钌盐提纯和高纯钌粉制取的理论与实验研究

Theory and Experiment of Purifying Ruthenium-Salt & Preparation of High-Purity Ruthenium-Powder

钌的精炼过程分为钌盐的精制和高纯钌的制取两个步骤。本文以氧化还原标准电极电位作为选择性氧化分离锇、钌的判据,从理论上分析了采用二段分步氧化蒸馏分离锇、钌的必要性和可行性。研究了氧化-真空蒸馏方法从一次钌盐酸吸收液中,一段氧化加入H_2O_2选择性氧化-真空蒸馏分离锇,使钌盐酸溶液中的锇被选择氧化而以OsO_4气体单独蒸馏出来并被NaOH溶液吸收,而未氧化的钌则留在蒸馏余液中;之后在分离锇后的一次钌盐酸蒸馏余液中,二段氧化加入H_2SO_4+NaClO_3进行氧化-真空蒸馏分离钌和残留的锇。氧化蒸馏出的RuO_4经HCl吸收并还原得到精制的二次钌盐酸溶液,进一步经硫化钠结晶沉淀提纯制得高纯硫化钌盐,并对沉钌过程做了初步的理论分析。所得精制硫化钌沉淀物在氢气氛围下煅烧还原制得高纯海绵钌,海绵钌经王水与氢氟酸混合酸煮洗后水洗,在氢气氛围下干燥后制得的钌粉经辉光放电质谱法(GDMS)分析,纯度达到4N5(99.995%)以上,可直接用于溅射靶材。本研究为靶材用5N(99.999%)高纯钌粉的制备及其工业化生产提供了理论和实验依据。

Ruthenium refining process could be divided into two steps which were purification of ruthenium salt and preparation of high-purity ruthenium powder. In this paper,the necessity and feasibility of separation osmium and ruthenium from each other by selective oxidation and vacuum distillation divided into two steps were analyzed theoretically,based on the redox standard electrode potential as a criterion of the selective oxidation separation for osmium and ruthenium. The first step was separating osmium oxidized from ruthenium hydrochloric acid absorption liquid by H_2O_2 selective oxidation and vacuum distillation,in which ruthenium was not oxidized and still in ruthenium hydrochloric acid distillation-residue. Osmium tetroxide（ OsO_4）,which formed in the process of oxidation and vacuum distillation,was absorbed in sodium hydroxide solution. And the second step,which was separating ruthenium oxidized and residual osmium oxidized from the first step＇s residue by oxidation and vacuum distillation with the addition of H_2SO_4 and NaClO_3,were studied. Ruthenium tetroxide（ RuO_4）,which formed in the process of the second step,was absorbed in hydrochloric acid solution and purified ruthenium hydrochloric acid absorption liquid was gotten. Pure ruthenium sulfide crystals could be obtained by crystallizing and precipitating the purified ruthenium hydrochloric acid absorption liquid with sodium sulfide,and all kinds of phenomena in the process were explained in theory. Sponge ruthenium powder was prepared by sintering the resultant ruthenium salt under the optimum operation condition of the sinter and reduction in hydrogen atmosphere. The sponge ruthenium powder was washed first by a mixed solution of aqua regia and hydrofluoric acid,and further washed by water before drying. The purity of prepared ruthenium powder was at least99. 995% excluding the gaseous ingredient elements analyzed by glow discharge mass spectrometry（ GDMS）,and could be used for preparing high-purity ruthenium sputtering target. This study provides the theoretical and experimental basis for industrialized production of high-purity ruthenium powder with purity of 5N（ 99. 999%）.