Soft melting pretreatment device and method for low-tin-layer electrolytic tinplate

The invention relates to a soft melting pretreatment device for a low-tin-layer electrolytic tinplate. The soft melting pretreatment device comprises a fluxing agent circulating tank, a fluxing agentstock solution tank, a fluxing agent solution supply pump, a fluxing working tank, a fluxing agent return pipeline and valve, a rinse water replenishing pipeline and corresponding valve, a fluxing working tank inner spraying pipe, a fluxing working tank inner spraying water pipe the and valve, a steam pipeline and valve, a rinse water discharge pipeline and valve and the like. According to the fluxing treatment process, a fluxing agent is added into the fluxing agent circulating tank by the fluxing agent stock solution tank through a feeding pipeline, the fluxing agent is mixed with water according to a certain concentration, and a prepared fluxing agent solution is pumped into the fluxing working tank through the fluxing agent solution supply pump and enters from the bottom of the fluxingworking tank. A rinsing a