Bedeschi is a major Italian manufacturer of bulk handling equipment. The company is located in Limena near Venice, in Italy’s Northeast. Since the beginning of the 20th century (the company was founded in 1908), Bedeschi has continued to add new products to its range, which originally included mainly brick and tile production. In the late 1970s, after almost 50 years of experience in the handling of moist and sticky materials for the brick industry, the company began its involvement in the cement, mining and energy production (coal and petcoke) industries, with a complete line of solutions for material handling.
The Bedeschi Group today comprises several units. Two of them are in Italy, and are the main companies:
1. Bedeschi, the parent company, which produces the whole range of machinery;
2. CTP Team, which completes Bedeschi’s offer with gas cleaning & dedusting equipment.
The others are local branches:
3. Bedeschi America Inc., based in Florida, has an engineering design department as well as a spares storage facility and after-sales assistance;
4. Bedeschi Dubai office, based in Dubai, develops marketing for both brands bulk material handling and marine equipment, projects management and after-sales activities for the Near and Middle East.
The group exports more than 90 % of its sales, therefore both foreign branches represent Bedeschi’s new attitude in favour of its customers with the aim of meeting their needs and supplying them with high quality local after- sales service.
Bedeschi’s main operations are related to:
The cement industry: supplying crushing equipment and various types of stackers and reclaimers.
The mining industry: supplying state-of-the-art crushing applications for different material, from sticky coal or clay to dry and wearing clinker, as well as iron ore, limestone, bauxite, marl, gypsum, cement and various minerals.
The marine industry: supplying equipment for shiploading and unloading.
The brick and tile industry: supplying complete plants for the production of various types of bricks and roofing tiles.
Bedeschi’s expertise is completed today thanks to a strategic business alliance signed in 2010 – BLL (Bulk Logistic Landmark) – that involves the partner companies Bedeschi, Liebherr and Logmarin. BLL aims to profit from the synergies, individual strengths and networks of each of the three partner companies to provide dependable, integrated, cost-effective software and hardware, and eco-friendly solutions to the dry-bulk supply chain.
Bedeschi provides reliable solutions and complete engineering services for the design, supervision and installation of new plants on a turnkey basis. Services are provided at all levels, profiting as much as possible from the company’s experience, references and expertise in the handling of difficult materials.
1 General concept about the technology
With stackers we mean all the equipment necessary to prepare and accumulate the raw material in piles or storages outdoor and indoor. Reclaimers are the equipment necessary to extract the material from the storage and convey it to the downstream process.
The storages are generally meant as intermediate buffer in the process to:
Separate the receiving of the raw materials from the downstream operation, thus allowing for more flexibility.
Cover the raw material and allow a certain stabilization of the physical characteristics like humidity.
Blend the material in order to reduce the volatility of the chemical composition of the outgoing material. (preblending and/or blending beds). This is achieved with special stacking patterns jointly with the proper reclaiming operation. This point is getting more and more important in most operations since the quarry’s quality is worsening due to the environmental restrictions.
Mixing of different raw materials like limestone and shale for example.
The choice of the proper equipment depends on the above points mentioned.
1.1 Storages of raw materials
Longitudinal: the shape develops in length and can be operated with lateral or frontal reclaimers.
Circular: the shape develops in circular and can be operated with lateral or frontal reclaimers.
Side walls: the shape develops between walls and can be operated with lateral or frontal reclaimers.
1.2 Stacking methods
1.2.1 Cone shell
Stacking is at the starting point of bulk handling processes. In the cone shell method (Fig. 1) the material moves along the belt conveyor and is discharged at a single point at the end of the boom. The boom remains stationary until a cone of the required height is formed. The stacker is then moved along its rails by a short distance – between one and five metres – and material is again poured from a fixed point, connecting a new cone to the first. The effect is to extend the pile longitudinally along its length with interconnected cones of material of different grades.
The important characteristics are the step-by-step storage, the limited drop of material, the reduced dust emission and the fact of not blending.
1.2.2 Chevron
Stacking occurs in layers along the center axis of the pile. The stacker goes back and forth between the two pile ends lifting the boom at every inversion. The resulting section is shown in Figure 2. Different layers are one on top of the other. This method provides excellent results in conjunction with a frontal reclaimer. When used to build a longitudinal pile, stacking takes place in one half portion of the stockpile, while the half portion is reclaimed. When used to build a circular pile there is a continuous round base with stacking at one end and reclaiming at another.
A minus in this method is the segregation: if the material size is not consistent, bigger lumps always tend to stay at the base of the pile.
1.2.3 Windrow
In the Windrow method, material is deposited from a number of positions across the full width of the pile (Fig. 3). This method, essentially followed to build up longitudinal stockpiles, prevents segregation and is preferred in cases where the reclaimer operates in one part of the pile cross-section at a time or where segregation may create situations of total unacceptability. Apart from segregation, the clogging tendency of materials is also an important consideration when deciding on a prehomogenization system.
1.2.4 Strata
Strata stacking requires a slightly more sophisticated boom. The boom used for strata stacking is longer and it must also be able to slew. An initial full-length small heap is created at one side of the storage area. Once at the end of the pile, the boom is slewed back a little and lifted. The stacker boom begins travelling in the opposite direction, pouring new material behind the back of the first row to create a new layer. By repeatedly slewing and lifting the boom at each end, layers of different qualities are built up parallel to the back slope of the pile (Fig. 4).
1.3 Stackers
Bedeschi produces a number of special stackers, such as the Travelling Stacker (STK, Fig. 5), the Circular Slewing Stacker (STK-RC, Fig. 6) and the Travelling & Shuttling Conveyor System (CAR-H, Fig. 7).
1.4 Reclaiming method
After having seen the different type of stacking methods and stackers we can divide the reclaimers in two major categories:
1.4.1 Frontal
These machines reclaim the pile from the front with a boom traveling perpendicularly to the pile or with a rake.
Frontal with rake
With lateral walls and buckets
1.4.2 Lateral
These machines operate the pile with a boom reclaiming the material from the side.
The boom can use buckets or blades, they are divided in:
Lateral cantilevered
Portal
Semi-portal
A separate mention for the circular storage is the combination of a rotating stacker and a frontal rake reclaimer.
1.5 Reclaimers
Bedeschi offers a number of reclaimers such as the Lateral bucket reclaimer (BEL F, Fig. 8), the Portal scraper reclaimer double arm (PAL PD, Fig. 9), the Bucket reclaimer (BEL C, Fig. 10, and the Bridge scraper reclaimer (PAL T, Fig. 11).
1.6 Hardware systems
For building up the stockpiles different types of stackers are used such as rigid or slewing or traveling, depending on the area available for reclaiming bulk materials from the stockpile. The versatile portal type scraper reclaimer is often used. When a fair level of prehomogenization is required, preference is given to a bridge-type scraper reclaimer. A circular storage system is generally provided with a cantilever scraper reclaimer, while a circular prehomogenizing system operates with a bridge-type scraper reclaimer.
The prehomogenizing system can be installed in open-air and covered buildings. The covered installation is preferred from considerations of environmental protection and avoidance of contamination. Depending on the purpose of the system, four different types of blending beds are considered which are shown in following figures.
Two separated stockpiles, each built by Chevron method, as in the case of a longitudinal system (Fig. 12). The stacker A is engaged in building up the first pile, while the bridge scraper reclaimer B is reclaiming from the second pile.
For better space utilization, it may be advantageous to leave a clear gap between the two piles. The reclaimer operates in two directions and therefore requires two harrows – one for each direction of rotation of the bridge and subsequent reclamation.
More consistency with the longitudinal blending bed is found in the overlapping Chevron piles (Fig. 13).
A simpler method of stacking is embodied in the stockpile built on the cone shell principle, described earlier (Fig. 14).
The stacker boom does not need a buffing movement and advances in small steps in only one direction. The drawback of this technique is that the reclaimer harrow slices through only a limited number of cone shell layers at any given time, thereby influencing the blending effects.
The Chevron method as shown in Fig. 15 is characterized by an excellent blending effect and a considerable operational adaptability. The stacker travels continuously to-and-fro in the circumferential direction of the pile; at each reversal of direction the stacker is moved forward by a certain distance.
2 Case studies
2.1. Saudi Arabia
2.1.1 Arabian Cement Company – Rabigh plant
During 2010 Bedeschi completed the commissioning of the installation of the equipment for new clay and sandstone longitudinal storages. The equipment supply was included in the revamping project of the old existing longitudinal storages for lines 1-4 in order to allow them be integrated into the expansion project started with installation of the new line 6 some years ago.
The two existing longitudinal storages currently operating with limestone and clay will operate respectively with clay and sandstone. Revamping was conceived with the replacement of old equipment with the new one and with the integration of the existing transport system with the new conveyors’ layout of the new line.
In recent years, Bedeschi operated the new line 6 and, as one of the main partners of ACC, was also involved with the installation of the equipment for the new raw material handling department: mainly the limestone circular storage (rail diam. 105 m with capacities of 200 tph (IN) and 900 tph (OUT), Fig. 16) and the entire belt conveyor transportation system.
2.2 Turkey
2.2.1 AS Cimento A.S. – Kizilkaya plant
During 2010 Bedeschi will commission for this unit a new additive scraper side reclaimer (400 tph capacity, Fig. 17). The equipment is going to be installed in the existing limestone longitudinal storage already equipped with Bedeschi stacker and bridge type reclaimer (both commissioned 2005). This operation was planned as an integration project of the raw material department for the old line 1 with the new line 2 which was commissioned during 2008. Bedeschi anyway was engaged with the new expansion project with the supply of the new circular storage equipment (80 000 t capacity rail diam. 105 m).
2.2.2 Ekon – Lafarge Yibitas plant
During 2009 Bedeschi SpA, together with EKON, completed the supply and commissioning of the complete raw material handling equipment for the new Lafarge Yibitas Cimento Sanayi Ve Ticaret A S greenfield clinker burning and cement grinding line at Hasanoglan near Ankara.
Bedeschi supplied in particular for line 1 clay crushing unit with a double roller primary crusher 250 tph capacity, line 1 clay pit storage equipment with a bridge bucket reclaimer with 100 tph reclaiming capacity, line 4 side portal reclaimers for the whole plant raw material longitudinal storages for additives and coal/petcoke (250 pth reclaiming capacity) and line 4 apron feeders for raw material reception (additives, limestone, clay, coal/petcoke) with capacities up to 250 tph.
The core activity in this project was the first realization for Bedeschi, in Turkey, of a vertical wall storage for the prehomogenization of the clay. This technology, for which Bedeschi has more than 100 yrs experience as market leader in the brick industry, is widely used today in the cement industry too (large groups such as Lafarge, Holcim, Colacem already use it) in the prehomo phase when special care need to be used for the management of clay and sticky materials instead of the classical longitudinal or circular storages served by a frontal bridge rake/paddle reclaimer.
All the remaining Bedeschi supply for this project was focused mainly on the receiving apron feeders and reclaiming equipment of the longitudinal storages as well as for the crushing unit for clay.
2.3 Morocco
2.3.1 Lafarge Maroc – Tetouan plant line No. 2
In 2010 Bedeschi commissioned the new installation of the equipment for the expansion project of the Tetouan plant (Fig. 18) with the second line after the successful outcome of the installed equipment for line 1 in 2002. For this unit the new project was a replication of the configuration of the equipment used for line 1. The raw material handling compartment was completed with all the dedusting filter sets supplied from the Bedeschi subsidiary CTP Team.
2.3.2 Ciments du Maroc (Italcimenti Group) –
Ait Baha plant (Agadir)
In 2011 Bedeschi commissioned the equipment for the complete raw material handling for the new Italcementi greenfield plant of Ait Baha (close to Agadir, Fig. 19). The plant includes n.4 longitudinal storages for the raw material plant feeding (included coal) and the complete set of equipment and transport system from limestone quarry up to the plant (1.5 km) as well as all the material receiving compartments with apron feeders, screens, bucket elevators, chain conveyors, belt conveyors (in total more than 5000 m length). All the dedusting filter sets (17 units) were supplied by Bedeschi with its subsidiary CTP Team.
3 Conclusion
The different case studies indicated show the general possible combination of stacking and reclaiming technology. The perfect choice of the best machines to be selected is dependent on several factors such as the main type of material handled and the requirements for blending. The Bedeschi Technical Dept. assists the users and recommends the most appropriate technical and commercial solution.
