Method for the purification of yellow phosphor
AssigneeLANXESS Deutschland GmbH
InventorsJan-Gerd HANSEL, Rolf-Michael JANSEN, Bernd ROSENOW
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Abstract
The present invention relates to a process for continuous purification of yellow phosphorus by adsorption onto activated carbon.
Claims19
A process for purifying impure phosphorus, hat the process comprising:
- a) continuously introducing and contacting liquid impure phosphorus, without prior treatment of the impure phosphorus with polyphosphoric add, with at least one activated carbon fixed bed containing at least one activated carbon, and
- b) continuously withdrawing liquid purified phosphorus from the activated carbon fixed bed.
The process as claimed in claim 15, wherein:
- the activated carbon fixed bed contains:
- 1 to 300 weight percent of activated carbon based on the amount of purified phosphorus withdrawn from the activated carbon fixed bed per hour in step b);
- and
- 0.5 to 10 weight percent, based on the activated carbon, of the one or more adsorbents;
- the contacting is performed at a temperature of 45° C. to 95° C., and a pressure of 0.1 to 3.0 bar;
- the liquid impure phosphorus is passed through the activated carbon fixed bed with a volume flow that ensures an average residence time of the phosphorus in the activated carbon fixed bed of 1 to 300 minutes;
- and
- the purified, phosphorus withdrawn in step b) contains at least 50 percent less organic impurities than the impure phosphorus employed in step a).
The process as claimed in claim 16, further comprising dividing the liquid impure phosphorus into two or more substreams, and, for each substream, performing the steps a) and b) in separate containers with separate activated carbon fixed beds, wherein the number of substreams and the number of containers with activated carbon fixed beds is chosen such that, when necessary, the activated carbon in at least one activated carbon fixed bed may be regenerated or replaced, while at least one other activated carbon fixed bed remains in use performing steps a) and b).
Dependencies are inferred from the claim text.