Reagents required:

1. Hydrofluoric acid (GB/T 620): 40% (mass fraction).

2. Sulfuric acid solution: c(1/2H2SO4) = 10 mol/L, take the amount of concentrated sulfuric acid (GB/T 625) 278 mL and slowly add to appropriate amount of water, stirring while adding, and then dilute to 1000 mL with water.

3. Sulfuric acid solution: c(1/2H2SO4) = 7.2 mol/L, take 200 mL concentrated sulfuric acid, slowly add appropriate amount of water, stir while adding, and then dilute to 1000 mL with water.

4. Ammonium molybdate-sulphuric acid solution: 17.2 g ammonium molybdate (GB/T 657) was dissolved in a suitable amount of sulphuric acid solution (4.3) and diluted to 1000 mL with sulphuric acid solution (4.3).

5. Ascorbic acid solution: 5 g ascorbic acid is weighed and dissolved in 100 mL water. It is now ready-made.

6. Antimony potassium tartrate solution: 0.34 g of antimony potassium tartrate was dissolved in 250ml water.

7. Mixed solution: add 10 ml ascorbic acid solution (4.5) and 5 ml antimony potassium tartrate solution (4.6) to 35 mL ammonium molybdate-sulphuric acid solution (4.4), mix well and prepare when used.

8. Standard phosphorus reserve solution (0.1mg/mL): 0.4392g of high-grade pure potassium dihydrogen phosphate (GB/T 1274) dried for 1 hour at 110 C was accurately weighed and dissolved in water, and diluted to 1000 mL with water.

9. Standard working solution of phosphorus (0.01 mg/mL): 10.0 mL standard reserve solution of phosphorus (4.8) was diluted to 100 mL with water and prepared when used.

Coal phosphorus analyzer supporting equipment:

1. Electronic balance

2. Muffle stove

3. Dryer

4. Electric heating plate