A vacuum refining furnace, including a furnace body, a graphite heater, an electrode, and a sealed furnace housing. The furnace body includes an evaporation laminate, a graphite condensing casing, and a graphite insulating casing. The evaporation laminate includes a plurality of evaporators. The evaporation laminate is nested within the graphite insulating casing, and the graphite insulating casing includes a plurality of through holes. At least two graphite condensing casings having different diameters are provided. The graphite insulating casing is nested within the graphite condensing casing having a smallest diameter, and the graphite condensing casing having a relatively small diameter is nested within the graphite condensing casing having a relatively large diameter. All the graphite condensing casings except for the graphite condensing casing having the largest diameter include a plurality of through holes.

A device for efficiently separating ethyl tin from molten crude tin is disclosed. The device includes grab buckets, connecting rods, an inverted T-shaped push rod, alloy legs, a hanger plate, a cylinder and a lifting ring; wherein one end of the connecting rod is fixedly connected with one side of the grab bucket, and the other end of the connecting rod is detachably connected with the bottom end of the inverted T-shaped push rod; a top flange of the inverted T-shaped push rod is detachably connected with the bottom flange of the cylinder through threads, and the inverted T-shaped push rod is powered by the cylinder to push and pull. The device has simple structure, small volume, light weight, convenient use and placement, reduced occupancy rate of production site space and flexible use; the invention adopts a remote control mode, mechanized operation, higher safety and labor saving.

A device for efficiently separating ethyl tin from molten crude tin is disclosed. The device includes grab buckets, connecting rods, an inverted T-shaped push rod, alloy legs, a hanger plate, a cylinder and a lifting ring; wherein one end of the connecting rod is fixedly connected with one side of the grab bucket, and the other end of the connecting rod is detachably connected with the bottom end of the inverted T-shaped push rod; a top flange of the inverted T-shaped push rod is detachably connected with the bottom flange of the cylinder through threads, and the inverted T-shaped push rod is powered by the cylinder to push and pull. The device has simple structure, small volume, light weight, convenient use and placement, reduced occupancy rate of production site space and flexible use; the invention adopts a remote control mode, mechanized operation, higher safety and labor saving.

A solder product 20 includes: a lead-free solder part 21 containing tin as a main component and a metal element other than lead as a secondary component; and a carboxylic acid having 10 to 20 carbons, the carboxylic acid being mainly distributed over the surface of the solder product 20 to form a surface layer 22. The carboxylic acid is preferably a fatty acid having 12 to 16 carbons, and more preferably a palmitic acid.