Xiangyang Zhou

Novel foaming agent used in preparation process of aluminum foams

Abstract The performances of a novel foaming agent used in the preparation process of aluminum foams were investigated, and the effects of some factors, such as addition of the foaming agent, foaming temperature on the porosity, and appearance of aluminum foams were also discussed. Experimental results show that the novel foaming agent has a wide decomposition temperature range and a mild decomposed rate; the foaming agent has the ability to enhance the viscosity of aluminum melt, as a result, an extra viscosifier such as Ca or SiCp is unnecessary while using this foaming agent; the bubble-free zone in material decreases and the foaming efficiency increases with the increase of foaming agent; the bubble-free zone disappears and the foaming efficiency is near 100% when the addition of foaming agent is more than 1.4wt%; the porosity of the aluminum foam increases with the increase of foaming agent when the addition of foaming agent is less than 2.2wt%.

Preparation of special silicon steel grade MgO from hydromagnesite

Abstract A preparation technology of MgO powder used in special silicon steel from hydromagnesite mineral has been developed. The preparation technology includes the following steps: (1) calcining the hydromagnesite at 700–750°C for 1.5–2 h; (2) hydrating the calcined hydromagnesite to be slurry containing the solid-liquid ratio of 15–20 g·L−1; (3) acquiring Mg(HCO3)2 solution by carbonating the slurry, the carbonation temperature, CO2 pressure, and end point PH value of carbonation are less than 40°C, 0.4–0.6 MPa, and 7 respectively during the carbonation process; (4) preparing precipitated basic magnesium carbonate by thermally decomposing the Mg(HCO3)2 solution at 90–100°C; (5) obtaining the MgO product by calcining the precipitated basic magnesium carbonate at 850–950°C for 30–60 min, and adopting flowing nitrogen during the cooling process. By using this technology, more than 80wt% magnesium in hydromagnesite mineral can be extracted, and high-performance MgO products used in special silicon steel can be obtained.