Organic recycling with metal addition
US7789931B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 14, 2007 |
| Grant date | Sep 7, 2010 |
| Priority date | — |
| Expiry date | Aug 8, 2028 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC05C3/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The invention is directed to methods for producing a granular nitrogen fertilizer from an organic material comprising adding a metallic salt to said organic material to form a slurry. Preferably the organic material comprises dewatered biosolids and contains water from a scrubber. Metallic salts that can be used comprise a salt of iron, zinc, or a mixture thereof. Preferred iron salts comprises ferric sulfate or ferric oxide, and preferred zinc salts comprises zinc sulfate or zinc oxide. Preferably, the metallic salt is mixed with an acid such as sulfuric acid to form an acidified metal salt. Slurry pH ranges from approximately 2-2.5. The acidified metal salt is added to the organic material in sufficient quantity to lower viscosity of the slurry such that the resulting fluid does not hinder fluid flow during operation. When the metallic salt comprises acidified ferric sulfate or ferrous sulfate, sufficient iron can be present to produce a fertilizer product with 0.1 weight percent to 10 weight percent iron sulfate calculated on a dry weight basis. The invention is also directed to fertilizer products made by the methods of the invention. Preferred products are granules and the met…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.