Current Situation of Domestic and Foreign Slag Vertical Mill：
MLK vertical roller mill is applied in pulverizing system of slag in steel works and also can be used for grinding cement clinker and other chemical raw materials. “High fineness and high adulteration” technology of slag is a kind of new technology developed in the recent ten years. NHI Cement Equipment Branch, by far the most important manufacturer of large vertical roller mill in China, has independently developed MPS (MLS) vertical roller mill of multi-specifications, including MLS36326 vertical roller mill applied widely in the market and domestic largest MLS4531 vertical roller mill with the max. production capacity of 5000t per day. North Heavy Industries, on the basis of absorbing advanced technology in China and overseas, has independently developed MLK series vertical roller mills used for grinding slag, which solves the critical technical difficulties of “stabilizing material bed to prevent vibration”, “de-ironing in mill”, “abrasion of grinding roller and millstone” and “high-efficiency powder selection” and so on.

Working Principle of MLK Vertical Roller Mill： 
MLK vertical roller mill is part of external force type roller mills. The motor drives the rotation of millstone via the main speed reducer and rotation of millstone drives the autorotation of three grinding rollers. Blast furnace slag enters the mill feeding through feeding device and falls onto the center of millstone. Under the action of centrifugal force produced during the rotation of millstone, the slag moves towards the edge of the millstone and is milled in the milling area between the bottom of grinding roller and the top of millstone lining plate. The milled materials get across the material baffle ring at the edge of millstone, are blown by the hot wind from the nozzle ring then enter the powder concentrator above the mill. The powder concentrator selects qualified fine powder. The coarse powder falls again onto the millstone for milling along the return hopper. The iron powder not taken away by hot wind is separated by the refined iron remover when passing the circulation system.

Latest technology Adopted by MLK Vertical Roller Mill：
High-efficiency and superfine powder selection technologyIt adopts the latest dynamic and static separator with high efficiency of powder selection. The rotation speed of rotary vane adopts the frequency conversion speed regulation. The adjustment range of fineness is wide. We adopt wind pressure sealing device of vertical roller mill separator (Chinese patent No.: 200520093439.X) possessed by Shenyang Heavy Machinery Group Co. Ltd to realize stable fineness and output and to reduce the air leakage so as to improve the powder selection efficiency and stabilize fineness.

Grinding material technologyGrinding roller and millstone use the latest carbide surfacing alloy materials. They adopt the technology and     welding material from TECH Company in South Korea and Welding Alloys Limited in Britain to perform the hard facing of hard alloy. The exterior of the surfaces is free from cracks. The base material is reusable with 2000~4000 hour service life. The grinding rollers and millstone could be repaired and welded on site by automatic welding machines provided by Shenyang Heavy Machinery Group Co. Ltd.

High-strength pressure increasing structure of grinding rollerGrinding roller and millstone adopt optimally designed curvature. Pressure increasing zone and high-pressure grinding zone are formed automatically during the process of material grinding to finish grinding with high efficiency. The function of pressure increasing zone is to get bulk materials rapidly compressed as well as to finish initial crushing and grinding. The high-efficiency grinding of material is eventually finished in the high-pressure grinding zone.

High-strength single-roller pressurized structureSingle-roller pressurized structure is adopted by grinding roller of MLK vertical roller mill. Independent pressurization system is used by every grinding roller. The pressurized system is pressurized by hydraulic system. The normal operating pressure of hydraulic system is approx 11MPa. The milling pressure of grinding roller is more than twice as much as that of cement raw material mill to satisfy the requirement of superfine grinding. All hydraulic components in grinding zone adopt the 31.5 MPa products to improve the stability of hydraulic system, for which can ensure reliable operation and no leakage of hydraulic system.

◆Structure of stabilizing material bed to prevent vibration
◆De-ironing structure in mill
◆Water spraying and material bed stabilizing device

Single-stage hammer crusher 
Our company has a long history of single-stage hammer crusher production. In 1980, PCY-S2020 single-stage hammer crusher produced for Guangxi Litang Cement Factory by our company, won the second prize of Liaoning Science and Technology Advance Prize. The large and medium single-stage hammer crushers produced by our company possess the characteristics of high production capability, large crushing ratio, even product size, and simple process flow and so on and have the double feeding rollers and single feeding roller function. The products have formed a series to satisfy the following requirements of 5000t/d cement production line for crushing the lime stones. 

1. Application and Features
MP coal mill is efficiency equipment with low energy dissipation, it is used for grinding anthracite, soft coal, lean coal, brown coal in power stations, mining, construction material and chemical industry.
In 1984, our company produced the first MP coal mill in China and in 1986, we introduced designs and manufactures technology from Babcock in Germany in three types of MP coal mill. With 20-year-experience of assimilae the introduced technology, its products form series from MP140 to MP290.We have the ability of mass production, design and manufacture MP coal mill with various series.
 
2. Technical Features
Low speed ,large-diameter roller and high load as a design principle has optimum effect compared with other types of coal mill. It has the widest application in various coal.

The force of grinding is transferred by static determinate support system, three grinding rollers has 120 degree interval to each other, pressure frame loads through three equispaced drag links, the force loaded in every roller is equal. The grinding roller is jointed with pressure frame by Roller pin, it can sway between 12-15degree,so the roller can adapt to the thickness of material, input size and the wear of roller well. Because of uniform wear and load, the vibration is less and has strong ability to resistance stone, wood and iron.

Because of load perpendicularly, the frame doesn’t bear grinding force and weight of roller directly ,the force is directly on the basis,so the force can be high and regardless of vibration.

High grinding ability ,high wind speed of air ring (70-90m/s),pebble coal discharge less(no more than 0.05% basic capacity, so the workload of every staff is less.

The roller up and down easily, can start-stop with no-load.

The roller shell and tray are manufactured by Ni-hardⅣ、Cr20 or overlay carbide. So the life is longer and can run steadily for a long time .

The coal mill has special hydraulic system to turn the roller over. It can make the repair of coal mill quickly.

The spray technical has been used, it rotaries with the disc to reduce the speed of air current, the life of spray ring is raised.