Preparation method for water-soluble potassium polymetaphosphate

Abstract

The present invention discloses a preparation method for water-soluble potassium polymetaphosphate, and relates to the technical field of potassium polymetaphosphate production and preparation. In the present invention, potassium dihydrogen phosphate is mixed with a divalent cationic metal oxide at a mixing mass ratio of 70-90:5-18 to obtained a mixture, wherein the divalent cationic metal oxide is one or more of calcia, magnesia and zinc oxide in the field of food processing; then the mixture is heated and melted, and the temperature is kept constant for 1-3 h at a temperature of 600-700° C.; and after temperature keeping, the melted mixture is cooled naturally to obtain a product. The water-soluble potassium polymetaphosphate prepared by the present invention has a high water solubility and effectively solves the application defect of a traditional potassium polymetaphosphate product which is insoluble in water.

Claims

1. A preparation method for water-soluble potassium polymetaphosphate, comprising the following steps: (1) mixing potassium dihydrogen phosphate with a divalent cationic metal oxide, at a mixing mass ratio of 86:14; (2) heating and melting the mixture at a temperature of 600-700° C., and keeping the temperature constant for 1-3 h to achieve complete polymerization; (3) cooling the melted mixture naturally and slowly after complete polymerization, wherein a time for cooling the melted mixture slowly to room temperature is 2-5 h, and thus water-soluble potassium polymetaphosphate is obtained; wherein the divalent cationic metal oxide is one or more of calcia, magnesia and zinc oxide.

2. The preparation method according to claim 1, wherein a heating temperature in step (2) is 650° C. and a constant temperature time is 2 h.

3. The preparation method according to claim 1, wherein a time for cooling naturally and slowly in step (3) is 4 h.

4. The preparation method according to claim 1, wherein the water-soluble potassium polymetaphosphate can be used in the fields of meat product rolling or injection process, cosmetic, coating, water-soluble phosphorus and potassium fertilizers, and water treatment.

Description

DETAILED DESCRIPTION

(1) To make the purpose, features and advantages of the present invention more clear and understandable, detailed description of the present invention will be explained below in details in combination with the embodiments. Several embodiments of the present invention are given in the detailed description. However, the present invention may be achieved in many different forms and will not be limited to the embodiments described herein. On the contrary, the purpose of providing the embodiments is to understand the disclosure in the present invention more thoroughly and comprehensively.

Embodiment 1

(2) 760 g of food-grade potassium dihydrogen phosphate and 140 g of calcia are uniformly mixed by a small V-type mixer to prepare a mixture;

(3) The mixture is contained in a 1000 mL porcelain dish and placed in a muffle furnace for heating and melting, and the temperature is kept constant for two hours at 650° C.; then the mixture is taken out and sprinkled on an 80×20×2 cm stainless steel plate, and cooled naturally and slowly to obtain the water-soluble potassium polymetaphosphate.

(4) As tested, the content of P.sub.2O.sub.5 in the water-soluble potassium polymetaphosphate prepared in the embodiment is 53.8 wt %, the content of K.sub.2O is 27.1 wt %, the content of Ca is 9.94 wt %, the dissolved quantity is 10 g/100 mLH.sub.2O, and the pH of a saturated aqueous solution is 7.3.

Embodiment 2

(5) 740 g of food-grade potassium dihydrogen phosphate and 160 g of magnesia are uniformly mixed by a small V-type mixer to prepare a mixture;

(6) The mixture is contained in a 1000 mL porcelain dish and placed in a muffle furnace for heating and melting, and the temperature is kept constant for two hours at 650° C.; then the mixture is taken out and sprinkled on an 80×20×2 cm stainless steel plate, and cooled naturally and slowly to obtain the water-soluble potassium polymetaphosphate.

(7) As tested, the content of P.sub.2O.sub.5 in the water-soluble potassium polymetaphosphate prepared in the embodiment is 54.1 wt %, the content of K.sub.2O is 26.8 wt %, the content of Mg is 9.96 wt %, the dissolved quantity is 10.1 g/100mLH.sub.2O, and the pH of a saturated aqueous solution is 7.5.

Embodiment 3

(8) 907 g of food-grade potassium dihydrogen phosphate, 43 g of calcia and 50 g of magnesia are uniformly mixed by a small V-type mixer to prepare a mixture;

(9) The mixture is contained in a 1000 mL porcelain dish and placed in a muffle furnace for heating and melting, and the temperature is kept constant for two hours at 650° C.; then the mixture is taken out and sprinkled on an 80×20×2 cm stainless steel plate, and cooled naturally and slowly to obtain the water-soluble potassium polymetaphosphate.

(10) As tested, the content of P.sub.2O.sub.5 in the water-soluble potassium polymetaphosphate prepared in the embodiment is 56.4 wt %, the content of K.sub.2O is 28.2 wt %, the content of Ca is 3 wt %, the content of Mg is 3 wt %, the dissolved quantity is 17.06 g/100mLH.sub.2O, and the pH of a saturated aqueous solution is 7.15.

Embodiment 4

(11) First, 776 g of phosphoric acid, 403 g of potassium hydroxide, 43 g of calcia and 50 g of magnesia are weighed. The potassium hydroxide, calcia and magnesia are uniformly mixed, placed in a 5000 mL beaker, added with water, and stirred to form a 55 wt % suspension. Then the phosphoric acid is added gradually under control, the phosphoric acid is added bit by bit while stirring, and stirring is continued after adding is finished until the suspension becomes clear.

(12) The clear suspension is contained in a 1000 mL porcelain dish and placed in a muffle furnace for heating, dehydrating and melting, and the temperature is kept constant for two hours at 650° C.; then the obtained material is taken out and sprinkled on an 80×20×2 cm stainless steel plate, and cooled naturally and slowly to obtain the water-soluble potassium polymetaphosphate.

(13) As tested, the content of P.sub.2O.sub.5 in the water-soluble potassium polymetaphosphate prepared in the embodiment is 56.1 wt %, the content of K.sub.2O is 28.05 wt %, the content of Ca is 3 wt %, the content of Mg is 3 wt %, the dissolved quantity is 16.5 g/100mLH.sub.2O, and the pH of a saturated aqueous solution is 7.1.

(14) The above embodiments only express several implementation modes of the present invention, and are described more specifically in details, but shall not be consequently interpreted as a limitation to the scope of the patent for the present invention. It should be noted that, for those ordinary skilled in the art, several deformations and improvements can also be made without departing from the concept of the present invention, all of which belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to appended claims.