有机肥料分析（Organic fertilizerAnalysis）

1、有机肥料2分析（Organic fertilizer 2 Analysis）Abstract: the content of nitrogen, phosphorus and potassium in organic fertilizer was determined by chemical analysis, that is, after digesting with sulfuric acid hydrogen peroxide,The preparation of the test solution, the test solution will use the NC - 2 type

2、rapid azotometer nitrogen determination, determination of phosphorus by Quinoline phosphomolybdate gravimetric method and four benzeneThe potassium gravimetric method for the determination of potassium, without the use of a spectrophotometer and a flame photometer, is suitable for general compound f

3、ertilizer plants, for nitrogen and phosphorus,The samples with potassium content of more than 011% can be determined by this method. The accuracy and precision of the method can meet the requirements of production.Key words: organic fertilizer; nitrogen, phosphorus and potassium; methods of chemical

4、 analysisThe determination of nitrogen, phosphorus and potassium in organic fertilizers is based on the requirements of the national trade standard NY525 - 2002, and nitrogen is used as a whole amount of distillation dropsDetermination of phosphorus content by phosphorus, vanadium and molybdenum yel

5、low spectrophotometry and potassium by flame photometric method. For common compound fertilizer plants, the first is the time of measuring nitrogenToo long; two, because these factories generally do not have a spectrophotometer and a flame photometer, they are not convenient for the determination of

6、 phosphorus and potassium. In order to solveThe manufacturers can analyze and determine the nitrogen, phosphorus and potassium in organic fertilizer. The author summed up the organic fertilizer suitable for manufacturers in the production practiceChemical analysis methods for rapid determination of

7、nitrogen, phosphorus and potassium in stock. The method is characterized with sulfuric acid hydrogen peroxide digestion sample preparation to be checked,Nitrogen, phosphorus and potassium were determined. NC - 2 fast nitrogen determination apparatus can be used to measure nitrogen distillation, abso

8、rption and titration within 10 minThe process is characterized by rapid and accurate determination of phosphorus using quinoline quinoline gravimetric method; potassium determination by four potassium borate gravimetric method. At 120 degrees centigradeUnder the condition that the phosphorus and pot

9、assium deposits are dried together for 115 h, phosphorus and potassium can be simultaneously determined, thus greatly shortening the operation time. thisThe method is used in production practice and is basically consistent with the analysis method of the national industry standard. A common compound

10、 fertilizer plant needs no analyzerThe method can be applied to determine the content of nitrogen, phosphorus and potassium in organic fertilizer to achieve guidanceProduction requirements.1 methods principleThe organic fertilizer is heated in the sulfuric acid solution, and the hydrogen peroxide so

11、lution is added to make the organic matter digest quickly. The preparation of nitrogen, phosphorus and potassium is to be measuredLiquid, then determine nitrogen and phosphorus by NC - 2 quick - type nitrogen - fixing apparatus. Quinoline gravimetric method for the determination of phosphorus, four

12、potassium borate, gravimetric method for the determination of potassium.2. instruments and reagentsHydrochloric acid standard solution 01025, mol/, L; mixed index agent: take bromine green 015 g and methyl red 011 g, dissolve in 100 mL BIn the alcohol, use the sodium hydroxide solution (about 011 mo

13、l/ L) and hydrochloric acid solution (about 011 mol/ L) to purple red (pH is about 415)Boric acid: 20 g/ L, mixed with a mixed indicator, with the sodium hydroxide and hydrochloric acid to purple. A reagent of fourSodium solution (according to the reference 4 preparation); sodium tetraphenylborate l

14、otion: dilute 1 times with 10 times of water solution of sodium tetraphenylborate.3 analysis steps3.1 sample solution preparationTake 215000 g sample in 250 mL triangle bottle, add 15mL concentrated sulfuric acid, cover with short neck funnel and heat up on the low temperature electric stoveWhite sm

15、oke for a few minutes, the sample digested into a black paste, stop heating, slightly cold after taking out the small funnel, with a dropper filled with hydrogen peroxide, slowSlowly drip from the triangle bottle wall until the solution is changed from black to colorless. Continue to cover the small

16、 funnel and repeat the operation to complete the organic matterComplete decomposition, stop adding hydrogen peroxide, continue to heat the solution at low temperature until the sulfuric acid white smoke 1520 min, cool, add water to 75 mL leftRight, then cool, transfer the solution to the 100 mL volu

17、metric flask. All the solutions are dried and the filtrate is kept for measuring nitrogen, phosphorus and potassium.3.2 determination of nitrogenDraw sample liquid to 10 mL, with the content shown in Figure 1 NC - 2 type rapid determination of nitrogen analyzer. The nitrogen detector uses side disti

18、llationThe method of side titration determines nitrogen, and within 10 min can complete the process of distillation, absorption and titration of nitrogen, followed by second samplesIt is one of the fastest instruments to determine the rate of nitrogen at home and abroad. It is heated by steamMethods

19、 ammonium nitrogen was distilled in an alkaline solution without the use of condensed water to cool down, and ammonium nitrogen was absorbed with a neutral boric acid solution.When the absorption liquid is alkaline, the mixed indicator is changed from violet red to bluish green and titrated with hyd

20、rochloric acid standard titration solution immediatelyThe liquid is purplish red (refer to reference 1 for specific operations) and do blank tests at the same time. The sample nitrogen content was measured in terms of nitrogen (N) mass fractionShow, pressLower form calculation:W (N) =C (V2 - V1) * 0

21、101401/m * 10/ 100Formula: the actual concentration of C - HCl standard titration solution, mol/, L;V1 - Blank Test consumes the volume of hydrochloric acid standard titration solution, mL;V2 - Determination of the volume of standard hydrochloric acid solution consumed by the sample, mL;M - quality

22、of the sample, g;0101401 - molar mass of nitrogen, M (N) = 0101401 g/mmol.3.3 determination of phosphorusFrom 25 mL to 250 mL for the liquid in the beaker, add nitrate (1+ 1) 10 mL, and 100 mL water, boil, slowSlowly add 35 mL, the reagent, boil 1 min, cool, filter with constant weight No. 4 glass s

23、and crucible, wash with waterNet beaker and sedimentation. Put the crucible in a dry oven at a constant temperature of 180 DEG C and dry for 45 min (if phosphorus and potassium are measured together, at constant temperature 120)Drying 115 h in a drying oven at C, remove the crucible, cool in the dry

24、er and weigh. The phosphorus content of the sample was determined by the quality of phosphorus (P205)Fractional representation, press calculation:W (P2O5) = (M1 - m2) * 0103207/m * 25/ 100In style:M1 - precipitation quality of quinoline quinoline precipitation, g;M2 - the quality of quinoline quinol

25、ine obtained in blank test, g;M - quality of the sample, g;The coefficient of 0103207 - Quinoline phosphomolybdate converted into phosphorus pentoxide quality quality.3.4 determination of potassiumFrom 25 mL to 250 mL for the liquid in the beaker, add EDTA solution (400 g/ L) 40 mL, add phenolphthal

26、ein (4g/LEthanol solution) 2 drops, with sodium hydroxide solution (400, g/, L) adjusted to the solution is red, and then 1 mL excess, add water to 100 mL, lowWarm up to boiling, keep 30 min, heating process according to the evaporation of water, at any time to add water to maintain about 100 mL, re

27、move cooling,The solution was filtered, washed with water and precipitated 34 beaker, adding sodium tetraphenylborate solution (filtrate is added to each of the 1 mg K2O plus four benzeneSodium borate solution 015 mL, and excess about 7 mL), stirring 1min, static 15 min or more. Filter the precipita

28、te at the constant weight No. 4Glass crucible, wash the beaker and precipitation with sodium tetraphenylborate solution 57 times, and finally washed 2 times. Place the crucible and sedimentation at a constant temperature of 120In a temperature oven, dry 115 h, remove, place in a desiccator, cool, an

29、d weigh. The potassium content of the sample is shown as a mass fraction of potassium (K2O)Press down calculation:W (K2O) = (M1 - m2) * 011314/m * 25/ 100In style:Quality of M1 - four potassium borate, g;M2 - the quality of four potassium borate obtained from a blank test, g;M - quality of the sampl

30、e, g;The coefficient of 011314 - four phenylboronic acid potassium converted into potassium oxide quality quality.4 results and discussion4.1 sample solution preparationIn this method, nitrogen, phosphorus and potassium are determined by chemical analysis. Compared with instrumental analysis, the am

31、ount of sample is large and accurateBecause the uniformity of the organic fertilizer is poor, the amount of sample is small and the reproducibility of the result will be worse. Simultaneous sampling can be performedDetermination of nitrogen, phosphorus and potassium in the same sample solution, has

32、the advantages of convenient and fast.4.2 relating to distillation, absorption, and titration of nitrogenIn 2000, the author assembled the NC - 2 rapid nitrogen determination device, which has been used in many compound fertilizer plants and analysis and testing unitsThe utility model has the advant

33、ages that the nitrogen is distilled, absorbed and titrated into a whole without using a condensing tube (that is, no cooling water), and the operation is convenient, fast and accurate,Within 10 min, the complete process of nitrogen distillation, absorption and titration can be completed.4.3 about th

34、e determination of phosphorusNitrogen, phosphorus and potassium in the tested liquid phosphorus determination by this method, improve the speed of analysis. Because many compound fertilizer plants do not buy anyThe photometric method can only be used for the determination of phosphorus by the quinol

35、ine quinoline gravimetric method. The accuracy and precision of phosphorus determination by gravimetric method are relatively highOnly a lower sensitivity, which has little impact on the compound fertilizer plant, because the phosphorus content of more than 011 of the sample can be measured by this

36、method, below011 per cent is of little significance to manufacturers, without consideration. In the determination of phosphorus and potassium, after many experiments, dried at 120 degrees centigradeThe phosphorus and potassium precipitate were dried at 115 h, which had no effect on the determination

37、 of phosphorus (i.e., drying at 45 min at 180 DEG C)The results of phosphorus under test are consistent, and simultaneous determination of phosphorus and potassium can be carried out simultaneously.4.4 about the determination of potassiumThe determination of potassium is also based on the fact that

38、the compound fertilizer plant is not equipped with a flame photometer, and is measured by the gravimetric method of four potassium borateSet. Determination of potassium in organic fertilizer by acid solution method, the dissolution of more metal cations,Although adding a sufficient amount of liquid in theEDTA solution, when the liquid to the alkaline when boiled for 15 min, there will still be a small amount of hydroxide precipitate, but this does not affect the potassiumDetermination, as long as the filter the precipitate was removed,