Recovery and Enrichment of Phosphorus from the Nitric Acid Extract of Dephosphorization Slag

A method for the recovery and enrichment of the phosphate from dephosphorization slag was examined. First, the elution of aqueous phosphate from dephosphorization slag using aqueous HNO3 was examined using both the batch and flow methods. With the batch method, 82% of the dephosphorization slag could be dissolved within 30 min using 1.0 mol/L HNO3, indicating that the batch method could be used for mass processing to extract phosphorus in the bulk phase, but all components contained in the slag were unselectively dissolved. In contrast, by using 0.05 mol/L HNO3 via the flow method, 22% of the slag was dissolved in 100 min giving a more selective dissolution of phosphate from the slag compared with the batch method, which indicated that this method would be incompatible with mass processing for the purpose of extracting phosphorus in the bulk phase. In order to remove the Fe-species in the aqueous solution obtained by the batch method using 1.0 mol/L HNO3, which has been referred to as the “slag solution,” it was necessary to add calcium hydroxyapatite (CaHAp) to the slag solution. The optimal conditions for the removal of Fe-species using CaHAp were observed at a solution pH of ca. 1.5, which resulted in 100% removal of the Fe-species after 4 h. When the pH of the slag solution was adjusted to 7.0 after removing the Fe species, a pale pink solid sample was precipitated. The amounts of phosphate in the slag solution and in the pink solid were 3.5 and 42.0 mol%, respectively, indicating that the treatment suggested in the present study could be used for the recovery and enrichment of phosphate, that is, phosphorous, from dephosphorization slag

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

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 HNO3 was used to examine the elution behavior of aqueous phosphate contained in the bag-powder. The main components of the bag-powder included Ca2+, PO4 3- and Y3+ along with Si4+, Sr2+ and lanthanide cations such as La3+ and Ce4+. Therefore, it seemed possible that, with the selective dissolution of Ca2+ and PO4 3- from 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 HNO3. 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 Sr2+, La3+ and Si4+ in the bag-powder, however, did not dissolve under the same conditions. Although Ca2+, PO4 3- and Y3+ were the main components in the nitric acid extract, Y3+ was separated as YPO4 at pH = 4.0, while Ca2+ and PO4 3- were separated as calcium phosphates at pH= 7.0. These results revealed that the separation of calcium phosphates, YPO4 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

Genome-wide association study revealed novel loci which aggravate asymptomatic hyperuricaemia into gout

Objective The first ever genome-wide association study (GWAS) of clinically defined gout cases and asymptomatic hyperuricaemia (AHUA) controls was performed to identify novel gout loci that aggravate AHUA into gout. Methods We carried out a GWAS of 945 clinically defined gout cases and 1003 AHUA controls followed by 2 replication studies. In total, 2860 gout cases and 3149 AHUA controls (all Japanese men) were analysed. We also compared the ORs for each locus in the present GWAS (gout vs AHUA) with those in the previous GWAS (gout vs normouricaemia). Results This new approach enabled us to identify two novel gout loci (rs7927466 of CNTN5 and rs9952962 of MIR302F) and one suggestive locus (rs12980365 of ZNF724) at the genome-wide significance level (p<5.0×10– 8). The present study also identified the loci of ABCG2, ALDH2 and SLC2A9. One of them, rs671 of ALDH2, was identified as a gout locus by GWAS for the first time. Comparing ORs for each locus in the present versus the previous GWAS revealed three ‘gout vs AHUA GWAS’-specific loci (CNTN5, MIR302F and ZNF724) to be clearly associated with mechanisms of gout development which distinctly differ from the known gout risk loci that basically elevate serum uric acid level. Conclusions This meta-analysis is the first to reveal the loci associated with crystal-induced inflammation, the last step in gout development that aggravates AHUA into gout. Our findings should help to elucidate the molecular mechanisms of gout development and assist the prevention of gout attacks in high-risk AHUA individuals