Recovery Of Valuable Metals From Jamesonite With United Pyrometallurgical And Hydrometallurgical Process

Recovery of valuable metals from jamesonite concentrate with united pyrometallurgical and hydrometallurgical technology is studied. First, jamesonite concentrate is smelted (soda and coal are added into the raw material), sulfur is put into smelting slag in the form of Na2S, and then lead-antimony alloy is produced. The antimony trioxide product is produced by directly blowing lead-antimony alloy, the obtained crude lead is transferred into the lead electrolysis system to produce electrolytic lead product, and silver in the anode slime is recovered. Then, Na2S recovered from smelting slag is used for antimony leaching from jamesonite concentrate to produce sodium pyroantimonate product and sodium hyposulfite by-product. Finally, the other metals such as zinc, iron and indium in the concentrate are enriched in the smelting slag, where Na2S has been recovered. This enriched metals such as zinc and iron are mostly in the form of sulfide, and can be separated by flotation. Thus, zinc, indium and other valuable metals are recovered from the zinc concentrate.In this study, the results of smelting process analyzed in theory shows that lead, antimony, silver and so on can easily be reduced into the metal phase (lead-antimony alloy) during smelting process. However, copper, iron, zinc and other elements is too diffcullt to be reduced, so that they exist in the smelting slag in the form of sulfide. In addition, sulfur is transferred into the smelting slag in the form of sodium sulfide.Thermod-ynamics of white antimony blowing from lead-antimony alloy has been researched. Iron, tin and other impurities can be removed with oxidation refining. Arsenic is removed by adding soda. In the temperature range of 500～1000℃, the vapor pressure ratio of antimony oxide to lead oxide (psb2O3/pPbP) is higher than that of antimony to lead (psSb/pPb)-Antimony is mainly transferred into gas phase in the form of antimony trioxide during lead-antimony alloy blowing.These raw materials of alkaline smelting jamesonite concentrate are mixed according to the mass ratio of jamesonite concentrate/soda/coal/ lime slurry equal to 100:50:10:10. And then they are prepared into pellets by a honeycomb briquet machine for the intensity, dimension and permeability of these pellets are suitable for blast furnace smelting.The smelting conditions are as follows:material column height-1.0-1.5m,air amount-61-65m3/min,air pressure-30-60mmHg, central temperature-1400℃, slag temperature-1000℃, coal rate-16.8%, and bed capability-110t pellet/(m2·d). The ratio of Pb, Sb, Ag into the alloy is 85.67%, 82.87%,87.08%, respectively. The recovery of Pb, Sb, Ag, Zn, In is 94.03%,96.70%,89.33%,97.63%,68.33%, respectively. The ratio of Cu and As entering into the slag is 72.63%and 68.88%. The smelting slag yield is 65.6% containing 52% sodium sulfide. The Pb and Sb content of lead-antimony alloy is 97.87%,with Pb being 61.66% and Sb being 36.21%. Antimony oxide powder recovery(based on concentrate input) is 7.36%. The sulfur from the materials is fixed by 99.3% as the sodium sulfide in the smelting slag, and SO2 concentration in the waste gas is 588 ppm reaching the industiral waste gas emission standard.During the industrial test of sodium sulfide leaching, the optimum conditions are as follows:S:L-1:4, temperature-90℃, time-90min. The leaching; of sodium sulfide is about 91%, the concentration is about 110g/L, the leaching of antimony is 91.83%, most part of As is leached and the rate is 80%, and the leaching slag contains 50% zinc. In the zinc slag, the metal elements such as zinc and iron exist in the form of sulfide. Zinc concentrate with high silver and indium content can be obtained by flotation. The sodium sulfide solution can be used to leach antimony in jamesonite concentrate or mixed antimony and lead oxides. The antimony leaching solution can be oxidized to produce sodium pyroantimonate product by pumping air. When the oxidation time is more than 45h, the sedimentation of antimony is 98%, and the antimony content in the filtration is less than 1g/L. The grade of the sodium pyroantimonate product meets with the second electronic industrial quality requirement. Antimony and arsenic can be decreased to 0.05g/L and 0.3g/L, respectively, by adding sulphuric acid to neutralize the oxidation solution or adding ferrous sulfate to precipitate them, and then qualified sodium thiosulfate can be produced by concentration and crystallization. The experiments of impurity removal from lead-antimony alloy by refining with sodium hydroxide such as arsenic show that better effects can be obtained by pumping air into the melt to enlarge reaction area. Thus, the NaOH+air system is selected as the alkaline refining system. The yield of refined Pb-Sb alloy is 95.84%, the removal of impurities such as Sn, As, Cu, S are 88.30%,96.45%,36.10%,56.64%, respectively. The direct recoveries of lead and antimony are 97.70%and 91.98%,separately. The As content can decrease to 0.010%. The conditions of antimony trioxide blowing are as follows:The melt temperature is (660±30)℃, air blowing temperature is about 100℃, the antimony content of the alloy is in the range of 15%～40%, the air amount and pressure are controlled to ruffle the melt surface. Under the above conditions, the antimony oxidation recoveries is 73.34%,with the contents of Sb and Pb in the alloy melt 15%and 83%. And then the great granularity is produced by increasing the crystallization temperature being 360～470℃, the distance from blowing pipe to molten alloy surface is more than or equal to 50mm. As a result, the granularity of the antimony trioxide exceeds 0.6μm.In the whole flow, the comprehensive recoveries of Pb, Sb, Ag and Zn are 92.1%,93.5%,97.6%,68.3%, respectively. As enters into the iron-arsenic residue by 74%. Cu enters into the zinc slag by 72.6%and into the lead system by 27%.Compared with the traditional sintering-blast furnace process, the process has the advantages of simple flow, high efficiency, less middle materials, high lead-antimony alloy quality, high metal recovery, better comprehensive utilization of resources, and less polution. So it is an energy-saving and environment-friendly process.