| In order to explore the indium, tin indium-tin alloy for effective separation and recovery, the method of this topic use containing indium alloy scrap recycling,reduce the native indium tin ore resources consumption, but also for enterprises to develop circular economy, promoting the sustainable development of enterprises play an important role. Discussed in this paper, we study from indium-tin alloy scrap recycling metal indium and tin experiment method, technological process, production control, equipment configuration, etc. By laboratory experiment, industrial experiment, steps, such as industrial production through analyzing mathematical experiment many times, grope for optimum technological parameter is discussed, and finally determine the simple technological process, technology is simple, economic indicators advanced wet process, And on the basis of the optimization of process flow and equipment configuration for industrial production. The main research conclusions are as follows.On the premise of analysis of all kinds of recycling method, using granular(water quench), acid soluble, purification, replacement, alkali cooking and easy operation of electrolytic process, from pure indium recycling indium tin alloy and tin.1. A granular(water quench) : the molten alloy liquid refinement particles take high pressure water shock water quenching method. After heat the indium-tin alloy scrap melting, the use of water cannons was running water fine metal particles(metal indium flower), nozzle pressure 1 kg to 2 kg, made the particle size of 1 mm to 8 mm, irregularly shaped.2. Acid soluble: mixing, the more the faster acid dissolution reaction. Particle size distribution of 4mm below 70%, 7mm~8mm was 6% under optimum reaction, and better control in practice. When the liquid-solid ratio(volume of hydrochloric acid and alloy weight ratio) in(4.5 ~ 5):1, acid dissolve faster, to under the influence of crude indium tin plate replacement and small. Sn react with HCl to generate only Sn2 +.The best solution to dissolve the indissolvable alloy is the nitric acid and hydrochloric acid ratio of 1:20. Using this solution, the HNO3 solution is not too much, all of them reacted with HCl to generate NOCl, Cl2.3. Purification: join the greater the amount of crude indium, purify reaction faster; Acidity on the reaction rate. Purification process: Sn2 +:Sn4 +(1.8~1.3):1; Crude indium consumption: crude production is(0.97~1.26):1; Early peeling tin, the frequency of 30 min ~ 40 min advisable, late peel tin frequency for 1 h.4. replacement: Fe3 +and Fe2 + will have influence on the rate of replacement. Displacement process, the ph control in 90g/L~110g/L, fast output indium and zinc ingot cost less. Intermediate reaction stage, the acidity of the consumption is not large, plus acid cycle in every 2h ~ 3h, the late acidity consumption is larger, but at the moment, indium content is less,depending on the reaction time and consumption, accelerate or extend the acid consumption cycle zinc ingots: crude indium output(1.46~1.65):1; Early reaction, the strip indium cycle control in about 20 min, and then extend the time of 1h ~2h.5. Alkali cooking: the higher alkali boiling temperature, alkali cooking indium recovery rate is higher, the alkali boiling temperature control at 350℃~ 450℃, the best alkali boiling indium recovery rate can reach 91%~ 97%; For the amount of sodium hydroxide for alkaline cooking recovery. The use of sodium hydroxide for tin alkali boiling recovery is not ideal; Using tin tin reduction furnace for melting recycling, recovery is more ideal, and reducing furnace alkali boiling temperature is higher, the tin recovery rate is higher, the reduction temperature control at 600℃~700℃, the best alkali boiling tin recovery can reach 91%~ 97%.6. Electrolytic refining and ingot casting:Use Yuguang indium electrolytic refining mature technology, the coarse indium plate electrolytic refining and ingot casting. Every batch of every time the water in the tank to join55~ 60 pieces of anode electrolysis.Control cell voltage of 0.2V ~ 0.3V, current density of 30A/m2~50 A/m2, electrolyte temperature 20℃~ 30℃, in addition to the ingot after isolation, thallium, get in line with the YS/T257 In99995 brands- 2009, indium content of 99.995% or more of pure indium.The subject to realize recycling from indium tin alloy metal indium and tin, crude indium, coarse tin recovery is more than 95%. Purification using waste alloy metal, relative to the purification of indium from the containing indium smelting slag metal, such as equipment investment greatly reduced, the production process is simple, less chemicals use, environmental protection benefit is remarkable. Reached a comprehensive recycling and utilization of resources, development of cleaner production and environmental friendly material of multiple purposes, is a kind of in line with the concept of circular economy and ecological economy of clean production technology. |
