Dixiu Wu, Wei Liu, Junwei Han
Nov 15, 2019
Citations
0
Influential Citations
14
Citations
Journal
Separation and Purification Technology
Abstract
Abstract Sodium stannate (Na 2 SnO 3 ·3H 2 O) has been widely applied in the field of electroplating and flame retardants preparation. In general, Na 2 SnO 3 ·3H 2 O is mainly prepared from cassiterite or metallic tin, which has the problems of high production costs and natural mineral shortage. This study investigated a combined process of roasting, leaching, purification, and evaporating-crystallizing to prepare Na 2 SnO 3 ·3H 2 O directly from lead refining dross. The effects of roasting process parameters (NaOH dosage, roasting temperature, and time) and leaching process parameters (leaching temperature, leaching time, liquid-to-solid ratio, and stirring speed) on the leaching efficiency of tin were detailly investigated. The results showed that about 93.5% of tin was converted into sodium stannate after NaOH roasting and thus could be leached out by water leaching. The optimized conditions have been established as: mass ratio of NaOH to the dross of 1.4 during roasting at 450 °C for 60 min and leaching at 75 °C for 90 min with 10 mL/g liquid-to-solid ratio and 300 r/min stirring speed. Meanwhile, the antimony was separated into the leaching residue, in which the content of antimony reached 31.32%. Thereafter, the leachate was purified by sulfide precipitation with Na 2 S. The purified solution was then subjected to an evaporating and crystallizing process for the preparation of Na 2 SnO 3 ·3H 2 O.