Chemical transformation of limestone product excluded Chapter 25 classification and shifted precipitated calcium carbonate to tariff entries for compounds.

Precipitated calcium carbonate produced from limestone by washing, crushing, calcination, hydration and carbonation was treated as a separate commercially known, chemically defined compound rather than a mere mineral product. The process was held to go beyond mechanical treatment under Chapter 25 and to attract Note 2 to that Chapter, so the product was excluded from Chapter 25 classification. The uncoated variety was classified as a carbonate under Chapter 28, while the coated variety, on the HSN-based view adopted, fell under Heading 3823.00. Reliance on technical literature and earlier exemption cases was not accepted because they concerned different tariff language. The Revenue's classification was upheld and the appeal failed.

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Issues: Whether precipitated calcium carbonate, both uncoated and coated, was classifiable under Chapter 25 as a mineral product or under Chapter 28 and Chapter 38 as a chemically processed product, and whether the process adopted amounted to manufacture.

Analysis: The product was obtained from limestone through washing, crushing, calcination, hydration and carbonation, resulting in precipitated calcium carbonate as a separate commercially known and chemically defined compound. The process went beyond mere mechanical treatment contemplated by Chapter 25 and attracted the exclusion contained in Note 2 to Chapter 25. The uncoated variety was treated as a carbonate falling within Chapter 28, while the coated variety, on the view accepting the HSN guidance, was regarded as falling under Heading 3823.00. The competing reliance on technical literature and earlier exemption cases did not alter the position because those decisions dealt with different tariff language and not the present classification question.

Conclusion: The product was not classifiable under Chapter 25. The classification adopted by the Revenue was upheld and the appeal failed.

Ratio Decidendi: Where a mineral raw material is subjected to chemical transformation resulting in a separate chemically defined compound, the product ceases to be a mere mineral substance for Chapter 25 and is to be classified according to the tariff entry applicable to the resulting compound.

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