Recovery of the Phosphorus from the Nitric Acid Extract of Powder Collected in a Bag Filter during the Recycling of Used Fluorescence Tubes

Abstract

During the recovery of phosphorus from the powder collected in a bag filter during the recycling of used fluorescence tubes (bag-powder), the batch method with aqueous HNO 3 was used to examine the elution behavior of aqueous phosphate contained in the bag-powder. The main components of the bag-powder included Ca 2+ , PO 4 3and Y 3+ along with Si 4+ , Sr 2+ and lanthanide cations such as La 3+ and Ce 4+. Therefore, it seemed possible that, with the selective dissolution of Ca 2+ and PO 4 3from the bag-powder, these lanthanide cations in the residue could be enriched. With the batch method, most of the phosphate in the bag-powder was dissolved within 0.2 min using 1.0 mol/L HNO 3. The dissolution behavior of calcium cation was similar to that of the phosphate. In contrast, the dissolution of yttrium, the content of which was the highest among the lanthanide cations in the bag-powder, was increased with the dissolution times, reaching complete dissolution after 24 h. The Sr 2+ , La 3+ and Si 4+ in the bagpowder, however, did not dissolve under the same conditions. Although Ca 2+ , PO 4 3and Y 3+ were the main components in the nitric acid extract, Y 3+ was separated as YPO 4 at pH = 4.0, while Ca 2+ and PO 4 3were separated as calcium phosphates at pH= 7.0. These results revealed that the separation of calcium phosphates, YPO 4 and some residue was possible, and resulted in the enrichment of lanthanide cations along with the recovery of phosphorus from the bag-powder. Using the present technique, 91% of the P in the bag-powder was recovered.

Phosphorus Recovery From Sewage-Sludge Molten Slag Using a Combination of Acid-Dissolution, Alkali-Precipitation, and Ion-Exchange

“…When our recovering procedure shown in Scheme 1 was used for other phosphorus-containing unused resources such as chicken manure, 2-5 dephosphorization slag, 6,7 powder collected in a bag filter during the recycling of used fluorescence tubes, 11 and the slag released by a chemical factory, 12 0.5 M of HNO3 was generally used as an eluting acid. However, since the elution characteristics of sewage-sludge molten slag were unknown, the results under normal conditions as an elution experiment for 1 h using 0.5 M HNO3 were compared with the results of an elution experiment for 168 h using 15 M HNO3, and these results appear in Figure 1.…”

“…[2][3][4][5][6][7]11,12 Figure 2 shows the effect of the treatment time for the elution of the sewage sludge molten slag using 0.5 M HNO3, although treatment times of less than 0.2-0.5 h are reported as suitable for the elution of phosphorus from various phosphorus-containing unused resources. [2][3][4][5][6][7]11,12 However, as shown in Figure 2, when using sewage-sludge molten slag, a longer treatment time resulted in a slight increase in the elution of phosphorous from the slag, while the elution of calcium as a second main element seemed insensitive to the concentration of HNO3. Since it seemed advantageous to avoid a long elution operation, 0.5 M nitric acid was used and the treatment time was set to 1.0 h for obtaining Filtrate ().…”

“…Then the solution was filtered to achieve Precipitation and Filtrate (). In previous studies on various phosphoruscontaining unused resources, [2][3][4][5][6][7]11,12 Filtrate (b) was immediately obtained after the filtration and used in the subsequent Process (3). However, letting the Filtrate () that was obtained here stand for one day resulted in the formation of a greater amount of precipitation.…”

Recovery of Calcium Phosphates from Composted Chicken Manure

“…However, it is generally accepted that phosphate rock as a raw material for phosphorus will disappear in the near future (Abelson, 1999). Therefore, our laboratory has reported on the recovery of phosphate from unused resources such as from rivers by using boehmite as an adsorbent, from dephosphorization slag, chemical slag, and used fluorescence tubes using acidic solutions as eluates (Sugiyama et al, 2011(Sugiyama et al, , 2012(Sugiyama et al, , 2014(Sugiyama et al, , 2015. In particular, a phosphate-containing solid was successfully precipitated from the nitric acid extract of dephosphorization slag, simply by adjusting the solution pH to 7.0 (Sugiyama et al, 2014).…”

Characteristics of Aligned Micropillar Electrodes for Size-Selective Particle Capture by Dielectrophoresis: A Model of Dielectrophoresis Using Carbon Nanotube Electrodes

“…Conventionally, there are many types of separation methods to capture particles dispersed in liquid; for example, filtering (Lorenzen et al, 2014;Ong et al, 2014;Iritani et al, 2015;Sugiyama et al, 2015;Sun et al, 2015), sedimentation (Durst and Raszillier, 1989;Tambun et al, 2012;Zhang et al, 2015), centrifugation (Cao et al, 2014;Zhu and Liow, 2014;Teduka and Nishioka, 2015), and so forth: These separation methods have been extensively developed. Nevertheless, it is not possible to use filtering when there is no clear difference in the particle sizes.…”