. Finally, the scope of application of the two is also different. When heavy separation or magnetic separation of tungsten tin ore and other rare metal ores, rod mills are often used to prevent excessive crushing; in the second-stage grinding process, rod mills are generally used As the first-stage grinding equipment, it has larger production capacity and higher efficiency. When processing soft or not too hard ores, rod mills can be used to replace short-head cone crushers for fine crushing, which is not only simple to configure, but also low in cost, and simplifies dust removal in the workshop.

Because of the fine grinding materials, the ball mill is prone to over-crushing. It is not suitable for the gravity separation production line in metal beneficiation, but is widely used in other beneficiation processes.

Due to the difference between ball mills and rod mills, users can choose according to their materials, grinding particle size, production methods, etc. In contrast, the products of ball mills are finer and the products of rod mills are rougher but more uniform.

What are the equipment needed for gold mining

 Gravity separation is an older method of beneficiation, which uses different settling speeds of materials in the medium for separation. For placer gold mines, due to mechanical and weathering effects, the gold-bearing parent rock is gradually broken into granular objects such as cuttings. Under the action of external force, minerals with larger specific gravity are deposited on river beds, mountain slopes and other places to form Enriched. For the sorting of placer gold ore, re-election is a more direct and economical method, and the beneficiation process of re-election includes cracking, screening, dehydration, separation and other stages. Reselection methods include jig selection, shaker selection, chute selection, centrifugal selection and other processes. These gravity separation methods are mostly used in placer gold ore with monomer dissociation, and are rarely used alone. They are generally used in combination with other processes to recover gold ore more effectively. The following briefly introduces the equipment used for reselection.

1. Jig

The jig uses water as the beneficiation medium and uses the difference in the specific gravity of the selected minerals and gangues for separation. The Xinhai mineral processing jig is improved on the basis of the traditional jig, so that the jigging pulse curve is in a sawtooth waveform, and the rising water flow is faster than the falling water flow, so that the heavy mineral particles in the mineral can be fully settled and the recovery rate is improved.

2. Spiral chute

The main equipment of the chute for gold selection is the spiral chute, which is sorted with the help of inclined water flow. Its working characteristic is that the end of the tank is concentrated, medium ore, and tailings, without flushing water during the sorting process. The position of the regulating valve block is used to change the cutting width of various products. The change of the cross-sectional curvature of the spiral chute is particularly suitable for the selection of fine-grained materials. The beneficiation chute can be lined with FRP, wear-resistant rubber, and polyurethane rubber for users to choose independently.

3. Shaker

The shaker is a device for sorting in a horizontal medium flow, which uses the asymmetric reciprocating motion of the bed surface to realize the sorting of light and heavy minerals. The ore particles are fed into the ore tank, and at the same time, horizontal flushing water is supplied from the water supply tank. Under the action of gravity, impulse, friction, etc., the ore particles are layered according to specific gravity and particle size, and make asymmetrical reciprocating movement along the bed surface. Discharge from different areas to get different products.

Treatment experience of bolt fracture of large gear ring of 3.2mx13m mill

Frequent bolt breakage is a phenomenon that often occurs during the working process of the mill. The reason for bolt breakage is that the manufacturing size of the large ring gear does not match the original design, and the rigidity of the ring gear is insufficient, which will cause the running track to appear elliptical and the large ring gear The excuse bolt is subjected to a lot of shearing force and breaks.
In order to strengthen the fastening capacity of the bolts, we will adopt larger grades and higher strength bolts to ensure its strength. When checking the broken bolts, it was found that the nuts of the broken bolts had a small or trace amount of polishing. It can be judged that the bolts were loosened first and then broken. If you can ensure that the bolts are not loose, or reduce the impact of the bolts, the problem may be solved.
To prevent loosening, you can try positive and negative buckle bolts and nylon composite nuts. You can do the following:
(1) Change the bolt structure. The original M60x300 single-head bolts and M60x380 stud bolts can all be selected from M60x380 positive and negative buckle double-headed studs with positive and negative buckle nylon composite nuts on the inside, and 40Cr for the outer back nut is better.
(2) Strengthen maintenance. After running for a week or a month, fix the bolts 2 to 3 times to prevent them from loosening. The tightening force should ensure that the inner nylon composite nut does not crack.

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