Method for preparing flocculant for efficient settling separation of high-silicon and high-iron type red mud generated through Bayer process

[0018] Preparation of Flocculant Containing Hydroxamic Acid and Carboxyl Group at the Same Reaction pH Conditions

[0019] 1) Dry high molecular weight polyacrylamide (mass average molecular weight of 20-30 million, intrinsic viscosity of 1200-1750mL / g) in a vacuum drying oven at 50°C for 12 hours, weigh 3.505g into a 250mL three-necked round bottom flask, Add 100mL of distilled water, stir in a 40℃ water bath, 45-60r / min for 3h to dissolve the high molecular weight polyacrylamide completely;

[0020] 2) Under a nitrogen atmosphere, dissolve hydroxylamine hydrochloride in an equimolar sodium hydroxide solution, slowly add it dropwise to the polyacrylamide solution obtained in step 1) with a dropping funnel to control the hydroxylamine hydrochloride and polyacrylamide The molar ratio of the amide groups is 1.2~1.5;

[0021] 3) The control conditions of the entire reaction process: 45-60r / min mechanical stirring, 20-40g / L NaOH is used to adjust the pH of the aqueous reaction system to...

[0024] Preparation of Flocculant Containing Hydroxamic Acid and Carboxyl Group at the Same Reaction Temperature

[0025] Except that the reaction process conditions are: the pH of the reaction system is 14, the reaction temperature is 90-100° C., and the reaction time is 48 h, the flocculant is prepared in the same manner as in Example 1.

[0027] Preparation of flocculant containing both hydroxamic acid and carboxyl group under different reaction time conditions

[0028] Except that the reaction process conditions are: the pH of the reaction system is 14, the reaction temperature is 90° C., and the reaction time is 24 to 48 h, the flocculant is prepared in the same manner as in Example 1.