Study On The Preparation Of High-purity Tantalum Powder For Sputtering Targets Directly From Tantalum-containing Waste

At present,ruthenium particles for target are dependent on imports in our country,the cost is high,direct preparation of high purity ruthenium particles from ruthenium waste has a very important practical significance.according to the characteristics of the target material ruthenium waste,puting forward the alkali fusion–water leaching-oxidation distillation-ion exchange purification-precipitation-calcination process,reducing,acid boiling from waste recycling ruthenium target,and high-purity ruthenium powder was prepared.The conclusions of this thesis are as follows:?1?Ruthenium waste alkali melting method and water leaching studies showed that in Na₂O₂+NaOH as the alkali flux,the alkali fusion temperature is 750?,Na₂O₂:NaOH: 4:3:1,alkali fusion time is 3h,water temperature is 95 ?,water immersion time under 4h,the leaching rate of ruthenium is up to 97% to obtain ruthenium containing solution.?2?With the study of ruthenium oxidation distillation solution shows that using Sulfuric acid was used as the medium system,and sodium chlorate was used as oxidant to do the oxidation distillation,ruthenate is oxidized to RuO4 volatilization,and hydrochloric acid absorption,to achieve the purpose of preliminary impurity removal,the solution of ruthenium acid chloride was obtained.The direct yield of ruthenium reached 94.4% at the distillation temperature of 95?and 0.08 MPa under the negative pressure of distillation.?3?The study of ion exchange impurity removal indicated that,D001 and 001×7 as the resin,the acidity of the solution was 0.5mol/L?H⁺ concentration?,the exchange rate was 2mL/min,the exchange series 11,after purification of metal impurities in chlororuthenium acid solution were lower than 0.0005g/L.?4?The study of precipitation showed that the ruthenium was converted into?NH4?2RuCl6?IV?ammonium acid by adding oxidant,so as to achieve further impurity removal;and through strict control of precipitation conditions,preparation of uniform particles,suitable size and good dispersion of particles.The optimum conditions were:the concentration of ruthenate is 30g/L,Before precipitating ruthenium,the oxidant is added and the oxidant is continuously added during the precipitation,the method of adding ammonium chloride is saturated solution,temperature is 90?,continuous agitation during reaction.?5?Study on calcination,reduction and mixed acid washing shows that,using nitrogen through calcination,through hydrogen reduction,the?NH4?2RuCl6 particles can be reduced to ruthenium powders with regular morphology and uniform size,with acid in the form of a further depth of impurity removal,the purity of ruthenium particles is up to 99.995%,requirements for high-purity ruthenium powders used in sputtering targets.The optimum technological conditions are as follows: calcination temperature 500?,calcination time 2 hours,reducing temperature 700 ?,reducing time 2 hours.Through the research,established the ruthenium containing process parameters and waste directly preparing high-purity ruthenium powder,the raw material adaptability,ruthenium recovery rate is higher,the prepared ruthenium powder with regular morphology,uniform particle size,high purity.