Introduction to magnesite drying and calcination system process:

The process of magnesite drying and calcination system adopts the combination system of flash dryer and flash fluidized calciner, which are patented products of our company.

Flash drying is a drying method to completely fluidize solids. The drying host has the mechanical, airflow dispersion, and columnar adjustment functions for drying materials. The paste and filter cake materials with high moisture content are added to the drying host and mixed with the heated hot medium. The materials form a double swirl granular fluidization state under the action of hot air and mechanical dispersion. The heat and mass exchange is completed instantly. The dried materials enter the collector to obtain powder products.

Magnesite generated by chemical method is calcined and decomposed into high-purity magnesium oxide. At present, the calciner used is a patented product developed and produced by our company - scintillating fluidized calciner. Scintillation fluidized bed calciner is a kind of furnace specially used for calcining magnesium carbonate. The magnesite filter cake formed after dehydration is dried by the waste heat of the calcination tail gas, and the dried powder enters the calciner for calcination and decomposition into high-purity magnesium oxide. The calcination time is 28 seconds, and the calcination temperature is 950~1030 ℃. The product calcined in the flash fluidized bed calciner is superior to the product formed by the traditional process in all indicators, and the purity of the product can reach 99.3~99.7%.

Working principle:

The tail gas produced by the flash fluidized bed calciner after calcining the materials enters the special dryer. The filter cake like magnesium carbonate with a water content of 45~50% is sent to the dryer by the feeder, and the powdered magnesium carbonate formed by the dispersion and drying enters the flash fluidized bed calciner. The hot air generated by coal, natural gas or coal gas enters the calciner, where it is mixed with the magnesium carbonate sent into the furnace for heat transfer and heated by hot air at 950~1030 ℃, Magnesium carbonate is rapidly decomposed into high-purity magnesium oxide after 28 seconds, and the decomposed high-purity magnesium oxide is captured by a trap and enters the storage bin.

Technological process:

Technical specifications:

The annual output of a single scintillating fluidized bed calciner within the series specifications is 50000 tons, 100000 tons, 150000 tons and 200000 tons (can be designed separately according to customer requirements).

Performance and characteristics:

● The whole system is closed without cross contamination, and the recovery rate is above 99%.

● Instant drying, 1~3 seconds between drying elbows, the retention time of materials is less than 10 seconds, the particle size distribution is uniform, the product is not overheated, and the fluidity is good.

● Hot air stove, steam and electricity are used as heat sources. Coal, gas and liquid are used as fuel, and the combustion mode is direct or indirect. The temperature of hot air is 80~1000 ℃.

● High thermal efficiency, strong evaporation capacity, heat consumption of 900~1500Kcal/kgH2O, and evaporation capacity of series products of 40~4000kgH2O/h (single set).

● It is suitable for drying filter cake and paste materials with high moisture content. The moisture content of the materials can reach more than 90, and the final moisture content is below 0.5%.

● Small floor area, simple and convenient operation, automatic control can be realized according to different requirements of users, and the comprehensive operation cost of equipment is low.

● The calcined materials are uniform and sufficient to produce active magnesium oxide.

● The equipment system is free of pollution and meets the environmental requirements.

● Energy consumption can be saved by 20~30% compared with shaft kiln

● Convenient operation and high degree of automation

System interface diagram:

Figure 1: Magnesite drying and calcination system diagram