The mineralogical, micromorphological, geochemical and crystallographic characteristics of the different types of apatite from the Catalão I alkaline-carbonatitic complex, Goias, Brazil, were determined by optical and scanning-electron microscopy, electron-microprobe analysis, Raman micro-spectroscopy, X-ray diffraction, thermodifferential and thermogravimetric analyses and Fourier-transform infrared spectroscopy. There are three main generations of apatite: igneous, postmagmatic or hydrothermal, and supergene. The composition of apatite of each generation has been determined. Data from primary apatite affected by weathering processes show compositional changes prior to the total destruction of grains. The main geochemical trends observed from the first to the third generation are: a) increase in CO 3 2-(that replaces PO 4 3-), in F (which follows the incorporation of carbonate), in Ca (owing to loss of substituting cations, mainly Sr, Na, and REE) and in the ratio CaO/P 2 O 5 (increase of Ca due to loss of the cations that substituted for Ca, and decrease of PO 4 3-, partially replaced by CO 3 2-), b) decrease in Si and P (replaced by C), in Sr, Na and REE (replaced by Ca) and in analytical totals (owing to an increase in components not detected using the electron microprobe, such as C and OH). These chemical changes, along with contemporaneous modification of the morphology of the apatite grains, contribute to an undesirable behavior of the apatite ore, once submitted to processes of industrial concentration. The types of apatite and the processes of their formation here defined and established for the Catalão I alkaline-carbonatitic complex are quite common and widely distributed in all carbonatitic phosphatic raw materials in Brazil, as observed in previous studies. The coexistence of these morphological and compositional varieties is responsible for the heterogeneity and complexity of these ores.

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This research aimed to evaluate the effects of zilpaterol hydrochloride (ZH; MSD Animal Health, São Paulo, SP, Brazil) on the performance, carcass traits, serum metabolites, body composition, and gain composition of nonimplanted Nellore heifers. Nellore heifers ( = 72; average BW = 267 ± 16 kg; average 18 mo of age) were maintained in a feedlot system for 118 d. Heifers were separated into 2 groups: Control and ZH. The ZH group received ZH (8.3 mg/kg diet DM) for 30 d with 3 d of withdrawal before slaughter. Heifers were allotted to 18 pens, 9 pens per treatment, and assigned to a randomized block design. The animals were weighed, blood samples were collected, and subgroups of heifers were slaughtered at the beginning of supplementation and after 20 and 33 d to evaluate performance, blood metabolites, empty BW (EBW), and EBW composition. Hot carcass and kidney-pelvic fat weights were recorded at slaughter. At 24 h postmortem, carcasses were fabricated and the 9-10-11th rib (HH) section was removed from the primal rib to analyze moisture, protein, ash, and ether extract (EE) content in empty body (EB) and gain composition. Heifers fed ZH had gains in HCW that were 19.7 kg greater than controls, reflecting the 30% increase ( < 0.01) in ADG. There was no change in DMI, resulting in a 20% greater G:F ratio ( < 0.01) for heifers fed ZH. Heifers supplemented with ZH had carcass dressing percentages that were 3% greater than controls ( < 0.01), and there was also a 19% reduction in kidney-pelvic fat ( = 0.05) in ZH-treated heifers. Zilpaterol increased serum creatinine ( < 0.01), tended to increase ( = 0.06) serum triacylglycerol, decreased serum NEFA ( = 0.04), and tended to decrease ( = 0.06) serum glucose. The EBW composition was changed after 20 d of ZH supplementation ( = 0.02), with ZH increasing the moisture, ash, and protein contents, whereas carcass fat was decreased by ZH by 14%. Consequently, the carcass CP:EE ratio after 20 d was increased ( = 0.03) by 24% with ZH supplementation. There was no change on EBW composition after 30 d of ZH supplementation ( = 0.17). Regarding carcass gain composition, ZH increased EBW gain ( = 0.02) by 842 g/d from d 0 to d 30, EB protein gain by 221 g/d ( = 0.05) from d 0 to d 20, and by 180 g/d ( = 0.01) from d 0 to d 33. In conclusion, ZH supplementation in nonimplanted Nellore heifers altered the composition of body weight gain, promoting greater lean tissue deposition and improving feed efficiency.

MINERALOG~MORPIIOLOG~AND CRYSTAL-CIIEMIS'I1IY OF MONAZITE F1IOM CMil lAo I (GO. BRAZIL) The Catetno alkalinc carbonatite complcx hostsa numbcr of minera l resources includin g monazite. This mineral is a common access ory phase in two lithological units: carbonatite and silexi te. Textural ev ide nce sugges t that mon azite replaced carbonates in the carbc natite and crys tallized simultaneously with qua rtz in the silexite. Monazite was resistant to the strong laterization that affected the massif, exce pt for the inc ipient transformation into gorce ixite or ccr ianitc. In both car bonatitc and sile xitc, monazite occu rs as a complex agg reg ate of sub-rnicrometric crystals, show ing unusua l morp hological and chem ical characte ristics. It contains Ca, Sr, and Ba in the A-site, and sho ws a certain deg ree of hydra tion indicated by ATD and IV data. Structuralform ulae calcu lated on the basis ofsum of cations > I show a mod erate ionic deficiency ill the anionic site. Rietveld rcffincm cnt indicated poor crystal linity. Notwi thstanding these peculiar charac teristics, cel l dimensions are similar to those of standa rd monazite.

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Optimization in the use of phosphate rocks is important and the residues of fertilizer production in the form of crandallite may be suitable for agronomic use after calcination. With the objective of evaluating the effect of thermal treatment of the aluminous phosphates of the crandallite group as related to solubility, crystalline structure and morphology, samples from the mine residues of three Brazilian phosphate deposits (Tapira-MG, Catalão-GO, and Juquiá-SP) were collected, air-dried, and screened to 100 mesh. Sub samples were thermally treated at 300, 500, 700, and 900°C for 2 hours. Treated and untreated materials were analyzed by X-ray diffraction, scanning electronic microscopy, energy dispersive X-ray spectrometry, and for the total and soluble P contents. The treatment of samples: (i) raised P solubility in neutral ammonium citrate solution, (ii) caused the disorganization of the crystalline structure of crandallite at 500°C and above, and (iii) altered their morphology (cracking and rounding). The increase in P solubility of samples after calcination indicates that the agronomic utilization of these marginal P sources may be of interest since plant growth may be favored due to higher P availability. New studies to evaluate these materials in order to determine their agronomic effectiveness must be carried out to establish adequate conditions that favor their use by plants. Key words: calcination, phosphate fertilizer, phosphate impurities TRATAMENTO TÉRMICO DE FOSFATOS ALUMINOSOS DO GRUPO DA CRANDALLITA E SEU EFEITO NA SOLUBILIDADE DO FÓSFORORESUMO: A otimização do uso de rochas fosfáticas é importante e resíduos da indústria de fertilizantes fosfatados na forma de crandallita poderão ser agronomicamente eficientes após calcinação. Com o objetivo de avaliar o efeito do tratamento térmico em fosfatos aluminosos do tipo crandallita quanto à solubilidade, estrutura cristalina, e morfologia, amostras do rejeito de mineração de três depósitos fosfáticos brasileiros (Tapira-MG, Catalão-GO e Juquiá-SP) foram coletadas, secas ao ar e separadas por peneiramento 100 mesh. Sub-amostras foram submetidas ao tratamento térmico a 300, 500, 700 e 900°C durante 2 horas. Os materiais tratados e não-tratados foram analisados por difratometria de raios X, observados por microscopia eletrônica de varredura e espectrometria por energia dispersiva, e seus teores de fósforo total e solúvel determinados. O tratamento térmico das amostras: (i) elevou, consideravelmente, a solubilidade em CNA dos materiais; (ii) promoveu a desorganização da estrutura cristalina da crandallita a temperaturas de 500°C e superiores; e (iii) causou alterações morfológicas (fraturamento e arredondamento) nas amostras. O aumento na solubilidade das amostras após o tratamento térmico indica que a utilização agronômica destas fontes marginais de P pode ser de interesse, uma vez que o crescimento das plantas pode ser favorecido pela maior disponibilidade de P. Estudos de avaliação desses materiais a fim de determinar sua eficiência agronômica...