The use of granulated slag as sand in the composition of concrete can meet two objectives that have a direct relationship with the cost of concrete: minimizing the amount of cement in the concrete composition and increasing the mechanical characteristic of concrete.
Beside above, what is molten slag? Steel slag, a by-product of steel making, is produced during the separation of the molten steel from impurities in steel-making furnaces. The slag occurs as a molten liquid melt and is a complex solution of silicates and oxides that solidifies upon cooling. The open hearth furnace process is no longer used.
The primary components of iron and steel slag are limestone (CaO) and silica (SiO2). Other components of blast furnace slag include alumina (Alsub>2O3) and magnesium oxide (MgO), as well as a small amount of sulfur (S), while steelmaking slag contains iron oxide (FeO) and magnesium oxide (MgO).
When an uncrushable object like tramp iron gets into thecrusher chamberthe predetermined pressure in the release cylinders is surpassed andthe jaw opens automatically. After the object has passed, the pressure drops and the crusherresets immediately back to original CSS setting.
Slag often contains valuable metals that can still be recovered and utilized. When crushed and sized properly, slag can be sold and used as valuable material in many different ways, for example, as aggregates.
To combat the issue of uncrushable objects, Nordberg jaw crushers can be equipped with with an optional Active Setting Control (ASC) system. Thanks to this technology, jaw crushers perform well in applications that would be challenging or even impossible to manage for otherwise.
The ASC protects your crusher against overloading. When a jaw crusher is equipped with the ASC system, the crushing forcesare carried by massive hydraulic cylinders mounted into the rear header casting.
If an uncrushable object enters the crusher cavity and crushing forces reach the preset maximum level, oil starts to escape out of the cylinders and the setting releases. This way the uncrushable object can get out of the cavity.
The functionality enables continuous crushing and protects the crusher from extreme overloads. When automated, the crusher setting is returned back to its original one when the uncrushable object has dropped out of the cavity.
With over 60 years (since 1958) of experience, Harbert's Products, Inc. is the Worlds Leader in Submerged Arc Welding (S.A.W.) Flux / Slag Crushing, S.A.W. Crushing Technology & Crushed (Reprocessed) SAW Flux Quality.
We are the Worlds only S.A.W. Slag Crusher that uses a "Sub Arc Flux Slag Crushing Machine" that is designed and built exclusively to crush to size SAW fluxes. Our Quality Control Program is in compliance ISO 9001: 2000. Plus, we are the Worlds only entirely Closed - Loop S.A.W. Crusher audited and recognized by the Canadian Welding Bureau (CWB).
4a. Removal of minor Nonconforming material if applicable (i.e. cigarette butts, paper, plastic, etc) from slag prior to entering the S.A.W. Flux / Slag Crushing unit. 4b. Size crushed flux to each customers particular requirements. 4c. Visually inspect slag at various stages of the crushing process. 4d. Removal of magnetic impurities i.e. magnetized flux, weld splatters, weld wire tips & base metal mill scale. 4e. Perform moisture tests at regular intervals. 4f. Package in sealed containers, complete with plastic liners.
6. Package crushed flux (or mixture of crushed flux and new / virgin flux) and mark containers in accordance with the latest issues of CSA Standard W48 Section 8.1 and/or ANSI I AWS A5.01 Filler Metal Procurement Guidelines and ANSI I AWS A5.17/A5.17M Specification for Carbon Steel Electrodes and Fluxes for Submerged Arc Welding (and ASME SFA-5.17) or A5.23/A5.23M Specification for Low Alloy Steel Electrodes and Fluxes for Submerged Arc Welding (and ASME SFA-5.23) as applicable.
*Harberts identify a LOT (or batch) of SAW flux / slag as: A specific type of S.A.W. slag that was generated by a specific customer, shipped to our facility as one shipment, load, and / or identified by a P.O. number and / or shipping number. The SAW flux / slag is then crushed and shipped back to the same specific customer that initially shipped the SAW flux / slag to our facility.
**Harberts has a QUALITY ASSURANCE SYSTEM that identifies any deficiencies and/or nonconforming materials. This Quality Assurance System address; A) identifying, action to be taken, B) identifying, disposal, labeling and action to be taken of nonconforming materials.
Geology is very important in this instance. You need to know what type of material youre working with, whether it is sandstone, limestone, or granite. Since the characteristics of each stone are very different, you must determine if you need a compression style crusher or an impact style crusher.
Knowing the material youre going to crush will help point you in the right direction of which type of crusher youll need. Youll need to know how difficult it is to crush the material, as well as how abrasive it might be. Some materials contain high amounts of silica, such as sandstone for instance, which is a more abrasive material that wears your liners out quicker. Versus something that might not be very abrasive, such as a marine limestone.
Once you understand the material youll be crushing, then you need to decide which type of crusher is right for you. Compression style crushers, such as a jaw crusher or a cone crusher, are typically used with more abrasive materials. Impact style crushers, such as a horizontal shaft impactor or a vertical shaft impactor, are used more for material that is less abrasive.
Some plants will use both styles of crusher. For example, the end result can also determine what type of crusher you need. If the shape of the stone is an issue, an impact crusher will give you a little better shape and give you more cubicity in the final product. Many times, customers will have existing plants that have crushers that generate significant amounts of flat and elongated pieces. They may have somewhat of an abrasive stone, but they could introduce an impact style crusher down the line to help shape the material.
Newer generation cone crushers from the late 1980s on made significant changes in the stroke and the throw and speed of the machines and that lends itself to a more cubical product. Cubicity can be better controlled with those types of machines, provided you dont exceed what we call the ratio of reduction, meaning just how far we are crushing a rock in a single stage.
With blast furnace slag, its not as abrasive or as hard as steel furnace slag. Blast furnace slag has just come out of a based oxygen furnace and all thats been added to it are iron ore pellets, which helps make molten iron. The slag that comes off of that is not as hard and dense as steel slag.
Steel slag is what happens when molten iron is introduced to other elements needed for steel, such as nickel, chromium, and manganese. The steel slag is much harder, making it harder to crush because of its higher compressive strength. According to Coverdale, if youre crushing steel slag, you want to use a compression style crusher, and when youre crushing blast furnace slag, you can get away with impact style crushers from time to time.
In a slag plant, youre after the metal. You want to be able to recycle it and sell it back to the mill. Many of these machines will use a tremendous number of magnets to remove the metal and separate it out so that the slag product itself can be used in the construction industry for cement, or even asphalt on roads.
There are many types of protection devices on these machines to help protect it from damage. For instance, a jaw crusher has a toggle plate on it, which is a safety fuse. If you were to get an uncrushable into that chamber, the toggle plate will bend or break before you do major damage to the bearings or shafts. Cone crushers are equipped with tramp relief systems on them that allow for uncrushables to pass through without damaging the machine.
The aggregate industry is a little different. Tramp metal is an issue and its something that could get loose in the plant. If the metal gets through, typically metal detectors and magnets can remove them, but you want to try to protect your crushers prior to that point. Unfortunately, jaw crushers get the least protection because its taking the raw feed coming in from the pit.
Thats something that can be fixed by adjusting the speed or the way the circuit is set up. This allows people to have the new technology and a machine that outperforms what theyre used to. Also remember that every quarry is different, so just because one company does something one way doesnt mean you can automatically do it the same way.
Something to also consider, just because one crusher might be cheaper, doesnt necessarily mean its the best one for you. For example, a customer decides he wants to get into the crushing business and sees that an impact crusher may be cheaper than a cone crusher. The customer then buys the impact crusher because its cheaper, but if theyre mining an abrasive stone he will end up changing the blow bar and liners much more frequently than he would in a compression style crusher. At the end of the year, he may spend the same amount of money he would have spent on the cone crusher, just in wear parts and downtime in changing those parts.
Theyre going to want to know the distribution of the size of the material going into the crusher. The largest piece obviously dictates the feed size opening. Another important thing theyll want to know is just what market you serve do you produce a lot of concrete stone, which tends to be coarser aggregates, or do they produce a lot of asphalt stone, which are somewhat finer. That can be answered simply be saying if theres an asphalt plant outside of your quarry or is there a concrete plant outside of your quarry. Youll definitely have a target on what you want to produce, so be upfront with the person youre working with, let them know everything so that they can better serve your needs when setting up your system.