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BR-102024018376-A2 - Production of ammonium sulfate from pyrite waste.

BR102024018376A2BR 102024018376 A2BR102024018376 A2BR 102024018376A2BR-102024018376-A2

Abstract

This application aims to promote the production of ammonium sulfate from the reaction between sulfur-rich coal beneficiation tailings and ammonia. The pyritic tailings are subjected to a combustion process in a fluidized bed furnace at a temperature of approximately 850°C, after which a reaction occurs between the acidic fumes and ammonia. The process, according to this application, also uses an atomizer integrated with reactive absorption towers for drying the material. The entire proposed plant utilizes concepts of energy recovery and energy self-sufficiency, since the calorific value of the pyritic tailings is very low (~800 to 1500 kcal/kg) compared to Santa Catarina's energy coal, which has 4500 kcal/kg. Without a reformulation of the process towards energy integration, self-sufficiency would not be possible.

Inventors

  • Agenor DE NONI JUNIOR
  • JOSÉ OCTÁVIO DA SILVA SIERRA FERNANDEZ
  • TALES MEIRA GASPAR

Assignees

  • UNIVERSIDADE FEDERAL DE SANTA CATARINA

Dates

Publication Date
20260317
Application Date
20240906

Claims (7)

  1. 1. Process for the production of fertilizer from pyritic waste characterized by comprising four stages, namely: a) Drying and Granulometric Preparation; b) Burning Stage; c) Gas Absorption and Reaction Stage; d) Concentration Stage.
  2. 2. Process, according to claim 1, characterized in that the drying and particle size preparation step includes unit operations such as sieves, mills and dryers, in order to guarantee maximum performance.
  3. 3. Process according to claim 1, characterized in that the reaction step results in the production of fertilizer, still in aqueous solution.
  4. 4. Process, according to claim 1, characterized in that the ammonium sulfate concentration step includes passing the ammonium sulfate solution through a dryer for water evaporation and subsequent pulverization of the material, wherein this step also includes operations such as filter presses, which recycle part of the fertilizer, and disposal of inert material in byproduct streams.
  5. 5. Process according to claim 1, characterized in that the ammonium sulfate concentration step can be carried out by means of a crystallizer.
  6. 6. Use of a characterized pyritic tailings for the production of ammonium sulfate within the process as described in any one of claims 1 to 5.
  7. 7. Process according to claim 1, characterized in that in the reaction step, sodium hydroxide, potassium hydroxide, calcium hydroxide or magnesium hydroxide can be used in place of ammonium or ammonia to produce their respective sulfate salts.

Description

FIELD OF THE INVENTION [01] This application aims to promote the production of ammonium sulfate from the reaction between the tailings from the beneficiation of mineral coal, rich in sulfur, and ammonia. The pyritic tailings are subjected to a combustion process in a fluidized bed furnace at a temperature of approximately 850 °C; subsequently, the reaction between the acidic fumes and ammonia occurs. The process according to this application also uses a dryer integrated with reactive absorption towers for drying the material. The entire proposed plant utilizes concepts of energy recovery and energy self-sufficiency, since the calorific value of the pyritic tailings is very low, between 800 and 1500 kcal/kg, compared to Santa Catarina's energy coal, with 4500 kcal/kg. The proposed energy integration, aiming at energy self-sufficiency, is fundamental for the technical and economic viability of ammonium sulfate production. BACKGROUND OF THE INVENTION [02] Several state-of-the-art studies evaluate the efficiency of SO2 removal from the exhaust stream using ammonia. One of the most consolidated approaches was published in 1969, which establishes a process for converting sulfur dioxide into ammonium sulfate, as revealed in document US3472618. However, this document uses amines that have a higher pKa than ammonia. In addition, alcohol is used to assist in the precipitation of ammonium sulfate. [03] Starting in the 1990s, Jiangsu New Century Environmental Protection Inc. (JNEP) began developing technologies for desulfurization using ammonia. Currently, the company covers 80% of the entire desulfurization market in China, being the leader in desulfurization technologies. In 2003, the same company filed two patent applications (documents CN1283346C and CN1321723C), in which parameters for cooling dust removal and aqueous absorption desulfurization are proposed, ensuring that the treated gases have a concentration of less than 100 mg/Nm3 of SOx. However, ammonia emissions in the columns were high, and aerosols were formed after gas treatment. [04] In 2005, Jiangsu New Century Environmental Protection Inc. (JNEP) filed yet another patent application (CN100428979C), which addressed the design of an absorption tower divided into the following sections: oxidation section, crystallization, cold absorption, main absorption, and dehydration using dehumidifiers (demisters). Chinese patent holders have filed patents related to the development of wet ammonia desulfurization technologies, for example, document CN10009642, which presented a solution for desulfurization and denitrification of streams. However, operating conditions such as the composition of the washing solution are not specified, and ammonia emission control is limited to adding ammonia at multiple points in the column; in other words, process conditions associated with medium-scale operations are not met. [05] Other gas scrubbers for desulfurization have also been proposed in the state of the art. Document US10449488, for example, teaches a gas scrubber in which it would be possible to remove SO2 with the addition of either ammonium hydroxide or ammonia. The gas stream, rich in SO2, enters the equipment at a temperature between 116 and 149 °C. The SO2 inlet occurs near the ammonium sulfate reservoir, in the lower region of the equipment. The heat from the combustion gases promotes the concentration of the motive liquid, an aqueous solution containing fractions of ammonia, ammonium sulfite, and ammonium sulfate. A portion of the water present in the motive solution is evaporated, aiding in the concentration of ammonium sulfate and initiating the precipitation of the fertilizer. The concentrated ammonium sulfate solution is partly purged to other equipment for purification in evaporators, centrifuges, or dryers. Such unit operations require very high energy consumption, making this process unfeasible on a small scale. Furthermore, the process does not provide for energy reintegration, which is necessary when the sulfur-rich material has a low calorific value. [06] Document CA2971655 is also directed to the production of ammonium sulfate from SO2 using ammonia. For combustion-derived gases with a concentration of less than or equal to 30,000 mg/Nm3 of SO2, this document reports achieving desulfurization that allows the treated gases to have a maximum concentration of 2 mg/Nm3 at the outlet. The invention provides for feeding ammonia at different points in the column to prevent ammonia escape and aerosol formation. The authors ultimately divide the column into three sections: pre-washing, absorption, and fine particle control. However, again, the process does not contemplate the energy reintegration of the process, making it unfeasible in small and medium-scale plants. [07] It is clear, in the state of the art, that there is a demand for alternative processes, especially considering the use of recycle streams, aiming at energy recovery, especially for drying a waste