Method for removing tin from lead bullion by adopting ferrous powder

Abstract

The invention discloses a method for removing tin from lead bullion by adopting ferrous powder. The method comprises the following steps of: smelting the tin-containing lead bullion in an open lead melting kettle, and then adding Fe powder into the molten tin-containing lead bullion at the temperature of between 600 and 850 DEG C; fully mixing the Fe powder and the molten bullion in a stirring way, and preparing compounds of FeSn2 and the like from the Fe powder and the tin in the molten bullion, wherein a specific gravity of the compounds is light, so the compounds float upward to the surface of the molten bullion to form dross, and then removing the dross; and stirring the molten bullion for 30 to 80 minutes and stopping stirring, and after fishing the dross on the surface of the molten bullion out, performing ingot casting. The refined and tin-removed lead ingot is prepared, and the content of the tin in the lead (wSn) is less than or equal to 0.001 mass percent; and the method reduces lead volatilization, removes alkali vapor and NOX gas, improves the working environment and contributes to physical and psychological health of production operators.

Description

technical field [0001] The invention relates to a method for lead, in particular to a method for removing tin from crude lead by using iron powder. Background technique [0002] The production cost of secondary lead is 38% lower than that of primary lead, and the energy consumption of secondary lead is only 25.1% to 31.4% of that of primary lead. For every ton of secondary lead produced, 1360 kg of standard coal can be saved, solid waste can be reduced by 98.7 tons, and water can be saved by 2.08 tons, reducing sulfur dioxide emissions by 0.66 tons. The general way to regenerate lead is to extract crude lead from various raw materials first, and then use different methods to remove impurity elements in crude lead. For example, crude lead generally contains tin elements, which must be removed in subsequent processes. In order to meet the standard requirements of refined lead, at the same time comprehensively recover the expensive metal tin. [0003] The traditional methods ...

AI Technical Summary

Problems solved by technology

The above-mentioned methods in the prior art all remove tin by reacting with other substances to form scum, and the temperature of oxidation refining generally must reach 800°C to 900°C to meet the conditions for oxidation reaction. Lead volatilization is serious, causing resources and affecting the working environment. At the same time, this method needs to heat all materials to a temperature above 800°C, which consumes a lot of energy and becomes the main cost of lead regeneration production, resulting in a waste of energy. The equipment puts forward higher requirements, the working environment is harsh, and lead is used as a raw material for slagging reaction, resulting in a waste of resources

The disadvantage of alkaline refining is that it needs to add a large amount of NaOH, NaNO 3 , the above substances are inevitably heated to form alkali mist and NO during operation X Gas, which seriously pollutes the environment and affects the health of operating workers

More importantly, the tin removal effect of the above two methods is not ideal, and can only reach about 80%. Both of them have the problems of long operation time and high equipment requirements.