A study for synthesis of dicalcium phosphate from various grades of phosphatic materials - Bui Quoc Huy

Journal of Science and Technology 54 (5A) (2016) 1-8 A STUDY FOR SYNTHESIS OF DICALCIUM PHOSPHATE FROM VARIOUS GRADES OF PHOSPHATIC MATERIALS Bui Quoc Huy1, Nguyen Thi Thanh1, Le Thi Nga2, Le Xuan Thanh2 1Hung Yen University of Technology and Education, Dan Tien, Khoai Chau, Hung Yen 2Hanoi University of Science and Technology, N 1, Dai Co Viet Str, Hanoi Received: 15 July 2016; Accepted for publication: 5 December 2016 ABSTRACT Anhydrous dicalcium phosphate with monetite structure plays a significant biological importance for the mineralization of bones and teeth. This compound can reconstruct the hard tissues due to its high solubility in the body than other calcium phosphate compounds. Di calcium phosphate is being used as a food - additive supplying calcium and phosphate for humans and animals. Due to the high effective P2O5 content, this compound is also used efficiently as a slowly soluble fertilizer in agriculture for all soil and crop types. This paper presents results of synthesis of di calcium phosphate monetite from Ca(OH)2 and phosphoric acid and di calcium phosphate brushite from the resulting solution after enriching of type II - Lao Cai apatite ore by phosphoric acid. The samples were examined by volumetric titration methods, XRD, SEM and EDS. Keywords: synthesis dicalcium phosphate, monetite, brushite. 1. INTRODUCTION Anhydrous dicalcium phosphate CaHPO4 with monetite structure plays an important role for the biomineralization in bones and teeth. Using this material, the hard tissues can be reconstructed more efficiently than other calcium phosphates due to its high solubility in the body thus one can find practical applications of CaHPO4 in dental cements and restorative materials [1 - 3], and in the food additive calcium and phosphate supplements for humans and animals as well [4]. Also due to the high effective P2O5 content, dicalcium phosphate is a slowly soluble form of fertilizer which is often used in agriculture for all types of soil and crops [5, 6]. There are many studies of preparation of dicalcium phosphate (DCP) recently [1, 2, 7 - 8]. The authors [1] prepared anhydrous dicalcium phosphate from Ca(NO3)2·4H2O and H3PO4 by the sol gel method. Gel obtained after 24 h of aging was heated at 300oC to create products. The authors [2] have produced of anhydrous calcium phosphate material with monetite structure from dihydrate calcium phosphate with brushite structure under hydrothermal method. The authors [4] have manufactured brushite dihidrat calcium phosphate from Ca(OH)2 suspension and phosphoric acid with concentration of 50 to 400 mmol/dm−3. This work presents the results of monetite synthesis from Ca (OH)2 and phosphoric acid and brushite from the solution obtained after enriching type II - Lao Cai apatite ore with phosphoric acid [9]. The samples were Bui Quoc Huy 2 examined by volumetric titration methods, XRD, SEM and EDS for the estimation of the synthesis performance. 2. EXPERIMENTAL 2.1. Equipments and chemicals Raw materials: solution obtained after enriching type II - Lao Cai apatite ore (AP2) by phosphoric acid, H3PO4, Ca(OH)2 and other chemicals. Some of main devices: X-ray diffraction was measured at the Faculty of Chemistry, Hanoi National University. The SEM and EDS were measured at the Hungyen University of Technical Education. 2.2. Experimental DCP was synthesized from H3PO4 and Ca(OH)2 or from the solution after enriching type II - Lao Cai apatite ore by phosphoric acid. In the former case, to examine the effect of phosphoric acid concentration, for 5 ml 85 % H3PO4 in 250 ml beaker, add various amounts of distilled water and heat to a temperature of 80 0C. The solution was stirred at a speed of 200 rev / min together with gradual addition of the required amount of Ca(OH)2 in 30 minutes and then stirred in 10 minutes more. The precipitation after filtering and washing was dried at 105 0C for 1 h. The synthesized performance was evaluated on the basis of the mass of obtained precipitation. 3. RESULTS AND DISCUSSION 3.1. Synthesis of dicalcium phosphate from Ca(OH)2 and phosphoric acid 3.1.1. The influence of the concentration of phosphoric acid To investigate the influence of the concentration of phosphoric acid, for 5 ml 85 % H3PO4 in 250 ml beaker, change the volume of distilled water added and heat to a temperature of 80 0C. Stir and add gradually the amount of Ca(OH)2 needed for 30 minutes, then stir 10 minutes further. After the reaction, pH of the solution was about 7 and this indicates that the acid is reacted completely. The precipitation was filtered, washed and dried at 1050C for 1 h. The synthesized yield was determined on the basis of the mass of obtained precipitation. The results are shown in Table 1. Table 1. Effect of concentration of phosphoric acid for DCP synthesis. Samples M1.1 M1.2 M1.3 M1.4 M1.5 Distilled water (ml) 10 20 35 45 70 Precipitate mass (g) 8,854 8,860 9,044 9,455 8,875 CaHPO4 yield (%) 89,00 89,06 90,91 95,04 89,21 As indicated by Figure 1, the precipitated product after drying is CaHPO4, so the reaction occurs during the synthesis: H3PO4 + Ca(OH)2 → CaHPO4↓ + 2H2O A study for synthesis of dicalcium phosphate from various grades of phosphatic materials 3 and from the above equation, mass of obtained CaHPO4 can be calculated based on the material balance as follows: mCaHPO4 theoretically = 5 ml*1,4341 * * = 9,95 g. - Phosphoric acid is a weak acid, its interaction is determined by two factors: the acid dissociation and concentration. It is two opposing factors: the more concentration decreases, the more dissociation increases and this favor the reaction between phosphoric acid and Ca(OH)2. Therefore, precipitating performance is increased from M1.1 to M1.4 samples. However, when the concentration decreases, the rate of collisions between reactant molecules decreases and this determines reduced performance from M1.4 to M1.5. As given in Table 1, the reaction between Ca(OH)2 and H3PO4 most effective at temperature of 80 0C for 40 minutes with 5 ml of 85% H3PO4 and 45 ml of distilled water. 3.1.2. Influence of the synthesis temperature Experiments were conducted similarly as M1.4 sample at various synthesis temperature. The results in Table 2 show that the reaction rate increases with temperature. The synthetic product yield of M2.5 samples reaches 97.43 %. Table 2. Influence of temperature for CaHPO4 synthesis from H3PO4 and Ca(OH)2. Samples M2.1 M2.2 M2.3 M2.4 M2.5 Temperature (oC) 50 60 70 80 90 Precipitate mass (g) 7,910 9,077 8,995 9,455 9,693 CaHPO4 yield (%) 79,51 91,25 90,41 95,04 97,43 3.1.3 Product characterization F acul ty o f C he m istry, H US , VN U, D8 A DV A NC E-Bruke r - Sam ple N 2,5 01 -0 70 -0 3 59 (C) - M o ne t ite, syn - Ca H PO 4 - Y : 6 6 .5 4 % - d x by: 1 . - W L: 1.5 4 06 - Tric lin ic - a 6.9 10 00 - b 6 .6 27 00 - c 6 .9 9 80 0 - a lp ha 96 .3 40 - be ta 1 03 .8 20 - ga m m a 8 8 .3 3 0 - P rim itiv e - P -1 (2 ) - 4 - 30 9 .2 7 File : Nga B K m au N2,5 .ra w - Type : 2Th /Th lo cke d - S ta rt : 10 .00 0 ° - E n d: 7 0.0 00 ° - Ste p : 0 .03 0 ° - S te p tim e: 0 .8 s - Te m p .: 2 5 °C ( Ro om ) - T im e S tar ted : 13 s - 2- The ta : 1 0.0 00 ° - Th eta : 5 .0 00 ° - C hi : 0 .00 Li n (C ps ) 0 10 20 30 40 50 60 70 80 90 10 0 11 0 12 0 13 0 14 0 15 0 16 0 17 0 18 0 19 0 20 0 21 0 22 0 23 0 24 0 25 0 26 0 27 0 28 0 29 0 30 0 2-Theta - Scale 1 0 20 3 0 40 50 60 7 d= 6. 77 0 d= 4. 28 1 d= 3. 48 4 d= 3. 35 6 d= 3. 12 9 d= 2. 95 8 d= 2. 88 0 d= 2. 75 6 d= 2. 72 4 d= 2. 49 5 d= 2. 30 6 d= 2. 24 9 d= 2. 19 7 d= 2. 15 9 d= 2. 11 5 d= 2. 09 0 d= 2. 03 2 d= 1. 99 5 d= 1. 91 7 d= 1. 84 9 d= 1. 80 0 d= 1. 75 6 d= 1. 72 5 d= 1. 69 0 d= 1. 65 3 d= 1. 64 0 d= 1. 61 0 d= 1. 36 1 d= 4. 04 2 d= 1. 57 1 d= 3. 69 5 d= 4. 99 5 Figure 1. XRD diagram of M 2.5 sample. Bui Quoc Huy 4 Figure 2. SEM image of M 2.5 sample. According to obtained SEM images, the product consists of spherical particles with fairly uniform and the majority of particles have a size of about 50 µm. Figure 3. EDS spectrum of M2.5 sample. The phase forms, morphology and composition of the product sample M2.5 are examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy scattering spectroscopy (EDS). Results are shown in Figure 1 – 3, respectively. XRD results show that the obtained product is of single phase anhydrous dicalcium phosphate with monetite triclinic structure. Unlike what shown in reference [4], the creation of monetite here is due to higher reaction temperatures. Compared to the works [1 - 2], the synthesis of anhydrous dicalcium phosphate with monetite structure presented in this paper is energy saving and simpler technology. A study for synthesis of dicalcium phosphate from various grades of phosphatic materials 5 According to the EDS results (depicted in Figure 3), the product contains the elements such as calcium, phosphorous, oxygen. Thus, the product contains fully elements specific to DCP. 3.2 DCP synthesis from the solution after enrichment The volume of obtained solution after beneficiation of 100g type II- Lao Cai apatite with solid:liquid ratio of 1:3 and in the right conditions [9] is 310 ml - denoted L solution. Its major components are Ca(H2PO4)2, Mg(H2PO4)2 and residual H3PO4. Similar to the above observation, add gradually Ca(OH)2 at 90 0C with stirring during 40 minutes, the received pH of the solution after the reaction was about 7. The precipitate was filtered, washed and dried at 10 0C - denoted as DCPrecovery. The precipitation yield was determined when analyzing the total magnesium and calcium content in the solution before and after the reaction. The results shown in Table 3 indicates that the performance of magnesium and calcium that enter precipitate reaches 95.5 %. The results are similar to solutions obtained when beneficiating with solid ratio: liquid of 1: 4 or 1: 5. Table 3. Results of analysis of residual acid, calcium and magnesium and precipitate yield. CCa, Mg, mol/l (1) 1.11 CCa, Mg (2) 0.065 CaHPO4 yield (%) 95.5 (1) Prior to the reaction, (2) After the reaction The main reaction equations occur when adding Ca(OH)2 into the solution L: H3PO4 + Ca(OH)2 → CaHPO4 + 2H2O Ca(H2PO4)2 + Ca(OH)2 → 2CaHPO4 + 2H2O Mg(H2PO4)2 + 2Ca(OH)2 → 2CaHPO4 + Mg(OH)2 + 2H2O 3.3. DCPrecovery product features Faculty of Chemistry, HUS, VNU, D8 ADVANCE-Bruker - Sample nuoc loc 00-003-0423 (D) - Calcium Hydrogen Phosphate - C aHPO4 - Y: 1.68 % - d x by: 1 . - W L: 1.5406 - 01-072-0713 (C) - Brushite - CaH PO4(H2O)2 - Y: 28.66 % - d x by: 1. - W L: 1.5406 - Monoclinic - a 5.81200 - b 15.18000 - c 6.23900 - alpha 90.000 - beta 116.430 - gamm a 90.000 - Body-centered - Ia (9) - File: Nga BK m au DCP nuoc loc.raw - Type: 2T h/Th lock ed - Start: 10.000 ° - End: 70.000 ° - Step: 0.030 ° - Step time: 0 .8 s - T em p.: 25 °C (Room) - T ime Started: 14 s - 2-Theta: 10.000 ° - Theta: 5.000 ° - Li n (C ps ) 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 2-Theta - Scale 10 20 30 40 50 60 7 d= 7. 61 6 d= 4. 92 4 d= 4. 24 6 d= 3. 80 2 d= 3. 37 2 d= 3. 34 6 d= 3. 04 8 d= 2. 95 8 d= 2. 92 9 d= 2. 85 5 d= 2. 67 1 d= 2. 62 8 d= 2. 60 4 d= 2. 43 7 d= 2. 42 1 d= 2. 26 9 d= 2. 17 3 d= 2. 14 9 d= 2. 10 2 d= 2. 02 2 d= 2. 00 2 d= 1. 97 6 d= 1. 89 7 d= 1. 87 8 d= 1. 85 4 d= 1. 81 6 d= 1. 79 8 d= 1. 71 0 d= 1. 55 4 d= 1. 52 3 d= 1. 45 4 d= 1. 37 1 Figure 4. XRD diagram of DCPrecovery sample. Bui Quoc Huy 6 The phase forms, morphology and composition of the product sample M2.5 were examined by X-ray diffraction, scanning electron microscopy and energy scattering spectroscopy (EDS). Results are shown in Figure 4-6, respectively. According to Figure 4, the main component of product is dicalcium phosphate dihidrate CaHPO4.2H2O with brushite monoclinic structure, that is mixed with a small amount of anhydrous dicalcium phosphate. This result is different from the one when synthesizing DCP from Ca(OH )2 and phosphoric acid. This difference is probably due to the solution L contains magnesium and other trace impurities that affect the structure of formed crystal. Figure 5. SEM image DCPrecovery sample. According to SEM images, the sample consists of spherical particles with a majority of particles of about 50 μm size. Figure 6. EDS spectrum of DCPrecovery sample. According to the results of EDS - Figure 6, the product contains elements such as calcium, magnesium, phosphorous and oxygen. Thus, the product fully contains elements specific to calcium magnesium phosphate. A study for synthesis of dicalcium phosphate from various grades of phosphatic materials 7 4. CONCLUSION The impact of solid-liquid ratio and the reaction temperature when synthesizing anhydrous dicalcium phosphate from phosphoric acid and Ca(OH)2 was examined in detail. The results show that the performance reached 97.43 % when adding gradually required amount of Ca(OH)2 into the mixture composed of 5ml 85 % phosphoric acid and 45 ml water with stirring at 90 oC during 40 minutes. Monetite product obtained is single phase, including spherical particles with the size of about 50 μm and can be used as additives for animal feed. Magnesium hydroxide and calcium hydrophotphate was prepared successfully from the solution after enriching apatite ore by phosphoric acid. The performance of magnesium and calcium that enter precipitate reaches 95.5 %. The calcium hydrophotphate is CaHPO4.2H2O with brushite structure including spherical particles with size of about 50 μm.The product can be used as slowly dissolved fertilizer. REFERENCES 1. Hossein Eshtiagh-Hosseini, Mohammad Reza Houssaindokht, Mohammad Chahkandhi, Abbas Youssefi - Preparation of anhydrous dicalcium phosphate, DCPA, through sol–gel process, identification and phase transformation evaluation, Journal of Non-Crystalline Solids 354 (32) (2008) 3854-3857. 2. Faleh Tamimi, Damien Le Nihouannen, Hazem Eimar, Zeeshan Sheikh, Svetlana Komarova, Jake Barralet - The effect of autoclaving on the physical and biological properties of dicalciumphosphate dihydrate bioceramics: Brushite vs. monetite, Acta Biomaterialia 8 (8) (2012) 3161-3169. 3. Faleh Tamimi, Zeeshan Sheikh, Jake Barralet - Dicalcium phosphate cements: Brushite and monetite, Acta Biomaterialia 8 (2) (2012) 474-487. 4. Oliveira C., Ferreira A., Rocha F. - Dicalcium Phosphate Dihydrate Precipitation: Characterization and Crystal Growth, Chemical Engineering Research and Design 85 (2007) 1655-1661. 5. Bridger G. L.. Horzella T. I., Lin K. H. - Fertilizer Manufacture, Dicalcium Phosphate Fertilizer by Treatment of Phosphate Rock with Mineral Acids, Journal of Agricultural and Food Chemistry 4 (1956) 331-337. 6. Marcato R., Giulietti M. - Production of dicalcium phosphate by treatment of phosphate rock concentrate with nitric acid, Fertilizer Research 34 (1993) 203-207. 7. Chengfeng Li, Xiaolu Ge, Guochang Li, Jiahai Bai, Rui Ding - Crystallization of dicalcium phosphate dihydrate with presence of glutamic acid and arginine at 37 °C Materials Science and Engineering: C 41 (2014) 283-291. 8. Xia Li, Zhengyang Weng, Wei Yuan, Xianzi Luo, Hoi Man Wong, Xiangmei Liu, Shuilin Wu, K. W. K. Yeung, Yufeng Zheng, Paul. K. Chu - Corrosion resistance of dicalcium phosphate dihydrate/poly(lactic-co-glycolic acid) hybrid coating on AZ31 magnesium alloy, Corrosion Science 102 (2016) 209-221. 9. Bùi Quốc Huy, Trần Thị Hường, Nguyễn Thanh Tùng, Lê Thị Nga, Bùi Hữu Trung, Lê Xuân Thành, Trương Vận - Nghiên cứu làm giàu quặng apatit Lào Cai loại II bằng Axit photphoric, Tạp chí Hóa học 53 (3e12) (2015) 445-448. Bui Quoc Huy 8 TÓM TẮT NGHIÊN CỨU TỔNG HỢP DICANXI PHOTPHAT TỪ MỘT SỐ NGUỒN NGUYÊN LIỆU Bùi Quốc Huy1, Nguyễn Thị Thanh1, Lê Thị Nga2, Lê Xuân Thành2 1Trường Đại học sư phạm kĩ thuật Hưng Yên, Dân Tiến, Khoái Châu, Hưng Yên 2Trường Đại học Bách khoa Hà Nội, Số 1, Đại Cồ Việt, Hà Nội *Email: huydung18@gmail.com Dicanxi photphat khan cấu trúc monetit góp phần quan trọng trong việc hình thành cấu trúc của xương và răng. Hợp chất này có thể tái tạo những mô cứng do chúng có độ hòa tan cao, dễ được cơ thể hấp thụ hơn so với các hợp chất canxi photphat khác. Dicanxi photphat có thể được sử dụng làm thực phẩm chức năng cung cấp canxi và photphat cho con người và động vật. Cũng do hàm lượng P2O5 cao, hợp chất này cũng có thể sử dụng làm phân bón chậm tan trong nông nghiệp cho tất cả các loại cây trồng. Bài viết này trình bày kết quả tổng hợp dicanxi photphat có cấu trúc monetit từ Ca(OH)2 và axit photphoric, đồng thời tổng hợp dicanxi photphat cấu trúc brush từ dung dịch sau làm giàu quặng apatit Lào Cai loại 2 bằng axít photphoric. Các mẫu được kiểm tra bằng phương pháp chuẩn độ thể tích, XRD, SEM và EDS. Từ khóa: tổng hợp dicanxi photphat, monetit, brushit.