Water-coal slurry additives

Based on their functions, water-coal slurry additives can be divided into three categories: dispersants, stabilizers, and auxiliaries, among which dispersants are the most important. Water coal slurry additives are important auxiliaries essential in the production process of water coal slurry; particularly in the preparation of high-concentration, highly stable water coal slurry, the role of these additives is crucial. Dispersants enable coal particles to be evenly dispersed in water and form a hydration film on the particle surfaces, thereby giving the coal slurry fluidity. Based on the degree of dissociation upon dissolution in water, coal water slurry dispersants can be classified into anionic, cationic, amphoteric, and non-ionic types. The price ratio among these is 1:3:4:2. Considering cost-effectiveness, the coal water slurry dispersants that have been developed and selected both domestically and internationally are mainly of the anionic and non-ionic types; these include those based on naphthalene, humic acid, lignin, polyolefins, acrylics, as well as related composite products. Water-coal slurry stabilizers have two functions: one is to endow the water-coal slurry with shear-thinning rheological properties, meaning that it has a high viscosity when left at rest, but its viscosity can drop rapidly once it starts to flow ； The other is to give the precipitate a soft structure, preventing the formation of irreversible hard precipitates. At present, the coal water slurry stabilizers used mainly fall into two categories: inorganic electrolytes and polymer compounds, such as various soluble salts, polymer surfactants, cellulose, polyacrylate salts, etc.

Is the poster using it for the particle size of water-coal slurry? There are many dispersants available on the market; common ones include sodium hexametaphosphate, sodium pyrophosphate, ammonia water, water glass, sodium chloride, and others.

Types of polymeric flocculants The polymeric flocculants currently used in water treatment are water-soluble organic polymers with molecular weights ranging from tens of thousands to millions. Organic polymer flocculants are capable of forming larger flocs between particles, resulting in a strong surface adsorption effect. Therefore, rapid progress has been made in research and application both domestically and internationally in recent years. There are many types of flocculants, which can be divided into two major categories based on their origin: natural and synthetically produced. Natural polymer flocculants include starch, tannins, cellulose, sodium alginate, guar gum, animal glue, and gelatin, among others. Natural polymer flocculants can be chemically modified in various ways to meet different requirements; for example, starch can be modified into dextrin, alkali-treated starch, starch containing phosphate groups –CH2OPO(CH)2, and starch containing amino groups –CH2CH2NH2. Generally, natural polymer flocculants are inexpensive, but they have a low molecular weight and are unstable; large amounts are required for use, resulting in poor performance, and they may cause problems such as BOD when discharged. Therefore, synthetic polymer flocculants are used taking toxicity into account. Among them, the most widely used are polyacrylamides with a molecular weight of over 3 million and their derivatives. Practice has shown that different polymer flocculants yield significantly varying results when used to treat different water qualities, and the dosage required for optimal performance is quite narrow; exceeding this range can instead lead to re-stabilization. Molecules of water-soluble organic polymers or copolymers with high molecular weight contain numerous active groups that can interact with certain sites on the surfaces of colloidal particles and fine suspended particles, and their molecular weights range from hundreds of thousands to several million. Based on the dissociation of active groups on polymer monomers in water, they can be classified into three types according to their functional groups: non-ionic, anionic, and cationic. Table 1 shows the main functional groups of many polymer flocculants. Representative polymer flocculants commonly used at home and abroad include: non-ionic – polyacrylamide (abbreviated as PAM, with a molecular weight of 1.5 million to 9 million, and a typical commercial concentration of 8%), polyethylene oxide ； Anionic – polyacrylic acid (PAA), hydrolyzed polyacrylamide of polymethacrylic acid (HPAM), polysulfonated styrene ； Cationic – butyl bromo polyvinylpyrrolidone, polydiacrylamide dimethylamine (PDADMA). The dosage is generally between one part per million and two parts per million of the wastewater volume. When the flocculant is ionic and its charge is opposite to that of the surface charge of the colloidal particles, it exerts both an effect of reducing the ξ potential and an adsorption bridging effect, resulting in particularly significant flocculation ； And when its point charge is equal to the surface charge of the colloidal particles, it is required that the charges of both be not too strong. To fully utilize the adsorption and bridging effects of the flocculant, its long chains should be grown to the maximum extent possible, while the dissociable groups should reach the highest degree of dissociation and be fully exposed, so as to generate more charged sites and provide more opportunities for collisions with particles; as a result, the flocculation effect can be enhanced several times over. Table 1: Major functional groups of polymeric flocculants. Non-ionic functional groups: ——OH hydroxyl group / ——CN nitrile / ——CONH2 amide. Cationic functional groups: ——NH2 primary amine / ——NH—R secondary amine / ——N—RR tertiary amine / R—N—RR quaternary amine. Cationic functional groups also include: ——COOH carboxylic acid / ——SO3H sulfonic acid / ——OSO3H sulfonate. Of course, the choice and dosage of flocculants depend on the specific properties of the wastewater; the general principle is that the flocculants used should be inexpensive, readily available, effective, and require a low dosage. The resulting flocs are easy to settle and separate. When using inorganic flocculants, attention should be paid to their suitable pH range; generally, a pH adjuster is added after introducing the inorganic salt flocculant. For polymer flocculants, in order to fully utilize their chemical bridging effect in water, it is necessary to use polymer compounds that can disperse and dissolve uniformly in water and possess adsorption-active groups, as well as water-soluble polymer compounds. To achieve a better dispersion in water, it is generally first dissolved in pure water or soft water to form a solution of a certain concentration, which is then added to the wastewater to be treated. Because these polymer compounds are often affected by water quality. This suppresses the diffusion of molecules and the dissociation of ion groups, resulting in a reduced treatment effect. ※　In terms of flocculation reactors, the commonly used types at present include: partitioned reaction tanks, vortex-type reaction tanks, mechanically stirred reaction tanks, static mixers, Venturi tube mixers, mechanically accelerated clarifiers, fixed flocculators, and so on. To destabilize the colloid and increase the size and density of the floc particles, as well as to reduce energy and chemical consumption, it is necessary to conduct in-depth research on the structural design of flocculation equipment and develop new, efficient types of such equipment. Two of the most effective flocculation devices are the multipolar eddy current tubular mixer designed based on eddy current theory, and the vertical reciprocating baffled flocculation reactor that enhances the flocculation effect by increasing water flow turbulence through a series of grids.

It’s available at the Weihe Fertilizer Factory; give them a call and ask

Currently, sodium lignosulfonate is generally used in the Texaco process.

:handshake Thank you all for your help:D :D

A water treatment center should be available in Tianjin!

Often, many types are required for experiments, but only small amounts are needed, making them difficult to obtain. . It is recommended that when you get in touch, do not say it’s for school use! ! This post was last edited by haohuang on 2009-2-17 15:43]

I produce here: water reducers, dispersants

I can provide 13920013121