The company “ENERGOSTEEL” completed the industrial test of grinding balls 40 mm of the fifth group of hardness (DSTU 3499-97) on the basis of one of the largest Ukrainian mining & processing enterprises in July 2016. Tests were carried out jointly by technical experts of the both companies. Grinding balls experimental batch have been loaded in the test mill MSHTS 4500х6000 with the following parameters: internal diameter – 4430 mm; the height of lining plates – 100 mm; lifter height – 83 mm and lifter width – 208mm. The material for grinding was middling product (the original ore hardness 9-11 Scale Protodjakonova). During the test was chosen a method of loading an experimental batch of balls in the mill, not the method “substitution”, because: The test mill was put into operation after overhaul. This method significantly reduces the duration of the test, because excluded the replacement of the grinding media used earlier with the experimental grinding balls. In addition to the specific consumption of grinding media during the industrial experiment also the technological parameters of the section was analyzed. According to the test results, based on obtained technical and technological performance of the test mill and work of the section […]
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At previous article we talked about the kinds of mills and grinding media. We have found that the most effective and widely used grinding media are grinding balls Production of grinding balls is regulated by DSTU 8538: 2015 (DSTU 3499-97). Grinding steel balls for ball mills are made of carbon steel and / or stainless steel. Table 1 shows the specific gravity of carbon and alloy steel. The specific gravity of metal is a physical quantity defined as the ratio of the weight of metal to the volume it occupies. Specific gravity of carbon and alloy steel Name (type of steel) Mark or designation Specific gravity (gr/sm3) Constructive (Structural) carbon high-quality steel 45,50,55,60 7,85 Constructive (Structural) leaf-spring steel 60Г, 65Г, 70Г, 55С2,60С2 7,85 Carbon micro-alloyed steel 76, 76Т, 76Ф, 76Ц 7,85 Constructive (Structural) ball bearing steel ШХ15, ШХ15СГ 7,81 Table 1. Specific gravity of carbon and alloy steel Grinding balls characterized by high hardness, resistance to abrasion. Surface of balls responds poorly to splitting and practically don’t crumble. Grinding balls usually classified into five groups of hardness: The first group includes balls with normal hardness. The second group includes grinding balls with increased hardness. The third group includes balls of […]
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The company “Energosteel” held a trial rental service of 100 mm grinding balls (volume – 100 tons) of high carbon alloy steel in July 2016. Experimental party of grinding balls showed higher hardness values throughout cross section of the ball with a surface hardness 58-60HRC and volumetric hardness – 57-59 HRC. According to a new national quality standard for steel grinding balls (DSTU 8538: 2015) these products comply with the fifth group of hardness. Ball Milling for Mining.
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The testing laboratory of “Energosteel” acquired a new instrument for measuring the hardness of grinding balls – updated combined hardness tester T-UD2. Hardness tester can measure the hardness of steel by scales Rockwell, Brinell and Vickers, as well as to carry out recalculation by the scale Brinell values of the tensile strength for pearlite class of steels. The device has the following advantages: Shock-resistant enclosure that withstands multiple falls from a height of 2 meters. High reliability and long service life expressed in more than 100 000 measurements ultrasonic transducer. Updated combined hardness tester T-UD2 is already included in the State Register of measuring instruments of Ukraine Hardness tester is certified in Europe (CE-certified). Combined hardness tester T-UD2 has an ultrasonic hardness testing method, which is suitable for controlling the hardness of hardened surface layers, thereby improving the quality of surface hardness testing of the grinding balls of Energosteel. An ultrasonic method includes a number of additional features and advantages, namely: Allows to measure the hardness of products of any mass with a thickness of 1 mm, which is inaccessible for dynamic hardness testers. In our case, it is the templates for measuring the bulk hardness of grinding balls with […]
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We have already described the primary processes of enrichment of minerals in mining and processing plants and equipment used in these processes. This article is about machines used in the process of grinding that called mills. Types of grinding mills: Mechanical mills. Destruction of grains and particles of material comes in result of blows grinding media or their abrasive actions. Aerodynamic and pneumomechanical mills. The destruction of pieces is due to the acceleration of the air stream and the subsequent impacts on the fixed armor. Mining and processing plants exclusively used mechanical mills as grinding machines. Mechanical mills classified by: Operating modes – continuous operation mills and batch operation mills; Grinding methods – wet grinding mills and dry grinding mills. According to the principle of operation and construction mills divided into: Drum mills Roller-ring mills Runner mills Disk mills Drum mills classified into a rotating drum mills, vibratory mills and centrifugal mills. Mining and processing plants use rotating drum mills (pic. 1). Depending on the form of the grinding media there are ball mills, rod mills, pebble mills and autogenous grinding mills. Grinding media – iron and steel balls with diameter of 15-120 mm, steel or cast iron cylpebs dimensions […]
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01.07.2016 new standard regulating the quality of grinding balls DSTU 8538: 2015 entered into force. In order to understand how to changed the requirements for the production of grinding balls, we decided to display them in a comparative table: 1. CLASSIFICATION AND DIMENSIONS DSTU 3499-97 Rated diameter, mm Nominal diameter, mm Limit deviations from the nominal diameter, mm Volume, сm3 Weight, кг 15 20 25 15,0 20,0 25,0 ± 1,0 1,76 4,18 8,18 0,014 0,033 0,064 30 35 40 45 31,5 36,5 41,5 46,5 ± 2,0 16,4 25,4 37,4 52,6 0,128 0,199 0,294 0,413 50 60 70 80 52,0 62,0 73,0 83,0 ± 3,0 74,0 125,0 204,0 299,0 0,580 0,980 1,600 2,350 90 100 94,0 104,0 ± 4,0 435,0 589,0 3,410 4,620 110 120 114,0 125,0 ± 5,0 776,0 1023,0 6,090 8,030 Note: 1. Deviations from the ball geometric form shall not exceed limit deviations from the nominal diameter. Note: 2. Calculation of ball volume and weight is performed using values of nominal diameter provided that the steel density is 7.85 g / cm3. DSTU 8538:2015 Claim 4 Table 1 without the calculated data that are presented in Attachment A Rated diameter, mm Nominal diameter, mm Limit deviations from […]
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The company “Energosteel” offers to customers products of European quality that has no analogues in Ukraine and CIS. We are talking about grinding balls of increased volumetric hardness and the fifth group of hardness, which production was launched by our factory in 2013. These products had already positively proved themselves in a number of enterprises in Ukraine and abroad. As a result of using these grinding balls achieved flow reduction by at least 20-30% compared to the balls of the 4th group of hardness. Grinding balls of the 5th group hardness have not only a high hardness on the surface, but also a high volumetric hardness that ensures uniform deterioration and shape retention during operating period. For example, we present hardness values over the entire section of the ball. Grinding balls 40mm: Hardness of the cross section, HRC Surface 0,25R 0,5R 0,75R center Volume 65-66 63,5-64 63,5-64 63-64 63-64 64 In addition, the grinding balls produced in steel with a unique chemical composition – higher carbon and other alloyed elements to provide hardwearing ball. Elaboration of the production technology of grinding balls of the 5th group of hardness took us six months because rather complicated technological task […]
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Mineral processing at concentrating plants includes a series of successive operations, which resulted to separation of mineral components from impurities. According to the destination the processes of mineral processing is divided into preparatory, basic (concentrating) and auxiliary (final). Preparatory processes are designed to mineral opening in result of the destruction splices minerals from the waste rock or splices of some minerals with others to form a mechanical mixture of particles and pieces of different mineral composition, as well as to bring minerals to the size required for further enrichment. Preparatory processes include crushing and grinding. In concentrating factories and metallurgical plants crushing and grinding of minerals are produced with a high degree of particle size reduction, prior to enrichment. For example, sometimes minerals need to grind to a particle size of less than 0.1 mm. Getting such a high degree of fragmentation in a crushing machine is almost impossible. As a result of their design, machines for crushing and grinding (crushers and mills) are working effectively only with a limited degree of grinding. Therefore, a rational way of crushing and grinding material from the original size to the desired size is using several sequentially operating crushing and grinding machines. Depending […]
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