Mainly divided into two categories: iron preparation series and aluminum preparation series, of course, also includes its cluster of high polymer series.
Inorganic flocculants include aluminum sulfate, aluminum chloride, ferric sulfate, and ferric chloride. Commonly used aluminum salts are aluminum sulfate AL2(SO4)3.18H2O and alum AL2(SO4)3.K2SO4.24H2O. The other type is iron salt with ferric chloride hydrate FeCL3.6H2O. Ferrous sulfate hydrate FeSO4.7H2O and Iron sulfate.
Simple inorganic polymer flocculant, this type of inorganic polymer flocculant is mainly aluminum salt and iron salt polymer. Such as polyaluminum chloride (PAC), polyaluminum sulfate (PAS), polyferric chloride (PFC) and polyferric sulfate (PFS). The fundamental reason why inorganic polymer flocculant is better than other inorganic flocculants is that it can provide a large amount of complex ions, and can strongly adsorb colloidal particles, through adsorption, bridge, and cross-linking, so as to make the colloid coagulate. At the same time, physical and chemical changes occur, neutralizing the charge on the surface of colloidal particles and suspended solids, lowering the δ potential, making the colloidal particles change from repulsion to attracting, destroying the stability of the micelles, and causing the colloidal particles to collide with each other. Flocculent coagulation sedimentation is formed, the surface area of the sedimentation can reach (200～1000)m2/g, which has great adsorption capacity.
Off-white powder or orthogonal prismatic crystal flowing light yellow powder. Sensitive to light. Easy to absorb moisture. It dissolves slowly in water, but dissolves faster when there is a trace of ferrous sulfate in water, slightly soluble in ethanol, and almost insoluble in acetone and ethyl acetate. Slowly hydrolyzed in aqueous solution, relative density (d18) 3.097, decomposed when heated to 480°C. Commodities usually contain about 20% water and are light yellow, and some contain 9 molecules of crystal water, with a relative density of 2.1, and loss of 7 molecules of crystal water at 175°C.
1. Used for silver analysis and sugar quantitative determination. Used as a dye. ink. Clean water. Engraving of aluminum. disinfect. Polymerization catalyst, etc.
2. Analytical reagents, quantitative determination of sugars, iron catalysts, mordants, pigments for water purifiers, drugs.
3. The water treatment industry is used as a coagulant for water purification and a treatment agent for sludge.
4. It is used as a mordant and coagulant for industrial wastewater, and also used in pigments.
5. In medicine, iron sulfate is used as astringent and hemostatic agent.
6. Used in electrolytes such as zinc-nickel-iron alloy plating and zinc-iron-cobalt alloy plating.
It is easily soluble in water. Aluminum sulfate cannot be dissolved in pure sulfuric acid (just coexist). It dissolves in water together with sulfuric acid in sulfuric acid solution. Therefore, the solubility of aluminum sulfate in sulfuric acid is the solubility of aluminum sulfate in water. The precipitation at room temperature contains 18 molecules of crystal water, which is aluminum sulfate 18 hydrate, and most of the industrial production is aluminum sulfate 18 hydrate. Contains 51.3% of anhydrous aluminum sulfate, it will not auto-dissolve even at 100℃ (dissolve in its own crystal water). It is not easy to weather and lose crystal water. It is relatively stable. It will lose water when heated. It will decompose into alumina and sulfur oxides at high temperature. When heated to 770°C, it begins to decompose into alumina, sulfur trioxide, sulfur dioxide and water vapor. It is soluble in water, acid and alkali, but insoluble in ethanol. The aqueous solution is acidic. After hydrolysis, aluminum hydroxide is formed. The aqueous solution boils for a long time to produce basic aluminum sulfate. Industrial products are off-white flakes, granules or lumps, which are light green due to low iron salts, and the surface becomes yellow due to oxidation of low iron salts. The crude product is an off-white porous material with fine crystal structure. Non-toxic, dust can irritate the eyes.
1. Used as a paper sizing agent in the paper industry to enhance the water resistance and impermeability of paper;
2. After being dissolved in water, the fine particles and natural rubber particles in the water can be coagulated into large flocs, which can be removed from the water, so it is used as a coagulant for water supply and wastewater;
3. Used as a purifying agent for turbid water, and also as a precipitating agent, fixing agent, filler, etc. Used as an antiperspirant cosmetic raw material (astringent) in cosmetics;
4. In the fire protection industry, it forms a foam fire extinguishing agent with baking soda and foaming agent;
5. Analytical reagent, mordant, leather tanning agent, oil decoloring agent, wood preservative;
6. Stabilizer for albumin pasteurization (including liquid or frozen whole eggs, white or egg yolk);
7. It can be used as raw material for the manufacture of artificial gemstones, high-grade ammonium alum, and other aluminates;
8. In the fuel industry, it is used as a precipitant in the production of chrome yellow and lake dyes, and at the same time it plays a role of fixing and filling agent.
Modified single-cation inorganic flocculant
In addition to the commonly used polyaluminum and polyiron, there are also polyactive silica gel and its modified products, such as polysilicate aluminum (iron) and polyphosphoaluminum (iron). The purpose of the modification is to introduce some highly charged ions to improve the neutralizing ability of the charge, and to introduce hydroxyl, phosphate, etc. to increase the coordination and complexing ability, thereby changing the flocculation effect. The possible reason is that some anions or cations can Change the morphological structure and distribution of the polymer, or synergistic effect between two or more polymers.
1. Polysilicic acid flocculant (PSAA) is a new type of inorganic polymer flocculant due to its simple preparation method, wide source of raw materials and low cost. It has stronger oil removal ability for the treatment of heavy oil produced water in oilfields. It has great development value and wide application prospects.
2. Polysilicate ferric sulfate (PFSS) flocculant, it is found that highly polymerized silicic acid and metal ions can produce good coagulation effect. The metal ions are introduced into polysilicic acid, and the average molecular weight of the obtained coagulant is as high as 2×10, which may partially replace the organic synthetic polymer flocculant in water treatment.
3. The high-valent anions in polyphosphoric ferric chloride (PPFC) have a strong affinity with Fe3+, which has a greater impact on the hydrolysis solution of Fe3+, can participate in the complexation reaction of Fe3+ and can bridge between iron atoms to form Multi-nuclear complex; the electric neutralization and adsorption bridging effect of the negatively charged diatomite colloid in the water is enhanced, and at the same time, the volume and density of the alum flower are increased due to the participation, and the flocculation effect is improved.
4. Polyphosphoaluminum chloride (PPAC) is also based on the strong polymerization of phosphate on polyaluminum (PAC). The introduction of appropriate amount of phosphate into polyaluminum, through the polymerization of phosphate, makes PPAC a new Like a highly charged multinuclear intermediate complex with phosphate.
5. Polysilicate iron (PSF) not only can handle low temperature and low turbidity water well, but also has obvious advantages over the flocculation effect of ferric sulfate, such as less dosage, wide feeding range, short formation time and shape of alum The roughness is easy to settle, can shorten the residence time of the water sample in the treatment system, etc., thus improving the treatment capacity of the system, and has basically no effect on the pH value of the treated water.
Modified multi-cation inorganic flocculant
1. Polyferric aluminum chloride sulfate (PAFCS) has a better effect than alum in the treatment of drinking water and sewage; PAFCS has better effects than PAC in oily wastewater and printing and dyeing wastewater, and its decolorizing ability is also excellent; It has high specific gravity, fast flocculation speed, easy filtration, and high water output rate; its raw materials are all derived from industrial waste residues, and the cost is low, which is suitable for industrial water treatment. Aluminum-iron copolymerization composite flocculant also belongs to this type of product. Its raw materials, aluminum chloride and ferric chloride, are cheap traditional inorganic flocculants with wide sources and simple production processes, which are beneficial to development and application. The copolymer of aluminum salt and iron salt is different from the mixture of two salts. It is a flocculant that more effectively combines the advantages of PAC and FeCl3 and enhances the turbidity removal effect. Its effective iron and aluminum content (AL2O3+Fe2O3) is greater than 22%, and the product has strong hygroscopicity. Studies have shown that when the effective aluminum content of polyaluminum chloride (PAC) is greater than the effective aluminum and iron content of PAFCS, PAFCS has better results than alum in sewage treatment; PAFCS is better than PAC in oily wastewater and printing and dyeing wastewater. The effects are excellent, and the decolorization ability is also strong. The floc has a high specific gravity, fast flocculation speed, easy filtration, and high water output rate. Its raw materials are all industrial waste residues, and the cost is low, which is suitable for wastewater treatment.
2. Polymeric polyferrosilicon flocculant is also one of them. When it is used to treat domestic sewage, its treatment effect and COD removal rate are better than those of polymerized iron. The turbidity removal rate is over 99%, the decolorization rate is 65% to 70%, and COD removal The rate is 70%, and most of the ammonia nitrogen and all phosphorus in the domestic sewage can be removed.
3. Aluminum-iron copolymerization composite flocculant also belongs to this type of product. Its raw materials, aluminum chloride and ferric chloride, are cheap traditional inorganic flocculants, with wide sources and simple production processes, which are beneficial to development and utilization. The copolymer of aluminum salt and iron salt is different from the mixture of two kinds of salts. It is a flocculant that more effectively combines the advantages of PAC and FeCL3 and enhances the turbidity removal effect. Among them, the influence of the iron content and form distribution in the aluminum-iron copolymerized composite flocculant on the flocculation performance needs to be further studied. The pH value of the copolymer is determined by the hydrolysis ability of the PAC and FeCL3 solution, and the pH value of the corresponding solution is between the two mother liquors. , Depending on the content of aluminum salt or iron salt.
1. Polyferric sulfate is a cationic inorganic polymer flocculant of polyhydroxy and polynuclear combination. It can be quickly mixed with water in any ratio. It has a larger molecular weight than general inorganic hybrid flocculants. It is used as water When treating agent, it has strong adsorption, flocculation, coagulation and sedimentation performance, and the formation of flocs is large and fast, the flocs are not easily broken, the recoagulation performance is good, the water after precipitation is filtered quickly, and the pH value of the purified water is wide. .
2. Polyaluminum chloride is an inorganic coagulant. Mainly drinking water treatment, municipal sewage treatment and papermaking printing and dyeing wastewater treatment. Its price is low and the market application range is wide.
3. A new type of high-efficiency coagulant prepared by adding elemental iron ions or iron trioxide with other iron-containing compounds. Mainly used for drinking water and industrial wastewater treatment.