Common salt is hygroscopic and water-soluble. If humidity of rock salt does not exceed 0.3% during transportation and storage, salt does not cake or freeze. Salt freezes up under adverse weather conditions, i.e. in case its humidity is higher than 0.3%, relative air humidity exceeds 75% and ambience temperature is lower than -15ºC. Provisions are made in the normative documents to add potassium ferrocyanide (K4[Fe(CN)6] • 3H2O) in order to prevent salt from freezing during transportation and storage under adverse weather conditions as follows: 1.DSTU 3583-97 (GOST 13830-97) and GOST R 51574-2000 – up to 10 g per metric ton; 2.GSTU 14.4-00032744-005-2003 and DSTU 4246:2003 – up to 150 g per metric ton.

It is possible to add other quantity of anticaking agent (n) for the products manufactured according to GSTU 14.4-00032744-005-2003 and DSTU 4246:2003, but maximum values may not exceed those of indicated standards. Should the Buyer order other quantity of anticaking agent, actual quantity of adding is reduced to 20% and extreme deviations from the nominal are limited to (n-0.2) ± 0,2 n.