How to determine water soluble Sulfates in clinker for optimum use of Gypsum

Hello Rajuram,

Water soluble sulphates can be extracted from finely ground clinker using hot water, followed by gravimetric determination of Barium Sulphate after treatment with Barium Chloride solution. eg

1. Grind 10g the clinker sample to completely pass 75um sieve.

2. Take 5g of the finely powdered clinker and add it to 150ml of water in a beaker.

3. Heat the contents of the beaker to 95oC and hold at this temperature for 10 mins.

4. Filter the contents of the beaker, while still hot, through a Whatman GF/F glass fiber filter, or a Whatman 540 filter paper. Washing the residue three times with small quantities (~20ml) of distilled water.

5. Acidify the filtrate with 10ml of conc. Hydrochloric acid.

6. Add 30ml of 5% Barium Chloride solution. Mix well and heat at 95oC for a further 10 mins to help coagulate the precipitate.

7. Filter the white barium sulphate precipitate from the solution, using a pre-weighed Whatman 540 filter paper, washing the precipitate in the filter paper three times with small quantities (~20ml) of distilled water. Make sure that all of the precipitate has been transferred from the beaker to the filter paper.

8. Dry the filter paper in an oven at 105oC for 1 hour.

9. Weigh the filter paper plus precipitate and subtract the weight of the filter paper to obtain the weight of BaSO4 precipitate.

10 The soluble sulphate content of the clinker (as SO4-2) is calculated by;-

     % SO4-2 = { (Weight of BaSO4)/233.43*96.06} / (Weight of clinker) * 100

Hope this helps,

Ted.

Dear Sir,

lot of thanks for your prompt response.

With warm Regards,