Ferrosilicon (FeSi) is an alloy of iron and silicon with a very variable silicon content between 10% and 90%. It is used as a so-called master alloy in steel production, which is added in small amounts in order to adjust the properties of the melt, the cooling process and the finished product.
The main advantage of FeSi is its deoxidizing effect (i. e. it reduces metals from their oxides), but it also helps to prevent the loss of carbon. Furthermore, ferrosilicon is used in electrode coatings and in the production of silicon, hydrogen and magnesium.
Ferrosilicon is produced either in a blast furnace or electric arc furnace by the reduction of quartz sand (SiO2) with coke in the presence of iron. The melt is poured out of the furnace and solidifies in the form of a flat sheet.
After cooling, this sheet is crushed by appropriate machinery and then further processed in a crusher. The resulting particle size distribution ranges from fine dust-like particles to cm-sized chunks. The FeSi is sifted into different size grades for further use.
Microtrac's CAMSIZER series is ideally suited for the particle size distribution analysis of ferrosilicon and other granular metals. Microtrac analyzers are used both for quality control industrial applications as well as research purposes.
What is inoculant and do you need it?
Inoculant is Rhizobium bacteria that is applied to legume seed (clovers, cowpeas, etc.) before planting. The nodules on the roots of legumes contain Rhizobium bacteria, which are responsible for fixing nitrogen for the plant. Applying inoculant to the seed ensures that the correct type of bacteria specific to that legume are available to the plant once it germinates.
Rhizobium bacteria is found in many soils, but planting legumes that have not been inoculated is taking a chance as to whether or not the specific strain of bacteria required for that legume is already present in the soil. In many cases, once a successful crop of a specific legume is grown in a field, there will be sufficient quantities of Rhizobium remaining in the soil to accommodate another planting of the same legume. But, many factors, such as cultural practices, weather conditions and soil conditions, may affect the survivability of the carry-over Rhizobium in the soil. In short, many people grow successful stands of legumes from seed that was not inoculated. However, there is no guarantee that the proper type of Rhizobium for the legume you are planting is present in your soil. Inoculating the seed is good insurance that the plant will be properly equipped to grow to its maximum potential and compete.
Some seeds are sold already coated with inoculant. In the case of un-inoculated seed, the inoculant will need to be applied and mixed with the seed before planting. The first step is to purchase the appropriate inoculant specific to the type of legume you are planting. Be sure that you have enough inoculant to treat your seed. Inoculant generally comes in the form of a fine, black powder sealed in a plastic package that should state which type of legume it will treat and how many pounds the package will treat. Also, check the expiration date on the package to make sure that the inoculant is still viable. The next step occurs immediately before planting. Dump the seed into your seed drill, broadcast spreader, or whatever type of planter you are using. Then apply the appropriate amount of inoculant to the seed. Stir the mixture until you feel that the inoculant has come into contact with the majority of seed. Then plant the seed as normal.
Some people have used liquids like milk, water or even soda pop as an adhesive agent for getting the inoculant to stick to the seed. If you choose to do this, be careful not to apply too much. Also, some liquids may damage the Rhizobium with any acidic contents they contain.
Recarburizers are used to adjust carbon levels: Materials that incorporate carbon into the steel in a liquid state. There are many types of materials with the possibility of being used as recarburizers, but the usual ones are:
The higher percentage carbon content in the recarburizer, the higher its effectivity. If the percentage of ash in the coal is high, the dissolution rate decreases due to the formation of a layer of impurities on the surface of the refueling agent, preventing the transfer of carbon to the molten bath, which increases production times and costs. Another aspect to consider is the negative influence of the acidic components of the ash on the basic refractory lining of the furnace.
The particle size plays an important role when the recarburizer is added to the surface of the bath. If the recarburizer is too fine:
It floats on the surface of the molten bath.
It burns prematurely.
It is sucked in by the gas collection system.
It is removed along with the slag.
If the material is too thick it penetrates deep into the bath, therefore, the reaction surface is too small, causing the recharging to be slow and ineffective.
The most important characteristics that a recarburizer must have are the following:
It should be easy to introduce to the molten bath.
High percentage of fixed carbon.
Low ash, volatile matter and moisture content.
Production of Ferro- Manganese
Ferro-manganese (Fe-Mn) is an important additive used as a deoxidizer in the production of steel. It is a master alloy of iron (Fe) and manganese (Mn) with a minimum Mn content of 65 %, and maximum Mn content of 95 %. It is produced by heating a mixture of the oxides of Mn (MnO2) and iron (Fe2O3) with carbon (C) normally as coke or coal.
Fe-Mn in a blast furnace (BF) with considerably higher Mn content than was possible earlier was first produced in 1872 by Lambert Von Pantz. The Fe-Mn produced had 37 % Mn instead of 12 % being obtained earlier. Metallurgical grade Mn ores having Mn content higher than 40 % are usually processed into suitable metallic ferro- alloy forms by pyro-metallurgical processes, which are very similar to the iron pyro-metallurgical processes. In its production process, a mixture of Mn ore, reductant (a form of C) and flux (CaO) are smelted at a temperature which is higher than 1200 deg C to enable reduction reactions and alloy formation. Standard grades of Fe-Mn can be produced either in a BF or in an electric submerged arc furnace (SAF).
The electric SAF process, however, is far more flexible than the BF process, in that slags can be further processed to Si-Mn and refined Fe-Mn. The choice of process is also dependent on the relative price of electric power and coke. In a three-phase SAF, the electrodes are buried in the charge material. The raw materials are heated and the Mn oxides pre-reduced by hot carbon mono oxide (CO) gas form the reaction zones deeper in the furnace. The exothermic reactions contribute favourably to the heat required. Efficient production of HC Fe-Mn depends on the degree of pre-reduction which occurs in the upper region of the furnace.
There are several grades of Fe-Mn which are divided into many groups. The three main groups are high C Fe-Mn, medium C Fe-Mn, and low C Fe-Mn. High C Fe-Mn can be made in BF and in SAF. In SAF it is made by two different practices namely (i) high Mn slag practice, and (ii) discard slag practice. Medium C Fe-Mn can be produced by a de-carbonation process or through a redox (reduction-oxidation) reaction between silicon (Si) in the silico-manganese (Si-Mn) alloy and Mn ores. Low C Fe-Mn is produced by the reaction of Mn ore and low C Si-Mn.
Ferrochrome plants their annual production capacity
Ferrochrome, or Ferrochromium (FeCr) is a type of ferroalloy, that is, an alloy between chromium and iron, generally containing 50% to 70% chromium and is used in the production of stainless steel, special steel and castings. Ferrochrome is divided up in three main products which are Low Carbon FeCr, Medium Carbon FeCr and High Carbon FeCr. It is produced in an energy-intensive process in electric furnaces from chrome ore, iron ore, and coal. The largest producing countries of ferrochrome are South Africa, Kazakhstan, India and China.