SU1161461A1 - Method of extracting phosphorus from slime - Google Patents

Abstract

A method of extracting phosphorus from sludge by treating the sludge with phosphoric acid in the presence of an inorganic reagent with heating and stirring characterized in that, in order to increase the degree of phosphorus recovery from sludge stabilized with silica gel, the amount of ammonium fluoride used in the amount of inorganic reagent is providing the mass fraction ammonium fluoride, sludge and phosphoric acid equal

Description

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05 The invention relates to a process for the processing of phosphorus sludge formed during the electrothermal production of phosphorus. A method is known for extracting phosphorus from sludge by treating it with sulfuric acid in an amount of 0.093-0.123 parts by weight. for 1 evening phosphorus, followed by dilution of the suspension with water or ammonium carbonate solution LJ. The method for extracting phosphorus from the sludge by treating it with a mixture of phosphoric acid and hydrogen peroxide G- is closest to the technical result. The components are taken in an amount that provides the mass ratio of phosphoric acid to hydrogen peroxide to phosphorus equal to (1.21, 3): (0.09-0.1): 1, and the process is carried out at 55-65 ° C and stirring. A disadvantage of the known methods is the low degree of phosphorus recovery from sludges stabilized predominantly by gel-like silica, not exceeding 30-45%. The purpose of the invention is to increase the degree of extraction of phosphorus jH3 spam stabilized with gel-like silica. The goal is achieved by the fact that according to the method of extracting phosphorus from sludge, including treating phosphoric acid with isham, in the presence of an inorganic reagent with heating and mixing, ammonium fluoride is used in an amount in an amount that provides for the massive reduction of ammonium fluoride, with a phosphoric acid sludge in a quantity of ammonium fluoride; O, 13–0.14); 1: (O, 37–0.40), and the process is carried out at 90–95 ° C. Example 1. 25 g of sludge containing 20 g of phosphorus are poured into a reactor heated with and heated) 00 g of a solution containing 3.5 g of NH, F and 1 0 g HjPO .: The mixture is stirred for 30 minutes. After turning off the stirrer, the mixture is kept until separation into phosphorus in this phase and the solution with the dephosphorized sludge above it. 19.8 g of phosphorus is recovered, which is 99%. In tab. Figure 1 shows the effect of ammonium fluoride in the mixture on the degree of phosphorus recovery. Conditions of experience: t weight ratio sludge - 1: 0.4, T 30 min. In tab. Figure 2 shows the effect of phosphoric acid in the mixture on the degree of phosphorus recovery. Conditions of the pyg: t, f 30 min, the weight ratio NHjjF slime is 0.14: 1. In all experiments, the concentration of Hj PO is 75%. In tab. Figure 3 shows the effect of process temperature on the degree of phosphorus recovery. EXPERIENCE CONDITIONS: NH4F slurry ratio - HjPO 0.14: 1: 0.4-, min. As can be seen from the tables, upon reaching the optimum values, the degree of phosphorus extraction decreases (as the temperature rises higher, the phosphorus losses increase due to sublimation). The following process mechanism is possible: ammonium fluoride. interacts with gel-like silica with the production of ammonium silicofluoride, water, and ammonia. With a lack of phosphoric acid, the equilibrium shifts towards the starting compounds. As can be seen from the table. With an acid consumption rate of 1: 0.20, the formation of ammonium silicofluoride is completed. Consequently, the second function of phosphoric acid is to destabilize the structure of their highly active surfactants and organic components, which are necessarily included in any composition of phosphorus-containing sludge. Thus, the proposed technical solution allows to increase the degree of phosphorus recovery from sludge up to 99%, 9%, as well as to ensure the processing of any composition of phosphorus sludge.

Table 1

Extraction of phosphorus,% 94,597.5 Extraction of phosphorus 49, 9 74.75 84.0 pa,% Extraction of phosphorus,% 78.84 83.37

table 2

Table 3 99.682.078.5 96.399.9 96.15 86.33 95.97 99.94 Sublands

Claims (1)

METHOD FOR REMOVING PHOSPHORUS FROM Sludge by treating the sludge with phosphoric acid in the presence of an inorganic reagent while heating and stirring ^ characterized in that, in order to increase the degree of extraction of phosphorus from sludges stabilized by gel silicon dioxide, ammonium fluoride is used as an inorganic reagent in an amount providing the mass ratio of ammonium fluoride, sludge and phosphoric acid is equal to (0.13-0.14): 1: (0.37-0.40), and the process. lead at 90-95 ° C. from 1 1161461