Coagulants for lead-silver slag filtration and their preparation methods

Abstract

This invention discloses a coagulant for filtering lead-silver slag and its preparation method. The coagulant consists of the following components by weight: 15-18 parts of a 10% acrylonitrile solution; 0.1-0.105 parts of water glass; 0.2-0.4 parts of sulfurous acid; 2.0-2.5 parts of calcium oxide; and 1.0-1.5 parts of aminosulfuric acid. The preparation method is as follows: acrylonitrile, water glass, and sulfurous acid are weighed and placed in a fixed-bed reactor, heated and pressurized to boiling, then calcium oxide is added. After sufficient reaction, aminosulfuric acid is added to adjust the pH of the solution to neutral. After cooling, the coagulant precipitates. The coagulant prepared by this method undergoes extension and expansion after hydrolysis, increasing the flocculation rate and enhancing the flocculation force. It can be adsorbed onto the surface of the target mineral, and through entrainment and bridging effects, it causes the fine target minerals to aggregate into large molecules, effectively disrupting the colloidal stability of the lead-silver slag and accelerating its settling speed. This coagulant is non-toxic, has strong adsorption capacity, is simple to prepare, has low cost, does not pollute the environment, and has good application prospects.

Description

Technical Field

[0001] This invention relates to the field of pretreatment technology for ores or waste residues, specifically to a coagulant for filtering lead-silver slag and its preparation method. Background Technology

[0002] The wet zinc smelting process generates a large amount of lead-silver slag. Due to its fine particle size, high acidity, and predominantly viscous colloidal state, the lead-silver slag settles very slowly, making filtration difficult and time-consuming. Selective flocculation, a process developed in the 1960s, aims to flocculate the target mineral from a multi-mineral dispersion system. Common flocculants include inorganic, organic, and polymeric flocculants. To accelerate the settling of lead-silver slag, the addition of flocculants was considered. Extensive trials were conducted, including adding CMC, polyacrylamide, starch, styrene-maleic anhydride polymer, polyethylene oxide, ferrous sulfate, potassium aluminum sulfate, tannins, and polymeric flocculants #1 and #2, but none of these methods effectively accelerated the settling of the lead-silver slag. Summary of the Invention

[0003] The purpose of this invention is to provide a coagulant for filtering lead-silver slag and its preparation method. This coagulant has strong selectivity, high adhesion, and can effectively disrupt the stability of lead-silver slag colloids while forming large-particle flocs of the target minerals, thereby improving the settling speed of lead-silver slag and solving the problem of difficult filtration.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A coagulant for filtering lead-silver slag comprises the following ingredients in parts by weight: 15-18 parts of acrylonitrile solution with a mass percentage concentration of 10%; 0.1-0.105 parts of water glass; 0.2-0.4 parts of sulfurous acid; 2.0-2.5 parts of calcium oxide; and 1.0-1.5 parts of aminosulfuric acid.

[0006] A method for preparing a coagulant for filtering lead-silver slag includes the following steps:

[0007] Step 1: Weigh 15-18 parts by weight of acrylonitrile (10% concentration), 0.1-0.105 parts of water glass, and 0.2-0.4 parts of sulfurous acid, mix them evenly, place them in a fixed-bed reactor, heat and pressurize until the mixture boils, slowly add 2.0-2.5 parts of calcium oxide catalyst to the mixture, and react for 50-55 minutes.

[0008] Step 2: Add 1.0-1.5 parts of aminosulfuric acid to the boiling mixture, adjust the pH of the solution to 6.0-7.0, and lower the temperature in the fixed-bed reactor to 0-4℃. Solids will precipitate out of the mixture.

[0009] Step 3: Add 2.0-3.0 parts of deionized water to rinse the precipitated solids to improve purity, and dry them to obtain a coagulant for filtering lead-silver slag. The coagulant is a milky white solid powder.

[0010] Preferably, in step 1, the temperature of the fixed-bed reactor during boiling of the mixed liquid is 100-110℃ and the pressure is 1.0Mpa-2.0Mpa.

[0011] Preferably, the modulus of the water glass is ≤3.

[0012] The reaction fraction that occurs in step 1 is as follows:

[0013] CH2=CHCN+H2SO3+Na2SiO3→CSiO3=CH-CSO3NH2·2NaH (1)

[0014] The reaction fraction that occurs in step 2 is as follows:

[0015] NH4SO3NH2+ CSiO3=CH-CSO3NH2·2NaH→CSiO3=CH-CSO3NH2+NaHSO3+2NH3↑ (2)

[0016] Verification has shown that the coagulant CSiO3=CH-CSO3NH2 prepared by this method can be hydrolyzed into —CSiO3=CHOH - With -CSO3NH3 + After hydrolysis, the coagulant molecules undergo significant extension and expansion, increasing their flocculation rate and enhancing their flocculation force. This coagulant exhibits good selectivity for lead-silver slag, undergoing multi-point adsorption at the lead-silver slag-water interface. It adheres tightly to the surface of the lead-silver slag, engaging in entrainment and bridging effects, rapidly transforming fine lead-silver slag particles into large flocs. This effectively disrupts the colloidal stability of the lead-silver slag, ensuring good dispersion of mineral particles and accelerating the settling speed of the lead-silver slag, thus solving the problem of difficult filtration.

[0017] The coagulant prepared by this invention is non-toxic, has strong adsorption capacity, and is simple to prepare, low in cost, and does not pollute the environment, thus having good application prospects. Attached Figure Description

[0018] Figure 1 This is a photograph of the coagulant prepared according to the present invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to specific embodiments.

[0020] Example 1

[0021] A coagulant for filtering lead-silver slag comprises the following ingredients in parts by weight: 16 parts of acrylonitrile solution with a mass percentage concentration of 10%; 0.1 parts of water glass; 0.4 parts of sulfurous acid; 2.1 parts of calcium oxide; and 1.25 parts of aminosulfuric acid.

[0022] A method for preparing a coagulant for filtering lead-silver slag includes the following steps:

[0023] Step 1: Weigh 16 parts by weight of acrylonitrile (10% concentration), 0.1 parts of water glass, and 0.4 parts of sulfurous acid, mix them evenly, place them in a fixed-bed reactor, heat to 105℃, pressurize to 2.0 MPa, and when the mixture boils, slowly add 2.1 parts of calcium oxide as a catalyst at a rate of 0.25 m / s, and react for 52 min.

[0024] Step 2: Add 1.25 parts of aminosulfuric acid to the boiling mixture, adjust the pH of the solution to 6.5, and lower the temperature in the fixed-bed reactor to 0°C. Solids will precipitate out of the mixture.

[0025] Step 3: Add 2.0 parts of deionized water to rinse the precipitated solids, and dry them to obtain the coagulant for filtering lead-silver slag.

[0026] Example 2

[0027] A coagulant for filtering lead-silver slag comprises the following ingredients in parts by weight: 17.5 parts of a 10% acrylonitrile solution; 0.105 parts of water glass; 0.35 parts of sulfurous acid; 2.25 parts of calcium oxide; and 1.5 parts of aminosulfuric acid.

[0028] A method for preparing a coagulant for filtering lead-silver slag includes the following steps:

[0029] Step 1: Weigh 17.5 parts by weight of 10% acrylonitrile, 0.105 parts by weight of water glass, and 0.35 parts by weight of sulfurous acid, mix them evenly, place them in a fixed-bed reactor, heat to 108℃, pressurize to 1.8 MPa, and when the mixture boils, slowly add 2.25 parts by weight of calcium oxide catalyst at a rate of 0.48 m / s, and react for 55 min.

[0030] Step 2: Add 1.5 parts of aminosulfuric acid to the boiling mixture, adjust the pH of the solution to 7.0, and lower the temperature in the fixed-bed reactor to 2°C. Solids will precipitate out of the mixture.

[0031] Step 3: Add 2.5 parts of deionized water to rinse the precipitated solids, and dry them to obtain the coagulant for filtering lead-silver slag.

[0032] Example 3

[0033] A coagulant for filtering lead-silver slag comprises the following ingredients in parts by weight: 18 parts of acrylonitrile solution with a mass percentage concentration of 10%; 0.105 parts of water glass; 0.4 parts of sulfurous acid; 2.0 parts of calcium oxide; and 1.15 parts of aminosulfuric acid.

[0034] A method for preparing a coagulant for filtering lead-silver slag includes the following steps:

[0035] Step 1: Weigh 18 parts by weight of acrylonitrile (10% concentration), 0.105 parts of water glass, and 0.4 parts of sulfurous acid, mix them evenly, place them in a fixed-bed reactor, heat to 110℃, pressurize to 1.75 MPa, and when the mixture boils, slowly add 2.0 parts of calcium oxide catalyst at a rate of 0.36 m / s to the mixture and react for 55 min.

[0036] Step 2: Add 1.15 parts of aminosulfuric acid to the boiling mixture, adjust the pH of the solution to 6.0, and lower the temperature in the fixed-bed reactor to 4°C. Solids will precipitate out of the mixture.

[0037] Step 3: Add 3.0 parts of deionized water to rinse the precipitated solids, and dry them to obtain the coagulant for filtering lead-silver slag.

[0038] Example 4

[0039] A coagulant for filtering lead-silver slag comprises the following ingredients in parts by weight: 15 parts of acrylonitrile solution with a mass percentage concentration of 10%; 0.102 parts of water glass; 0.3 parts of sulfurous acid; 2.5 parts of calcium oxide; and 1.2 parts of aminosulfuric acid.

[0040] A method for preparing a coagulant for filtering lead-silver slag includes the following steps:

[0041] Step 1: Weigh 15 parts by weight of acrylonitrile (10% concentration), 0.102 parts of water glass, and 0.3 parts of sulfurous acid, mix them evenly, place them in a fixed-bed reactor, heat to 100℃, pressurize to 1.5 MPa, and when the mixture boils, slowly add 2.5 parts of calcium oxide catalyst at a rate of 0.5 m / s to the mixture and react for 50 min.

[0042] Step 2: Add 1.2 parts of aminosulfuric acid to the boiling mixture, adjust the pH of the solution to 7, and lower the temperature in the fixed-bed reactor to 3°C. Solids will precipitate out of the mixture.

[0043] Step 3: Add 2.2 parts of deionized water to rinse the precipitated solids, and dry them to obtain the coagulant for filtering lead-silver slag.

[0044] Example 5

[0045] A coagulant for filtering lead-silver slag comprises the following ingredients in parts by weight: 17 parts of acrylonitrile solution with a mass percentage concentration of 10%; 0.103 parts of water glass; 0.2 parts of sulfurous acid; 2.3 parts of calcium oxide; and 1.0 part of aminosulfuric acid.

[0046] A method for preparing a coagulant for filtering lead-silver slag includes the following steps:

[0047] Step 1: Weigh 17 parts by weight of acrylonitrile (10% concentration), 0.103 parts of water glass, and 0.2 parts of sulfurous acid, mix them evenly, place them in a fixed-bed reactor, heat to 106℃, pressurize to 1.0 MPa, and when the mixture boils, slowly add 2.3 parts of calcium oxide as a catalyst at a rate of 0.31 m / s, and react for 53 min.

[0048] Step 2: Add 1.0 g of aminosulfuric acid to the boiling mixture, adjust the pH of the solution to 6.0, and lower the temperature in the fixed-bed reactor to 1°C. Solids will precipitate out of the mixture.

[0049] Step 3: Add 2.8 parts of deionized water to rinse the precipitated solids, and dry them to obtain the coagulant for filtering lead-silver slag.

[0050] In the above embodiments, the modulus of the water glass is ≤3.

[0051] The coagulant CSiO3=CH-CSO3NH2 prepared by this method can be hydrolyzed to —CSiO3=CHOH - With -CSO3NH3 + After hydrolysis, the coagulant molecules undergo significant extension and expansion, increasing their flocculation rate and enhancing their flocculation force. This coagulant exhibits good selectivity for lead-silver slag, undergoing multi-point adsorption at the lead-silver slag-water interface. It adheres tightly to the surface of the lead-silver slag, engaging in entrainment and bridging effects, rapidly transforming fine lead-silver slag particles into large flocs. This effectively disrupts the colloidal stability of the lead-silver slag, ensuring good dispersion of mineral particles and accelerating the settling speed of the lead-silver slag, thus solving the problem of difficult filtration.

[0052] The above are merely preferred embodiments of the present invention. It should be noted that, for those skilled in the art, other equivalent modifications and improvements can be made based on the technical teachings provided by the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a coagulant for filtering lead-silver slag, characterized in that: The ingredients include the following parts by weight: 15-18 parts of a 10% acrylonitrile solution; 0.1-0.105 parts of water glass; 0.2-0.4 parts of sulfurous acid; 2.0-2.5 parts of calcium oxide; and 1.0-1.5 parts of aminosulfuric acid. The preparation steps are as follows: Step 1: Weigh 15-18 parts by weight of 10% acrylonitrile, 0.1-0.105 parts of water glass, and 0.2-0.4 parts of sulfurous acid, mix them evenly, place them in a fixed-bed reactor, heat and pressurize until the mixture boils, slowly add 2.0-2.5 parts of calcium oxide to the mixture at a rate of 0.25-0.5 m / s, and react for 50-55 min. Step 2: Add 1.0-1.5 parts of aminosulfuric acid to the boiling mixture, adjust the pH of the solution to 6.0-7.0, and lower the temperature in the fixed-bed reactor to 0-4℃. Solids will precipitate out of the mixture. Step 3: Add 2.0-3.0 parts of deionized water to rinse the precipitated solids, and dry them to obtain a coagulant for filtering lead-silver slag. The coagulant is a milky white solid powder.

2. The method for preparing the coagulant according to claim 1, characterized in that: In step 1, the temperature of the fixed-bed reactor during the boiling of the mixed liquid is 100-110℃ and the pressure is 1.0Mpa-2.0Mpa.

3. The method for preparing the coagulant according to claim 1 or 2, characterized in that: The modulus of the water glass is ≤3.

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