![]() It is pointless to inject SiC and carbon materials that do not provide full carbon or silicon recovery. Mastermelt engineers spent two years developing the technology and skill needed to determine the specific materials that can be injected effectively. ![]() Trimming chemistry - Both carbon and silicon-carbide can be injected to trim the cupola metal chemistry. Carbon must possess an equally high dissolution rate in molten iron and no commonly available graphite carbon raisers meet this qualifying standard. SiC must possess a high dissolution rate in the molten iron, and only a few grades of SiC qualify. Simply, lower-quality materials do not work and using them discredits tuyere injection as a reliable melting tool. The materials to be injected must be "injection-grade" and "injection-quality": Standard-grade silicon carbide (SiC) and graphite do not qualify. Then, silicon and carbon can be injected in any amounts needed to trim the chemistry. Tuyere injection can be used to counter oxidation losses in a cupola, in addition to supplementing carbon and silicon in molten metal exiting the cupola. One-hundred-ton-per-hour cupola furnaces have been operated for entire daylong campaigns with carbon variation of 0.01% C, and such exceptional chemistry control is possible with any melting operation. Oxidation must be controlled in order to attain “straight-line” chemistry.Ĭan carbon be controlled to produce straight-line chemistry? Unequivocally, yes. It is a simple analytical comparison: Chemistry will vary by 50% when a 50% oxidation loss occurs. The wide variations in metal chemistry faced by some ferrous foundries are caused by oxidation loss of the key elements. You must experience melting without oxidation loss to appreciate the significance of this. Unwanted weight variations in charge ingredients, which frequently are assumed to lead to chemistry variations, in fact are a minor influence in most melting operations. Oxidation losses cause 99% of all chemistry variations in molten iron. (2) Chemical reactions (slag/metal reactions) that occur during the melting process and cause unpredictable and widely varying loss of C, Si, MN and other necessary elements. (1) Accuracy of the weight of individual metallic and alloy ingredients in the charge and, ![]() Molten iron chemistry variations result from two primary sources: Melting is not simply the process of re-melting existing metallic materials: Slag-induced influences during the melting process - caused or produced by the slag/metal chemical reaction - have a consequential role in iron chemistry and finished metal quality Unfortunately, formulating the charge does not determine the final chemistry or quality of the molten iron. So there's no simple rule for learning the number of electrons an atom may gain or lose in a compound (and using electricity, for example, it's possible to remove electrons well below the valence shell), though the number of electrons in the valence shell is unique.The ingredients of a furnace charge, whether it is an electric furnace or a cupola melter, are formulated to produce the final chemistry required for the castings to be poured. " So an element has a specific valence, depending on its group (e.g., C, 4 or Xe, 0), but may have multiple values for valency, such as in $\ce$. It's not simply the column that determines the ionic charge of an element, but also other factors, such as row and with what other elements it's combined.Įpediaa states, "valence refers to the ability of an atom to be combined with another atom whereas valency refers to the maximum number of electrons that an atom can lose or gain in order to stabilize itself.
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