CGN wet pan mill gold mining also called wet gold grinding machine is used for amalgamation gold extraction of sulfide-free gold mines and is suitable for operations in field areas without power supply by equipped with a diesel generator.
1. The Application of Wet Pan Mill gold mining CGN wet pan mill also called wet gold grinding machine is used for amalgamation gold extraction of sulfide-free gold mines and is suitable for operations in field areas without power supply by equipped with a diesel generator. This machine, which has functions of crusher and ball mill, can crush the ores once for all in the purpose of gold extraction in amalgamation method.
3.Working principle of Wet Pan Mill The diesel generator is responsible for power supply in operation. The reducer and the interlocked main shaft are driven via the belt to run the grinding wheel and grind the ores. When crushed to 0.05-1mm, the ores are added for mercury cycle operations. When extracting mercury cream, the machine should be stopped.
4. Principle of Amalgamation for gold Amalgamation method is to extract gold particles in the ores. When crushed to 0.05-1mm grain size or more, most of the gold particles can be separated and drift in the water. The gold particles in 0.05mm-1mm grain size are surrounded by mercury, and compound reaction occurs to generate mercury paste of AuHg2, Au2Hg and Au3Hg, which is also known as gold amalgam. Since gold and silver are usually associated, there is silver in the mercury paste in addition to gold, and is separated from other metallic minerals. The amalgamation process takes place under the infiltration effect of water, gold and mercury. The recovery of gold depends on grinding size, cleanliness of gold particle, ore pulp concentration, temperature, and pH value. To save the consumption of mercury, the ores are usually ground to 0.05-1mm before added to mercury. The mercury per ton of ore depends on the grade of raw ores. 2% of lime should be added to reduce the viscosity of the ore pulp, the pH value of the ore pulp should be adjusted to PH8-9, and the concentration should be in 30%-40% for amalgamation operations. After amalgamation, water is added to dilute the ore pulp for mercury deposition and accumulation. The mercury paste can be recycled after the gold particles treated and removed.
6.Installation, Usage and Maintenance 1. The machine should be installed on a concrete foundation, placed on level and the anchor bolts should be tightened. 2. Operation steps: Shift the clutch handle to ON position to start the diesel generator. Engage the clutch to drive the host when the operation is normal, and feed materials and water for operation. Disconnect the clutch to stop the machine before cleaning up the mercury paste. 3. Add water, engine oil and diesel oil to the diesel generator on regular basis. See the instructions for details. Lubricate the clutch and upper bearing cover once and add engine oil into reducer once every 30 days. 4. The power section should be kept from sunlight and rain, and ore pulp infiltration to be avoided in operation.
ZJH mainly focus on producing and supply crushers, ore grinding equipment, mineral Beneficiation equipment, laboratory and pilot scale ore dressing equipment for Mining and Mineral Processing Industry. Our aim is to work together with Mines, Mineral Beneficiation Plantsfor helping to reduce the operating cost ,to improve the operating efficiency.
The final fineness of the product mainly depends on the number of times the ore particles pass through the grinder. The longer the grinding, the smaller the particle size. Separate crushing and grinding steps are necessary, the ball mill can only receive the broken ore particle, and then grind to the grinding fineness required for flotation.
In order to separate the concentrate from the ore, the ore should be ground fine enough to release the target mineral from the non-mineral grains. The degree of grinding required for this depends on the size of the mineral particles in the ore. A laboratory-scale flotation test is usually required on materials of different particle sizes to determine the grinding particle size required to release the target minerals.The fineness of the ore particles produced by grinding is crucial to recover the minerals by flotation. The most common grinding machines are semi-automatic (SAG) and automatic (AG) mills and ball mills.
Determining an optimal grinding size can maximize the recovery of target minerals in the subsequent flotation process.The grinding size is too large, and some ore particles and non-ore particles cannot be separated, thus preventing their flotation. If the particle size is too fine, the bubbles that rise during the flotation will push the very fine ore-containing particles away, preventing them from contacting the bubbles, thereby reducing their ability to be recovered into the concentrate.In addition, extremely fine rock and iron sulfide particles may agglomerate with extremely fine sulfide ore particles, preventing the ore particles from floating.
According to the test, the particles usually need to be ground to a diameter of about 100 mm to release minerals from each other. When the particles are less than about 10 mm, this is not conducive to the flotation effect.Grinding operations are very power-hungry, which is another reason to avoid excessive grinding.
The crushed products are ground in SAG or AG mills. The self-grinding machine can grind ore without grinding media such as iron ball, or steel rod, as long as the hardness of the ore is sufficient for the rolling ore to grind by itself.A large vibrating screen is used to sieve the ground products to separate the oversized particles. A small cone crusher to recover the oversized material, and then sent them return to the SAG or AG mill for re-grinding. The correct size material is sent to the ball mill for final grinding.
The ball mill is the fine grinding machine connect the SAG or AG mill and flotation machine. Ball mills produce fine particles with a uniform size for flotation, its grinding medias commonly are steel ball. The ball mill rolls grinding media together with the ore, as the ore grinds, these balls initially 5-10 cm in diameter but gradually wear out.Grinding is always carried out under wet conditions, with about 70% solid mixture in water.This procedure maximizes ore production and minimizes power consumption.
DOVE Ball Mills are supplied in a wide variety of capacities and specifications. DOVE small Ball Mills designed for laboratories ball milling process are supplied in 4 models, capacity range of (200g/h-1000 g/h). For small to large scale operations, DOVE Ball Mills are supplied in 17 models, capacity range of (0.3 TPH 80 TPH).
With over 50 years experience in Grinding Mill Machine fabrication, DOVE Ball Mills as critical component of DOVE Crushing plants are designed with highest quality of material for long life and minimum maintenance, to grind ores to 35 mesh or finer.
DOVE Grinding Mills are supplied in a wide range of capacities and specifications, for reliable and effective grinding, size reduction applications and for diverse applications of either dry or wet ore.
DOVE Ball Mills have extended history in the Mining and Mineral Processing Industry, Construction, Solid Waste Processing, Food Processing Industry, Chemical and Biochemical Industry, for Pyrotechnics and Ceramics.
DOVE Ball Mills are designed to operate with various types of grinding media, including Ball Mills Balls. DOVE supply Steel Balls in Various sizes and specifications. Cast Iron steel Balls, Forged grinding steel balls, High Chrome cast steel bars, with hardness of 60-68 HRC. We also supply Grinding Cylpebs with surface hard ness of 60-68 HRC, and grinding Rod with surface hardness of 55-60 HRC.
DOVE Ball Mills are made of high grade cast and carbon steel for extra strength, long and trouble-free operations. The inner lining plate designed with high manganese steel for long life and minimum wear off.
DOVE Ball Mill can be integrated in a Complete Plant designed by DOVE Engineering Services, provided for our Clients application and supplied with all components of the plant for efficient processing, smooth operation and efficient integration with the balance of the Processing Plant.
DOVE Ball mills, also known as Grinding mill, Mining mill, Pebble mill, Ball & Pebble mill, is an important machinery in the mining and various other industries, which would require grinding different material.
They are highly efficient Grinding mill machines, designed for grinding applications, where fine material is required. DOVE Ball Mills are used in supplied and applicable for wet and dry grinding applications within the following branches of industries:
DOVE ball mills is a rotating horizontal cylinder that tumbles the material to grind with a certain media. The standard media that we use in our ball milling process are the steel grinding balls, however depending on the specific application, we can configure the grinding mill with different media.
DOVE supplies various types and sizes of Ball Mill Balls, including; Cast Iron steel Balls, Forged grinding steel balls, High Chrome cast steel bars, with surface hardness of 60-68 HRC. DOVE Ball Mills achieves size reduction by impact and attrition. When the cylinder rotates, the balls are dragged to almost the top of the shell, and from there, they fall unto the material, which lead to the material breaking due to the impact.
DOVE Ball Mills are used in hard rock mineral processing plants as an ore-dressing step to grind the rocks into fine powder size, liberating the mineral particles from the rocks. This will ensure that the ore is well prepared for the next stage of processing and optimize the recovery of the minerals.
DOVE ball mill is integrated and used in DOVE Portable and Semi-Stationary Hard Rock plants (Hard Rock processing plants) to efficiently grind the ore from primary deposit until the liberation size of valuable minerals is reached. DOVE ball mill is the key grinding equipment after material is crushed. It is used to grind and blend bulk material into powder form using different sized balls. The working principle is simple, impact and attrition size reduction take place as the ball drops from near the top of the rotating hollow cylindrical shell of the Ball Mill. The output materials will be feed to the processing and recovery machines.
DOVE Ball Mills are deigned for either wet or dry grinding of materials, in various models, and in accordance to the processing and the crushing plant design, to cater to the liberation size of the minerals and the hardness of the ore.
DOVE supplies two different kinds of ball mills Grate type, and Overfall type. The difference between the two type is according to their ways of discharging material, and the plant flow design specifications.
The Grinding Balls will grind the material into powder size of 20 to 75 micron. In mining operations, this will allow for the liberation of gold and other precious metals that are hosted by the rocks. Many types of grinding media are suitable for use in a ball mill, each material having its own specific properties, specification and advantages.
Media Size: The grinding media particles should be substantially larger than the largest pieces of final material after grinding. The smaller the media particles, the smaller the particle size of the final product.
Composition: Each ball mill application has different requirements. Some of these requirements are relates to the grinding media being in the finished product, while others are based on how the media will react with the material being milled. Therefor, grinding media selection plays major factor on the final milled product.
Contamination: In certain grinding mill process, low contamination is important, the grinding media may be selected for ease of separation from the finished product, for example steel dust produced from steel balls can be magnetically separated from non-ferrous products. An alternative to separation is to use media of the same material as the product being milled.
Corrosive:Certain type of media, such as steel balls, may react with corrosive materials. For this reason, stainless steel balls, or ceramic balls, and flint grinding media may each be used when corrosive substances are present during grinding.
Application of value engineering techniques to grinding process modelling led to the identification of two basic functions of the ball mill-classifier circuit. In terms of a specified circuit product size which is used to differentiate between coarse or oversize material and fines or undersize material, these basic functions are (a) breakage of the coarse material and (b) removal of the fines. It was proposed that it may be useful to relate circuit design and operating variables to these basic circuit functions, which although related, are conceptually quite distinguishable. If each could be quantified by a suitable parameter, then either or the two together may be correlated to overall circuit efficiency, and hence used to link individual design and operating variables to overall circuit performance.
Major design and operating variables in closed circuit ball milling of a specified feed to a desired product size are summarized in Table 1. The purpose of process modelling is to establish cause and effect relationships between physical design and operating variables and the performance objectives of the circuit. Subsequently, output and efficiency can be maximized. The fundamental issue addressed by ball mill circuit modelling is thus depicted in Figure 1 (McIvor, 1989).
In the simplest form of plant experimentation, a key performance parameter (such as the fineness of the final product) is measured with and without a specific change to the circuit. Within the constraints imposed by the accuracy of measurements and assumptions about the constancy of other inputs (including the ore characteristics), the relative values of this parameter are used to evaluate the effect of the change on circuit performance.
Bond work index analysis takes this method of experimentation several steps further. During comparative testwork, variations in the ore grindability, grinding energy input, and feed and product sizing are measured and accounted for through the grinding circuit model embodied in the work index formulation. For each set of data, both the circuit operating work index and the laboratory test work index of the circuit feed are determined. Relative work index efficiencies with and without the change to the circuit can then be calculated and compared.
Consider a ball mill circuit processing material of a given feed size and at a given throughput rate to a target product size, the latter which once again distinguishes the fines from the coarse material. The production rate of fines or new product size material can be calculated from the circuit feed and product size distributions and the throughput rate of the circuit. Based on the energy expended in the ball mill, the production rate of new product size material (tonnes/h) equals the amount produced per unit of energy applied (tonnes/kwh) times the rate at which energy is applied (kwh/h). The rate at which energy is applied is the power draw of the ball mill. If we then define the production per unit, of energy applied as the energy specific production rate of the circuit, then we can write the following equation:
All the production of new product size material takes place in the mill as coarse is ground into fines. However, the proportion of the total mill power applied to size reduction of coarse particles is equal to the fraction of coarse solids inventory, or the so defined circuit classification system efficiency.
The mill specific grinding rate reflects both the efficiency of the mill environment in breaking the coarse particles, as well as the grindability characteristic of the ore over the particular size reduction range.
To arrive at a term which reflects only the efficiency of the mill environment, we must factor out the grindability of the ore, such as the net grams per revolution measured in a Bond work index test. This will yield the specific grinding rate in the plant ball mill relative to the measured specific grinding rate in a standard test mill, and may be termed the grinding rate ratio.
The grinding rate ratio may be considered dimensionless because each revolution of the test mill requires a fixed amount of power. It is based on breakage of only the coarse material in both the plant ball mill and the standard laboratory test mill. It is therefore proposed that the grinding rate ratio is a direct measure of the relative overall breakage efficiency of the environment of the plant ball mill.
The above described parameters for system breakage and classification system efficiency factor the overall task of the ball mill circuit into its two distinct basic functions, namely, fines generation and fines removal. The effect of design and operating variables on each can be studied separately, and when the product of the two is maximized, maximum overall circuit efficiency will be achieved. Equation 2 may be re-written as:
This has been termed the ball mill circuit functional performance equation (McIvor, 1989). It states that the output of new product size material of a ball mill circuit with a given feed size is determined by:
a. the total mill power draw; b. the classification system efficiency, which defines the fraction of the total mill power effectively applied to the grinding of coarse material; c. the grindability characteristic of the ore over the size reduction range of the circuit; and, d. the breakage efficiency of the ball mill environment on the coarse material.
While all four factors clearly influence the circuit output, overall circuit efficiency will be determined by classification and breakage efficiency. Specific design and operating variables can now be considered in terms of their individual effects on classification and breakage efficiency, and subsequently on the overall efficiency of the circuit. This provides an intermediate level of ball mill circuit performance characterization, as shown in Figure 5.