It is not allowed to have the shrinkage cavity, shrinking porosity, gas porosity, inclusion, and other cavity defects on the section including plane pasting through the pouring gate and the ball centre.
The chemical composition of the high chromium type product should conform to the below table. We can also manufacture the product with special chemical composition in accordance with the requirements of the customers.
The environment in primary ball milling can best be described by giving equal considerations to both impact and abrasive conditions. The relatively large ball sizes employed [3 4 (75 100 mm)] contribute a significant impact component to the overall wear. The number of impacts in primary ball mills are far more frequent but have less magnitude than those experienced in SAG mills. The increased frequency is due to the Increase in charge volume (35 40% versus 5 10%), higher mill speeds, and the larger number of balls per unit charge weight. The lower impact forces are due to a combination of both smaller ball masses and lower drop heights resulting from the use of smaller balls and smaller mill diameters, respectively.
The feed ore in primary grinding mills is typically very abrasive owing to its particle size, shape, and mineralogy. Wear speeds approaching or exceeding 20 m/hr. have been measured for very abrasive Au. Cu, and Mo ores, while wear speeds on the order of 10-15 m/hr. have been encountered in softer primary ores.
Steel grinding media used in primary grinding must be designed for maximum abrasive wear resistance while maintaining good toughness. Toughness is particularly important in grate discharge mills where pulp levels at the discharge end of the mill can approach zero. Moroz and Lorenzetti (1981) found that maximum abrasion resistance is achieved by the combination of alloying with maximum amounts of carbon and heat treating the balls to their optimal microstructure.
High Cr media for primary grinding will typically contain maximum levels of eutectic carbide (30 35% by volume) and are heat treated to their maximum hardness (HRC 65 68). However, not many high Cr balls are used in primary grinding because the improvement obtained in wear resistance relative to steel, typically 25 30%, is not enough to offset Its higher cost.
In primary ball milling, wear speed is largely independent of ball diameter and mill volume. (The same is true for secondary, tertiary, and regrind grinding.) In these applications, Equation 4 can be used to quantitatively predict how ball size and ball volume charges will affect wear rates. For example, a 5% increase in charge volume (42% versus 40%) will increase hourly ball consumption by 5%. If a corresponding 5% increase in feed rate is not also achieved, then the wear rate (lbs./ton) will be increased. The same analysis can be made for ball size.
In secondary ball milling, abrasive and corrosive conditions predominate. The smaller balls [< 2, (65 mm)] typically used in secondary milling environments effectively reduce the impact component of wear to the point where grinding media must be primarily designed to reduce abrasive and corrosive wear. It can be seen in Figure 3 that the range of wear speeds in secondary grinding widely overlap the range of wear speeds measured in primary grinding. This represents the large variations in abrasive and corrosive wear conditions found at the various testing locations. The best way to compare primary versus secondary grinding conditions is to review MBWT data from primary and secondary applications for the same mill. This comparison is presented in Table IV. The Wear Speeds in secondary grinding are found to be 25 40% lower than those seen in primary milling when grinding the same, but finer, ore. This comparison shows that the reduction of the impact component of wear due to the smaller media size offsets the increase in an abrasive wear expected when grinding to finer product sizes.
The performance of high Cr balls in secondary grinding depends on the abrasive/corrosive environment of the mill. In most secondary Au, Cu, and Mo grinding, the relative wear rates of high Cr compared to forged steel show a performance improvement of 25 30%, similar to that seen in primary grinding. However, for corrosive environments with low abrasion, the high Cr ball can result In Improvements of 50% or more compared to forged steel. This is particularly true for some of the secondary grinding (primary ball mills) of magnetic iron ores. In magnetic iron ore grinding, the silica levels are continually being decreased from crushing to rod milling to ball milling by intermediate concentration steps. Subsequently, the wear environment becomes progressively less abrasive. Meulendyke, Moroz, and Smith (1987) reported that it is in the low abrasive environments where the corrosive component of wear can become quite significant. In these environments, if the proper high Cr alloy is used to avoid corrosion pitting, then high Cr balls can become cost-effective.
Ore ball mill sometimes called ore grinding mill, is generally used in mineral processing concentrator, processing materials include iron ore, copper ore, gold ore, molybdenum ore and all kinds of nonferrous metal ore. The core function of the ore ball mill is to grind the materials, and also to separate and screen different mineral materials, and to separate the tailings, which is very important to improve the quality of the selected mineral materials.
The ore ball mill designed by our company, which is represented by gold ore ball mill and iron ore ball mill, is manufactured with high-quality materials and advanced technology. They have the characteristics of high efficiency, energy-saving, green environmental protection, simple operation, stable operation, and low failure rate, and have a good reputation in the industry.
The crushing ratio of the ore grinding mill is very large, and it is easy to adjust the fineness of the grinding product. The ore grinding mill has strong sealing performance and can be operated under negative pressure. It is widely used in chemical industry, metallurgy, new building materials and other fields.
We offer different types of ore ball mills for customers to choose from. There are energy-saving ore ball mill, dry and wet ball mill,wet grate ball mill, andwet overflow ball mill. Customers can choose to purchase according to material conditions.
Mineral processing is the most important link in the entire production process of mineral products. It is a process of separating useful minerals from useless minerals (usually called gangue) or harmful minerals in a mineral raw material by physical or chemical methods, or a process of separating multiple useful minerals The process is called mineral processing, also known as ore processing.
The first step in the ore processing is to select the useful minerals. In order to select useful minerals from ore, the ore must be crushed first. Sometimes, in order to meet the requirements of subsequent operations on the particle size of materials, it is necessary to add a certain ore grinding operation in the process.
The preparation before beneficiation is usually carried out in two stages: crushing screening operation and mineral classification operation. Crusher and ore ball mill are the main equipment in these two stages.
As a ball mills supplier with 22 years of experience in the grinding industry, we can provide customers with types of ball mill, vertical mill, rod mill and AG/SAG mill for grinding in a variety of industries and materials.
Fitting degree of four functions to PSD was quantitatively evaluated.The parameters of the four functions were detailed analyzed.Impacts of operation parameters on specific energy input of stirred mill were conducted.A new prediction model for full-scale PSD was established by coupling the size-energy model and RRB function.
The wet grinding of iron ore powder was investigated using a stirred media mill. In this study, the fitting degree of four cumulative undersize distribution functions was compared and the parameters of the four functions were discussed. It was concluded that the particle size distribution (PSD) of grinding products followed well with the Rosin Rammler Benne (RRB) function. In addition, operational parameters such as ball filling rates, stirrer tip speeds and grinding time have been investigated in terms of the width of PSD and specific energy input. The results indicated that slight differences in the width of PSD could be observed at different ball filling rates and stirrer tip speeds. It was also found that increasing the ball filling rate and stirrer tip speed could improve energy efficiency. Furthermore, an equation was established to predict PSD based on the characteristic particle size of the RRB function and size-energy model, which provided a sound fit to the grinding products under various grinding conditions