| As a kind of typical secondary resource containing precious metals, the discarded firebrick of glass fiber industry contains a great quantity of Pt and Rh compared with ores, which the sum of Pt and Rh is about 0.2-2kg/t.How to recover high value metals from this waste always has been paid attention. Focusing on how to effectively recycling Pt and Rh, the researchers put forward methods of dressing, iron captured, aqua regia dissolved and alkali activated successively, but these methods all have different degree of flawed.This paper is based on the alkali-activated method which has industry future, the key process such as alkali activated, hydrochloric acid leaching are researched Focusing on the difficulties of alkali-activated response slowly, clinker sintering uneven, pulp filters difficultly in acid leaching process, we find an efficiency method to recover and enrichment Pt and Rh from this secondary resource.Through the thermodynamic analysis of alkali activated process we know that high temperature environment is beneficial to alkali activated activation reaction. By orthogonal design experiments we get the optimization of the conditions in conventional heating:temperature 1000℃; heating time:2h, additive NaOH:150%.Unlike conventional heat conduction mode, Microwave radiation heating has many advantages such as whole heating,distribute heating evenly and rapid heating. To the problem that clinker sinters uneven, reaction time long, comparison tests of microwave alkali-activated and conventional alkali-activated for discarded firebrick were carried out and the results show that the temperature was lower 100℃and heating time is shorter 1.5h at microwave alkali-activated condition than conventional. The optimization of conditions by microwave alkali-activated reaction are: temperature 800℃; heating time:0.5h, additive NaOH:140%.The clinker filters difficultly because of the formation of silica gel in HCl acid leaching process. The process of the formation and influencing factor are discussed. The new idea that firstly clinker was water dissolved and filtered, the residue was leached in HCl acid secondly was put forward and the optimization experiment were carried out, the result show:the clinker was dissolved in water at 90℃dissolving time 15min and ratio of water to clinker 15g/mL, the residue was leaching at optimum conditions, which are HCl 3 mol/L, leaching time 5 min and ratio of HCl to residue 15 g/mL. The residue generation rate is 2.98%. Slurry filtrate rate is 1080 L/(m2·h) and slurry filtrates well. XRD analysis shows that the components of residue are corundum, which silica and mullite don't exist.By material flow analysis of Pt and Rh for the improved process, the trend and distribution of Pt and Rh were revealed. The analysis result shows that Pt and Rh were beneficiated well in the process of alkali-activated and water-dissolved. However, they have a small loss in acid-leached process. Pt was beneficiated about 34.80 times in residue and the beneficiate rate is 97.93%.Rh was beneficiated about 33.32 times in residue and the beneficiate rate is 90.099%... |
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