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Nomozov Shuhratjon Yuldashali-o'gli, of Sciences, Ph D., student Institute of General and Inorganic Chemistry of the Republic of Uzbekistan Academy Jumanova Miyasar Ortikovna, doctor of sciences, Institute of General and Inorganic Chemistry of the Republic of Uzbekistan Academy of Sciences, E-mail: jumanova@mail.ru Namazov Shafoat Sattarovich, academician, Institute of General and Inorganic Chemistry of the Republic of Uzbekistan Academy of Sciences
SUSPENDED LIQUID COMPLEX FERTILIZERS FROM UNEVAPORATED WET-PROCESS PHOSPHORIC ACID
Abstract: This article analysis techniques of the production of suspended liquid complex fertilizers from un-evaporated wet-process phosphoric acid of phosphorites of the Central Kyzylkum. Suspending clays influence on the quality and physical and chemical properties of liquid complex fertilizers was studied. The optimum concentration of the addition of clay in the dispersed system is established. The degree of clarification of LCF and SLCF was studied.
Keywords: phosphate, liquid complex fertilizers, neutralization, suspended liquid complex fertilizers, bentonite clay, degree of clarification.
Introduction. Compared to solid complex fertilizers, liquid complex fertilizers (LCF) have many advantages, for this reason the production of LCF has been on a rise in recent years. When using LCF, it is possible to make the process of applying fertilizers to the soil fully mechanized and to evenly distribute the active substances, as well as apply herbicides, pesticides and microelements simultaneously with fertilizers. Initial expenses and material processing cost are significantly reduced in the production of LCF, since there are no stages of granulation, cooling, crushing, sifting, conditioning, and a large number of vehicles [1].
The calculations of research institute of fertilizers and insectofungicide show that liquid complex fertilizers have a higher economic viability than their solid complex fertilizers equivalent in content of active substances. For example, in estimating the initial components used to produce solid complex fertilizers, the resulted costs for the production of 1 ton of P205 in the mixed fertilizer produced on the basis of am-mophos is 138% with respect to liquid complex fertilizers [2].
The results of research in the field of production and consumption of liquid fertilizers show an increasing significance of liquid fertilizers in agriculture. This is due to the fact that liquid complex fertilizers (LCF) and suspended liquid complex fertilizers (SLCF) do not dust, clod, have free flow, their quality parameters are not significantly affected by adverse climatic conditions during storage.
The most common among the commercially available liquid fertilizer forms are nitrogen-phosphate solutions containing 10% nitrogen and 34% phosphate expressed in terms of P2O5. The technology for obtaining LCF of 10-34 grade includes high-temperature ammoniation of super-phosphoric or polyphosphoric acid with a concentration of 62-64% of P205, and a high content of nutrients that is provided by the polyols of P205. However, the main drawbacks of the known method are the use of expensive phosphoric acids, significant content of impurities, as well as an imbalance in the composition of LCF in terms of nitrogen and phosphorus content.
In this research [3], we proposed a method for obtaining a liquid complex fertilizer, including neutralization of wet-process phosphoric acid obtained from phosphorites of the Central Kyzylkum, to obtain a nitrogen-phosphorus nutrient solution containing 3.32-6.29% nitrogen and 16.00-16.22% P205. Their rheological properties were also determined [4].
Differentiation of LCF into liquid and solid phases, increase in the crystal size of the supersaturated solution, creates a number of difficulties in transporting, storing and applying fertilizers to the soil.
One of the ways to improve the physical and chemical properties of LCF is to obtain sufficiently stable disperse systems by adding various clays to LCF, resulting in the production of suspended liquid complex fertilizers (SLCF).
On the territory of Uzbekistan there are huge reserves of bentonite clays (about 200 deposits) which have a highly developed specific surface and a porous structure. Therefore, we studied the effect of suspending clays on the quality and physical and chemical properties of LCF, as well as the establishment of an optimum concentration of the additive in the suspension.
The purpose of this research is to study the production of suspended liquid complex fertilizers based on low-concentration wet-process phosphoric acid (WPPA).
Subjects and techniques of research. In the laboratory experiments, wet-process phosphoric acid that was obtained from the phosphorites of the Central Kyzylkum (CK) was used, with the following composition: 17.17% P2Os, 2.2%
SO3, 0.16% Ca, 0.22% Mg, 0.39% Fe203 and 0.53% Al203 produced by JSC "Ammofos-Maxam". The process of WPPA neutralization was carried out with gaseous ammonia in a special reactor with vigorous stirring at pH in the range from 3.5 to 6.5. Measurement of the pH value of ammoniated pulps was carried out using a laboratory ionomer I-130M with an electrode system consisting of ECL 63-07 (high stability electrode), EVL-1M3.1 (lanthanide tungsten electrode) and TKA-7 (thermal compensator) with accuracy of 0.05 pH units. After ammonization, the products obtained were analyzed for the content of various components [5].
As suspending agents bentonites of Kattakurgan and Navbakhor (PPD) deposit were used. The chemical composition of bentonites is given in (Table 1).
Table 1.- The chemical composition of bentonites
№ Bentonite deposit SiO2 TiO2 Al2O3 pe2°3 MgO MnO CaO Na2O K20 P2O5 SO3 H20 C02
1. Navbahor (PPD) 46.06 0.39 8.78 3 4.33 0.27 12.2 0.75 1.05 0.77 1.39 6 9.35
2. Kattakurgan 57.89 0.71 16.71 5.19 2.9 0.03 1.12 1.68 3.92 0.14 < 0.1 6.17 < 0.2
Results and discussion. A 26% clay suspension was used because it has the highest effective viscosity and is characterized by the stability of the coagulation structure of the pulp. The weight ratio of AWPPA: BCS (ammoniated wet-process
phosphoric acid to the bentonite clay suspension) varied in the range 100: (1-3). Determine the degree of clarification LCF without adding bentonite and with bentonite for 3 days. The results are shown in (Tables 2 and 3).
Tables 2.- The degree of clarification of ammoniated pulps over time (%)
№ pH 1 h 2 h 3 h 4 h 5 h 8 h 23 h 24 h 28 h 48 h 54 h 60 h 72 h
1. 3.54 3.92 4.85 4.96 5.77 7.69 15.38 36.54 36.54 38.46 44.23 44.23 44.23 44.23
2. 3.86 5.77 8.65 13.46 17.31 21.15 38.46 49.04 50.0 51.92 51.92 51.92 51.92 51.92
3. 4.26 3.85 5.77 6.25 8.65 11.54 26.92 42.31 43.27 44.23 46.15 46.15 46.15 46.15
4. 4.51 3.74 5.60 6.04 8.13 9.66 19.32 34.41 36.30 37.25 45.34 45.34 45.34 45.34
5. 4.95 3.52 4.85 5.77 7.69 9.54 20.15 42.01 42.01 42.27 44.15 44.15 44.15 44.15
6. 5.53 3.85 4.73 5.62 8.46 9.15 19.62 37.50 38.46 38.46 39.42 39.42 39.42 39.42
7. 6.07 3.56 3.92 4.32 8.05 9.00 18.28 38.11 38.76 37.85 38.22 38.22 38.37 38.37
8. 6.56 3.85 5.77 7.69 10.58 13.46 19.23 33.65 34.62 34.62 37.53 37.53 37.53 37.53
Table 3.- The degree of clarification of ammoniated pulps over time with the addition of bentonite (%)
AWPPA: BCS ratio 1 h 5 h 23 h 24 h 25 h 26 h 27 h 28 h 48 h 60 h 72 h
1 2 3 4 5 6 7 8 9 10 11 12
pH=3.54
100:1(PPD) 3.25 6.11 24.6 24.68 24.71 24.75 24.8 24.8 29.73 29.73 29.73
100:2(PPD) 3.19 6.00 19.68 19.76 19.76 19.83 19.90 20.01 27.27 27.27 27.27
100:3(PPD) 2.89 5.73 16.32 16.34 16.39 16.44 16.62 16.64 25.58 25.58 25.58
100:1 (Kattakurgan) 2.19 5.01 20.2 20.23 20.25 20.32 20.45 20.52 25.27 25.27 25.27
100:2 (Kattakurgan) 2.06 4.94 18.42 18.45 18.48 18.53 18.60 18.74 23.26 23.26 23.26
100:3 (Kattakurgan) 1.04 3.65 15.61 15.64 15.65 15.69 15.72 15.80 22.77 22.77 22.77
pH=4.26
100:1(PPD) 2.82 5.65 21.54 21.56 21.63 21.69 21.72 21.75 26.31 26.31 26.31
1 2 3 4 5 6 7 8 9 10 11 12
100:2(PPD) 2.71 5.49 19.77 19.77 19.82 19.84 19.88 19.90 25.77 25.77 25.77
100:3(PPD) 2.18 5.20 17.43 17.46 17.53 17.54 17.63 17.67 23.25 23.25 23.25
100:1 (Kattakurgan) 1.94 4.45 16.93 16.94 16.95 16.97 16.99 17.03 23.39 23.39 23.39
100:2 (Kattakurgan) 1.82 4.33 14.67 14.67 14.70 14.72 14.75 14.80 22.66 22.66 22.66
100:3 (Kattakurgan) 0.99 3.76 12.73 12.75 12.78 12.83 12.86 12.91 20.17 20.17 20.17
рН=4.95
100:1(PPD) 2.10 4.91 20.11 20.14 20.17 20.18 20.23 20.31 25.42 25.42 25.42
100:2(PPD) 2.06 4.80 19.24 19.26 19.28 19.33 19.35 19.35 24.53 24.53 24.53
100:3(PPD) 1.00 3.62 17.02 17.04 17.08 17.12 17.12 17.15 22.75 22.75 22.75
100:1 (Kattakurgan) 1.07 3.76 16.35 16.35 16.38 16.38 16.40 16.40 22.56 22.56 22.56
100:2 (Kattakurgan) 1.04 3.45 14.00 14.02 14.02 14.06 14.06 14.06 21.45 21.45 21.45
100:3 (Kattakurgan) 0.84 3.52 12.10 12.14 12.14 12.16 12.16 12.18 20.12 20.12 20.12
рН=6.07
100:1(PPD) 1.06 4.10 18.21 18.21 18.25 18.25 18.28 18.3 23.76 23.76 23.76
100:2(PPD) 1.03 4.02 17.51 17.51 17.51 17.59 17.63 17.63 22.89 22.89 22.89
100:3(PPD) 1.01 3.76 15.78 15.78 15.80 15.80 15.80 15.80 20.51 20.51 20.51
100:1 (Kattakurgan) 1.00 3.85 15.41 15.44 15.44 15.50 15.53 15.53 20.63 20.63 20.63
100:2 (Kattakurgan) 0.62 3.31 13.23 13.23 13.25 13.25 13.25 13.25 19.55 19.55 19.55
100:3 (Kattakurgan) 0.53 3.00 10.94 10.94 11.03 11.03 11.05 11.05 18.13 18.13 18.13
After settling the ammoniated pulps for 48 hours, the degree of clarification increased, and then it became rectilinear. For example, the degree of clarification of ammoniated pulp at pH = 3.54 for 2 days was from 3.92 to 44.23%, and at pH = 6.56 - from 3.85 to 37.53%.
The results in Table 3 show that sufficiently stable suspended fertilizers are obtained when a clay suspension is used - the Kattakurgan field.
The stability of the SLCF depends on the amount of clay added to the dispersed system. For example, with the addition of bentonite of PPD and Kattakurgan field at the ratio of AWPPA: BCS = 100: 1, the degree of clarification was 3.25 to 29.73% and 2.19 to 25.27%, and with the ratio AWPPA:
BCS = 100: 3 - from 2.89 to 25.58% and from 1.04 to 22.77%, respectively. The degree of clarification of the SLCF after a period of time is less by 1.48-2.19 times than the LCF. It should be emphasized that the amount of suspending agent, equal to 3% by weight, is optimal. It should also be noted that the physicochemical processes occurring in the production of liquid complex fertilizers are primarily determined by the reactions of neutralizing phosphoric acid [6-14], which have been extensively studied.
Therefore, a method for producing suspended liquid complex fertilizers is proposed. It has been established that the properties of SLCF depend to a great extent on the type and amount of the applied bentonite clay suspension.
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