| 摘要 |
<p>1,147,738. Refining baddeleyite. TH. GOLDSCHMIDT A.G. 1 Feb., 1968 [17 March, 1967], No. 5197/68. Heading C1A. Baddeleyite (ZrO 2 ) is refined by leaching in a first stage with a solution comprising 120 g/l. HCl in the presence of 10-50 g/l. of sulphate and 1-30 g/l. of fluoride ions at above 80‹ C., then leaching below 60‹ C. with HCl of at least 200 g/l. concentration, separating the HCl liquor and washing and drying the product. In the preferred process the ore is first crushed to a particle diameter of less than 0À1 mm. In addition to the fluoride and sulphate ions, nitrate ions may be present in the first stage. In the first stage the ore is digested and copper sulphide oxidized, silicates are dissolved and some iron is precipitated. The remaining iron is removed in the second stage, as are titanium contaminants. Fluoride may be added as ammonium bifluoride or as HF and the sulphate as sulphuric acid or ammonium sulphate. The nitrate is preferably added as ammonium nitrate or as nitric acid. If required, acid from either stage may be recycled to the first stage, replenishing the acid as necessary.</p> |
