At some cement factories, cement mill bearing is likely to be burned, which belongs to major accident. The main reasons for it are foreign materials entering into bearing or the poor lubrication system. In some cases, it can lead to damage to hollow shaft neck of bearing. Once burning occurred, it needs over ten hours or even a couple of days to repair. In order to solve cement mill bearing lubrication and management problems, people keep on researching sealing modes, installation technology and lubrication measures to guarantee bearing running in good condition. Here, we take 02.2mx6.5m cement mill as an example, talk about the oil lubrication of bearing.
Generally, cement plants often choose dynamic pressure lubricating method, which is major I will discuss in this article. At first, we should choose proper lubricating oil as well as additives, so that improve milling machine lubricating condition. The work features of cement mill bearing are large overload and linear velocity, suffering from impact and vibrating; the size of bearing bush and hollow shaft is also big, the improvement of shape, size, accuracy and smooth degree are effected by manufacturing conditions. Therefore, main bearings do not guarantee total liquid lubrication, but in boundary lubrication conditions. Excellent boundary lubrication (depending on the performance and strength of boundary film) can significantly reduce the coefficient of friction, reduce bearing wear. So, according to temperature, linear velocity of hollow shaft, and main bearing overload, we can make a favorable choice to lubricating oil type. In south China, as for this type cement mill, we can choose N220 and 0320 industrial gear oil in winter and summer respectively. On the other hand, due to discharging port temperature is higher than that of feeding mouth, we might take it into consideration that high viscosity oil can be chosen as lubricating oil for bearing at the end of discharging port.
Secondly, depending on regular use period, we should add or replace lubricating oil at regular time and proper amount. Besides, lubrication oil management and waste oil recycling is also an important work.
Thirdly, we should establish a perfect cement mill check system. Cement mill worker shall check main bearing temperature, oil quality and oil amount regularly. Especially when it comes to abnormal oil temperature, the worker is suggested increase check frequency. He should report in no second once found machine abnormal.
To a large extend, cement mill malfunction is caused by no proper lubricating of main bearing. As cement machine develops to the direction of large scale and automatic, it is necessary to make out a thoughtful predictive maintenance plan.
Raymond mill, also called raymond grinding mill, is suitable for all kinds of ore powder preparation and pulverized coal preparation, such as raw ore, gypsum mine, coal and other materials powder processing cement plant equipments. Its apperance looks like a erect steel container. The raymond mill has air intake and air outlet and there is feed inlet in the middle part. There is electrical machine in the bottom of raymond mill and this electrical machine can drive internal grinding stick and millstone rotating so that the materials can be crushed or ground. Through the wind that come from air intake, the finished materials are blowed on. In the mill, there is separator in the upper parts. The separator can separate the thick powder and fine powder. Then through the wind that comes from the air outlet, the powder comes out of the raymond mill.
Raymond mill common fault 1: the raymond mill does not make powder out, or the powder amount is less, or low yield
Reason: (1)The powder lock is not adjusted into a good condition and the seal imprecision, causing powder pour absorpt into cement plant equipment; (2) Shovel knife is seriously worn and the materials can be fully ground.
processing method: (1) checking and adjusting the powder lock, the air leakage place should be sealed up. (2) Replacing new shovel knife.
Raymond mill common fault 2: Finished product powder is too thick or too thin
Reason: (1) The blades of raymond mill are seriously worn and cannot afford grading role. (2) Fan delivery is not suitable.
Processing method: (1) changing the blades, turning down the draught fan.(2)If the powder is too fine, improve the fan delivery.
Raymond mill common fault 3: the electric current in raymond mill main engine is rising, machine temperature is rising by the heated circulating air, machine temperature is rising,fan current is declining, jaw crusher.
Reason: (1)The feeding material is excessive, air channel is blocked by powder, pipe exhaust not free, cycle airstream fever that Lord of the current, high temperature of the machine, fan current decline jaw grinder.
processing method: (1) Reducing charging rate, clearing accumulated powder in air channel (2) Opening valves of the air hoses, the fed materials temperature should be controlled to under 6℃.
Raymond mill common fault 4: main engine will produce large noise and there is large vibration.
Reason: (1)The feeding material is less, shovel knife is seriously worn, anchor bolt is looseness. Vibration feeder. (2) the materials are hard and have large impact, or there is the materials layer without materials. (3) Grinding roll and grinding ring are not rounded are serious deformation. mobile crusher.
processing method: (1) Adjusting the amount of feeding materials in raymond mill and replace new shovel knife. (2) Replacing the feeding grain size. (3) Replacing the grinding rod and grinding ring.
Raymond mill common fault 5</strong>: draught fan vibrating.
Reason: (1)there is accumulated powder on the fan blades or the blades are seriously worn.(2) anchor bolt is looseness.
Processing method: (1)Clearing accumulated powder on the fan blades, or replacing the fan blades. (2)Tightening the anchor bolts.
Raymond mill common fault 6: the temperatures of the transmission device and analytical engine and the fuel tank are rising.
Reason: (1)Engine oil has high viscosity and the oil layer is thick, the screw pump oil can not be added on the upper bearings so the bearings are lack of oils.
Processing method: (1) Checking the oil grades and viscosity to see whether the oil meet the requirements. (2) Checking the running direction of analysis machine.
Raymond mill common fault 7</strong>: the powder comes into the grinding rod, the bearings are broken.
Reason: (1)The oil is not enough, or the seal ring is broken. (2) Long-term lack of maintenance and cleaning
Processing method: (1)According to the stipulated time, the oil should be added timely. (2)Regular cleaning, replace the oil seal.
With the current state of the global economy, mining specialist Deswik International has identified an untapped area of business that could see it establish a significant presence within the Zimbabwean mining sector. Deswik Technologies sales director, Dave Capstick, tells Laura Cornish about a specialised technology that could deliver considerable gold ounces by unlocking the potential value contained within some selected mine waste dumps in Zimbabwe.
While Zimbabwe still remains untouched by the majority of the mining community, despite a changing government, Deswik International is carving a niche business in the country which could see it emerge as a significant gold processor.
The Deswik International group, through its subsidiaries, offers a variety of services, including consulting (Deswik Mining Consultants) and ultra-fine grinding mill solutions (Deswik Technologies).
While Zimbabwe remains a high-risk investment option, the new government is trying to introduce progressive policies. In the interim, Deswik International is carving a niche business in the country which could see it emerge as a significant gold processor.
Considering the market’s current state, and the slow re-emergence of Zimbabwe as a business-worthy country, Deswik has completed the installation of its first pilot site at Zimbabwean Mining Investments’ (ZMI) Farvic gold mine in southern Matabeleland, Zimbabwe.
The project is a joint venture between Deswik International and ZMI – its local partner – whereby the combined entity can conduct laboratory testing on dump material to ascertain its applicability to fine grinding and the consequent increase in metal recovery.
On a positive result from lab testing, a larger bulk sample is recovered from the dump (50t – 100t) and processed at the fine grind bulk testing pilot plant facility at the Farvic mine. “The gold reefs in Zimbabwe are most collectively part of a greenstone belt, constituting refractory ore, which lends itself to fine grinding technology,” Capstick indicates. The Deswik Technologies mill is capable of milling to a size of between 10 and 20 microns extremely fine – and one of the only solutions viable for re-processing dump material.
It has thus far been proven that the ultra-fine grind Deswik mill in combination with a customised CIP/CIL circuit can result in gold recoveries of 70% upwards, on refractory dump material which previously would only yield a 20-30% recovery.
Capstick says a Deswik Technologies plant reduces leach time by half, with (usually) substantially less cyanide. The plant will come with a cyanide destruction system prior to the re-deposition of the tailings. In some circumstances a Merrill Crowe recovery system will be used which produces a dry tail as opposed to a carbon-in-leach (CIL) plant.
The pilot plant consists of a 24m pre-conditioning tank that prepares the dump material prior to milling and can produce between six and 10 dry tonnes of product per day. This particular mill at Farvic will process about 0.5tph, but plants can be built up to a processing size of about 40tph. The mill took five weeks to construct and install.
Capstick says there are hundreds of dumps in Zimbabwe, mostly constituting high-grade gold from small size mines. Thus far, six top priority dumps have been identified. The Deswik-ZMI JV offers dump owners a range of turnkey solutions to extract value from their dump. These include the design, manufacture, installation and commissioning of the fine grind gold recovery plant, which will include the long-term management of the plant.
The combination of the technology, skills and local knowledge gives the Deswik-ZMI JV the ability to be able to extract value from otherwise uneconomic assets. Although it is still early days, Capstick says there is already potential, and a “natural progression” for the company to become involved in processing current arisings as well. Further more, the intention is to use the technology for nickel, chrome and platinum operations.
Gravity concentration is often used in roughing separation of tantalum-niobium ores. And in the concentrating of ores, we often adopt gravity concentration, flotation, electromagnetic separation or dressing-metallurgy combining process. Ore washer and efficient ore grinder and grader are also utilized to increase the fineness of ores.
Techniques for processing tantalum-niobium ore
Generally, in the first step, we adopt gravity concentration to dispose of most gangue minerals to get low grade mixed ores. In the process of concentrating ores, the separation can be very difficult due to the complicated composition of the mixture that contains various kinds of useful minerals. There are many ways to process tantalum-niobium ores, including gravity concentration, flotation, electromagnetic separation or dressing-metallurgy combining technique. We can utilize one or more of these techniques to separate the minerals.
Technological process of tantalum-niobiums ore beneficiation
We mainly use gravity concentrators for roughing separation of tantalum-niobium ores. And flotator is adopted only to process fine slimes through several simple procedures.
Tantalum-niobium ore processing plant has effective grinding and grading machines to protect the ores from sliming. Usually the rod mill and vibrating screen are operated together in a closed circuit for ore processing. For example,a ball mill is designed to work with a horizontal vibrating screen(linear screen) in a closed circuit to screen 2.5 mm sized particles. A high frequency vibrating fine screen is installed under the screen, which grades particles by 0.2mm. And -2.5+0.2mm sized particles will be processed by spiral concentrator, and tailings will be returned for further grinding after being dewatered by sieve bend.The ball mill grinds ores in two closed circuits.With proper adjustments, the loop bears a load rate of around 180% in the cycle.Overgrinding is likely to increase when there is lower load in the cycle.
In the first closed circuit, we use a rod mill operating together with a screen in order to avoid overgrinding. In the second closed circuit, we adopt a ball mill operating with a high frequency vibrating fine screen. The design will not only put particle size under strict control, but also enhance the processing capability, thus improving grinding efficiency. Roughing separation of ores shall be completed in one gravity concentrating process.Gravity concentrators include GL spiral concentrator, spiral chute and table.
Generally, ores obtained after the roughing separation process belong to mixed ores, and need to be concentrated so as to separate those useful minerals from the mixture. We can dispose of strong magnetic minerals and iron scraps through low-intensity magnetic separation. Then we dry the ores and divide them into three grades, namely +0.2, +0.1 and -0.1mm. After roughing separation and scavenging process through the dry high-intensity magnetic separator, we will get tantalum-niobium ore concentrate.
Gold mining equipment
SBM Group is a manufacturer of gold mining equipment, who can design and provide the complete gold mining equipment, gold mining crushing machine, gold mining grinding machine, gold processing plant etc. In gold ore mining, we will choose the suitable gold ore crusher for your gold ore mining, according to your requirements and character of gold ore. SBM gold mining machine stands the test of time.
Gold processing plant
Grinding process could be gold processing line’s stage two, after gold ore crushed, require gold powder, in order to process gold, grinding machine is effective, ball mill processing gold, vertical mill machine, stamp mill, process machinery.
1. Crushing – primary crushing (jaw crusher) and crushed ore stockpile.
2. Grinding – grinding and classification (ball mill & SAG mill).
3. Leaching and adsorption.
4. Elution, desorption and carbon regeneration.
5. Electrowinning and smelting; pour gold and silver dore bars.
6. Cyanide reduction & destruction.
7. Reagent mixing and storage.
8. Tailings pump and disposal to tailings storage facility.
Gold mining crushing machine
Gold ore mining crusher is widely used in gold mining process all over the world named gold crusher. The mainstream gold ore dressing technology is generally through the ore dressing equipment (crusher) to broken gold ore, and then sent into the gold beneficiation to be smashed and grinded. After the gravity separation and flotation, concentrate ore and tailings are extracted, and then by using chemical methods and final smelting, the finished product eventually become gold.
Gold mining grinding machine
Ball mill is definitely an efficient tool for grinding many materials into fine powder. The ball mill can be used to grind many different types of mine as well as other materials, in order to find the mine, popular in building material, chemical industry, etc. There are two means of grinding: the dry process and also the wet process. It can be divided into tabular type and flowing type based on variations of discharging material.
Crushing is the first step in converting shot rock into usable products. Essentially, crushing is no more than taking large rocks and reducing them to small pieces. Crushing is sometimes continued until only fines remain.
At some operations, all the crushing is accomplished in one step, by a primary crusher. At other operations, crushing is done in two or three steps, with a primary crusher that is followed by a secondary crusher, and sometimes a tertiary crusher.
There are several different types of primary crushers, however, there are many similarities in the job procedures followed by crusher operators.
Raw material, of various sizes, is brought to the primary crusher by rear-dump haul units, or carried by a wheel front-end loader. Primary crushing reduces this run-of-mine rock to a more manageable size. The different types of primary crushers are: jaw crushers, gyratory crushers, impact crushers, and autogenous crushers.
The jaw crusher squeezes rock between two surfaces, one of which opens and closes like a jaw. Rock enters the jaw crusher from the top. Pieces of rock, that are larger than the opening at the bottom of the jaw, lodge between the two metal plates of the jaw. The opening and closing action of the movable jaw against the fixed jaw continues to reduce the size of lodged pieces of rock until the pieces are small enough to fall through the opening at the bottom of the jaw.
A gyratory crusher breaks rock by squeezing the rock between an eccentrically gyrating spindle, which is covered by a wear resistant mantle, and the enclosing concave hopper. As run-of-mine rock enters the top of the gyratory crusher, it becomes wedged and squeezed between the mantle and hopper. Large pieces of ore are broken once, and then fall to a lower position (because they are now smaller) where they are broken again. This process continues until the pieces are small enough to fall through the narrow opening at the bottom of the crusher.
Impact crushers, which are also called hammer mills, break rock by impacting the rock with hammers that swing on a rotating shaft. The practical use of impact crushers is limited to soft materials, such as phosphate, gypsum, weathered shales, etc. Impact crushers cannot handle as large a top sized material as jaw, or gyratory, crushers can; however, impact crushers can make a finer sized product.
In recent years, autogenous crushers have been adapted for crushing run-of-mine rock in primary crushing circuits. Consequently, autogenous mills have increased in importance as a means of crushing and grinding. In autogenous crushers, the rock to be crushed also provides the crushing force. Crushing is accomplished by the tumbling action of the rock. Flexible crushing circuits can be constructed so that hard ores, as well as soft ores, can be processed. Wet, sticky ores can be processed in autogenous mills, while the same ore would present difficulties for other types of crushers.
SBM ball mill and stone crushers are used in quartz rock mining and silica sand production.
Ball mill works in both dry and wet methods, to mill, mix and discharge materials such as feldspar, quartz, and clay. SBM ball mill capacity can be from 1 t/h to 30 TPH.
Quartz stone is mainly used to produce silica sand. In the silica sand making line, quartz stones firstly go through coarse crushing, fine crushing process to produce manufactured sands. Size range of Normal silica sand is 5 to 220 mesh. Refined quartz sand can be up to 500 mesh. In this sand production line, ball mill can also be used as fine sand making machine.
SBM offer stone crushers and ball mills to quartz stone mining, and quartz sand production line in India. SBM also supplies the right grinding solution to every method and application according to process design, equipment selection, and layout.
A grinding mill is generally a type of machine that breaks a material into smaller pieces. These mills can differ in terms of the types of materials they can grind, and how they grind them. The grinding mill is an industrial tool that reduces solid materials into a desired particle size and is vital in reducing solids, such as cement, into a more manageable and powdered form. It is also used to mix solids with liquids or change the gradient of animal feed and mills come in a variety of forms suited for different tasks and challenges. Some of the most common types include ball mill, rod mill, hammer mill, raymond mill and vertical mill.
Engineers and other professionals often refer to the process of grinding as a unit operation. This is a term used to describe a specific step in a process. For example, a material might be needed in a certain final form, such as a granule, in order to be applied for a specific task, or to make a specific product. The grinding mill is used to achieve this desired form.
A ball mill uses centrifugal force and many metal balls to grind substances into a fine powder. It is a vital tool for regrinding work and is used mainly on materials such as cement, glass and chemical fertilizer. Its primary design is a large horizontal metal cylinder with two warehouses, or compartments, containing metal balls and scale-boarded, or grooved, edges. The cylinder is then rotated to create centrifugal force to lift the balls and drop them on the material, grinding them. The first warehouse is made to start the grinding process and when the material is made fine enough, it enters through specified holes into the second warehouse, which – with different specification balls and scale boards – grinds the material into a finer powder.
Ball Mills accept feed that range in size from 80% passing 20mm to fine feeds in regrind operations. Products may be as coarse as 0.5mm or as fine as 80% of 40 microns. In a ball mill the length may be less than, equal to, or greater than its diameter. A short length mill has a lower retention time and produces a coarser product. Longer mills have a longer retention practice and generally utilize closed circuit operation. Most Ball Mills operate with a reduction ration of 1:20 to 1:200.
Like a ball mill, a rod mill is a large horizontal cylinder that uses centrifugal force to grind material. However, instead of balls, it uses long metal rods that are placed almost parallel to each other and the cylinder. The walls of the grinder are also scale-boarded, so when the rods tumble, they crush the material against them. A rod mill creates a relatively unified gradient, and is great for reducing very coarse material into a size manageable by ball mills.
Rod mills can accept feed up to approximately 2″ diameter and generally are selected to grind product to the – 4 mesh to – 35 mesh range. Grinding actions is by line contact between rods extending the length of the mill. Rods tumble and spin in roughly parallel alignment and in so doing simulate the crushing and grinding action from a series of roll crushers. Large particles spread the ends of rods and is so doing impart an additional action termed scissoring. These actions result in preferential grinding of coarse material and a minimum production of slimes and excessively large material termed tramp oversize. A relatively uniform sized product is produced. Due to the nature of the grinding action, rod mills can sometimes advantageously replace the fine crushing of damp or sticky material that tends to coat the faces of crushing surfaces. Rod mills can produce a final product on sand brick, lime, or coke breeze where the feed contains low moisture and is often ground dry. In the metal mining industry most rod mill applications involve wet grinding were material is reduced in size from crusher product size to a size suitable for ball mill feed. Rod milling in the size range utilized is more efficient than ball milling in that the desired product is obtained at a lower cost per ton.
A hammer mill is a machine whose purpose is to shred material into fine particles. They have many sorts of applications in many industries, including:
The concept is fairly straightforward. A hammermill is essentially a steel drum containing a vertical or horizontal cross-shaped rotor on which pivoting hammers are mounted. The hammers are free to swing on the ends of the cross. The rotor is spun at a high speed inside the drum while material is fed into a feed hopper. The material is impacted by the hammers on the ends of the rotating cross and thereby is shredded and expelled through screens in the drum.
Slow speed horizontal pallet grinder. Small grain hammer mills can be operated on household current. Large automobile shredders can use one or more 2000 horsepower (1.5 MW) diesel engines to power the hammer mill.
Raymond Mill (or raymond grinder) is a kind of grinding machine which is widely used to grind non-flammable and non-explosive materials like barite, calcite, potash feldspar, dolomite, gypsum, talcum, mica, marble, limestone, kaolin, clay, coal etc. The raw materials should be below scale 7 Moth’s hardness. The fineness of the finished product can be adjusted from 100 to 425 mesh (35micron) according to requirements.
In the vertical mill the spindle axis is vertically oriented. Milling cutters are held in the spindle and rotate on its axis. The spindle can generally be extended (or the table can be raised/lowered, giving the same effect), allowing plunge cuts and drilling. There are two subcategories of vertical mills: the bed mill and the turret mill.
- A turret mill has a stationary spindle and the table is moved both perpendicular and parallel to the spindle axis to accomplish cutting. The most common example of this type is the Bridgeport, described below. Turret mills often have a quill which allows the milling cutter to be raised and lowered in a manner similar to a drill press. This type of machine provides two methods of cutting in the vertical (Z) direction: by raising or lowering the quill, and by moving the knee.
- In the bed mill, however, the table moves only perpendicular to the spindle’s axis, while the spindle itself moves parallel to its own axis.
Turret mills are generally considered by some to be more versatile of the two designs. However, turret mills are only practical as long as the machine remains relatively small. As machine size increases, moving the knee up and down requires considerable effort and it also becomes difficult to reach the quill feed handle (if equipped). Therefore, larger milling machines are usually of the bed type.
Also of note is a lighter machine, called a mill-drill. It is quite popular with hobbyists, due to its small size and lower price. A mill-drill is similar to a small drill press but equipped with an X-Y table. These are frequently of lower quality than other types of machines.
Artificial sand is the sand produced by artificial sand making machine and other accessory equipments, It is widely used in road construction, concrete industry, etc. As the field of industry application gradually expanded, the gradual application of natural sand work more and failed to keep pace with the various sectors of modern world development needs.
For the most part, artificial sand is produced to meet the great needs. As we all known that the reserves of natural sands is limited, but the demand for sands is still growing, and the quality of artificial sand as well as natural sand, so artificial sand making industry become an important role in society construction. The raw materials of artificial sand mainly are granite,
limestone, basalt, pebbles etc, through a series of crushing and screening equipment in order to reach required level. More advanced sand making machines have been invented to push forward human civilization. Its finished products are more rules, and we can produce different standards sand according to different technical requirements, which could better meet the daily needs.
Artificial sand manufacturing process
The artificial sand manufacturing process is as follows: The raw material is transferred to jaw crusher for primary crushing by vibrating feeder through hopper, then the crushed materials whose size is larger than 40 mm are transferred to vsi crusher through belt conveyor for secondary crushing. The materials which is smaller than 40mm will be transferred to vsi5x crusher, after being washed by sand washers, then clean final products will be discharged. The others with unsuitable size will be transferred return to the vsi5x crusher for the secondary crush, thus forms a closed circuit manifold cycles. If it is the dry process, the classifier and deduster will be attached according to you requirement.
Artificial sand making plant consists of vibrating feeder, jaw crusher, sand making machine, vibrating screen, belt conveyor and other equipments. According to different technical requirements, we can combine various types of equipments to meet customers' needs. Sizes of final products will be according to our customers' requirements, when the input size of stones is smaller than 40mm, we recommend the sand making flow equipped with VSI5X series sand making machine, and it is suitable for VSI series sand making machine when the stone size is larger than 40 mm.
Artificial sand making machine
- Larger than 40mm sand making process artificial sand making plant:
Feed hopper -> vibrating feeder -> PE primary jaw crusher -> JC secondary jaw crusher -> PF secondary impact crusher (PFW impact crusher optional) -> VSI series sand making machine -> vibrating screen -> sand washing machine -> belt conveyor -> final artificial sand.
- Less than 40mm sand making process artificial sand making plant:
Feed hopper -> vibrating feeder -> PE primary jaw crusher -> JC secondary jaw crusher -> cone crusher -> VSI5X series sand making machine -> vibrating screen -> belt conveyor -> final artificial sand.
Jaw crusher is usually used as primary crusher in artificial making plant, which features simple structure and easy maintenance, Stable performance and low operating cost, High crushing ratio and so on.
Impact crusher is used as secondary crusher in sand making plant, whose roles is to further crush the material out of jaw crusher. The impact crusher is suitable for materials whose compressive strength is under 360Mpa and side length is under 500mm.
Sand making machine (VSI series or VSI5X series), is the key equipment in artificial sand manufacturing process, which can be used as a crusher or a shaper by changing feeding methods and core structure of the crushing cavity. It is widely applied in expressway and railway building, hydropower station construction, bridge and tunnel building, concrete batching plant, etc.