US PATENT SUBCLASS 71 / 44
.~.~.~.~ Heat-treatment

Current as of: June, 1999
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71 /   HD   CHEMISTRY: FERTILIZERS

1  DF  PROCESSES AND PRODUCTS {5}
31  DF  .~ Inorganic material {5}
32  DF  .~.~ Phosphorus-containing {1}
33  DF  .~.~.~ Phosphates {6}
44.~.~.~.~ Heat-treatment {3}
45  DF  .~.~.~.~.~> Alkali metal and silicon values
46  DF  .~.~.~.~.~> Alkali metal values
47  DF  .~.~.~.~.~> Carbonates, oxides, sulfates, silicon, and halides

DEFINITION

Classification: 71/44

(under subclass 33) Methods of preparing phosphate containing fertilizers wherein the raw materials are subjected to a heat treatment, usually a high temperature heat treatment which is the essential or dominating feature of the process. Thus, the heat treatment of phosphate rock alone or in the presence of an inorganic substance at white, red or fusion heat temperatures, belongs here, irrespective of whether or not the substance is distinctly alkaline.