Elucidation of Removal Mechanisifrof Impurities from Copper Scrap by Using Cu_2O-based Slag

为了阐明Cu 2 O基渣系对废杂铜熔体的除杂机理，进行了以下实验研究。本研究从废杂铜中提取了Cu_2 O、Cu_2 O-CaO和Cu_2 O-SiO_2渣系，并提取了Sn、Co和Pb杂质。(1)Cu_2 O基渣平衡铜液中氧溶解度及氧在渣中溶解速率的测定在1573 K的Ar气氛中，在Cu_2 O基渣的共存下，保温一定时间，用石英管取样（取样法）。特别是对于Cu_2O渣，采用氧化铝管、不锈钢棒等取样方法，在1573 K下，用ZrO_2固体电解质电动势法测定了渣-金界面的氧分压。根据实验结果，认为渣-金界面的反应速率（Cu_20（渣中）= 2Cu（1）+O（Cu中））是决定渣-金界面反应速率的因素。 ...更多信息 测定氧溶解速率的步骤。(2)Cu_2 O基渣除杂速率的测定在1573 K下，采用取样法（与实验（1）相同），不仅测定了除杂速率，而且测定了氧的溶解速率。在这些实验条件下，对于相同的初始氧含量，杂质的去除速率按Sn、Co、Pb的顺序快。当初始氧含量为0.03%时，氧的溶解速率和杂质去除速率均比初始氧含量高于0.8%时的速率慢。实验结果表明：铜液中的传质是杂质去除速率的决定步骤，活性剂（ex.在Cu 2 O基渣精炼废杂铜过程中，铜液中的氧改变了铜液与Cu 2 O基渣的界面面积，对杂质的去除和氧的溶解行为有很大影响。少

In order to elucidate mechanism of impurity removal from molten copper scrap by using Cu_2O-based slag, the following experiments were conducted. In the present study, Cu_2O, Cu_2O-CaO and Cu_2O-SiO_2 were picked up as a slag system, and Sn, Co and Pb were picked up as an impurity in copper scrap.(1) Measurements of Oxygen Solubilities on Molten Copper Equilibrated with Cu_2O-based Slags and Oxygen Dissolution Rates into Molten Copper from the Slags.Molten Cu-O alloy was held under coexistence of Cu_2O-based slag in Ar atmosphere at 1573 K.At an appropriate time interval, metallic sample was taken by using a quartz tube (Sampled method). Especially, in case of Cu_2O slag, the sampled methods with an alumina tube, stainless rod, etc., and an EMF method using ZrO_2 solid electrolyte to determine oxygen partial pressure were also conducted at 1573 K.Based on the results, the reaction rate at the slag-metal interface (Cu_20(in slag) = 2Cu(l) +O(in Cu)) is considered to be the rate-determin … More ing step for the oxygen dissolution rate.(2) Measurement of Impurity Removal Rate in Molten Copper by Using Cu_2O-based SlagBy a sampled method (same as the experiment (1)), not only impurity removal rate but also oxygen dissolution rate were measured at 1573 K.Under these experimental conditions, impurity removal rates are faster in order of Sn, Co and Pb for the same initial oxygen content. For initial oxygen content of 0.03 %, both oxygen dissolution rate and impurity removal rate are slower than those rates at an initial oxygen content higher than 0.8 %. From these experiments, the following results were obtained :The mass transfer in molten copper phase is considered to be the rate-determining step for the impurity removal rate.The active agent (ex. Oxygen) in molten copper phase, which changes the interface area between molten copper and the Cu_2O-based slag, seems to greatly affect the behaviors of impurity removal and oxygen dissolution in the copper scrap refining process by using Cu_2O-based slag. Less