SU1395356A1 - Method of extracting metals from catalytic sludge when oxidizing paraffin - Google Patents

Abstract

The invention relates to catalytic chemistry, in particular the recovery of metals from catalyst slurry obtained during the wax oxidation process. The extraction of metals (MP, PB) from the sludge is carried out by treatment with an aqueous solution of K2COz at pH 7.5-8.5, followed by the separation of organic matter from the product containing metals. Then the latter is treated with 1-5 M solution of H2SO4. The method makes it possible to eliminate the discharge of lead with. sewage, up to 85-90% extract organic matter, 1 tab. 52% lead and 81.6% manganese.

Description

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This invention relates to the isolation of manganese and lead compounds from solid wastes from the production of synthetic fatty acids, obtained by the oxidation of paraffin in the presence of a catalyst, electrolytic manganese dioxide, containing impurities of lead compounds.

The purpose of the invention is the possibility of selectively extracting manganese and lead from the sludge due to certain conditions of processing the sludge and the product containing its metals.

; Example 1. 100 g of catalyst slurry obtained at the stage of washing the iieHHoro oxide with paraffin from the spent cat-visor and containing, in wt.%; manganese 27.2, lead 2.5, sodium 3.2, and organic compounds 30.5 (metals are present as oxides and salts of carboxylic acids) are placed in a two-neck flask with a bottom selection of products, equipped with a stirrer. 184 g of a 20% sodium carbonate solution are poured in and stirring is started. In this case, the sludge forms a lightly mobile suspension, which, after 30 minutes of stirring, is settled for 1 hour, the pH at this reaches 7.5, and the aqueous precipitate is drained through the bottom extraction. The precipitate is washed with a weakly alkaline solution of soda ash (0.5 g of Na2SO3 per 1 l of water) in a 1: 1 ratio and filtered. The amount of sediment is 101.6 g with a moisture content of 49.8%, the residual content of organic compounds is 0.5% or 1.4% of their content in the starting product. The resulting manganese and lead carbonates are insoluble in water and they remain almost completely in the sediment, since no manganese and lead compounds were found in the aqueous solution and filtrate. The filter cake is transferred to a beaker and treated with a 1 M solution of sulfuric acid in an amount equimolar with respect to metals (616.5 g). At the same time, the precipitate is dissolved and a secondary white precipitate is formed, which is separated by filtration (the amount of the precipitate is 20.5 g, the humidity is 50%). The aqueous solution (693 g) contains mainly manganese compounds (Mn — 3.92%) and a small amount of lead impurities (, 4). Characteristics of the products in the process are shown in table 1.

Example 2. 100 g of catalyst slurry containing, in wt.%: Manganese 19.2, sodium 3.5, lead 1.3, organic compounds 20, 170 g of a 10% aqueous solution of sodium carbonate are processed. After half an hour of stirring, the mixture with pH 8.0 is settled and the precipitate is separated by filtration. Sediment weight 86.5 g, humidity 44.3%. The precipitate is transferred from the filter to a beaker and treated with 86 g of 5 M sulfuric acid. As a result, a secondary precipitate of lead sulfate is formed, which is separated by filtration through a dense filter and sulphate solution.

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manganese veil. Obtain 4.4 g of secondary sediment with a moisture content of 45.5%, containing,%: lead 29.5, manganese 4.5 and 168.0 g of a solution of manganese sulfate with the content,%: manganese 11.0 and lead impurities 0.2 10. The degree of extraction of manganese in the form of a solution of MnSO4, containing 11% of manganese, is 99.0%, of lead as a precipitate of Pb8O4 - 99.8%. Characteristics of the products of the process are shown in the table. 0 The results for examples 3, 4, 5, 6 and 7, carried out in the specified parameters, are given in the table.

Example 8 (known) 100 g of sludge containing, in wt.%: Manganese 27.2, sodium 5.0, lead 2.5, organic compounds 30, are treated with glacial acetic acid in an excess amount with respect to equimolar ( on the content of metals - 70.2 g). The resulting suspension is thoroughly mixed for 30 minutes. Extraction is then carried out with diethyl ether. In this case, 44.7 g of organic compounds are recovered. After extraction, 500 ml of water are added to the suspension, the mixture is left to stand for 2 hours and the precipitate is separated by filtration. The amount of sediment after washing is 66.9 g (humidity 59.3%, content,%: manganese 14.7, lead 1.2 and organic compounds 7.7). 52% of lead compounds and 63.5% of manganese are transferred from the sludge to the aqueous solution, i.e., the operation is treated with acetic acid, the extraction of organic compounds with subsequent treatment with water does not effectively isolate metal compounds from the sludge.

The resulting solution is treated with sodium carbonate solution to pH 8.5 and the resulting secondary precipitate of metal carbonates is separated by filtration (the amount of sediment is 135.2 g, content,%: moisture 59.6, lead 1.7, manganese 23.2). Lead and manganese compounds are not detected in the filtrate. When treated with sodium carbonate, manganese and lead are precipitated from the solution together.

The separation of metals from catalyst slurry containing electrolytic manganese oxides under the conditions of the prototype method shows that already at the stage of separation of metals from the slurry, their loss with sediment and partial separation with water phase are observed, and subsequent treatment of Mg2CO3 leads to joint precipitation of manganese and lead with solid phase (secondary sediment). The degree of metal recovery is 52% for lead and 81.6% for manganese. The method also allows, in the proposed parameters, to extract with an aqueous solution of sodium carbonate, 85-5% 90% of the organic compounds contained in the catalyst slurry.

As can be seen from the table, the dissolution of organic compounds at pH 7.5-8.5 is optimal. Lower pH leads

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loss of manganese and lead from the aqueous phase, and an increase leads to a reduction in the recovery of lead from the precipitate. A 1-5 M solution of sulfuric acid is optimal when processing the solid phase, since a decrease in the indicated concentration leads to a decrease in the degree of lead precipitation, and an increase to the joint precipitation of manganese and lead. The resulting solution of manganese can be returned to the oxidation of paraffin as a catalyst.

The proposed method allows to eliminate the discharge of lead with wastewater, which has an important environmental effect. This also extracts organic compounds that are disposed of by industry. In addition, the implementation of the process at the specified optimal pH values of dissolution and concentration of sulfuric acid during the treatment of the solid phase allows you to avoid the loss of metals and

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with a high degree of selectivity, isolate them from solid catalyst slurries containing electrolytic manganese oxides.

Claims (1)

Invention Formula A method for separating metals from a catalytic slurry oxidation process of paraffin containing a catalyst in the form of a solid phase and organic compounds, including dissolving organic compounds, separating organic compounds from a product containing metals, and treating it with a chemical reagent, characterized in that the possibility of selectively extracting manganese and lead from sludge, dissolving is carried out with an aqueous solution of sodium carbonate at pH 7.5-8.5, and using 1-5 M solution of sulfuric acid as a chemical regenerant lots. 27.2 2.5 2.5 2.5 5.0 30.5 Water Phase 27.2 2.5 5.0 30.5 2.0 74 , 3-18, 3 30, 99.7 5.852, Os ryotka N3 Secondary sediment