The grinding machine is used in combination with a classifier to form a grinding and grading process. A large piece of ore is ground to the desired fineness, generally in stages, with each section only completing a portion of the entire grinding process, which is referred to as the grinding section. Modern multi-application beneficiation plant in paragraph or two grinding process, rarely used more than three-stage grinding process. The number of grinding sections is mainly determined by the size of the mine, the grindability of the ore, the size of the useful mineral crystal grain, the size of the ore and the particle size of the final product. In general, when the upper limit of the final product particle size is greater than 0.15 mm, a one-stage grinding process can be used; when the final product particle size upper limit is less than 0.15 mm, a two-stage grinding process should be used. The number of suitable grinding processes should be determined according to the specific circumstances and after technical and economic comparison. Figure a, an inspection period of closed-circuit grinding classification process, applicable to the case of rough grinding the grinding fineness greater than 0.15 mm, are widely used in the concentrator of gold.
Quantum has extensive experience in the correct selection and design of screw conveyors, screw dischargers, hopper unloading and screw metering systems. The above list is typical of the type of equipment we have supplied to a variety of industries for varying applications. Whether your process and application requires mixing during conveying, dewatering, batch metering interlocked to weigh system or conventional transfer conveying we have the experience and standard equipment to ensure you have a reliable trouble free installation.
QUANTUM designs and supplies a complete range of Screw Conveyors.
These types include:
• Conveying and transfer conveyors:
• Inclined Screw conveyor
• Horizontal Screw conveyors
• Storage Hopper Discharging & Live Bottom Bin Discharging systems
• Hopper Discharge
• Dosing and metering screw dischargers
• Twin Shafted Screw Conveyors
• Dewatering and compacting screw conveyors
• Batch metering screw feeders with self-emptying storage hoppers.
• Shaftless Screw Conveyors (Auger Covneyors)
Quantum have specialized screw conveying systems installed in chemical, mineral as well as the food and beverage industries. Our designs cater for stainless steel, mild steel with liners and special steel for abrasive materials, through to fully polished, sanitary clean down applications requiring full clean out and knock down construction. Materials handled can be micro powder to granular and lumps. The selection and type of conveyor recommended is critically dependent on the material to be conveyed.
Conveying and Transfer Conveyors:
Quantum manufacture a standard range of screw conveyors incorporating intermediate center bearings or center less screw conveying for difficult sticky materials. Length of conveyors and size of conveyor depends on capacity and material characteristics.
Inclined and vertical conveying:
Quantum have designed and installed both vertical and inclined screw conveyor systems. It is recommended to design all incline conveyors without using an intermediate bearing, if possible and to keep incline to less than 75o for optimum efficiency. Whether your application requires a tubular inclined conveyor or trough conveyor, Quantum will select the most suitable conveyor for your application that is suited to the material characteristics, environment, length conveyed and your specific needs such as clean down and residue. Efficiency of vertical conveyors can be as little as 10% and generally require specific design considerations; the nature of material and feed method. Our engineers can assist with the best and most suited conveyor for your needs.
Horizontal transfer conveyors
A single conveyor can incorporate several hanger bearings over length in access of 100m. However length is very much dependent on the nature and characteristics of the material and the conveying capacity. Some materials cannot be successfully conveyed using any hanger bearings, whilst other materials will accommodate several hanger bearings trouble free. We has a general rule of maximum conveyor percentage full by volume be no more than 40% when using hanger bearings with no more that 1mm/m deflection of center pipe. Quantum design all conveyors for full load start up with much consideration given to conveyor speed to eliminate excessive wear. All our conveyors are designed with gland seal packing to protect spherical bearings.
Hopper and Live Bottom Bin dischargers
Our hopper and Bin dischargers are used when non free flowing materials need to be discharged from hoppers or storage bins. Size and quantity of screws depend on the hopper configuration and the material characteristics. Using multiple screw dischargers can increase volume of hoppers whilst ensuring a positive discharge of material at a controlled out feed. Each screw can be independently powered or interlocked with one or two drive assemblies depending on loading and capacity of the system.
Generally installed with slow speed counter rotating screw flights that can be over locked for maximum discharging capabilities they are variable pitch or variable flight diameters to ensure even material discharge across hopper.
Heating and Cooling Jackets
All Quantum Screw Conveyors can be fitted with heating and cooling jackets utilizing steam, thermal liquids, refrigerant, water or brine. Heating or cooling can be designed by our process engineers who will recommend the most suitable size and type of conveyor for your production and needs.
Clean Design
Quantum is familiar with the specific needs of the food and beverage industries. All our Screw Conveyors can be fitted with CIP spray balls and manifolds, with quick knockdown in mind to ensure complete clean-down where required. Screw Conveyors can be constructed from mild steel, 304 or 316 stainless steel, depending on the material being conveyed. Surface finish will be provided to suit specific requirements. All components such as IP ratings of electric motors and switches are selected with these specific requirements in mind to ensure compatibility with your operating procedures.
After sales support
Quantum can provide a customized service contract using experienced technicians with many years` experience in servicing and troubleshooting Screw Conveyors in all states. This service ensures your equipment is functioning to its optimum capabilities and reduces down time due to parts replacement and potential damage. Our technicians have standard customer maintenance, checking and reporting procedures.
Screw Conveyor,Tubular Screw Conveyor,Single Shaft Screw Conveyor,Twin Shafted Auger Conveyor Quantum Conveying Systems Yangzhou Co.,Ltd. , https://www.fkconveyor.com
There are many forms of grinding grading, but the most basic ones are shown below. 
Figure b shows a closed-circuit grinding process with inspection grading and controlled grading. Suitable for small concentrators, in order to simplify the grinding process, the grinding fineness can be used when the fineness is not less than 0.15 mm. This process can reduce over-grinding.
As shown in Figure c, there are two sections of closed-circuit grinding process for inspection and classification, which are suitable for use in ore dressing plants with large grain size and large production scale. In the first section, a common rod mill is used for open grinding, and the ore of 20 to 25 mm is ground to about 3 mm and then finely ground by a ball mill .
Figure d shows the two-stage two closed-circuit grinding process, and the pre-grading and inspection grading of the second-stage grinding are combined. It is commonly used in large and medium-sized concentrators where the final product size is less than 0.15 mm. This process must correctly distribute the load of the first and second stages of the mill to improve the grinding efficiency.
Grinding classification process commonly used in mineral processing plants