Metal Magnesium Rotary Kiln

Metal magnesium rotary kiln

Our metal magnesium rotary kiln cylinder specifications range of Ø1.6×32m-Ø4.0×80m, the selection of supporting vertical preheater (YRQ04-YRQ20) and vertical cooling machine (LSF36-LSF112) can meet the production needs of different capacity scales.

Capacity: 2-20t/h

Specification: Ø1.6×32m-Ø4.0×80m

Applicable materials: Metal magnesium production line dolomite calcination

Metal magnesium rotary kiln product introduction

Magnesium metal rotary kiln is a special rotary kiln developed according to the calcining characteristics of dolomite and the process requirements of Pijiang process for magnesium smelting. It is the key equipment of dolomite calcining system. The calcined white produced by the rotary kiln has the characteristics of stable and uniform quality, high activity and low burning loss, which fully meets the process requirements of Pijiang process for magnesium smelting and makes the magnesium extraction rate and silicon utilization rate relatively high. The production cost of magnesium metal is reduced, and it is an ideal equipment for calcining dolomite in magnesium industry.

Outstanding advantage

1. The rotary kiln is composed of cylinder body, support device, transmission device, kiln tail and kiln head seal, etc.

2, the length to diameter ratio of rotary kiln is reduced from the traditional 20-25 to 14-15, reducing the surface heat loss of rotary kiln;

3, the transmission system adopts frequency conversion speed regulating motor, equipped with frequency converter has the advantages of wide speed regulating range and heavy load starting;

4, kiln head, kiln tail using heat-resistant steel flake seal to replace the original seal, not only reduces the kiln head and tail air leakage, but also durable.

Working principle

Dolomite is fed into the kiln through the kiln tail (high-end) chute. Because of the tilt and slow rotation of the cylinder, one side of the dolomite rolls around the circumference, and the other side moves axially from the kiln tail (high-end) to the kiln head (low-end). Fuel from the kiln head through the burner into the kiln for combustion, heat by radiation, convection, conduction and other ways to the dolomite, dolomite in the kiln after preheating, decomposition, burning and other processes, calcined into calcined white, and then discharged from the kiln head device.

One Production raw material

1) Dolomite

The granularity of dolomite is required to be 10 ~ 40mm, and the part exceeding the upper limit of 40mm and the lower limit of 10mm shall not exceed 5%.

Chemical composition of dolomite:

MgO: 19 ~ 21%; CaO: 30 ~ 33%; SiO2 < 0.5%; Fe2O3 < 0.5%; Al2O3<0.5%; Na2O<0.005%; K2O<0.005%; Mn<0.0005%; Where CaO/ MgO=1.394 (mass ratio), CaO/ MgO=1.0 (molar ratio).

2) Ferrosilicon

Ferrosilicon is 75# ferrosilicon with Si≥ 75%, that is, it is composed of 49.92% Si and 50.08% FeSi2.

3) fluorite powder

CaF2 in fluorite powder is more than 90%, and its particle size is 200 mesh

2. Production technology

★ Metal magnesium smelting in the process selection of the use of mature technology, reliable, reasonable new Pijiang method magnesium smelting process. Qualified dolomite is sent to the rotary kiln for calcining; Then the calcined dolomite, fluorite, ferrosilicon according to a fixed proportion of ingredients, through ball milling and pressed into pellets; It was put into the reduction tank under the condition of vacuuming and carried out high-temperature thermal reduction to obtain crystalline magnesium. Magnesium metal can be obtained after crystalline magnesium is remelted and refined. Including raw material reserve, dolomite calcination, grinding ball, reduction and refining sections.

Raw material reserve

★, the dolomite is broken in the mine to meet the required particle size, and stored in the dolomite yard in the factory. Ferrosilicon and fluorite are stored directly in the factory warehouse. Reserves are considered according to the consumption required for half a month of production.

Dolomite calcining workshop

★ Choose energy-saving and environment-friendly rotary kiln, with vertical preheater and vertical cooler. The dolomite with external particle size and quality that meet the requirements is discharged to the material yard, the loading machine carries out the material stacking and collecting operation, and the vibrating screen carries out the screening after that, the dolomite with 10 ~ 40mm particle size is transported by belt to the top silo of the vertical preheater of the rotary kiln, and enters the preheater through the material pipe to exchange heat with the high temperature flue gas flowing from the rotary kiln, and the material is preheated to more than 800℃. After falling into the transfer chute, it is calcined into active calcined white in the rotary kiln at high temperature of 1250℃, and then discharged into the cooler, where the high temperature calcined white is exchanged with the cold air pumped into the fan, the active calcined white is cooled below 100℃, and the air is preheated to more than 600℃. After cooling, the activated calcined white is discharged from the cooler and transported to the ball making workshop by the scale conveyor.

The main reactions are as follows:

★, CaCO3? MgCO3= CaO? MgO + 2CO2

The high-temperature flue gas produced by the combustion of rotary kiln, after heat exchange with dolomite in the preheater, the temperature drops below 220℃, and then enters the bag dust collector, and is discharged into the atmosphere by the high-temperature fan after dust removal, and the dust concentration of the discharged gas is less than 30mg/m3. The whole line adopts advanced technology and reliable performance PLC control system, centralized operation and management in the main control room.

Pelletizing plant

★, Calcined dolomite by the elevator into the 1 # bunker reserve; The ferrosilicon is broken by the jaw crusher to less than 20mm, and lifted by the elevator into the 2 # ferrosilicon block storage bin for use; Fluorite powder is lifted from a single bucket into the 3 # bunker. The three raw materials stored in the storage bin are continuously mixed into the ball mill by microcomputer control, and the particle size is < 100 mesh. The mixed powder is then passed through the elevator, the storage bin, and the buried scraper conveyor, and enters the ball press to make pellets. The batching system uses an intelligent control system, and the whole process is fully automated by computer monitoring. The ball mill is driven by 10kV high voltage motor, which reduces the power consumption loss compared with the original 380V low voltage distribution operation. There are 3 sets of dust removal systems in the ball making workshop. C1# dust removal system is set in the crushing place of ferrosilicon, C2# dust removal system is set in the batching mill, and C3# dust removal system is set in the pressing place. After comprehensive dust removal treatment, the operating environment of the ball making workshop is greatly improved compared with the traditional workshop, and the working environment of the workers is improved.

Reduction and refining plant

★, The reduction furnace adopts high temperature air rapid reversing regenerative combustion technology, and the regenerative reduction furnace uses gas as fuel for continuous heating. The pellets are added by the feeder to the reduction tank in the reduction furnace. The magnesium vapor generated by the reduction tank is cooled into crystallized magnesium (coarse magnesium) in the end condenser, and the coarse magnesium is removed and sent to the refining and alloy production line.

Magnesium metal rotary kiln is mainly composed of transmission device, supporting device, supporting device of supporting wheel, cylinder, kiln head, kiln tail and sealing device, etc. The main structural characteristics are:

1, according to the kiln type selection of mechanical or hydraulic stop wheel, both have high accuracy and reliability, stability, and easy to adjust;

2, the whole kiln has 2 ~ 4 fulcrum (mostly 3 fulcrum), easy to ensure that the support wheel and the kiln wheel belt contact surface parallel to the axis of the cylinder;

3, the supporting device adopts rolling bearings, which greatly simplifies the supporting structure of the supporting wheel, which can reduce the loss of idle work during the operation of the kiln, and also make maintenance and overhaul more convenient;

4, kiln head, kiln tail seal using heat-resistant steel flake seal instead of the old labyrinth seal, so that the sealing performance is better, higher reliability, and longer service life, replacement is more convenient;

5, in order to facilitate installation, debugging, while ensuring that the main drive system maintenance or other abnormal conditions can still be carried out disk kiln operation, to prevent the kiln cylinder bending deformation during the cooling process, with a slow disk kiln mechanism.

Technical parameter