Details description

The magnesite powder or the concentrate powder after flotation adopts the new technology and equipment of the flash swirl dynamic calciner to obtain high-grade light-burning activated magnesia: the superior performance of this system and equipment is fully reflected in the heat treatment of the powder material ;It first uses the waste heat of calcination to quickly disperse, dry and dehydrate the original powder or wet powder to ≤1%, restore the original particle size, and then heat up the dry powder through the preheating section and then enter the flash swirl dynamic calciner, and the powder is in the kiln. The high-temperature rotating airflow disperses instantaneously, that is, the maximum specific surface area is formed, and the particles are fully thermally decomposed in the rotating upward airflow at 950-1000 °C. That is, the calcination process is completed, there is no over-burning and under-burning phenomenon, the system is closed and negative pressure operation has no dust exposure, the recovery efficiency is ≥99.9%, the activity of the citric acid method is 50-80s, and the ignition loss is ≤2-1%. The new technology of the calciner is equipped with energy saving and emission reduction, realizing clean production, and can also be applied to the calcining treatment of flotation tailings. , High-strength building cement, fire-resistant materials are better.

The reserves of magnesite (MgCO3) in Liaoning area of my country are about 2.57 billion tons, of which Yingkou, Dashiqiao and Haicheng magnesite are the main producing areas, and the magnesite is famous for its high quality magnesite. However, after many years of mining, the magnesium oxide (MgO) content of about 46.5% has been mined with a good grade of about 46.5%, and the blasting mining can only select large pieces of material into the shaft kiln, and the smaller pieces are used for paving stones or discarded to fill trenches. In the face of a large number of low-grade ores and the full utilization of crushed ores, it is imperative to eat and squeeze the precious ores. From the perspective of mineral deep processing methods, the current better process is to use first grinding and then calcining or using first. For flotation to improve the main grade of magnesium and then calcining, the key is powder calcining equipment. It is very important to need an advanced calcining technology and equipment that is more in line with technical conditions. First of all, environmental protection, energy saving, emission reduction and low operating costs must be guaranteed. The thermal decomposition rate and the activity of the light-burning powder should also ensure the recovery efficiency of the powder: the particle size of the concentrate powder after flotation is 75-10 μm, the moisture content of the wet material is about 11-12%, and the fine powder is viscous and easy to form agglomeration Phenomenon; the traditional equipment commonly used in our country are light burning shaft kiln, rotary kiln, boiling kiln, suspension roasting furnace, multi-layer roasting furnace, and reverberatory kiln. The sieved fine powder can not be reused, which wastes resources. The calcination time of the block size is not uniform, and the calcination time is not easy to control. It is easy to cause under-burning or over-burning. The quality is uneven, fine grinding and grading are required after calcination, and moisture absorption and secondary pollution are prone to occur in the subsequent process. The above equipment has various degrees of defects, and the product quality is unstable. So that the resources can be used reasonably, and a blue sky and white clouds will be given to the place.

In order to implement the requirements of the Liaoning Provincial Magnesium Resource Protection Office and the municipal governments for the environmental protection and clean production of the magnesite industry and the urgent need for high-end equipment to transform the backward production process, the spirit of instruction to speed up the improvement of the production level of my country's magnesite industry. In view of the calcination process and technical conditions suitable for magnesite powder and flotation powder, Liaoning Dongda Powder Engineering Technology Co., Ltd. has developed and designed a flash cyclone dynamic calcination based on the calcination experience of various powder materials. Furnace new technology equipment, the calciner system process route set: energy-saving heating, metered feeding, granule drying, preheating and heating, powder calcination, heat exchange and supplementary combustion, dust collection, clinker cooling, waste heat utilization, transportation The integration of advanced technologies such as powder storage, continuous packaging, and system automation control fully reflects the superior performance of environmental protection and energy saving and the stable and controllable performance of product quality. blank, and obtained a national patent.

According to the basic physical and chemical changes of magnesite in the calcination process: one is the thermal decomposition of magnesite, the crystal growth of periclase crystals; the other is the interaction between impurity chlorides or impurity oxides and MgO under the action of high temperature action to form new minerals.

∆

According to the main chemical composition of magnesite, MgC03 decomposes at about 700 ℃ during calcination, releases CO2, generates MgO, and is accompanied by a large volume shrinkage. Its reaction formula MgC03 → MgO + C02 is completely decomposed when heated to 1000 ℃. It produces lightly burned MgO with loose texture and great chemical activity. Continue to heat up, the volume of MgO shrinks, the chemical activity decreases, and the density increases.

Technical conditions and classification of light-burned magnesia: national standard GB9354-88

Adopt our company's new technology equipment of flash swirl dynamic calciner

At present, industrial production has been realized, and the production process data are as follows:

1. The original magnesite powder: Dashiqiao, Liaoning, the place of origin, and its phase composition is CaMg(C03)2,

The chemical composition is MgO 21.95; CaO 30.42; Si02 0.435; Fe2O3 0.219; Al203 0.194; Mn02 0.142; P205 0.069;

2. Concentrate powder after flotation: water about 11～12%, MgO 47.5; CaO 0.22～0.6; Si02 0.17～0.2; Fe203 0.1～0.32; Al2o3 0.05～0.13;

3. After calcination: decomposition rate ≥98～99%, particle size ≥75μm, lemon method activity 50～80s, ignition loss ≤2～1%.

The working principle and characteristics of the flash swirl dynamic burner:

The SKDS flash cyclone dynamic calciner system is mainly composed of; heating and energy-saving gas hot blast stove, metering feeding, granulation dryer, preheating heater, calciner main body, cyclone dust collector, heat exchanger, dust collector, air cooling system , blower, induced draft fan, temperature measurement, pressure, electronic control system.

The calcination heat source adopts combustion gas or natural gas hot blast furnace: firstly, the waste heat negative pressure of the calciner is introduced into the drying host: the raw ore powder or wet powder material is continuously transported into the drying host, and the material and the hot air conduct high-speed mass transfer and heat transfer, instantly vaporizing water molecules Evaporation, drying and dehydration to ≤1%, the drying process is completed in about 3 to 5 seconds, that is, the dry exhaust gas enters the cyclone dust collector and the bag filter together for gas-solid separation, and the exhaust gas filtered and purified by the cloth bag is drawn out by the induced draft fan; The dust collector is discharged into the preheating thermostat, and the material is preheated in multiple stages and then enters the flash swirl dynamic calciner. The particles fully undergo thermal decomposition reaction in the rotating upward airflow. The particles are heated at high temperature and instantly release CO2 and crystal water, which are decomposed into oxidation Magnesium is decomposed into magnesium oxide porous particles, and the calcination process is completed in 3 to 5 seconds. The material enters the gas-solid separator from the outlet of the calciner with the negative pressure airflow, and the separated powder enters the indirect heat exchange clinker silo. The valve is discharged, and the hot clinker enters the negative pressure air cooling system, and the material is cooled and sent to the storage bin.

In summary, its technical characteristics: the new technology equipment system of the flash cyclone dynamic calciner is fully enclosed negative pressure operation, no dust is exposed, the recovery efficiency of the cyclone dust collector is ≥ 85%, the recovery efficiency of the bag filter is ≥ 99.9%, the gas solid Evenly mixed, fully thermally decomposed, instantly calcined, the product has no over-burning or under-burning phenomenon, hydration activity is 80-120, lemon method activity is 50-80s, ignition loss is ≤ 2%, which is beneficial to high-activity products and subsequent deep processing products , continuous production, calcining temperature, air volume, feeder speed can be adjusted, product quality is stable, the working environment meets the national environmental protection requirements, the machine system is equipped with an air-air heat exchanger, and the hot air can be supplied to the combustion chamber secondary air. The waste heat of the calciner is combined with preheating, heat exchange and drying, and the heat source is fully utilized to form high-efficiency, energy-saving and environmental protection technology equipment. This technology is suitable for the calcination of flotation minerals, as well as for the calcination of low-grade raw ore powder, and also for the calcination of flotation tailing powder. And building materials or flue gas desulfurizer materials are more effective.

The new technology equipment of SKDS flash swirl dynamic calciner has been successfully applied and is being used in China, Yingkou Yijia Magnesium Technology Co., Ltd., Liaoning Donghe New Materials Co., Ltd., etc. The successful application of this technology has solved the problems of environmental pollution, low resource utilization and high energy consumption caused by the calcination of light calcined powder. In order to improve the industrial production level, the local clean environment and a blue sky will be restored.

Field application pictures