machinery to screen iron ore pellets

china pellet iron ore, pellet iron ore manufacturers, suppliers, price

china pellet iron ore, pellet iron ore manufacturers, suppliers, price

China manufacturing industries are full of strong and consistent exporters. We are here to bring together China factories that supply manufacturing systems and machinery that are used by processing industries including but not limited to: pellet machine, disc pelletizer, pelletizing equipment. Here we are going to show you some of the process equipments for sale that featured by our reliable suppliers and manufacturers, such as Pellet Iron Ore. We will do everything we can just to keep every buyer updated with this highly competitive industry & factory and its latest trends. Whether you are for group or individual sourcing, we will provide you with the latest technology and the comprehensive data of Chinese suppliers like Pellet Iron Ore factory list to enhance your sourcing performance in the business line of manufacturing & processing machinery.

iron ore pellets screening solutions

iron ore pellets screening solutions

The size distribution of iron ore pellets is among the most important quality parameters for the end users of those pellets, the steel mills. The tighter the distribution is, the better the performance and energy efficient the steel making process will be. It all relates to pellet bed permeability or how easily the gases travel in between the pellets in the process.

We have served this industry for more than 4 decades. We have been involved in numerous screening projects in most markets worldwide, and have been exposed to a wide range of ore specifications, plant configuration and needs.

Whether you are seeking equipment for your balling lines or a larger roller feeder for your grate feeding station or both, whether the need is for a new pellet plant project or an existing pelletizing line, Metal 7 is in position to offer optimal solutions.

The iron ore and additives with given moisture content are pelletized (formed into small balls referred to as green balls or green pellets) in a balling device. This could be a balling drum or a balling disk Pellets of various sizes exiting the balling device are discharged afterward on a deck of rollers, the roller screen, for removal of the pellets that are not within the sizing range.

In most modern pelletizing plants, we find two pellets screening stations. The first one is located at the balling department. The balling dept. includes some roller screens, and often as many as balling devices (one roller screen by balling disc). However, some fines would be created in the conveying of the green balls/pellets from the balling department to the indurating furnace. Therefore, a second screening station with a single larger roller screen is located just prior to the indurating furnace.

Replacement of existing roller screens by new state-of-the-art machines has proven a small investment to trigger important gains for pelletizing plants. Such gains are also carried on to their customers, the steel making plants, which are also benefiting from this better sizing.

Rollers supplied by Metal 7 last longer and screens operate more efficiently with constant gaps. The engineering group also customizes the screen designs, bearing in mind it should require low maintenance and maximise the equipment availability. Increases in production tonnage are closely associated with higher equipment availability and we achieve that through the following:

Our roller screens operate smoothly with components designed to reduce friction, noise level and power consumption. Our most popular option, with a single drive motor driving all the rolls, contributes also in reducing the power consumption associated with your pellet screening operation.

The improvement of its existing products and the development of new screening systems still represent a major part of the yearly investment in Research & Development. Metal 7 constantly strives to offer more to its customers. The latest developments include the new triple deck design, the new discharge.

Sizing also has a significant impact on the productivity of the pelletizing plants themselves. For purposes of handling and shipping, the pellets have to be hardened in an induration furnace. Firing, to include the fuel required for firing, is the most important cost center for a pelletizing plant. Improved permeability of the bed of pellets obtained with an efficient sizing system will reduced the quantity of fuel required to fire a ton of pellets. More consistent sizing means also a better and complete firing of the pellets. Improvement in the firing allows accelerating the speed of the grate carrying the pellets in the furnace with a direct increase in the production per hour of the pelletizing line.

The best scenario for both the pelletizing plant and the steel making plant would be to have all the pellets exactly at the same diameter. That is hardly possible for plants producing millions of pellets per year. The challenge is therefore to narrow the size distribution to its minimum. Metal 7 has been working on this specific task for the last 40 years. No wonder it has become the number one provider of green iron ore pellet screening equipment, the roller screen.

We are not only manufacturing roller screens. We design solutions for new plants or for existing pellets plants seeking increases of productivity. Over 40 pellet plants worldwide operate with rollers manufactured by Metal 7 and more are converting every year. Metal 7 has manufactured over 50000 rolls and over 200 rollers screens.

The roller screen includes a frame supporting a number of rollers of a specific diameter brought in rotation to move the pellets forward. The roller deck is also inclined to accelerate the pellets movement. Rollers are assembled in such a way that precise gaps are obtained between each roll. Pellets that are smaller than the gaps would fall in between the rolls.

Various configurations are possible, but the most standard one for the balling line roller screen is a tri-product screening arrangement. The first section at the charging end of the screen will remove the fines/undersize pellets with a smaller gap, for instance at 9 mm which will eliminate all the pellets smaller than 9 mm. The second section will recover the good pellets, for instance with a gap of 16 mm, all the pellets between 9 and 16 mm will fall in this section. Finally the bigger pellets, more than 16 mm in our example, will be discharged at the end of the screen. In other words, the roller screen segregates the pellets into three fractions. But only the good pellets will move forward in the process. The fines/undersizes and the oversizes will be returned to the balling process.

It is not uncommon to see pelletizing plants operating without roller screens at the balling lines, and particularly for smaller plants, or with roller screen removing only the fines/undersize. But in such cases, the large roller screen at the furnace feeding station would be adapted to both process a larger load and for the removal of the oversize pellets.

This has two purposes. The first function is to remove all the undersize pellets and fines that would come on the conveyor bringing the pellets from the balling department. Second, it evenly discharges the pellets on the moving grate of the furnace. That is why this larger roller screen is often referred to as a roller feeder. It feeds the green balls in the furnace.

This second function is critical. A uniform pellet bed on the grate is very important for the efficient firing of the pellets. Any deviation in the layout of the pellets on the grate will cause deviation in the firing process and the quality of the fired pellets.

Each pelletizing plant defines its sizing requirements, which are often dictated by their customers specifications. Metal 7 does not just aim at meeting this requirement in designing its roller screen. Its objective is always to deliver equipment allowing an ever tighter size distribution. This latter achievement is also explaining why Metal 7 is so active in the retrofit market.

The engineering team of Metal 7 reviews the existing equipment and plant layout. They design new screens that would fit in the room available minimizing the CAPEX investment for the customer. The new screen will come with optimized screening capacity and features with lower OPEX for the operations of the screening system. The return on investment is often within a few months of the commissioning of the new equipment.

What is the minimum diameter we can select for the application? It depends on the screen size, the load of pellets to process, and particularly the amount of fines to remove, and other factors. But the objective for Metal 7 is always the same. The smaller the diameter, the higher the number of rolls, thus a greater number of gaps, and larger capacity.

Thanks to the protective coatings Metal 7 has developed for the rolls, we offer the smallest diameter rolls found in the industry. The coating prevents wear of rollers. Therefore, it is not necessary to add extra material on the roller diameter to compensate progressive wear. Metal 7s coated rolls will retain their integrity for all their life. No other competitor matches the effectiveness of the coated rolls of Metal 7.

As for the length of the rolls, physical limitations, including the plant structure and layout, usually dictates the maximum length of the rolls. For the larger roller feeder, the width of the furnace grate would limit the length of the rolls.

Our survey of your needs will also include a review of other equipment surrounding the screen. For instance, how will you discharge the pellets on the roller screen? We will evaluate the pellets spreading pattern on the screen and consider this element in our calculation of the number of gaps required to screen the maximum of fines.

Two factors need to be considered in the selection of the roll material and the surface texture: the transport function of the rolls and the eventual sticking of pellet material on the roller surface.

- The pellets have to travel freely on the roller screen. Although the roller deck is tilted, the roller surface texture has an influence on the movement of the pellets from one roller to the other. Mistakes are easily made in the selection of the material and texture leading to pellets blocking the gaps with inadequate transport properties of the roller.

- The opposite situation is also possible, in which the roller has good transport characteristics but causes sticking of pellet material on the roller surface. The progressive build-up of material will modify the sizing distribution and eventually prevent the screening by blinding the gaps.

Metal 7 has a preference for chain driven screens with one single motor driving all the rolls. It is based on their lower costs, their high efficiency and their lower operation costs (lower power consumption). We also produced several roller feeders assembled with motor on every roller and this option is always considered for larger machines.

The minimum roller diameter, and consequently the number of gaps, is sometime one of the drawbacks of the individual drive option. The motor reducer width could be a limitation the selection of the roller diameter. This restriction is the reason why the individual drive design is hardly ever considered for the smaller roller screens of the balling lines.

With the chain driven option, Metal 7 adapts its design to meet your intentions and safety criteria. For instance, the single drive motor reducer could be located either at the upper end of the screen or at its lower end. Both options are available.

Pellet charging system (ex: reciprocating belt conveyor or shuttle belt conveyor). Improving the discharge of the pellets onto the screen will have a very positive contribution on the improvement of the sizing.

We design our equipment with specific attention on all the chute points. They include the drops from the balling unit to the screen, from the screen to the good product conveyor, from the wide belt conveyor to the roller feeder and from the roller feeder to the furnace grate. Pellet fracturing is one of its main concerns at every drop point. The lower the drop, the fewer pellets will be broken.

Metal 7 now introduces yet another innovation, its new EPSILON discharge end (chute) at the lower end of its roller feeder (also for its double deck roller screen/feeder or triple deck roller screen/feeder machines). The lower end rolls at the discharge of the feeder are positioned in such a way that the green pellets keeps rotating up to their discharge on the grate. They do not fall or drop on the pellet bed of the grate. This new design reduces green pellet fracturing or pellet plastic deformation.

The productive operation of a pelletizing plant is closely linked with its capacity to effectively screen green balls prior to their induration. The narrower the pellet size distribution is within the required pocket size range, the higher the plant efficiency will be. Better pellet sizing leads to improvement in plant productivity, reduction in induration costs (fuel for instance) and higher pellet quality.

Furthermore, the requirement for better sizing of pellets goes beyond the operational needs of the pelletizing plant. It is also one of the main quality criteria for the steel making plant buying the pellets.

Screening through roller screens is known for decades. But many roller types and roller screen designs are available on the market. They provide large differences in the segregation efficiency of the pellet sizes. Few roller screen designs really perform in service.

- Increase productivity of the pelletizing line; - Recover all the good size pellets; - Provide size distribution within the narrowest bell-curve shape (for instance pellets between 10 12.5 mm); - Reduce to a minimum the pellet breakage occurring in the green pellet handling, screening and discharging; - Distribute pellets on the grate in order to ensure their uniform firing in the furnace; - Optimize pellet bed permeability one of the most, if not the most, important function of a screening solution; - Low maintenance and high availability of the pellet screening line;

The constant improvement of their rollers also led them to design their own roller screen system to get even better screening performance out of its rolls. Existing designs in the industry had limitations. They could not accommodate the smaller diameter rolls developed by Metal 7. They did not provide the versatility of adjustment in service (RPM of the rolls, inclination, etc.) and they had lower availability in operation.

Its roller screen systems have become the most cost-effective solution and even the standard in the iron ore industry. No one attains the same efficiency thanks to the combination of their special rolls and well-designed equipment.

Through its expertise in material and surface engineering, Metal 7 selects the most appropriate material for the manufacturing the rolls for every application. In most projects, our objective is to use the smallest possible roll. The smaller the rolls, the more rolls and more gaps in the screen.. We pay close attention to the eventual deformation during service, and particularly for the longer rolls of the roller feeder at sometimes more than 4 meters long.

Other suppliers compensate for the lower strength of their roll by increasing the diameter of the roller. This goes counter to the maximisation of the screening surface in the design of a roller screen (bigger rolls equal less gaps per screen).

The engineering team develops the specifications of the rollers to ensure the adequate transportation of the pellets from one roller to the other without generating sticking on the roller surface. The characteristics of the ore and pellet content are taken into consideration. Pellet breakage is also considered.

Rolls are assembled with shafts. We offer different fixed or removable shaft arrangements (bolted, central screw types, etc.). We determine what is most suitable according to the specific needs of a roller screen, including the size of the rolls, the driving mechanism, the location, etc.

The coated rolls do not really wear. Therefore, they last much longer than uncoated rolls found in the market. Experience has shown increases in life expectancy by a factor of up to 10 when converting to such coated rollers of Metal 7. The coated roller replacement will not be related with wear. Other mechanical related causes will provoke the replacement of coated rolls (shaft problems, damages of the coating surface, etc.).

Most coated rollers could be reconditioned to give them a second or third life in service. It is more popular for larger rolls of the roller screen/feeder located at the entrance of the indurating surface.

However, the increase in the workign life expectancy is not the main contribution to the coating. The fact they do not wear means also that the gaps between rolls stay constant all through the life of the rolls. Therefore, the screening performance remains at its best without requiring periodic calibration of the gaps. That is by far the most important feature of the coated rolls.

The wear resistance of the coated rolls is also a key contributor to the use of smaller diameter rolls on Metal 7screens. It is not necessary to provide extra material on the roller diameter to compensate the wear. They will retain their integrity for the entire life of the roller.

M7-A19 (or M7-C19 for smaller rolls): Carbide base coating with high hardness (68 HRc), good transport property, high impact resistance, etc. This coating option is particularly adapted to plants handling material with more contaminants or leading to more building-up on roller surface.

M7-D130: Metallic base coating with material hardness increasing with the contact of pellets, very high transport property, etc. It is considered only for handling dry pellets (very low moisture). Other coatings are available including many variations of the above coating families.

The involvement of Metal 7 in the production of rollers for roller screen for the last 40 years had exposed us to a lot of different roller screen designs and technologies. However, its engineering team did not find one that was addressing all their concerns to really provide the end users with all the possible benefits our special rolls could provide.

So, in the 1990s they developed their own design gathering all the best features found on different screen technologies and in innovating with their own ideas. In the last 25 years, the company has invested major resources in the constant improvement of its most popular product family, the roller screen.

- We optimise the screening surface. They can accommodate the smallest available rolls, which provides more screening gaps. The screen width (roller length) is also lengthened to the maximum allowed by the plant layout and limitations;

- Metal 7 offers a wide range of options and features in the design. Each screen is customised for every application to maximise productivity, lower CAPEX, OPEX and maintenance costs and surpass the expectations of the end users;

Metal 7 offers all the screening solutions for your pelletizing plant whether it is for your balling department (single deck roller screen two product or tri-product versions) or for your induration furnace grate feeding station (roller feeder). In this latter case, several configurations are available with the individual drive or chain driven options including the :

A comprehensive screening solution is also offered to Metal 7s customers optimizing the complete green pellet screening function and the pellets discharge on the grate of induration furnace. Its project scope could include the roller screens and roller feeders but also all other related equipment involved in the screening operations, including:

This comprehensive approach permits a complete integration of the equipment without interference. It also optimises the overall performance of the screening function. Improved pellet quality and productivity, lower pellet breaking and the uniform laying of the pellets on the grate according to the desired profile are the main focus of this integrated approach.

- Larger screening surface allowing higher throughput of the line, the screening capacity often being a bottleneck in plants; - Higher productivity of the pelletizing plant with a better sizing and superior bed permeability in the surface; - More cost-effective machines with lower and easier maintenance and higher equipment availability through less maintenance (or calibration) related interruption of the pelletizing line;

- Gains in efficiency: All good pellets go to the induration instead of being wrongly recirculated in the process (wear resistant rolls equal constant gaps); - Smarter use of the energy. Better sizing reduces the consumption of fuel. - Better quality: final product is more attractive for the steel making plants with a narrower sizing and better firing of the pellets;

Metal 7 is one of Canada's biggest players in the metallic and ceramic coating field. Thanks to its leading expertise, the company stands out from its competitors by proposing extremely sophisticated, high-performance solutions. This competitive edge allows the company to thrive on the international market. The products manufactured in its workshops are used in nearly fifty plants in 20 countries, on all five continents. Metal 7 exports over 70% of its annual production outside Canada.

Related Equipments