In the sand washing plant
, the purification of quartz sand is mainly scrubbing, magnetic separation and flotation. The water content of quartz sand is mainly surface water, which is easy to remove. Therefore, the drying process of quartz sand is mainly considered from the aspects of output, material characteristics of finished products, operation convenience, investment and operation cost.
The main drying machines of quartz sand are rotary dryer
, hot air convection dryer, fluidized bed dryer, infrared dryer and microwave dryer.
1.Hot air convection dryer
When quartz sand is in contact with hot air, hot air transfers heat energy to the surface of quartz sand and from the surface to the interior of material. The moisture in quartz sand diffuses from the material surface to the hot air through the gas film. Hot gas generally uses the heat energy produced by fuel oil or natural gas.
Advantages of hot air convection dryer: quartz sand particles have good dispersion under high-speed hot air stirring, large contact area between hot air and materials, intense heat transfer and drying process, fast drying speed and short drying time.
Disadvantages of hot air convection dryer: high velocity of hot air and serious abrasion of air drying tube; The hot air temperature is too high and the thermal efficiency is low; All the hot and humid air from the drying room is directly discharged into the atmosphere, resulting in the low energy efficiency of this drying equipment.
2.Fluidized bed dryer
A horizontal multi chamber single-layer fluidized bed dryer was used to stack the wet quartz sand on the air distributor. The hot air was evenly distributed through the air distributor and then entered the fluidization section. When the air flow acted between the critical velocity and the entrainment velocity of the quartz sand group, the quartz sand particles formed fluidization movement, so as to strengthen the heat and mass transfer between them. By means of fluidization technology, quartz sand can be dried in a boiling state under the action of thermal medium.
Advantages of fluidized bed dryer
The results show that the contact area between the surface of quartz sand and hot air is large, the effect of heat and mass transfer is good, the drying rate is fast and the treatment capacity is large.
Disadvantages of fluidized bed dryer
The fluidized bed dryer covers a large area and the manufacturing cost is high.
The rotary dryer adopts a drum which is inclined and can rotate. With the help of the slow rotation of the drum, the material moves from the higher end to the lower end under the action of gravity, so that the hot air in the drum can effectively contact the quartz sand for drying.
Advantages of rotary dryer
The production capacity of rotary dryer is large; The resistance of drying medium passing through the rotary drum is small; It has strong adaptability to materials, stable and convenient operation, low operation cost, and is the mainstream equipment for quartz sand drying.
Disadvantages of rotary dryer
The contact area between hot air and quartz sand in rotary drum drying system is small, and the heat utilization rate is slightly low.
The infrared ray emitted by electric heater makes the material heated to achieve the purpose of drying. After the infrared ray is absorbed by the material, it becomes hot, and the moisture in the material evaporates. Infrared has a certain penetration, can reach the internal of the material particles, can speed up the drying speed, shorten the drying time.
Infrared drying is especially suitable for materials with large and thin surface area and complex shapes. For quartz sand, the drying effect is not good, and the operation cost is very high.
Microwave drying is an internal heating method, which has the advantages of high drying rate, clean production and easy automatic control. However, microwave consumes advanced energy, the efficiency of electromagnetic conversion is not high, and the equipment investment and operation cost are higher than ordinary conventional drying methods. At present, it is seldom used.
For more information about quartz sand drying and sand washing plant, please visit Sinonine website https://www.9silica.com , or contact us directly by +86-18118821087(whatsapp).