New Process Technology And Theory Studies In Extracting Chromium

The Chromium and its chemical compound are widely used in metal materials, chemical industry, refractory and everyday life. Now the methods to extract the chromium metal from the ore are the electrolysis method and metal thermal-reduction method. In the metal thermal-reduction method, the cost of production is high because of the high price of the aluminum powder as reduction agent, and the quality is lower to compare with the electrolysis method. In the present technology, not only the productions of extracting chromium are very complicated,, but also the energy consumes and the cost of the production are very high.In this paper, as accordance with their insufficient in extracting chromium, we study the new technology process in the principle with the quantum chemistry and the molecular dynamics computer simulation method, we calculated the structure and characters of the about the chromium and it's chemical compound. With the results of the experiments and computer calculations, the best technology parameters and new technological process were obtained.The synthetically commentary about physical-chemistry characters of the chromium and its chemical compound. The commentary also did about the present technological process to extract the metal chromium. On these commentaries, we obtained the new process with the roast, dissolution, reduction and electrolysis technology.The experiments were carried on the roasting of chromium washed ore. The effects of the additive as dolomite and soda to the roast process were studied by different additive amounts. The roasting time and process temperature to effects the roast were also experimented. The roasting processes were analyzed with the experimental results.In this paper, we tested the leaching process of chromium burnt ore after roast. The influences of the burnt ore size, leaching temperature, solution-solid ration and the leaching time to leaching rate of the sodium chromate were studied in first section. The best technological process parameters were obtained by these tests. The second section leaching process was also experimented in this paper. With the experiments of the purify on the solution, the purify process and purify mechanism were studied. The best purify results were obtained by different test on temperature and time. In the reduction process, the best way is using the mix reducing agent of sulphur and sodium sulphide. We tested the different amounts and the additive pattern of the reducing agent. The influences of sodium-hydroxide concentration, reducing temperature, time and sodium chromate concentration to reducing process were analyzed.The process and mechanism of the electrolysis of chromium were studied by experiments. The effects of the temperature and pH of the electrolyte solution to the electrolysis were tested. The current efficiency and the electricity energy consume were obtained by different current density.It is important tool to study the molecular structure with quantum chemistry. In this paper, we used the ab initio calculation method of quantum chemistry to calculate the molecular structure and nature about the chromium. On base the three basic approximate of the ab initio, the calculation mode was obtained. With the Gaussian 98 software, the geometry structure of CrO₄^2- and Cr₂O₃ were studied. The front-track energy, front-track electron density were calculated on the molecular.Using the suitable potential function, the structure and the properties of the sodium chromites solution can be calculated by molecular dynamics (MD) computer simulation method. The radial distribution function (RDF) and the pair count of different ions in the sodium chromate solution were obtained. We studied the Cr-O-Cr key-angle distribution and chromium-oxygen four-side distribution in the solution. With the mean square displacement (MSD) and autocorrelation function, we obtained the transports properties in the sodium chromate solution.