| The paper introduced a new measure of increasing the content of the silicon on metallurgy. The waste material of graphite electrode that is mainly composed of silicon carbide (sic) is put into to improve the content of silicon in this Experiment. Experimental results indicate the effect offered by the waste material of graphite electrode is the same as silicoferrite. Silicon is an important element used in the foundry, in general cast iron, the content of silicon is 1.3%～3.0%. The beneficial effects of the presence of silicon have been explained in many different ways. It is common knowledge that the addition of silicon to cast iron does improve the ratio of graphite formation. The content of silicon influence obviously cast iron structure, which accelerates graphite formation. Owing to the addition of silicon, the cast iron facilitates crystal towards stabilization system. Study found that the content is better; the trend to stabilization system is easier. During the metallurgy the content of silicon in raw material is often smaller than that we expect in finished product. For the sake of this purpose, assistant raw material often is added to adjust the content of silicon. In course of traditional metallurgy, silicoferrite can be used to modulate silicon content. But the enhancement of silicoferrite price boosted greatly the cost of cast iron. So it is necessary/urgency to look for a kind of substitute of silicoferrite. This experiment just uses the waste material of graphite electrode as a substitute for silicoferrite. The advantages of using the waste material of graphite electrode in the course of metallurgy, such as the low of the price, the convenience of collection and because it comprises mainly two components carbon and silicon, which can be used in adjusting this kind of two elements at the same time. The experimental research consisted of two parts, namely, analysis of the element of the waste material of graphite electrode and study of the effect of the waste material of graphite electrode that substitute for silicoferrite. The materials used for the studies were obtained from graphite electrode factory. The results show that the sample mainly consists of SiC SiO2 and C. To analyze the detail element of the SiC, the samples are averagely separated into 4 parts. All the powders are dissolved in hydrogen fluoride (HF) and all the powders were calcined at 1173K for 10h, then the powders were then cooled to room temperature in a desiccator before being finely ground in an agate mortar. The content of sic used for the studies as well as for the waster of the graphite electrode factory is 82.55% SiC. During the experiment the sample of the waste material of graphite electrode must have some form. For this purpose, the sample powders in the proportions of 98wt% the waste material of graphite electrode and 2wt% adhesive were mixed in a porcelain enamel plate for more than 20min. The mixture was packed in a pure iron tube, 20 mm in inner diameter and 103 mm in height, namely the mixture was made into a cylinder 20 mm in inner diameter and 103 mm in height and 110g in weight. Finally the cylinders are placed in drying-out and heated up to a temperature of 373K then kept at that temperature for 10h to ensure complete dryness. The experiments were carried out using a faradic furnace instrument. The raw materials are composed of 1.5kg cast iron and 1.5kg waste steel. Both raw materials and sample of the waste material of graphite electrode were added into a faradic furnace to smelt together. The prepared samples were subjected to spectral analysis. The first sample is the raw sample, namely no addition, the others are the final sample, and namely, the waste material of graphite electrode has been added into the raw materials.the results show that the raw material contains 1.9756% of carbon and 0.8454% of silicon and the other sample average the carbon and silicon are respectively 2.8760% and 3.1296%. The content of carbon and silicon respectively increased 45.58% and 270.19% owing to the addition of the waste material of graphite electrode. SiC does not dissolve immediately when added to the melt and its dissolution is slow, giving a pre-inoculation effect that fades slowly and remains effective for several hours. The pre-inoculation behavior of SiC in gray cast iron melts is notwell understood, but it has been claimed that during the dissolution of SiC in the melt, graphite clusters are formed around the SiC particles, as a result of local super saturation of the melt with Si and C. These graphite clusters, which are thermodynamically metastable for a certain period of time, play an important role in the pre-inoculation effect of SiC in the melt and promote the graphite formation and eutectic nucleation. The dissolution of FeSi can also lead to graphite cluster formation, but because of its faster dissolution rate, these clusters remain stable for only short periods. Hence, during the dissolution of SiC, more graphite clusters are formed which persist for longer than during dissolution of FeSi. The SiC additions could result in the higher graphite formation observed in the SiC treated irons as shown in The waste material of graphite electrode is mainly composed of sic that acts as silicoferrite during the metallurgy. Many research groups have discussed the cardinal principle in many different ways. Research indicates that sic shall be decomposed silicon and carbon in some temperature. The silicon diffused into hot metal and form silicoferrite solid solution. The carbon gathered around the silicoferrite and form graphite. The correlative reactions were shown: SiC→[Si]+ C ( s) [1] 或SiC ( s) + Fe ( s) = Fe3Si( s) + C ( s) [2] The relations of standard Gibbs free energy and temperature can be got by thermodynamics calculate. △G0T=-38220+5.04T △G01300℃=-3.03KJ·mol-1 It is obvious that SiC/Fe is a thermal instability system. The negative △G0T offers the drive for the reaction and promote it. The waste material of graphite electrode separately use silicon and carbon as "penetrative source". Along with apart from the waste material of graphite electrode, the content silicon and carbon is gradually reduced. The following is why this experiment uses the waste material of graphite electrode as a substitute for silicoferrite 1. The waste material of graphite electrode was come from the waste of the factory, so the price is very low. It is 1000rmb/t but the silicoferrite is...
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