DE1068683B - Process for the production of pure zirconium tetrachloride by sublimation - Google Patents

Description

Process for the production of pure zirconium tetrachloride by sublimation The present invention relates to a process for the production of high purity, anhydrous zirconium tetrachloride from raw zirconium tetrachloride, which is replaced by chlorides of others Elements such as iron, aluminum, titanium, silicon, etc. is contaminated.

The usual impurities of the zirconium tetrachloride can through simple sublimation cannot be separated because the sublimation points of their chlorides too close to the sublimation point of the ZrCl. The common procedures for Separation of interfering foreign elements are recrystallization or precipitation of various Zirconium compounds. These operations are technically difficult to perform and in any case associated with greater effort than sublimations.

Process in which zirconium tetrachloride in the presence of hydrogen or metal sulfides are sublimed, do not lead to satisfactory degrees of purity and have other procedural and principle disadvantages.

By subliming zirconium tetrachloride in the presence of non-volatile, Organic substances (e.g. fats, stearin, heavy oil) result in a very pure product. However, the process is difficult to operate continuously and requires one relatively large, technical effort, since the organic substances in the form of Solutions in carbon tetrachloride, gasoline or the like mixed with the zirconium tetrachloride must be and the sublimation only after distilling off the more volatile Solvent can be carried out.

It has now been found, avoiding the disadvantages mentioned, that even from impure starting material, high-purity zirconium tetrachloride is simple can be recovered when sublimed in a hydrocarbon-containing atmosphere is, with limiting as hydrocarbons here those with more than one C atom and a boiling point below 60 ° C come into question. The simplest is unsuitable Hydrocarbon, the methane. Ethane and ethylene have proven to be particularly effective, however also propane and propylene, butylene or mixtures, also with inert gases, e.g. B.

Coal gas.

If you carry the vapors rising from the heated raw material with you a directed, e.g. B. Äthanstrom, in a relatively cooler room, so you get there a pure white zirconium tetrachloride, which is soluble in water and free of ionic Hydrolysis products is. The remains in the dark-colored sublimation residue Foreign elements partly in water-soluble, partly in water-insoluble form, independently whether sublimed at normal pressure or in a partial vacuum or at elevated pressure will. In general, one will refrain from doing this in a vacuum because of the effort required to work.

The gas mixture remaining after the zirconium tetrachloride has been deposited or gas can be withdrawn and added again to the ethane stream. The best Exploitation can be achieved with such hydrocarbons at room temperature are gaseous or have a boiling point below 500 C. It recommends to mix them with inert gas in approximately comparable amounts.

The method according to the invention is illustrated by the following examples the following are explained in more detail: Examples 1. 14 kg of raw zirconium tetrachloride, colored earth-brown (1.6010 Fe, 1.70 per Al, 0.013% Ti, 0.25% Si, each based on Zr) were under Normal pressure sublimed in a stream of ethylene. It became a pure white colored sublimate with contents of 0.0010 / 0 Fe, 0.087010 Al, <0.001010 Ti and 0.0060 /, Si.

2. 11 kg of the crude zirconium tetrachloride mentioned in Example 1 were in a gas stream containing ethylene and nitrogen in a volume ratio of 1: 1, sublimated.

The concentrations of the foreign elements in the sublimate were 0.010010 Fe, 0.035010 Al, 0.0050 /, Ti and 0.005 ° / 0 Si.

3. 12 kg raw zirconium tetrachloride (1.6 per Fe, 1.70 / 0 Al, 0.050 /, Ti) were sublimated in the ethane stream. The sublimate still contained 0.0020 /, Fe, 0.0300 /, Al, <0.001010 Ti.

4. 40 g of crude zirconium tetrachloride (0.09% Fe, 1.3% per Ti) were in the Propane stream sublimed. The final concentrations in sublimate were 0.01301, Fe, 0.0840 /, Ti.

5. 40 g of crude zirconium tetrachloride with a content of 1.6% per Fe, 0.013 01, Ti and 1.7 Al were in a stream of nitrogen, which at 35 ° C with petroleum ether (boiling range 40 to 600 C, main components C5 and C6) was saturated, sublimed. The sublimate still contained 0.040% Fe, 0.0010% Ti and 0.06% Al.

The process of the invention can also be very easily carried out continuously shape, a very important technical advantage. It is recommended to at least with partial recirculation of the hydrocarbon contained Working gases. Ultimately, the purest material is required (if it is heavily contaminated Raw material), o the sublimation can easily be repeated without great effort.

Claims (3)

PATENT CLAIMS: 1. Process for the production of pure, anhydrous Zirconium tetrachloride from impure raw zirconium tetrachloride by sublimation, thereby marked draws that hydrocarbons sublime in an inert atmosphere with more than one carbon atom and a boiling point of up to about 60 ° C. 2. The method according to claim 1, characterized in that the hydrocarbons be diluted with inert gases, preferably 1: 1. 3. The method according to claim 1 and 2, characterized in that as Hydrocarbons, preferably ethane, ethylene, propane, propylene or mixtures thereof be used.