Introduction

Phosphogypsum is the waste residue produced in the production of phosphoric acid and phosphate fertilizer. Its particle size is d<80 mesh, and the 180 mesh screen is generally about 20%. The PH value is 3 to 4, and the content of CaSO4 is> 70 to 80%. The impurities are mainly phosphate gangue, such SiO2, Al2O3, Fe2O3, M0O, P, F and residual acids, etc., vary from place to place and are very complicated. In order to use it, all free water and part of crystal water need to be removed to turn it into β-type hemihydrate phosphogypsum. Our company plans to adopt high-efficiency and energy-saving adjustable rotary drying and calcining kiln, high-temperature boiling furnace rapid calcination technology, and high-efficiency high-temperature-resistant cloth bag dust removal technology to meet the requirements of high-yield and energy-saving.

   The combustion of the boiling furnace is a kind of combustion method between the layered combustion and the suspension combustion. The combustion situation is: the fuel is violently tossing up and down within the material layer height of the furnace, just like water boiling in a pot. Boiling state. The boiling furnace has enhanced combustion. The heat transfer effect is good, and the structure is simple, and it is easy to realize the advantages of mechanized operation. Basically, inferior coal that cannot be burned by other hot blast stoves can be used, such as coal gangue and oil shale with a calorific value of 4000Kcal/kg, and the burnout rate is above 95%. In addition, the bed area of the fluidized bed furnace can produce 2.8-3.3t/h of hot flue gas, and its thermal efficiency is 2-4 times that of other combustion circuits, and can continuously supply high-temperature hot flue gas at 600-1000°C to the dryer. Therefore, the boiling furnace is a highly efficient furnace type.

New high-yield energy-saving drying and calcining kiln

  1. At present, most domestic rotary drying and calcining kilns adopt ordinary arc-shaped lifting plates in their internal lifting devices, which have the characteristics of simple structure and strong adaptability to materials. However, the dispersion of the lifted material is low, and the uniformity is poor, which cannot form an ideal material curtain. In addition, some grid-type lifting plates are also used, which can make the lifting part more uniform, but the lifting plates are easily deformed by heating, the welds are cracked, and it is not easy to clean and maintain, especially not suitable for drying large pieces with high viscosity. materials. The new combined lifting plate has a large lifting angle and good material sprayability. A new type of lifting plate structure can be optimized according to the different drying areas of the material in the dryer and combined with the actual production. Through reasonable adjustment of the material The residence time in the dryer realizes the accelerated drying, constant-speed drying, and reduced-speed drying stages of the material in the dryer, which greatly increases the water evaporation speed and intensity, which is the dryer to increase the output Key measures.

   The feed material of the traditional dryer is in the upper part of the boiling furnace, and the material is fed through the heat-resistant blanking tube. Due to the high temperature of the boiling furnace, even the blanking tube of heat-resistant steel casting is easy to burn out, and frequent replacement will seriously affect the drying. The normal operation of the machine. Feeding through a special device before drying and calcination eliminates the need for a blanking tube, and there is no problem of blanking tube replacement at all. At the same time, the feed pipe is eliminated, and the ventilation in the drying and calcining is more common and the effect is better.

In order to meet the different requirements of different materials for the speed of the dryer, and when conditions permit, appropriately increase the speed of the dryer, and the height of the dryer is increased, so that the material can be sprayed better and the drying effect is better. Replace the Y series motor with a speed-regulating motor. The speed-regulating range is between 132-1320 rpm. Frequency conversion can also be used. The speed of the dryer can generally be controlled at 0-6 rpm, which can fully meet production needs. From the perspective of usage, the transmission system runs stably, which is helpful for improving the efficiency of drying and calcining and increasing production.

   Compared with the traditional adjustable gear structure with spring steel plate, the drying and calcining cylinder body is processed, and the gear is inlaid on the cylinder body, with higher concentricity, better drying and calcining rigidity, smooth operation and low vibration.