Consumers are very important to find out what it is – a domain slag. The correct deep characteristic cannot limit the acquaintance with the density of the granulated slag, with its differences from steel-smelting, with a weight of 1 m3 and chemical composition. Be sure to find out yet, what is the use of sections of crushing and what private types of such products are.
What it is?
The name “Domain Slag” refers to the specific type of artificial stone masses. They appear as a side result of the production of domain melting of metal – from here and the general name. An empty breed is melted with fluxes contained in the mixture, like this, loose products appear.
If the domain process is carried out strictly according to the technology, then the slag looks like a bright product (light gray, with yellow, greenish and some other notes). If the manufacturer violates the established technology, then another color appears – black, this indicates a high concentration of iron in the products produced.
The texture of the slag is also different in wide range. Options are known:
- Similar to china.
Composition and characteristics
Since even in one enterprise, receiving raw materials from the stable circle of suppliers, the technological nuances may vary, it is natural that in different cases the properties and composition of the slag are also quite significantly different. Often you can read that this product is close to chemical to cement. And such approval is not devoid of grounds. However, calcium oxide in slag mass is slightly smaller, but silicon dioxide, aluminum oxide and other similar compounds – is clearly more.
It is worth noting that oxides are usually present not in pure form, but as part of other connections. Also, since the technological process involves a sharp cooling of the treated mass, the chemical composition of the slag includes aluminosilicate glass. It is characterized by an impressive response capacity with other substances. A separate important topic is the share of 1 m3 of the domain slag, it is a bulk density, in fact (sometimes these concepts are bred, but they still remain closely interrelated for obvious reasons). This indicator may vary from 800 to 3200 kg, depending on the initial raw materials, processing methods and other technological subtleties.
In practice, most slag weighs, however, at least 2.5 and not more than 3.6 g per 1 cm3. Sometimes it is even easier than molten metal. Nothing surprising – otherwise it would be impossible to clearly and competently separate the slag mass from the main product of metallurgical plants. There is even a special GOST 3476 for a domain slag, adopted in 1974.
Notice: This standard does not cover the products obtained from ferroalloys and magnetite ores of any origin.
The standard is normalized:
- The content of aluminum oxide and some other substances;
- The proportion of non-full granulation of fragments;
- Nominal size of the standard batch (500 tons);
- Requirements for testing samples taken from each brought part separately;
- re-testing procedure for dubious or ambiguous indicators;
- Requirements for storage and moving finished products.
Standardized level of thermal conductivity of domain slags is taken equal to 0.21 W / (MS). This is a completely decent indicator, and still the worst than mineral wool. Therefore, such a heater will have to put a thicker layer. The characteristic of the supplied batch of goods must necessarily indicate such a parameter as the Beschy. The larger the proportion of smooth grains, the less “coupling” between them, and it is also harder to prepare a solution and make a mass of them.
Its useful to note, Unfortunately, the environmental friendliness of a domain slag causes big doubts. Applying it in direct contact with the environment, for example, during road construction, causes serious risks, first of all, contributes to the spread of heavy metals. But if we exclude the erosion of the mass by sozing, thawed waters and precipitation, then the problem is largely solved. Therefore, it is not necessary to give up the use of slag products – this is in any case it is better to directly throw it. However, it is necessary to pay attention to the conditions of application.
Differences from steel-smelting slag
The main specificity is that such a product is obtained at a completely different technology. And therefore its chemical composition, and therefore, of course, and properties are very different. Steel-smelting waste is denser and obviously not suitable as a simple mineral aggregate or insulation. but It is sometimes used as ballast in road construction or as a filler with asphalt concrete mixtures.
Experiments give encouraging results, but still the classic domain slag remains a more convenient and attractive product.
The manufacture of slag is associated with smelting in a special oven, for example, cast iron. The substance necessary for us leaves the domain unit, being heated at least up to 1500 degrees. Because you can work with it, you need to cool the slag. Wait until this happens naturally, it would be too long. Therefore, practice:
- swelling (or otherwise, cold water supply);
- blowing air jets;
- Crushing or grinding on special equipment.
It is worth noting that the processing method directly affects the composition and characteristics of the finished product. All granulars know about it, and therefore they take into account such a moment when a certain task is set. Let’s say with air-cooled in the slag, silicates and aluminosilicates will prevail. In some cases, the slag is also crushed mechanically – this procedure is applied either while it is still liquid or after partial frozen. Large pieces are processed in small grains in such a way that it improves further performance and improves the quality of the finished product.
Of course, specially no one domain slag produces. We emphasize that it is always only a by-product of metallurgical production.
Granule production can be made by various methods using specific devices. Known systems for wet and semi-dry granulation. In the wet technique, slags are loaded into reinforced concrete pools filled with water.
It is customary to share pools on a number of sectors. This approach ensures the continuity of the production of the procedure. As soon as the heated raw material merges, the other is already ready to unload the cold slag. At modern enterprises, unloading is made by grab cranes. The amount of residual water depends on porosity, and the porosity itself is determined by the characteristics of the cooling process.
To make a semi-dry slag, usually resort to mechanical crushing. Similar effect is achieved due to discarding in the air cold, but not yet until the end of the frozen slag. As a result, the material is rapid and harder, compared with the wet granulation. The humidity of the finished product will be 5-10%. The larger the temperature of the melting, the easier it will be a finished product.
Metallurgical domain slag is obtained when smelting cast iron. Depending on the fraction and from bulk density, such a product is considered a porous or dense product. The porrows recognize the crushed stone of the specific bulk density below 1000 kg per 1 m3 and sand of the specific bulk density below 1200 kg per 1 m2.
An important role is also played by the so-called module of basicity, which determines the alkaline or acidic nature of the substance.
In the process of cooling, the substance may:
- maintain amorphy;
- undergo partial crystallization.
Ground slags produce from granulated varieties by additional grinding. Depending on the target task there can be introduced hydrophobic additive. Typically, the product complies with the specifications adopted in 2013. Dump slag is produced as waste. Its value directly for metallurgical production is small, but there are already demanding technologies for the recycling.
Scope of application
Use the domain slag quite wide. Its main scope – obtaining building materials. So far, such a sphere is developed unevenly in different regions of the country. However, the reduction of the transportation distances of building materials to construction objects can only be welcomed. Abroad in road construction use not only a domain, but also steel-smelting slag, but this is the topic for a separate conversation.
A simple dump product is able to quickly capture, which makes it an analogue of cement. Gradually expands the use of such a mass in the swelling of road cloths. Also in many places seek to strengthen the supporting platforms foundations. Developments on the use of sections of crushing as the main component of concrete appear as the main component of concrete. There are already a number of publications in which such an experience is encouraged.
Slag crushed stone produces, fraction of a dump slag and passing it through the screens. The concrete application affects, above all, the material fraction. Worked for the use of such a product as:
- fillers of durable concrete mixes;
- Ballast pillows on railway tracks;
- means of strengthening slopes;
- Pier and pier material;
- Means of arrangement of platforms.
Granulated slag enjoyed when receiving slag blocks. It needs it for thermal insulation. Sometimes a domain slag is used for drainage: in this capacity, it will quickly degrade, turns into the sand, but still works fine. Granulated mass can be used for sandblasting.
Its use occurs quite often, and the necessary product is offered by many leading manufacturers.