A method for preparing carboxymethyl starch for vanadium-titanium magnetite concentrate pellets

Abstract

The invention discloses a method for preparing carboxymethyl starch for vanadium-titanium magnetite concentrate pellets, which comprises mixing NaOH and ethanol to obtain an alkalized material, mixing the alkalized material with corn starch and then crushing it, adding isooctyl alcohol polyoxyethylene ether monophosphate or polyoxyethylene octylphenol ether, and then adding sodium sulfite, and alkalizing the material at 35°C; cooling the alkalized material to room temperature, adding chloroacetic acid solution and the alkalized material; kneading the material at 65°C and then cooling it to room temperature, and crushing it to obtain carboxymethyl starch. The invention overcomes the defects of excessive use of organic solvents in traditional processes, so that the reaction is only carried out on the surface of starch particles, and the degree of substitution of the product and the viscosity of the paste are difficult to improve; and also overcomes the technical problem that the alkali and etherifying agent in the dry process are difficult to penetrate into the starch particles, resulting in uneven distribution of substituents. The uniformity of dry-process carboxymethyl starch can be effectively improved, and it can be applied to the preparation of vanadium-titanium magnetite pellets to significantly improve the strength of the pellets.

Description

Technical Field

[0001] The invention belongs to the technical field of modified starch, and in particular relates to a method for preparing carboxymethyl starch for vanadium-titanium magnetite concentrate pellets. Background Art

[0002] The research on carboxymethyl starch began in 1924, and the research and development of carboxymethyl starch in my country began in the mid-1980s. Carboxymethyl starch (CMS for short) is an important type of etherified starch derivative. It is a cold water-soluble polymer electrolyte produced by the etherification reaction of starch with sodium chloroacetate under alkaline conditions. It has been widely used in food, textiles, medicine, papermaking, agriculture and petrochemicals.

[0003] At present, most domestic CMS production adopts water-soluble method and organic solvent method. In the solvent method, alkali and chloroacetic acid react with starch at a large bath ratio to generate carboxymethyl starch ether. In order to keep the starch granules and avoid alkali swelling, an excess of organic solvent must be used, which is about 1-4 times the weight of starch. Under such conditions, the reaction still takes place on the surface of starch granules, and it is difficult for the reagent to enter the starch crystals to react. It is difficult to increase the degree of substitution and the viscosity of the paste. Although the color and alkalinity of the obtained product have improved after multiple organic solvent washings, the organic solvent consumption is very large, about 3-6 times the amount of starch, which increases the product cost. The dry preparation process has less solvent addition, less pollution, short process, low energy consumption, and simple equipment; but because the starch and reaction reagents in the dry process are difficult to mix evenly, the alkali and etherifying agent are difficult to penetrate into the starch granules, and the substituent distribution is uneven, which seriously affects the actual application effect of carboxymethyl starch. Summary of the invention

[0004] In order to overcome the defects of the above-mentioned prior art, the present invention proposes a dry modification method of starch, which can effectively improve the uniformity of dry carboxymethyl starch. The modified carboxymethyl starch is applied to the preparation of vanadium-titanium magnetite pellets, which can significantly improve the strength of the pellets and make the pellets have good metallurgical properties.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides a method for preparing carboxymethyl starch for vanadium-titanium magnetite concentrate pellets, comprising the following steps:

[0006] ① Mix 5 parts of NaOH, 5 parts of ethanol and 1 part of water evenly by mass to obtain an alkalized material.

[0007] ② Mix 9 parts of the alkalized material obtained in step ① with 23 parts of corn starch, and then crush them into 20-40 meshes using a crusher; the moisture content of the corn starch is less than or equal to 14%.

[0008] ③ Add 0.2-0.3 parts of polyoxyethylene isooctyl ether monophosphate or polyoxyethylene octylphenol ether to the material obtained in step ②, and then add 0.1 parts of sodium sulfite to the above material and mix well.

[0009] ④Alkalize the material obtained in step ③ at 35°C for 50 min.

[0010] ⑤ Cool the material after alkalization in step ④ to room temperature, add 10 parts of chloroacetic acid solution with a mass concentration of 84%, and add 2 parts of the alkalized material obtained in step ①.

[0011] ⑥ The material obtained in step ⑤ was kneaded in a kneader at 65°C for 2h.

[0012] ⑦ Cool the material obtained in step ⑥ to room temperature, and crush it to less than 100 meshes to obtain carboxymethyl starch.

[0013] In the above technical solution, further, the NaOH and ethanol in step ① are analytically pure; the grade of the corn starch in step ② is industrial grade one.

[0014] A carboxymethyl starch prepared by the above preparation method.

[0015] The carboxymethyl starch and the vanadium-titanium magnetite concentrate are mixed in a mass ratio of 15:3000 and then pelletized in a disc pelletizer to obtain green pellets with a particle size of 10 mm to 13 mm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the present invention overcomes the defects of the traditional process of producing carboxymethyl starch, that is, excessive use of organic solvents causes the reaction to proceed only on the surface of starch particles, and it is difficult to increase the degree of substitution and viscosity of the paste; it also overcomes the technical problem that the dry process alkali and etherifying agent are difficult to penetrate into the starch particles, resulting in uneven distribution of substituents, which seriously affects the actual application effect. The dry modification method of starch proposed by the present invention can effectively improve the uniformity of dry carboxymethyl starch, and the carboxymethyl starch is applied to the preparation of vanadium-titanium magnetite pellets, which can significantly improve the strength of the pellets and make the pellets have good metallurgical properties. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with specific examples, but the present invention is not limited in any way. To avoid redundant description, the raw materials in the following examples are all commercially available unless otherwise specified, and the methods used are all conventional methods unless otherwise specified. NaOH and ethanol in the examples are analytically pure, and corn starch meets the first-class product requirements of GB / T12309-1990 "Industrial Corn Starch".

[0018] Example 1

[0019] A method for preparing carboxymethyl starch for vanadium-titanium magnetite concentrate pellets comprises the following steps:

[0020] ① Mix 5 parts of NaOH, 5 parts of ethanol and 1 part of water evenly by mass to obtain an alkalized material.

[0021] ② Mix 9 parts of the alkalized material obtained in step ① with 23 parts of corn starch, and then crush it twice with a crusher to 20 mesh; the moisture content of the corn starch is less than or equal to 14%.

[0022] ③ Add 0.2 parts of isooctyl polyoxyethylene ether monophosphoric acid to the material obtained in step ②, and then add 0.1 parts of sodium sulfite to the above material and mix well.

[0023] ④Alkalize the material obtained in step ③ at 35°C for 50 min.

[0024] ⑤ Cool the material after alkalization in step ④ to room temperature, add 10 parts of chloroacetic acid solution with a mass concentration of 84%, and add 2 parts of the alkalized material obtained in step ①.

[0025] ⑥ The material obtained in step ⑤ was kneaded in a kneader at 65°C for 2h.

[0026] ⑦ Cool the material obtained in step ⑥ to room temperature, and crush it to less than 100 meshes to obtain carboxymethyl starch.

[0027] The carboxymethyl starch and vanadium-titanium magnetite concentrate were mixed and pelletized in a disc pelletizer, wherein vanadium-titanium magnetite concentrate was 3000 parts by mass, the carboxymethyl starch was 15 parts by mass, the pelletizing time was controlled to be 20 minutes, and the raw ball particle size was 10 mm-13 mm. The raw ball drop strength was measured to be 3.7 times.

[0028] Example 2

[0029] A method for preparing carboxymethyl starch for vanadium-titanium magnetite concentrate pellets comprises the following steps:

[0030] ① Mix 5 parts of NaOH, 5 parts of ethanol and 1 part of water evenly by mass to obtain an alkalized material.

[0031] ② Mix 9 parts of the alkalized material obtained in step ① with 23 parts of corn starch, and then crush them twice with a crusher to 40 mesh; the moisture content of the corn starch is less than or equal to 14%.

[0032] ③ Add 0.25 parts of polyoxyethylene octylphenol ether to the material obtained in step ②, and then add 0.1 parts of sodium sulfite to the above material and mix well.

[0033] ④Alkalize the material obtained in step ③ at 35°C for 50 min.

[0034] ⑤ Cool the material after alkalization in step ④ to room temperature, add 10 parts of chloroacetic acid solution with a mass concentration of 84%, and add 2 parts of the alkalized material obtained in step ①.

[0035] ⑥ The material obtained in step ⑤ was kneaded in a kneader at 65°C for 2h.

[0036] ⑦ Cool the material obtained in step ⑥ to room temperature, and crush it to less than 100 meshes to obtain carboxymethyl starch.

[0037] The carboxymethyl starch and vanadium-titanium magnetite concentrate were mixed and then pelletized in a disc pelletizer, wherein 3000 parts of vanadium-titanium magnetite concentrate and 15 parts of carboxymethyl starch were added, the pelletizing time was controlled to be 20 minutes, and the raw ball particle size was 10mm-13mm. The raw ball drop strength was measured to be 4.1 times.

[0038] Example 3

[0039] A method for preparing carboxymethyl starch for vanadium-titanium magnetite concentrate pellets comprises the following steps:

[0040] ① Mix 5 parts of NaOH, 5 parts of ethanol and 1 part of water evenly by mass to obtain an alkalized material.

[0041] ② Mix 9 parts of the alkalized material obtained in step ① with 23 parts of corn starch, and then crush it twice with a crusher to 30 mesh; the moisture content of the corn starch is less than or equal to 14%.

[0042] ③ Add 0.3 parts of polyoxyethylene octylphenol ether to the material obtained in step ②, and then add 0.1 parts of sodium sulfite to the above material and mix well.

[0043] ④Alkalize the material obtained in step ③ at 35°C for 50 min.

[0044] ⑤ Cool the material after alkalization in step ④ to room temperature, add 10 parts of chloroacetic acid solution with a mass concentration of 84%, and add 2 parts of the alkalized material obtained in step ①.

[0045] ⑥ The material obtained in step ⑤ was kneaded in a kneader at 65°C for 2h.

[0046] ⑦ Cool the material obtained in step ⑥ to room temperature, and crush it to less than 100 meshes to obtain carboxymethyl starch.

[0047] The carboxymethyl starch and vanadium-titanium magnetite concentrate were mixed and pelletized in a disc pelletizer, wherein 3000 parts of vanadium-titanium magnetite concentrate and 15 parts of carboxymethyl starch were added, the pelletizing time was controlled to be 20 minutes, and the raw ball particle size was 10mm-13mm. The raw ball drop strength was measured to be 3.4 times.

[0048] For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing carboxymethyl starch for vanadium-titanium magnetite concentrate pellets, characterized in that: The method comprises the following steps: ① Evenly mix 5 parts of NaOH, 5 parts of ethanol and 1 part of water by mass to obtain an alkalized material; ② Mix 9 parts of the alkalized material obtained in step ① with 23 parts of corn starch, and then crush them twice with a crusher to 40 mesh; the moisture content of the corn starch is less than or equal to 14%; ③ Add 0.25 parts of polyoxyethylene octylphenol ether to the material obtained in step ②, and then add 0.1 parts of sodium sulfite to the above material and mix well; ④Alkalize the material obtained in step ③ at 35°C for 50 min; ⑤ Cool the material after alkalization in step ④ to room temperature, add 10 parts of chloroacetic acid solution with a mass concentration of 84%, and add 2 parts of the alkalized material obtained in step ①; ⑥ Knead the material obtained in step ⑤ in a kneader at 65°C for 2 h; ⑦ Cool the material obtained in step ⑥ to room temperature, crush it to less than 100 meshes, and obtain dry-process carboxymethyl starch; The dry carboxymethyl starch is mixed with vanadium-titanium magnetite concentrate and then pelletized in a disc pelletizer, wherein 3000 parts of vanadium-titanium magnetite concentrate and 15 parts of carboxymethyl starch are added. The pelletizing time is controlled to be 20 min, and the particle size of the green balls is 10-13 mm. The drop strength of the green balls is measured to be 4.1 times.

2. The method for preparing carboxymethyl starch for vanadium-titanium magnetite concentrate pellets according to claim 1, characterized in that: The NaOH and ethanol described in step ① are analytically pure.

3. The method for preparing carboxymethyl starch for vanadium-titanium magnetite concentrate pellets according to claim 1, characterized in that: The grade of the corn starch in step ② is industrial grade one.

4. A carboxymethyl starch prepared by the method according to any one of claims 1 to 3.