Fugu County Xintian Magnesium Alloy Co., Ltd. originally had 2 rotary kiln dolomite calcination lines, all of which are products of Henan Zhengzhou Mining Machinery Co., Ltd. Due to the stable and reliable equipment and the needs of business expansion, it was decided to install another vertical preheating line in 2017. The supply, installation and commissioning of the dolomite calcination production line with an annual output of 20,000 tons are undertaken by Henan Zhengzhou Mining Machinery Co., Ltd. The two parties signed the contract on July 7, 2017, and the installation and commissioning were completed in May 2018 and passed the acceptance.

Signing date: 2017-07-07

Processing material: Dolomite

Processing capacity: 20,000 tons per year

Equipment configuration: rotary kiln, vertical preheater, cooler, ball mill, dust collector, electrical instruments, etc.

1. Project overview:

The bid for the 20,000 tons of Xintian dolomite calcination project, Yulin, Fugu County, Shaanxi Province was completed in July 2017. Henan Zheng Mining Machinery Co., Ltd. was identified as the supplier and installation supplier of the production line. Commissioning and acceptance were completed in May 2018. The quality and safety of the equipment are recognized by the other party, and the production line is energy-saving, environmentally friendly and easy to operate.

Henan Zhengzhou Mining Machinery Co., Ltd. specializes in the production of mechanical equipment for the magnesium metal smelting industry. According to the improvement of the smelting process and the improvement of the equipment level in the magnesium plant, the performance of the equipment is continuously improved, and the product functions are improved. The preheater independently developed and produced has been successfully applied to dolomite. The calcination of the gas, the heat recovery and utilization in the exhaust gas, save fuel, increase the output, and also facilitate the dust removal of the flue gas, and the emission index meets the environmental protection standard.

The existing complete set of dolomite calcination production equipment of Xintian Magnesium Alloy Co., Ltd. was developed and manufactured by Henan ZK Corp. Currently, the equipment is stable and reliable. Henan ZK Corp was listed as a supplier, as soon as Xintian Magnesium had a preliminary business expansion plan. After friendly technical and business communication and exchanges between the two parties, Henan ZK Corp was successfully identified as the supplier of the project. This project mainly uses the rotary kiln to complete the calcination of dolomite ore according to the expected quality and capacity, but compared with the previous dolomite calcination production line, it pays more attention to energy consumption and environmental protection indicators.

2. Solution:

The production line adopts the following main design solutions to solve the key issues in the process, energy and environmental protection in the production of magnesium forging white, and meet customer requirements.

1) Plan the process flow according to the actual situation of the customer's site, and reasonably arrange the equipment. Because the customer site is square and has a limited area, there are not only large equipment and civil construction facilities such as rotary kilns, preheaters, and coolers, but also factory buildings and warehouses. This requires full use of land and reasonable planning and layout. The project has a compact and reasonable layout of coolers, ball mills, kiln tail dust removal facilities, and warehouses, which not only meets production needs, but also saves land area.

2) The vertical preheater with pusher is adopted, which is energy-saving and environmentally friendly. The vertical preheater with pusher is a patented product of Zhengzhou Mining Machinery, which is used in conjunction with the magnesium rotary kiln. Before the dolomite enters the kiln, the hot air from the kiln end passes through the material layer and is preheated to 800°C to fully absorb heat. At the same time, reduce the exhaust gas temperature and dust concentration, avoid high temperature damage to the subsequent bag dust collection filter bag, and optimize the particulate emission index.

3) Energy-saving and environmentally-friendly rotary kiln is used for dolomite. Metal magnesium rotary kiln is a special rotary kiln developed for the calcination characteristics of dolomite and the technological requirements of Pidgeon method for smelting magnesium. It is the key equipment of the dolomite calcination system. The length to diameter ratio of the rotary kiln is reduced from the traditional 20-25 to 20. , Reducing the heat loss from the surface of the rotary kiln. The calcining temperature of dolomite is 1250℃.

4) Single-tube cooler is used for material cooling. The high-temperature forging white out of the kiln is written into the cooling function, which exchanges heat with the cold air in the cooler and the chain device to cool the active calcined white to below 100°C, and is sent to the forging white warehouse. The air is preheated to above 600°C and enters the kiln. Combustion.

5) Preparation of coal powder. The raw material used by the system uses pulverized coal, and the preparation of pulverized coal uses an air-swept ball mill. The drying heat source is hot air drawn from the kiln head. The output material is equipped with a powder separator. The fine material is the finished product, and the coarse powder is re-ground and ground again. A cold air baffle is installed on the hot air duct of the kiln head to control the temperature of the hot air entering the mill according to production needs.

6) Due to higher environmental protection requirements, a dust collection port is set for each dust collection point, and the dust collector is reasonably arranged to realize the partition management of the dust collection point to meet the environmental protection requirements; the exhaust gas is cooled by the preheater and then enters the bag filter for filtration Purified, discharged into the atmosphere from the chimney through the traction fan, and the dust emission concentration is below 30mg/Nm3.