Design of dewatering equipment and drying for magnesite pellet mesh belt dryer

In order to understand the absorption characteristics of the ore ball to infrared radiation, the absorption spectrum experiment should be carried out. Based on the analysis of experimental data and the experimental results, the experimental study on drying kinetics of magnesite ball provides a basis for the design of drying channel.

Design of dewatering equipment and drying for magnesite pellet mesh belt dryer

The preparation of anhydrous MgCl2 is an important process in the traditional process of magnesium production in China. In the past, magnesite particles were chlorinated in the magnesium workshop, and a shaft chlorination furnace with a diameter of 3.1 m was used to produce magnesium, and the consumption of chlorine gas was 0.1-1.7 t per day. MgO pellets were synthesized by seawater dolomite in the magnesium plant of Norsk hidro company in Norway. The daily output of anhydrous MgCl was 220t in a vertical chlorination furnace with a diameter of 3M. Therefore, it is necessary to study the dehydration process of magnesite pellets.

In order to make magnesium, the magnesite ball is usually put in the high temperature hot blast stove above 400 ℃, and the free water, absorbed water and crystal water in the ore ball are removed. The dehydrated ore ball should be complete and free to fall on the cement floor at a height of 1m from the ground without fragmentation. According to the development of production, it is recommended to use infrared furnace instead of hot blast stove for dehydration.

Magnesite ball is a kind of hard to dry material, which needs not only free water (water in large capillary), adsorbed water (water in small capillary), but also crystallization water. It is necessary to carry out DTA and TGA analysis of magnesite pellets at what temperature. In order to understand the absorption characteristics of the ore ball to infrared radiation, the absorption spectrum experiment should be carried out. Based on the analysis of experimental data and the experimental results, the experimental study on drying kinetics of magnesite ball provides a basis for the design of drying channel.

According to the above experimental data and the experimental data of drying magnesite ball in infrared heating furnace of Jinan water tank plant, the main design parameters are as follows:

(1) Overall dimension of furnace body: 44.37m × 2.18M × 1.78m

(2) Total power: 768kw

(3) Heating element: SHQ opal quartz tube, diameter 18mm × 2100mm, power of each tube is 2kW.

(4) Drying temperature: 350 ℃ - 400 ℃

(5) Drying time: 25-30min

(6) Output of magnesite pellet: 2T / h

(7) Structure design: considering the convenience of production, transportation and manufacturing, the furnace body is composed of 17 sections, the total length of the furnace body is 32.98m, 50 mm thick aluminum silicate fiber felt is sandwiched between each unit to solve the problem of thermal expansion and cold contraction. The outer layer of the furnace body is insulated with aluminum silicate fiber felt, and the inner wall is made of stainless steel plate for anti-corrosion. Each furnace body unit is equipped with two ash removal doors. As the exhaust gas has HCl gas and water vapor. The top of the furnace body is provided with a natural ventilation hole and a regulating valve. The upper part of the butterfly valve is connected with the lower part of the main exhaust pipe.

The transmission speed of mesh belt is manually adjusted by speed regulating motor. Compared with the existing rotary kiln heating, it can shorten the heating time by 50% and reduce the heating temperature by 25% - 35%. Due to the high-temperature directional radiation, the energy utilization is concentrated on magnesite pellets, instead of heating the whole furnace and heating pipe like the hot-air rotary kiln, so the heat loss is small. This is the unique advantage of high-temperature infrared radiation, and the high-temperature circulating fan is omitted Therefore, the high temperature directional radiation drying channel can save energy and money, and reduce the investment in infrastructure and equipment. High temperature radiation drying channel has many advantages, which can not be compared with hot air heating.