| This thesis through three trials, the use of ICP-MS method for the determination of the three types of feed-grade phosphate (dicalcalcium phosphate, potassium dihydrogen phosphate, potassium dipotassium hydrogen phosphate) Product poisoning metal element content analysis there may be security risks; comprehensive analysis determination of the technology indicators and safety indicators, update or develop for phosphate-quality standards, risk assessment provides a theoretical basis; further study of chromium source of feed-grade DCP, for the control of calcium hydrogen phosphate The chromium content in the product to provide a theoretical basis.Experiment1:Feed grade dicalcalcium phosphate, potassium dihydrogen phosphate and disodium hydrogen phosphate, potassium metal element analysisTest using ICP-MS semi-quantitative detection method for feed-grade DCP, potassium dihydrogen phosphate and potassium dipotassium hydrogen phosphate products of metal elements analyzed. The results show that the feed grade dicalcium phosphate were detected up to33kinds of metal elements, sodium, magnesium, iron average is greater than1000mg/kg; aluminum, silicon, potassium, titanium, manganese, iron, silicon, strontium average content in100～1000mg/kg between; vanadium, zinc average content between10～100mg/kg; lithium, beryllium, boron, scandium, chromium, cobalt, copper, arsenic, iodine, barium, lead the average content of between1～10mmg/kg; gallium, germanium, selenium, bromine, molybdenum, tin, antimony, cadmium, mercury and the average content of less than lmg/kg. Feed grade potassium dihydrogen phosphate were detected in27kinds of metal elements, sodium, calcium, titanium average is greater than100mg/kg. Silicon, chromium, iron, an average bromine content of between10～100mg/kg; magnesium, aluminum, manganese, copper, zinc, arsenic, antimony, lead the average content of between1～10mg/kg; lithium, boron, vanadium, cobalt, nickel, gallium, strontium, molybdenum, tin, iodine, barium average content of less than1mg/kg. Potassium dipotassium hydrogen phosphate feed grade detected in28kinds of metal elements, sodium, silicon, calcium, titanium, an average bromine content of greater than100mg/kg. Iron, zinc and the average content of between10～100mg/kg; magnesium, aluminum, chromium, copper, zinc, arsenic, lead, antimony average content of between110mg/kg; lithium, boron, scandium, vanadium, manganese, nickel, gallium, germanium, selenium, strontium, molybdenum, tin, iodine, barium average content of less than lmg/kg. The results suggest that feed-grade DCP magnesium, iron, manganese, selenium and iodine content is high, the introduction of the diet may have to meet the requirements of pig and chicken, pig and chicken diet in preparation to be considered by the feed-grade DCP the introduction amount of these elements, the requirements to prevent over pig and chicken which adversely affect the animal. Feed-grade DCP vanadium content is higher, potentially harmful for animal production. Three kinds of high content of chromium phosphate, food safety, animal and a potential threat.Experiment2:Feed grade dicalcium phosphate, potassium dihydrogen phosphate and dipotassium hydrogen quality analysisIn this study, using the national standard test methods on34feed-grade DCP,18and18hydrogen phosphate, potassium dihydrogen phosphate, dipotassium technical indicators and safety indicators were measured and compared with the relevant product standards, exploring the reasonableness standard. The results for the feed-grade DCP technical indicators calcium17.09%～28.13%,16.60%～21.26%of phosphorus, calcium and phosphorus mass ratio from0.94to1.56, fineness87.30%～ 100.00%,0.89%w ater of crystallization～7.50%, moisture0.26%～4.86%, pH5.13～7.91, sulfate0.72%～6.19%; safety indicators fluorinated874.04～2357.03mg/kg; arsenic0.57～25.58mg/kg; Pb0.00～59.55mg/kg; cadmium0.07～3.57mg/kg, chromium2.32～25.09mg/kg, mercury0.01～10.89mg/kg. Technical indicators feed grade potassium dihydrogen phosphate containing potassium dihydrogen phosphate main content98.06～99.40%,27.60-31.45%potassium, phosphorus22.32～22.63%, water insoluble matter0.00to0.02%, Chloride0.00～0.42%, pH4.48～4.70,0.02～0.30%moisture,0.05to1.72%sulfate; safety index fluorine-containing0.45～5.60mg/kg, Pb3.51～10.49mg/kg, arsenic0.42～46.17mg/kg, cadmium0.00to0.12mg/kg, chromium2.56～21.08mg/kg, mercury0.12～0.04mg/kg. Potassium hydrogen phosphate anhydrous technical indicators potassium dipotassium hydrogen phosphate containing98.19～99.47%Main content, potassium36.45～46.07%,17.46～17.69%phosphorus, potassium hydrogen phosphate trihydrate containing technical indicators potassium dipotassium hydrogen phosphate trihydrate main content of97.35～98.52%,34.89～37.91%of potassium, phosphorus13.22～13.38%; potassium dipotassium hydrogen phosphate aqueous insoluble technical indicators0.00to0.26%, chloride0.00～0.11%, pH9.18～9.28,0.49～water1.78%, from0.01to2.85%sulfate; safety indicators fluorinated0.03～2.51mg/kg; Pb0.00～8.76mg/kg, arsenic0.67～16.18mg/kg, Cd0.00～0.31mg/kg, chromium1.86～21.08mg/kg, mercury0.06～0.34mg/kg. The results showed that:1) GB/T22549-2008"feed-grade DCP" in the sub-type of feed-grade DCP unreasonable. GB13078-2001standard requirements for feed hygiene arsenic in inconsistent effects of arsenic exceedances DCP judgment requiring fewer indicators. New feed-grade DCP national standards should provide calcium, phosphorus, calcium and phosphorus mass ratio, pH, sulfate, fluoride, arsenic, lead and chromium. The DCP crystal water content is classified as a national standard defining quality indicators, is worthy of study.2) HG/T2860-2011"feed grade potassium dihydrogen phosphate" standards for the main content of potassium dihydrogen phosphate, phosphorus, potassium content, moisture, chloride, sulfate, pH, arsenic, lead and fluorine limited, products are in line with the actual situation. Potassium dihydrogen phosphate feed grade national standards may be formulated in accordance with the industry standards. National standards in order to improve product quality by adding water insoluble requirements. The study found that higher levels of chromium potassium dihydrogen phosphate, the standard should be limited to this heavy metal.3) Feed Grade Potassium phosphate dibasic no relevant industry standards and national standards. National standards can refer to the relevant product standards and standards of potassium dihydrogen phosphate, potassium hydrogen phosphate feed grade national standard main content, phosphorus and potassium content, moisture, water insoluble, chlorides, sulfates, pH, arsenic, lead, fluorine and chromium limit.Experiment3:Feed grade DCP chromium sourcesProduction of feed-grade DCP two paragraphs and precipitation, phosphate and sulfate formation reaction of fertilizer-grade phosphoric acid, phosphoric acid and calcium source calcium hydrogen phosphate and some clear liquid, some clear liquid generated reacts with calcium salts fertilizer grade dicalcium phosphate and Sec supernatant, Sec supernatant generated reacts with calcium salts of feed-grade DCP and three sections of clear liquid. Select the7wet-sulfuricacid for production of feed-grade DCP manufacturers in Sichuan Province.Acquisition of feed grade dicalcium phosphate phosphate production process, sulfuric acid, calcium source, phosphoric acid,9kinds of samples of some serum, Sec supernatant, three sections supernatant, fertilizer grade dicalcium phosphate, feed grade dicalcium phosphate, wherein the chromium content was measured. The results showed that the phosphate rock, sulfuric acid, source of calcium, phosphate, some clear liquid, Sec supernatant, three sections of clear liquid fertilizer grade DCP, feed grade DCP chromium content ranges from31.33to70.74mg/kg,1.79～28.00mg/kg,3.62～8.04mg/kg,22.1450.54mg/kg,11.77-29.86mg/kg,7.74～16.21mg/kg,0.22～1.49mg/kg,37.6384.24mg/kg and5.82～20.15mg/kg; chromium content of the average of is44.92,7.53,5.40,37.50,19.06,11.14,0.69,56.69and14.91mg/kg. The results show that the use of chromium from the wet sulfuric acid production of feed-grade DCP phosphate, sulfate and calcium, Sec and precipitation of chromium transfer into fertilizer grade calcium hydrogen phosphate, and reduce the feed-grade DCP in order to control the content of chromium in good calcium hydrogen phosphate, to control the content of phosphate, sulfate and calcium salts of chromium. |
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