Preparation method for iron sodium ethylene diamine tetraacetate

Abstract

The invention discloses a preparation method for iron sodium ethylene diamine tetraacetate. The preparation method comprises the following steps: (1) weighing a predetermined amount of ferrous sulfate heptahydrate, adding ferrous sulfate heptahydrate into deionized water, weighing a predetermined amount of bicarbonate, carbonate or a mixture of bicarbonate and carbonate, adding the weighed bicarbonate, carbonate or mixture into a ferrous sulphate solution, carrying out a reaction so as to obtain large-grain ferrous hydroxide precipitate and introducing air to completely oxidize ferrous hydroxide into reddish brown iron hydroxide powder for subsequent usage; (2) weighing a predetermined amount of ethylene diamine tetraacetic acid and sodium hydroxide and adding ethylene diamine tetraacetic acid and sodium hydroxide into deionized water; and (3) addin gthe iron hydroxide powder into the solution obtained in the step (2) under stirring according to a predetermined mol ratio, adjusting a pH value to 4.5 to 6.0, heating the solution to 60 to 80 DEG C, carrying out stirring reaction for 30 to 50 min and subjecting the solution to filtering and crystallization so as to obtain finished iron sodium ethylene diamine tetraacetate. The method provided by the invention prepares iron hydroxide through on-site oxidation of ferrous hydroxide, and the prepared iron hydroxide has high reaction activity, needs short time for subsequent chelation reaction and enables product yield to be high and production efficiency to be greatly improved.

Description

technical field [0001] The invention relates to a chelated trace element fertilizer, in particular to a preparation method of sodium ferric edetate. Background technique [0002] Although the content of iron in crops is small, it has two important functions: first, it is an important part of some enzymes and many electron transfer proteins; second, it can regulate the synthesis of chloroplast protein and chlorophyll. If the plant is deficient in iron, it will cause chlorosis between the leaf veins, which will affect the photosynthesis and respiration of the plant, resulting in reduced yield and quality of crops. The supplement of iron mainly includes inorganic iron fertilizers, such as ferrous sulfate, ferric sulfate, ferric chloride, etc., and chelated iron fertilizers, such as sodium ferric ethylenediamine tetraacetate, sodium ferric diethylenetriamine pentaacetate, Sodium ferric ethylenediamine di-o-hydroxyphenylacetate, etc. Inorganic iron fertilizer is easy to precipi...

AI Technical Summary

Problems solved by technology

[0004] 1. When ferric chloride or ferric sulfate is used as raw material for direct preparation in the process, the product will contain a large amount of inorganic salt by-products such as sodium chloride and sodium sulfate, which will be difficult to separate later and increase the cost of industrial production

[0005] 2. When disodium edetate is used as raw material in the process, there will also be a large amount of sodium ions in the product, which will reduce the purity of the product

[0006] 3. When iron oxide is used to prepare chelated iron, due to the low reactivity of iron oxide, high reaction temperature is required, and the reaction time will be greatly extended at the same time, resulting in high energy consumption and low efficiency.

Colloids are difficult to filter and wash, which will bring difficulties to subsequent production