High-Efficiency Roller Mills's usage in nowadays

1. Traditionally, ball mills are used in cement industry for raw material, fuel and product grinding. Ball mills use an established technology and offer certain advantages. However, they have higher energy demands. By using an appropriate kind of the more efficient roller mill technologies – either as a replacement or in combination with ball mills – considerable energy savings can be achieved without compromising product quality. The following roller mill concepts are applicable to cement manufacturing:

   2. Vertical roller mills: In these mills materials are crushed between a rotating grinding table and 2 to 6 grinding rollers positioned slightly less than 90 degrees from the table surface and pressed hydraulically against it. Main advantages of vertical roller mills include:

relatively low power consumption (less than 10 kWh/t – for medium raw material hardness and medium fineness);

ability to combine grinding, drying (using waste heat from kiln system) and separation;

ability to manage larger variations in mass flow rate (30 to 100% of mill capacity).

Vertical roller mills are available in a wide range of capacities – 5 to 1200 t/h. 

According to National Development Reform Commission of China, VRMs have the following generic power consumption values when used for different purposes in a 6:

for raw material grinding, power consumption may range between 14 ~ 17kWh/t-material;

for coal grinding, power consumption may range between 20 ~ 22kWh/t-coal;

slag grinding, electricity consumption may range between 39 ~ 45kWh/t-slag.

The life-time of the wear resistant material is reported to vary between 8000 to 12000 hours. (NDRC,2008. p.50).

In China, market penetration of VRMs within the building materials sector was expected to reach 50% during the eleventh five-year development period, requiring an investment of around 1.08 billion RMB, and holding a potential to reduce energy consumption by 500 GWh (NDRC, p.51). 

VRMs are installed in new cement plants with dry systems, and also often replace ball mills during plant modernization, where the raw material moisture content is less than 25%. As of 2010, VRMs for raw material preparation had a penetration rate of 45% in Chinese market. During the twelfth five-year period, the market penetration of the technology is expected to reach 80% (MIIT, 2012. p.20)

Horizontal roller mills: Here materials are crushed inside of a rotating mill tube which also contains a grinding roller that is hydraulically pressed against the inside surface of the tube. Horizontal roller mills use 65-70% of the energy used in ball mills.

Roller press (high-pressure grinding rolls): In this technology materials are crushed between two counter-rotating rollers. These rollers are up to 2 m in diameter and 1.4 m long. Roller presses use 50-65% of the energy used in ball mills.

Vertical coal milll application and advantage

Vertical coal mill is typically designed to process materials in medium hardness, like soft coal or bituminous coal, and it is mainly used in positive pressure pulverizing system of soft coal.It is widely used in electricity field, metallurgy sector, building material industry, chemical industry, etc. It is an ideal device that integrates crushing, drying, grinding, and grading conveying all together.

　　Coal pulveriser design

　　In general, coal pulverisers are designed to achieve the maximum rated capacity grinding coal with a grind ability of 55 HGI and 8-12% moisture and achieving a discharge fineness of 70% passing a 200 mesh screen (74 micron) and 99.5% passing a 50 mesh screen. Variation of the coal hardness and moisture content will effect, up or down, the discharge capacity or the discharge fineness.

　　To achieve these design considerations it is essential that the grinding elements are in good condition and they maintain a consistent profile. The loss of the grinding profile results in a loss of grinding efficiency, meaning the pulveriser must work harder to achieve an equal result.

　　Ultimately a point will be reached in which either a loss of capacity or a loss of fineness will result under uniform conditions. Longer lasting, more consistent grinding elements are crucial to pulveriser operation yielding longer operating campaigns, reduced maintenance and a lower overall invested cost.

　　Environmental Friendly

　　With small vibration, low noise, and the overall sealing, the system works under negative pressure, so there is no dust going out. (It meets the requirements of the state environmental protection.)

　　High Drying Ability

　　As the hot air inside contacts directly with the material, drying ability is higher, and it saves energy. By regulating the air temperature, it can meet requirements with different humidity.

　　Simple and Reliable Operation

　　Firstly, it is equipped with automatic control systems, so remote control makes it easy to operate. Second, it is equipped with one device, which prevents the roller from contacting with the liner directly, and avoids the destructive impact and severe vibration.

Great Wall Machinery: professional manufacturer of lime kiln

With the lime widely used in the iron and steel industry, calcium carbide industry, coking industry and other industrial production more, the demand for active lime is increasing, which opened up a broad market.

　　Lime kiln lime is the key equipment for producing active lime, and its technical parameters, performance and operating conditions, to a large extent determine the quality, yield and cost. Great Wall Machinery’s lime rotary kiln has advantages of advanced structure, energy saving, large output and many other advantages, using advanced technique, combined with 50 years of experience in large-scale rotary kiln production.

　　Main advantages of Great Wall lime production line

　　1. good activation

　　Great Wall’s lime kiln can improve the preheating effect, increase productivity, produce good quality lime (lime degree of activity ≥300 (ml)),deal to advanced structure, low loss vertical preheater. Great Wall lime kiln is ideal energy saving kiln.

　　2. avarage save above 40% energy

　　Fully sealed furnace, refractory,hotinsulation layer adopts multilayer refractory with more than 5 years’ lifetime, good mild . For efficient use of energy, the upper and lower furnace have heat exchange, which greatly reduce the heat loss from the upper and lower.The power of lime kilns work has adopted the inverter control and run, which avoid large horse-drawn carriage and operatio with no-load, and save 40% energy and more.

　　3. daily output up to 1200 tons

　　Several Great Wall’s lime production line applied in large and medium-sized building materials enterprises with capacity 150 tons -1200 tons of kiln is running in good condition. Especially φ4.8 × 74m rotary kiln is the largest rotary kiln in China, output up to 1200 tons.

　　Great Wall Machinery supply active lime production line with output 200 tons to 1,500 tons per day based on user needs. We supply "turnkey" service including scientific reports, design, equipment, civil construction, installation, commissioning, reach output targets.

Advantages and development of Great Wall’s vertical roller mill

Now our government has put the comprehensive utilization of solid waste as a long term strategy of economic and society development. In the “Tenth five years plan” and “Eleventh five years plan” of the government energy saving and resource comprehensive usage, they all have clearly put forward the goal of industry waste comprehensive usage. In this way, promoting the harmonious developing of economic, resource and environment.

　　Now the Chinese steel plant all are facing the problems below:

　　1. Mineral, water and coal etc are becoming more and more shortage, With the cost rising, their benefits are reducing.

　　2. The wasted steel slags cause resources wasting.

　　3. Steel slag occupies large area, also cause deeply environment pollution.

　　Under this new situation, steel industry has put forward new demands to equipment and production line.

　　1. Developing the production process, saving the resource and developing the secondary resource reasonably.

　　2. Improving the resource usage rate, turn waste into wealth.

　　3. Improving the production process and equipment, reducing the dust pollution.

　　The features of Great Wall’s vertical roller mill

　　1. Compared with Ball mill, the vertical roller mill can saving power consumption 20%~30%.

　　Vertical roller mill take the material bed grinding principle, lower the consumption. And with the increase of raw materials’ moisture, the electric saving will be more obvious.

　　2. The vertical roller mill’s noise control meets the Industrial enterprises noise discharging standards (GB12348-2008)

　　During working, the vertical roller mill do not have the noise of steel ball crashing in ball mill, so it is noise is low. Lower 20--25dB to ball mill.

　　3. Low dust concentration.

　　Vertical roller mill take the closed system and work in negative pressure. Without the raise dust and keep environment clean. The dust discharge index has reach the Cement industry air pollutant emission standards.

　　4. Highly material drying ability, the final products’ moisture is 0.5~1.0%.

　　Vertical roller mill use hot wind to convey the materials. It can control the wind temperature when grinding large moisture materials, and make the products’ moisture meet the requirement.

　　5. Little wear and lower the metal wastage of each unit

　　During running, there’s no directly grinding between roller and grinding table, so reduce the wear, lengthen its life and reduce the production cost.

　　6. Specific surface area of slag powder is 4200~4500cm²/g.

　　The materials stay short in the mill. It is easy to inspect and control the products’ fineness and chemical component. It can reduce the over grinding and ensure product quality stability.

　　7. The occupied area of vertical roller mill is only 50% of ball mill, and reduce the investment directly.

　　As the vertical roller mill process is simple, occupied area is small and can layout outside. It directly reduce the investment.

　　Great Wall Machinery takes the “ one stop service, one window external” as our service principle. We provide the successful solving projects to steel plants, helping them improve the usage of steel slag and improving their benefits.

Xinxiang Greatwall Machinery Attend the 2nd China-Russia Expo

Approved by governments of China and Russia, the 2nd China-Russia Expo (hereinafter as the Expo) will be open from October 12 to 15, 2015 in the China Harbin international conference exhibition and sports center. As first-class grinding system integrated service provider in China, Xinxiang Greatwall Group will show its new energy-saving ball mill, high-efficiency vertical roller mill and spare parts including grinding roller, grinding table, slag pot and other large steel castings in the exhibition.

　　It is reported that China-Russia Expo will show advantages of both sides basing on theme of "mutual cooperation - Silk Road Economy brings new opportunities", also gives full play to the our advantages, so as to expand cooperation fields and enhance cooperation level. In recent years, Xinxiang Greatwall Machinery actively expands the international market basing on high product quality, good service concept. Right now it has built cooperation with world famous vertical roller mill manufacturer -Denmark FLSmidth to establish strategic, also has long time cooperation with the world largest iron and steel group Mittal Steel Group for slag pots. It shows Xinxiang Greatwall Machinery has higher visibility and reputation in the international market.

　　Xinxiang Greatwall Machinery , as first-class grinding system integrated service provider in China, with 57 years grinding equipment manufacturing experience, and complete capability to manufacture all kinds of large grinding equipments, such as ball mill, rod mill, high efficiency and energy saving ball mill, energy-saving rotary kiln, GRM vertical roller mill, etc. Xinxiang Greatwall Machinery’s new vertical roller mill with 40% power saving innovative advantage, and it has become the best choice of domestic cement, slag grinding with wide application.

　　To shoulder social responsibility to a larger extent, Xinxiang Greatwall Machinery was the first company to make achievements on industrial waste residue treatment, and has built China's first 600,000t/a slag powder line demonstration training base and industrial waste residues, research and development center of slag research, steel slag.

　　It can make full use of steel slag, slag, nickel slag waste into cement, concrete admixture and it has won national recognition. At present, it has built more than 70 nickel slag lines, steel slag lines, slag production lines in China, and it has completed the Shanghai Baosteel, Hebei Aosen Steel, Xuzhou Iron and Steel Slag with annual output of 20-150 million tons of cement/slag EPC project.

　　Welcome to visit Xinxiang Greatwall Machinery from October 12 to 15, 2015 on 2nd China-Russia Expo for sincere cooperation and common development. (all visitors at the booth or to our factory, can get the exquisite gift from our booth).

Magnesium Oxide rotary kiln / Dolomite kiln / Magnesite kiln / Titanium dioxide rotary kiln

Raw material:Magnesite, dolomite

　　Product introduction:

　　The dolomite calcined by Great wall machinery magnesium oxide rotary kiln are well selected for most of the magnesium oxide plants, with a number of advantages such as high capacity, high degree of mechanization, easy maintenance, high activity, low burning loss, high ratio of magnesium extraction and silicon utilization.

　　Performance features:

　　(1)By using 3D design and simulation, the design and structure of main parts are optimized so as to reasonable and safe working status.

　　(2)Top grade raw material and processing technology leads stable and reliable running.

　　(3)Easy, flexible and reliable operating.

　　Working principle：

　　A whole set of magnesium oxide rotary kiln involves rotating cylinder, supporting device, belt pulley kiln head, tail sealing device, coal spraying pipe devices and so on. The kiln body installs in a certain angle with sea level, supported by roller, and also gear wheels controlling the up and down movement of kiln body. For the transmission part, besides the main drive, the auxiliary drive devices, which can continuously ensue running and avoid deforming, are included in case of main power supply interrupt. The clam shell seal on kiln head and axial contact sealing device on kiln tail ensure the sealing reliability for the whole machine.

Nickel Iron Rotary Kiln/ Nickel Ore Rotary Kiln

-Introduction of Laterite Nickel Ore

Laterite nickel ore resource is formed from nickel sulfide ore rock, after weathering, leaching, sedimentary into surface weathering crust deposit, and found in tropical countries within 30 degrees north and south of the equator line in the world, mainly concentrated in tropical, subtropical areas of the Pacific rim, mainly including: Cuba, Brazil of America, Indonesia and the Philippines of Southeast Asia, new caledonia, Papua New Guinea of Oceania Australia, etc.

-Second, Structure of Laterite Nickel Ore Rotary Kiln 

Nickel ore rotary kilns consist of cylinder, rotating device, supporting device, kiln liner, kiln inlet, kiln seal and fuel device, etc. Kiln cylinder is heated rotating part, adopting winded welding of high quality carbon steel plate. The cylinder is supported by the tyre with different shifts equipped with mechanical or hydraulic type, so as to control the axial rotation of cylinder. Driving devices work through gear in the middle part so as to control speed of cylinder according to technological requirements. Due to need of installation and maintenance, large nickel rotary kiln body will rotate at very low speed. To prevent cold air into the dust and dust overflows from cylinder, the reliable seal devices of kiln inlet and outlet will be equipped.  

-Three, Strengths of Rotary Kiln for Laterite Nickel Ore Structure

(1) The main energy is coal, [1] rather than expensive coke or electricity.

(2) Free choice of raw material, various laterite nickel ores available in Southeast Asia.

(3)High quality nickel and iron (including about Ni 20 %), can be directly used for the production of stainless steel. 

(4)Meanwhile it can be used as a coolant when melting steel.

-Four, Smelting Method and Process of Laterite Nickel Ore Rotary Kiln 

Preprocessing step is to mix the ground laterite nickel ore with carbon materials and flux limestone straightly, then feed them into the rotary kiln continously. The burnt material from rotary kiln will be for water treatment. The gravity concentration and magnetic separation will recover nickel and iron from the discharge. The nickel and iron separated is 2~3 mm in diameter like sand particles, and 1 ~ 2% slag entrainment with chemical composition is C0.1 %, Ni18 ~ 22%, S0.45 %, P0.015 %.