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BR-102021009685-B1 - Thermophosphate production process by blow molding.

BR102021009685B1BR 102021009685 B1BR102021009685 B1BR 102021009685B1BR-102021009685-B1

Abstract

PROCESS FOR PRODUCING THERMOPHOSPHATE BY BLOW MOLDING SINTERING. This invention patent describes a process for producing thermophosphate, obtained from a blow molding sintering process. The process is characterized by the following steps: Selection of raw materials; Segregation of raw materials into batches; Analysis of raw materials; Weighing of raw materials according to recipe; Mixing of raw materials; Pelletizing of the mixture; Sintering of the mixture in a blow molding sintering furnace; Crushing of the sinter mass; Grinding of the crushed product; Product analysis; and Packaging.

Inventors

  • JOSE ROBERTO VARELLA
  • ALINE CRISTINA PEREIRA SOUSA DE CAUX
  • TONY JEFFERSON SALES VILELA
  • SUELAINE COSTA DA SILVA

Assignees

  • VAMTEC S/A

Dates

Publication Date
20260317
Application Date
20210519

Claims (13)

  1. 1. THERMOPHOSPHATE PRODUCTION PROCESS BY BLOW SINTERING characterized by the fact that the process follows the following steps: a) Selection of raw materials b) Segregation of raw materials into batches c) Analysis of raw materials d) Weighing of raw materials according to recipe e) Mixing of raw materials f) Pelletizing the mixture in a pelletizing disc g) Sintering the mixture in a blow sintering furnace; the maximum sintering temperature being between 1250 and 1350°C h) Crushing of the sinter mass i) Grinding of the crushed product j) Product analysis k) Packaging; and by the fact that the process uses Anthracite, Soda Ash, Coke, Coal Mill Fiber and Phosphate Rock as raw materials.
  2. 2. A process for producing thermophosphate by blow molding sintering according to claim 1, characterized in that the segregation step occurs for each batch of raw material, separating and identifying the products.
  3. 3. PROCESS FOR PRODUCING THERMOPHOSPHATE BY SINTERING VIA BLOW MOLDING according to claim 1, characterized in that the analysis of the raw materials comprises physical tests evaluating particle size, density and moisture, and chemical tests evaluating the total and phosphorus content soluble in CNA - NEUTRAL AMMONIUM CITRATE via laboratory.
  4. 4. PROCESS FOR PRODUCING THERMOPHOSPHATE BY SINTERING VIA BLOW MOLDING according to claim 1, characterized by the weighing step – measuring the weight of the raw material using scales.
  5. 5. PROCESS FOR PRODUCING THERMOPHOSPHATE BY SINTERING VIA BLOW MOLDING according to claim 1, characterized in that the mixing step is carried out, determining the endpoint when complete homogeneity of the samples and the beginning of granulation are observed.
  6. 6. PROCESS FOR PRODUCING THERMOPHOSPHATE BY SINTERING VIA BLOW MOLDING according to claim 1, characterized in that the pelletizing step of a pre-granulated mixture is added to a pelletizing disc and water is added until the complete formation of micro-pellets ranging from 2-6 mm in average diameter.
  7. 7. PROCESS FOR PRODUCING THERMOPHOSPHATE BY SINTERING VIA BLOWING according to claim 1, characterized in that the sintering step comprises inserting the granulated material into a furnace equipped with five ventilation outlets covered by charcoal embers; with the formation of a combustion front that will traverse the entire mixture contained in the furnace by the forced passage of air blown from below the furnace, it will promote the burning of the coke, releasing energy that will serve to remove moisture from the mixture, calcination of carbonates and hydrates, chemical reactions with consequent formation of the soluble phase and partial melting of part of the material.
  8. 8. PROCESS FOR PRODUCING THERMOPHOSPHATE BY BLOW MOLDING SINTERING according to claim 7, characterized in that the sintering process variables are defined by the particle size of the mixture being between 1.0 mm < 90% < 6.0 mm; the maximum sintering temperature between 1250 and 1350°C; the ignition blow pressure at 490 Pa; ignition time between 2 and 5 min; process blow pressure between 3430 and 3920 Pa; bed height between 1200 and 2000 mm; and the sintering time between 45 and 60 min.
  9. 9. PROCESS FOR PRODUCING THERMOPHOSPHATE BY SINTERING VIA BLOW MOLDING according to claim 1, characterized in that crushing occurs after cooling to ambient temperature (23°C) by means of a cone/hammer crusher that will reduce the agglomerates to a size smaller than 5 mm.
  10. 10. THERMOPHOSPHATE PRODUCTION PROCESS BY BLOW SINTERING according to claim 1, characterized in that the grinding is carried out in a rod/ball mill for 30 minutes, aiming for 100% of the material to pass through a 0.150 mm sieve.
  11. 11. PROCESS FOR PRODUCING THERMOPHOSPHATE BY SINTERING VIA BLOW MOLDING according to claim 1, characterized in that the product obtained in each production cycle is sent to a laboratory for evaluation of the minimum required particle size (100% passing 0.150 mm), % Phosphate (20% minimum) and % Soluble Phosphate (14% minimum).
  12. 12. PROCESS FOR PRODUCING THERMOPHOSPHATE BY BLOW MOLDING SINTERING according to claim 1, characterized in that the product is packaged in big bags (1000 kg packages).
  13. 13. PRODUCT produced by the processes of claims 1 to 12, characterized in that said product consists of a sinter, composed of the raw materials: phosphate rock (fluorapatite), soda ash and solid fuel, and by the composition of 65.2% phosphate rock; 12.0% fuel (coal, coke, anthracite, among others); and 22.8% sodium carbonate.

Description

TECHNICAL FIELD [0001] This patent application consists of a process for producing thermophosphate from a blow molding sintering process, applied in the agronomy sector, more specifically in the fertilizer market. FUNDAMENTALS OF THE INVENTION [0002] Thermophosphates are phosphate fertilizers whose production process is based on heating phosphate rock. [0003] These phosphate fertilizers have low solubility in water, but are highly soluble in citric acid. This means that it is a source of phosphorus with gradual release promoted by the natural acidity of the soil solution or the influence of roots, especially for thermally treated thermophosphates. [0004] Thanks to the gradual release, that is, the slower the release, the efficiency of the fertilizer increases. This occurs due to the low fixation of phosphate by the soil, allowing for greater absorption by the plants. [0005] In short, the thermophosphate production process occurs through calcination or fusion. In the first case, developed in Germany in 1917, the process takes place at around 1300°C and aims to form rhenanite. This process consists of calcining phosphate rocks with alkaline salts, usually sodium carbonate. [0006] However, the production of thermophosphate by calcination is of low efficiency and productivity, in addition to the fact that it presents difficulties in controlling the temperature and composition of the mixture during the reaction along the furnace. [0007] Production via fusion, widely used in thermophosphate producing industries, aims to alter the structure of the phosphorus source rock, usually apatite, making the phosphorus more soluble (EMBRAPA, 1986). The fusion process, in which fluxing materials can be added to the charge, takes place in electric furnaces, with the molten mass being rapidly cooled with water after fusion to prevent rearrangement of the material's crystalline structure. The product is then crushed and ground to the required particle size. [0008] Thermophosphate is typically soluble in citric acid and insoluble in water, a characteristic that allows its gradual release into the soil when used in agronomic applications. This aspect presents an advantage over water-soluble phosphates, since the soil has soluble phosphorus available throughout the plant's growth. [0009] Rhenanite, a calcium and sodium phosphate with the chemical formula CaNaPO4, is a compound soluble in citric acid. This material is obtained from the calcination of a mixture of phosphate rock, soda ash, and silica, according to the reaction (Agrominerais para o Brasil, 2010): Ca10(PO4)6F2 + 4 Na2CO3 + 2 SiO2 = 6 CaNaPO4 + 2 Ca2SiO4 + 2 NaF + 4 CO2 STATE OF THE ART [00010] Currently in the state of the art there are some proposed solutions such as, for example, patent PI 9501458-6 B1, entitled PROCESS FOR USING LD STEEL SLAG IN A SINTERING PROCESS FOR THE PRODUCTION OF THERMOPHOSPHATE AGRICULTURAL FERTILIZERS, which describes a process for using LD steel slag in which it is mixed with phosphate substances, lime and/or dolomitic lime (or another source of magnesium), sodium salts, solid carbonaceous fuel, water and return fines, in appropriate proportions, in a mixer (8). The mixture is subjected to the Sintering Process, in a Sintering unit (10), the agglomerate being processed in a crusher (12), then classified in a screening system (14) and the raw product comminuted in a mill (17) to obtain the final product, in the desired granulometry. Among other advantages, the process offers solutions to environmental and economic problems arising from slag storage, very simple operational control, and lower operational investment costs when compared to traditional processes for obtaining thermophosphate agricultural fertilizers. [00011] Another document is BR 11 2012 010210 9, IMPROVED PROCESS FOR PRODUCING A THERMAL FERTILIZER FROM POTASSIUM-CONTAINING MINERALS, which teaches about a heat treatment process described as a method for producing a thermal fertilizer based on the sintering of mixtures containing phosphate rock, potassium-containing minerals, preferably Verdete ore, limestone and other water-soluble potassium sources such as sylvinite and potassium muriate (potassium chloride), aiming to increase the potassium content in the thermal fertilizer. [00012] Another document, BR 10 2017 017292 9, entitled PRODUCT AND PROCESS FOR PELLETIZING ALUMINUM PHOSPHATES WITH POLYMERIC SUSPENSION BASED ON CASSAVA STARCH PLASTICIZED WITH POLYOLS, discloses a process and product of fertilizer material in the form of pellets for use in the fertilizer industry. The formulation of fertilizer pellets based on thermophosphate-starch-polyol is produced from aqueous polymeric suspensions based on starch-polyol for the aggregation of thermophosphate material in order to produce pellets used in the fertilizer industry. The thermophosphate-starch-polyol aggregate pellets were produced with polymeric suspensions based on cassava starch, plasticized with polyols. [00013] Cu