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选用废旧WC-8Co硬质合金为原料,采用氧化法研究了通氧速率、注水速率和炉体转速对其氧化行为的影响,通过Factsage热力学软件对硬质合金的氧化产物进行了预测,采用热重-差热(TG-DTA)分析确定了氧化温度范围,并用X衍射分析仪(XRD)和场发射电子扫描电镜(SEM)对氧化混合物的物相和形貌进行了表征。结果表明:WC-8Co废旧硬质合金在富氧、潮湿和旋转条件下能迅速氧化为WO_3和CoWO_4混合物,H_2-H_2O-O_2组成的氧化-还原体系与炉体转动产生的复杂应力协同促进氧化进程。当注水速率为1.2 ml·min~(-1),氧气速率为0.125m3·h~(-1),炉体转速为15 r·min~(-1)时,废旧硬质合金仅需在850℃下氧化1 h就能完全氧化,其氧化增重为16%,氧化物颗粒形貌多为近球形,分布均匀且粒径分布较窄,主要分布在0.26~2.86μm范围内,其平均粒径为0.93μm。
Oxidation was used to study the effects of oxygen passage rate, water injection rate and furnace rotation speed on the oxidation behavior of WC-8Co cemented carbide. The oxidation products of cemented carbide were predicted by Factsage thermodynamic software. The oxidation temperature range was determined by TG-DTA analysis. The phase and morphology of the oxidized mixture were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (SEM). The results show that the WC-8Co alloy can rapidly oxidize into WO_3 and CoWO_4 mixtures under the conditions of oxygen enrichment, humidity and rotation. The complex oxidation-reduction system composed of H_2-H_2O-O_2 and the complex stress caused by the rotation of the furnace body can promote the oxidation process. When the water injection rate was 1.2 ml · min -1, the oxygen rate was 0.125 m 3 · h -1 and the furnace rotation speed was 15 r · min -1, the waste cemented carbide only needed 850 ℃ oxidation for 1 h can be completely oxidized, the oxidation weight gain of 16%, the morphology of oxide particles mostly spherical shape, uniform distribution and narrow particle size distribution, mainly in the 0.26 ~ 2.86μm range, the average particle size The diameter is 0.93 μm.