Study on Function of Rare Earth During Producing Phosphate Fertilizer by Wet Process

JOURNAL OF RARE EARTHSVol. 22, Spec. , Dec, 2004, p. 261Study on Function of Rare Earth During Producing PhosphateFertilizer by Wet Process*Wang Jiachen( 王甲辰)'，Liu Xiangsheng(刘向生), Yang Jun(杨军), Fan Yubin(樊玉斌), Wu Yanping(伍艳平)( Bejing General Research Instiutes for Nonferrous Metals, 100088 Beijing，China National Rare Earth Centerfor Agriculture of China, 100088 Bejing, China; Grirem Advanced Materials Co.，Ltd. Bejing 100088, Chi-na)Abstract: The impacts of the Rare Earth (RE) on the contents of available Phosphorus (P) and the physical characterof the calcium superphosphate produced by the wet process on the basis of simulating the consumption of concentratedsulphuric acid, the slury concentration and the cure conditions in different wet process were studied in laboratory, andthe results show that adding RE into different wet process does not raise available P, but changes its physical character,for example, the composite is loose and the color is offwhite.Key words: rare earth phosphate fertilizer, wet process , physical characteristics, available PCLC number: 0614.3Document Code: AArticle ID:1002 -0721(2004) -0261 -04A lot of researches showed that RE phosphate1.2 Methodsfertilizer could improve crop's ability in resisting saline-alkali , increase the yield and improve the quality1.2.1 Non-cure Process and cure processTheof the crops; and the RE phosphate fertilizer showednon-cure process was that mix proper phosphoriteremarkable impact of increasing the yield of crop,powder with water into slurry and add some concen-such as wheat, paddy rice, soybean, sorghum, cot-trated sulphuric acid. Mix them, and react for aboutton, sunflower and potato-s ; furthermore, it had30 min, then put them in a place and dry in the air.good impact on amending soil and ameliorating sa-The cure process was that mix proper phosphoriteline- alkali soil. At present, it has been applied in 13powder with water into slurry, adding some concen-provinces and 214 counties, the total application areatrutd sulphuric acid and reacted in half an hour, thenwere more than 20 thousand hectares, and obtainedkeeping them at 50 C for 7 d( complement arity Wa-very good impact for crop yieldl2). In 2002, it hadter every 12 h) and dried them in the air.been listed in the important task of national “ Tenth-1.2.2 Experiment plans(1) In order to testFive- Year-plan". However, the mechanism of REthe proper concentrated sulphuric acid consumed induring producing calcium superphosphate has notthe process, the treatments are listed in Table 1.been reported, and this study would be good to re-veal the mechanism of the increasing crop yield andTable 1 Make sure of proper consumption of concentrat-resisting salt of RE phosphate fertilizer and offer theed sulphuric acidtheoretical base for reconstructing the traditionalPhosphoriteConcentratedWater/gphosphate fertilizer industry and large area extension.Codepowder/gsulpburic acid/g.1 Materials and Methods529. 7869.493528. 5866.6927.3963.921.1 Materials26. 2061.14Phosphorite powder ( Offered by Guanghan cit-23. 8255. 58y, Sichuan province), RE carbonate ( 65% REO),21. 44.50. 22Concentrated sulphuric acid(98% ), Calcium carbon-20.5247.24ate and Distilled water.中国煤化工_44. 46MHCNMHG。Received date: 2004 -09 - 10; revised date: 2004-10- 15Foundation item: Project supponted by National Important Tackling Research Foundation of China (2002BA315A-7)Biography: Wang Jiachen ( 1965 - ), Male, Doctor; Major in: plant nutrition and RE aplication for agriculture* Corresponding author( E - mail: nhwjc@ tom. com)262JOURNAL OF RARE EARTHS, Vol.22, Spec.，Dec. 2004(2) In order to test proper slurry concentration(4) Impact of added RE on calcium sulphatein phosphate fertilizer process, the treatments are lis-physical charactersted in Table 2.Because a lot of calcium sulphate was producedduring the phosphate fertilizer production, the RETable 2 Make sure of proper slurry concentrationfunction in the process was simulated by adding theCode Phosphorite ConcentrWater/gSlurrysame quantity of RE into the reaction of the calciumpowder/gatedconcentrcarbonate and concentrated sulphuric acid. The ex-sulphurieacid/gation/gperment included 4 treatments was done as follows:3:23. 8265.5823:55.58 .38.64Table 5 Impact of RE on calcium sulphate solifyingtime23.8250. 5840.90Code CalciunConcentrRE45.5843.44Carbonate/gatsulphuriccarbon23.82 .40.58 .46.31ate/g23.82.35.5849. 599.813. 8830.5853. 372100.0225. 5857.770.0410.08(3) In order to confirm the impact of added REon available P and free acid, the follow experiments1.2. 3 Measurements The measurements of the a-were done: The experiment of preparing small phos-vailable P and the free acid in the phosphate fertilizerphate fertilizer samples( non - cure) included 5 treat-were quinoline phosphomolybdate gravimetric methodments as Table 3. The experiment of preparing bigand capacity method4!.phosphate fertilizer samples ( cure) included 6 treat-2 Results and Analysisments are listed in Table 4.2. 1 Process conditionsTable 3 Prepare small phosphate fertilizer samples( non -2.1.1 Consumption of concentrated sulphuric acidCode Phospho Concentrat Water/g RPhosphateWith consumption of concentrated sulphuric acidriteexfertilizerincreased gradually and the concentration of sulphuricRE contenv/(% ,REO)acid kept at 30% among the treatments , the acid solu-5tion prepared was added into the 35 g phosphorite3500.090.1powder and the contents of available P and free acid100.170.2were separately analyzed after reaction. Results show0.260.3that the content of free acid decreases, but the con-23. 82.400.43 .0.5tent of available P does not change among the former5 treatments, and then decreases with the consump-Table 4 Preparing big phosphate fertilizer samples( cure)tion of the concentrated sulphuric acid being reducedCode Phosphor- Concentr Water/g RProcess .20n 20itcarbonate/gpowder/g，191:179.0107.2225(179.21. 22Core .影325(145. 0.285. 5Experiment中国煤化I4250YHCNMHG7825258.5CodeOContent of available P圃Content of free acid285.51.22TwoFig.1 Consumption of concentrated sulphuric acidconfirmed in phosphate fertilizer processWangJCet al. Study on Function of Rare Earth During Producing Phosphate Ferilizer by Wet Process26320r，1:5t10器10I0L3468Code口Content of available P:围Content of fee acidFig.2 Slurry concentration was confirmed in phosphate fertilizer process(Fig.1). When the consumption of the concentratedfree acid were separately tested (Fig.4, Fig.5). The .sulphuric acid is the theoretical quantity (23. 82 g),impact of the added RE on the available P is notits free acid is 7. 63% which approached the nationalgreat, and the added RE does not raise available P bystandards. So the concentrated sulphuric acid con-cured process. The impact of added RE on the con-sumed for preparing small samples is 23.82 g.tent of free acid is not great in the core process and2.1.2 Required slurry concentration35 g phos-the experiment process two, but in the experimentphorite powder was mixed with different weight ofprocess one the added RE increases the free acidwater into different slurries, and 23. 82 g concentrat-which might be caused by the reaction system error.ed sulphuric acid was added into them. After reac-20tion, the contents of available P and free acid were1separately analyzed (Fig. 2). With the slurry con-centration increased, the content of available P is not号1different among the treatments and the content of freeacid decreases at first and then increases, but there isno difference among the treatments. When the slurryconcentration is 46. 31%，the content of available Pis the highest one. So the slury concentration forpreparing small samples is around 46% .Code .DContent of available P:冠Content of free acid2.2 Impact of added REFig.3 Impact of the added RE on contents of available2.2.1 On Available P and free acid AccordingP and free acid ( non-cure)to the chosen conditions above， 35g phosphoritepowder was put into the breaker, then 40g water wasadded and mixed into the slurry, and some RE car-bonate and 23. 82 g concentrated sulphuric acid wereput into it. The available P and free acid were sepa-rately analyzed after the reaction (Fig. 3). The avail-able P and free acid are not different among the treat-ments with the added RE increased. It is obvious that2the added RE does not raise the available P.Because the prepared small samples did not中国煤化工Scure, and the cure process is very important in thefactory, the results of the content of available PJYHC N M H Gomtent of awilableP(cured for 7 d)might bring the warp with the fact. So the experi-1: Core process; 2: Experiment process one;ments of big phosphate fertilizer were done according3: Experiment process twoto the plan above, and the contents of available P and264JOURNAL OF RARE EARTHS, Vol. 22, Spec. , Dec. 20043 Discussion and Summary品10The results show that the RE added into thephosphate fertilizer process does not raise the availa-ble P in the phosphate fertilizer, but quickens the so-lidified rate of the composite in this kind of researchprogram. The cation radius of the rare earths isKinds of process0.106 ~0. 125 nm which is close to the Ca2+ (0.106nm)3], so the cation of the RE could replace theONo RE. ;@ Added RECa2+ in the crystal of the calcium sulphate, whichFig. 5 Impact of the added RE on the content ofgoes against the formation of the crystal of the calci-free acid( cured for 7 d)1: Core process; 2: Experiment processum sulphate in the composite and makes the compos-one; 3: Experiment process twoite loose and enlarges the interface area between theRE phosphate fertilizer and the crop roots in the soil2.2. 2 Physical Character The solidified rate ofwhich is beneficial to crop activating, absorbing, andcomposite, which is like beehive and whose color isutilizing the P nutrition. Furthermore, the RE in theoffwhite, is observed quickly with the added RE in-phosphate fertilizer could promote the croPcreasing when the impact of the RE on the availablegrowth'. The interaction of the P and the RE couldP and free acid was studied. In order to study moreincrease the crop yield's).about the mechanism of the RE added into producingIn brief, the added RE does not raise the availa-phosphate fertilizer process on the solidified rate ofble P in the phosphate fertilizer. The RE phosphatethe composite, calcium carbonate , RE carbonate andferilizer increases the crop yield by changing thewater were mixed uniformly, then added correspond-.physics structure of the phosphate fertilizer which ising concentrated sulphric acid. The starting time ofbenefical to the crop activating, absorbing, and utili-the reaction and the finished time of the productionzing the P nutrition and the interaction of the P andsolidified completely were recorded and the reactionthe RE could increase the yield, too.time was calculated ( Table 6). The results show thatReferences:the completely solidified time of the composite isshortened, the solidified rate is quickened and theI ] Meng Chunxiang, Jia Shulong. The Impact of Rareproduction is dispersed more granules.Earth on the wheat growth [J] . Hebei Agr. Sci. andTechn.1994, (1) :22.Table 6 Impact of RE added into the reaction system[2] Mou Qingquan. The Rare Earth Phosphate Fertilizerof calcium carbonate and concentrated sulP]. China: CN 1185423A.，1998phric acid on soldified rate of composite[3] Guo Baisheng, et al. eds. Rare Earths in AgricultureStarting time ofFinished time of Reaction time/min[M]. The first edition, Beijing; China AgriculturalCodereactionScience and Technology Press, 1990. 62.9:3420:17643[ 4] Bao Shidan eds.. Soil and Agricultural Chemistry Anal-ysis [M]. The Third Edition, Beijing: China Agricul-9:39 .9:5415ture Press, 2000. 417.39:479:53[5] Liang Jinsheng, Liang Guangchuan, Qi Hongfei, et al.Influence of Rare Earth/ Composite Phosphate Inorgan-10:10ic Antibacterial Materials on Activated Water Propertyof Ceramic[J]. Journal of the Chinese Rare Earth Soci .ety. 2003, 21(2): 241.中国煤化工MYHCNMHG