Efficient biodegradable dust suppressant for open-pit mine and preparation method therefor

An efficient biodegradable dust suppressant for an open-pit mine, comprising the following components in percentage by weight:

• 2%-3.5% of gallic acid, 1.5%-2% of sodium alginate, 0.25%-2% of a surfactant, 0.5%-1% of an antifreeze liquid, and balance water;
• and a method for preparing the efficient biodegradable dust suppressant for an open-pit mine, comprising the following steps:
• (1) extracting the gallic acid from a pomegranate peel by supercritical extraction:
• using methanol or ethanol as an entrainer and performing the extraction at an extraction pressure of 25-40 MPa, an extraction temperature of 45-57° C., a CO2 flow rate of 9-12 L·h-1, a separation pressure of 4.5-5 MPa, and a separation temperature of 45-60° C. for 1-3 h;
• (2) preparing the antifreeze liquid by reacting formic acid with potassium carbonate, or potassium hydroxide with carbon monoxide in water under heating and pressurizing;
• (3) weighing the components in parts by weight;
• (4) placing the extracted gallic acid in deionized water with the pH approximately equal to 8.5, adding the sodium alginate after the gallic acid is completely dissolved, magnetically stirring the same until the sodium alginate is uniformly dissolved, then adding the antifreeze liquid, and fully stirring the same at a rotating speed of 50-80 r/min for 30-40 min at 40-50° C.;
• (5) adding the surfactant into the solution and fully stirring the same at a rotating speed of 150-200 r/min for 40-50 min;
• (6) after adding the balance water, fully stirring the same at a rotating speed of 150-250 r/min for 30-50 min to obtain the efficient biodegradable dust suppressant for an open-pit mine.