Rare earths separation from fluorescent lamp wastes using ionic liquids as extractant agents.

Processing of end-of-life products has become essential in the rare earth elements (REEs) recovery field because the demand for these metals has increased over the last years due to their intensive use in advanced technologies. Fluorescent lamp wastes are considered one of the most interesting end-of-life products for investigation due to their high REEs content, mainly yttrium and europium. As a result, red phosphors (Y2O3:Eu3+ - YOX) have been chosen for evaluating their REEs' recovery potential. The REEs from a YOX reach liquor, coming from a soft leaching process have been precipitated adding oxalic acid and calcined to get the REEs in oxide form. Cyanex 572, D2EHPA and the ionic liquids, Primene 81R·Cyanex 572 IL and Primene 81R·D2EHPA IL, have been chosen to investigate the efficiency of REEs separation in chloride media. Yttrium, europium and cerium have been individually recovered by a four stages cross-flow solvent extraction process using the Primene 81R·D2EHPA IL and the Primene 81R·Cyanex 572 IL as extractants. Ce(III), Eu(III) and Y(III) have been obtained at high purities ≥ 99.9%. 4 mol/L HCl has been used to recover the yttrium and the europium from the organic phases.

Neodymium recovery from NdFeB magnet wastes using Primene 81R·Cyanex 572 IL by solvent extraction.

The necessity of Rare Earth Elements (REEs) recycling is crucial to minimizing their supply risk and provide an alternative to greener technologies. Hence, the REEs recovery from NdFeB magnet wastes using cationic extractants by solvent extraction technique has been investigated in this research. Due to the difficulty in maintaining the aqueous pH in the industrial counter-current devices when extractants like Cyanex 272 or Cyanex 572 are used, the Primene 81R·Cyanex 572 ionic liquid has been synthesised to overcome this. 99.99% Nd(III) recovery with a purity of 99.7% from an aqueous mixture of Nd/Tb/Dy in chloride medium, the three representative REEs present in the NdFeB magnets wastes, has been achieved after two stages counter-current extraction process using 0.30 M of Primene 81R·Cyanex 572 ionic liquid (1:4 A:O ratio) diluted in Solvesso 100, without any aqueous pH conditioning.

Mathematical modeling of cadmium(II) solvent extraction from neutral and acidic chloride media using Cyanex 923 extractant as a metal carrier.

This paper describes experimental work and the mathematical modeling of solvent extraction of cadmium(II) from neutral and acidic aqueous chloride media with a Cyanex 923 extractant in Exxol D-100. Solvent extraction experiments were carried out to analyze the influence of variations in the composition of the aqueous and organic phases on the efficiency of cadmium(II) extraction. In neutral and acidic chloride conditions, the extraction of cadmium(II) by the organophosphorous extractant Cyanex 923 (L) is based on the solvation mechanism of neutral H(n)CdCl((2+n)) species and the formation of H(n)CdCl((2+n))L(q) complexes in the organic phase, where n=0, 1, 2 and q=1, 2. The mathematical model of cadmium(II) extraction was derived from the mass balances and chemical equilibria involved in the separation system. The model was computed with the Matlab software. The equilibrium parameters for metal extraction, i.e. the stability constants of the aqueous Cd-Cl complexes, the formation constants of the acidic Cd-Cl species and the metal equilibrium extraction constants, were proposed. The optimized constants were appropriate, as there was good agreement when the model was fitted to the experimental data for each of the experiments.

Results of intensive chemotherapy in children with juvenile chronic myelomonocytic leukemia: a pilot study.

BACKGROUND: The use of chemotherapy in juvenile chronic myelomonocytic leukemia (J-CMML) has not generally been successful. Our previous experience in 11 patients demonstrated that chemotherapy with low doses of daunorubicin or cytarabine resulted in a 90% fatal outcome and a median survival rate of only 7 months. PROCEDURE AND RESULTS: Between 1985 and 1997, six children (five boys and one girl) aged 3-67 months (median age: 20.5) were diagnosed with J-CMML and underwent intensive combination chemotherapy similar to that used for acute myeloblastic leukemia. Two patients with high-risk factors developed progressive disease with fatal outcome at 5 and 18 months postdiagnosis, respectively. However, four patients without poor prognosis indices responded and were alive 145, 82, 51, and 6 months after diagnosis. Overall survival in this small series at 7 years from diagnosis is 60% (CI: 17-100). CONCLUSIONS: The use of intensive combination chemotherapy in children with J-CMML can result in long-term survival in some patients.

Umbilical cord blood as a good alternative to bone marrow for allogeneic cell transplantation in children with hemoblastosis.

Umbilical cord blood (UCB) is an alternative source of hematopoietic progenitors and has potential advantages over bone marrow. We present our experience with UCB transplants performed between July 1994 and June 1997 in seven children with hemoblastosis. Two patients underwent transplantation from an HLA-identical sibling donor and five from an unrelated donor. Engraftment was obtained in all but one patient. Acute GVHD was absent in patients with related donors and present in all patients with unrelated donors. No patient showed chronic GVHD. Two patients died from transplant-related complications and a further two relapsed. Four patients were alive with a follow-up of 14, 15, 21 and 39 months post-transplant, respectively. Overall survival was 57% (s.e. 0.19). We conclude that cord blood is a good alternative source of hematopoietic stem cells for children with malignant hematologic diseases.

Allogeneic and autologous bone marrow transplantation in AML in first remission. The Spanish experience.

From 1983 to 1994 two types of trials were performed. Between 1983 and 1987 a modified VAPA protocol (post-remission therapy with intensive sequential blocks for 12-16 months) was given to 40 patients from two institutions. CR was attained in 75% and 5-year EFS was 35%. In 1988 a post-remission protocol based on intensification chemotherapy (two high-dose Ara C treatments combined with mitoxantrone in the first and amsacrine in the second) followed by BMT was initiated. Remission induction was DAE combination (1 or 2). Patients in CR or PR with HLA-compatible donor received an allogeneic transplant (al-BMT) and those without an autologous transplant (ABMT) with "purged" marrow. Pre-BMT therapy was fractionated TBI and CYCLO in patients over 3 years and Busulfan + CYCLO + VP-16 in those under 3. Between April '88 and December '94, 51 patients (aged 3 months to 15 years) were enrolled. 80% attained CR, 14% were failures or partial responses and 6% died before the 30th day. During the intensification phase, 5 patients attained CR and one relapsed and died. 47 patients (45 in CR and 2 in PR) proceeded to the BMT phase. 16 patients (14 in CR and 2 in PR) received al-BMT and 31 (all in CR) ABMT. Both group characteristics were comparable.

Meningococcal meningitis with 'normal' cerebrospinal fluid.

A prospective study was made of all patients with normal CSF counts and positive cultures for Neisseria meningitidis diagnosed in "El Vallés" County, Barcelona between January 1987 and December 1990. Meningococcal meningitis was documented in 82 patients, eight of whom (seven children, five boys and two girls with a mean age of 5.6 +/- 3.3 years, and a 69-year-old male patient) had no apparent CSF abnormalities in the initial lumbar puncture. At the time of admission all patients had fever (mean 39.1 degrees C) of 10.8 +/- 5.6 hour duration and petechial rash which had been present for a mean of 3.6 +/- 3.3 hours. Signs of meningeal irritation were not found. A 4-month-old infant with symptoms of circulatory collapse, intracranial hypertension and impairment of consciousness subsequently died of septicemia in 48 hours. Group B N. meningitidis was isolated in six cases (reduced penicillin-susceptibility in two cases) and group C N. meningitidis in the remaining two (reduced penicillin-susceptibility in one case). Patients without pleocytosis did not differ in a statistically significant fashion from the patients with high pleocytosis in the duration of temperature, and petechial rash, leukopenia, positive blood culture and fatal outcome.