Patent GB-831918-A (GB)
Title: Method of extracting tartaric acid and potassium as pure nitrate from tartaric materials
IPC: C01D9/04
Filed: 1958-02-19
Abstract: Tartaric acid and potassium as pure nitrate are extracted from unroasted tartaric material by treating unroasted low-grade tartaric material having a content of up to 25% tartaric acid, unroasted high-grade tartaric material having a content of at least 40% tartaric acid, or a mixture of the high and low-grade unroasted materials in the cold with a mixture of nitric acid and sulphuric acid in the presence of water.  Particularly suitable tartaric materials are those derived from wine manufacture and which comprise a low-grade material containing about 15 to 25% tartaric acid and a high-grade material containing about 40 to 70% tartaric acid.  In one form of the invention the unroasted low-grade material or the unroasted high-grade material only is treated with a mixture of nitric and sulphuric acid in which the nitric acid is present in a stoichiometric amount equivalent to the amount of the potassium present in the starting material and in which the sulphuric acid is present in an amount in excess of the stoichiometric amount equivalent to the amount of calcium present in the starting material. In this case the excess of sulphuric acid present serves to dissolve completely the tartaric acid present.  In another form the unroasted low-grade material is treated with a mixture of nitric and sulphuric acid in which the nitric acid is present in an amount in excess of the stoichiometric amount equivalent to the amount of potassium present in the starting material and in which the sulphuric acid is present in a stoichiometric amount equivalent to the amount of calcium present in the starting material, the unroasted high-grade tartaric material being then added to the reaction mixture.  This second stage may be carried out at 60 DEG  to 80 DEG  C. or the temperature may be raised to 60 DEG  to 80 DEG  C. after the addition of the high-grade material.  The product may be treated with calcium carbonate to precipitate calcium tartrate, which is treated in conventional manner to obtain tartaric acid, while, the calcium tartrate mother liquors are purified, concentrated and crystallized to yield pure potassium nitrate.  The tartaric materials are preferably granulated prior to treatment with the acid mixture, the treatment being preferably carried out in a double-bottom vessel, the inner wall of which comprises a perforated plate on which the ground material is arranged in layers prior to contact with the acid mixture, the bottom layer comprising the coarsest particles and the top layer comprising the smallest particles.  The acid mixture passes downwards through the layers and is then recirculated on to the top layer.  The treatment may also be carried out in a column by percolation and recycling of the liquid.  An example is given.ALSO:Tartaric acid and potassium as pure nitrate are extracted from unroasted tartaric material by treating unroasted low-grade tartaric material having a content of up to 25% tartaric acid, unroasted high-grade tartaric material having a content of at least 40% tartaric acid, or a mixture of the high and low-grade unroasted materials in the cold with a mixture of nitric acid and sulphuric acid in the presence of water.  Particularly suitable tartaric materials are those derived from wine manufacture and which comprise a low-grade material containing about 15 to 25% tartaric acid and a high-grade material containing about 40 to 70% tartaric acid.  In one form of the invention the un-roasted low-grade material or the unroasted high-grade material only is treated with a mixture of nitric and sulphuric acid in which the nitric acid is present in a stoichiometric amount equivalent to the amount of the potassium present in the starting material and in which the sulphuric acid is present in an amount in excess of the stoichiometric amount equivalent to the amount of calcium present in the starting material. In this case the excess of sulphuric acid present serves to dissolve completely the tartaric acid present.  In another form the unroasted low-grade material is treated with a mixture of nitric and sulphuric acid in which the nitric acid is present in an amount in excess of the stoichiometric amount equivalent to the amount of potassium present in the starting material and in which the sulphuric acid is present in a stoichiometric amount equivalent to the amount of calcium present in the starting material, the unroasted high-grade tartaric material being then added to the reaction mixture.  This second stage may be carried out at 60 DEG  to 80 DEG  C. or the temperature may be raised to 60 DEG  to 80 DEG  C. after the addition of the high-grade material.  The product may be treated with calcium carbonate to precipitate calcium tartrate, which is treated in conventional manner to obtain tartaric acid, while the calcium tartrate mother liquors are purified, concentrated and crystallized to yield pure potassium nitrate.  The tartaric materials are preferably granulated prior to treatment with the acid mixture, the treatment being preferably carried out in a double bottom vessel the inner wall of which comprises a perforated plate on which the ground material is arranged in layers prior to contact with the acid mixture, the bottom layer comprising the coarsest particles and the top layer comprising the smallest particles.  The acid mixture passes downwards through the layers and is then recirculated on to the top layer.  The treatment may also be carried out in a column by percolation and recycling of the liquid.  An example is given.