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All-rounder for calcium hydroxide water treatment solutions

　　Calcium hydroxide (Ca(OH)₂), commonly known as slaked lime, by virtue of its strong alkalinity (pH 12.4), high reactivity and low-cost features, has become a sewage treatment plant, electroplating, printing and dyeing, chemical industry and other essential agents. So, do you know what are the specific uses of calcium hydroxide water treatment? As a professional manufacturer of calcium hydroxide, we are committed to providing customers with high-quality products and customized solutions to help you achieve efficient and environmentally friendly water treatment goals. This article will summarize the seven core technologies in calcium hydroxidethe water treatment solution.

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Seven core technologies for calcium hydroxide water treatment solutions

　　1. Precise neutralization and adjustment of sewage and wastewater

　　Water treatment work, one of the indispensable step is to first neutralize and adjust the sewage wastewater so that the pH value of sewage wastewater to meet the subsequent treatment and discharge requirements. The pH value of sewage should be between 6.0~9.0, we can use calcium hydroxide to carry out PH neutralization, pre-adjustment of acidic sewage network, calcium hydroxide has a strong alkaline, can protect the pipeline to avoid the corrosion of acidic sewage, prolonging the use of the network time, which can greatly save the investment cost. The aqueous solution of calcium hydroxide is strongly alkaline, it can neutralize the acidic wastewater before discharging it, which protects the service life of underground water pipes.

　　Mechanism of action:

　　Rapidly adjust the pH value of acidic wastewater through neutralization reaction:

　　Ca(OH)₂ + 2H⁺ → Ca²⁺ + 2H₂O

　　Industry Applications:

　　Electroplating pickling wastewater (pH<3) treatment

　　Mining acidic wastewater (containing sulfuric acid) neutralization

　　Pre-treatment of chemical organic acid wastewater (e.g. citric acid)

　　Technical Advantage:

　　Compared with sodium hydroxide, the slow-release property of calcium hydroxide can avoid drastic fluctuation of pH value and reduce the treatment cost by about 45%.

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　　2. Cation replacement and water softening

　　Calcium hydroxide calcium ions can replace metal cations in water, especially in the process of wastewater treatment containing metal cations, in order to reduce the metal cations and some highly toxic substances on the biochemical section of the damage, the pretreatment process with calcium chloride to remove these toxic and harmful substances play a key role, and in the effluent section of the use of this substance, chlorine ions play a bactericidal role, the calcium ions generated Calcium hydroxide precipitation is removed by precipitation.

　　Mechanism of action:

　　Removes calcium and magnesium ions from water by ion exchange:

　　Ca(OH)₂ + Mg²⁺ → Mg(OH)₂↓ + Ca²⁺

　　Typical case:

　　Boiler feed water pretreatment hardness reduction

　　Textile industry to prevent calcium and magnesium deposits damage to equipment

　　3. Anion depth removal technology

　　Calcium hydroxide can effectively remove anions such as phosphate, sulfate and fluoride ions. In practice, it is also common to use milk of lime as a phosphate remover, because it is in addition to coagulation and precipitation, acid neutralization effect, calcium hydroxide as a coagulant has a good coagulation effect, and other pollutants also have a good removal effect, in alkaline conditions, when the PH value of about 10, the phosphate content in the water, the effect of phosphorus removal, the effluent can reach the comprehensive sewage discharge standards on the quality concentration of phosphate less than 1.0mg/ L of the provisions of the comprehensive sewage discharge standard.

　　Reaction equation:

　　3Ca(OH)₂ + 2PO₄³- → Ca₃(PO₄)₂↓ + 6OH-

　　Treatment effect:

　　Phosphorus removal rate >95% (up to GB 8978 Class A standard)

　　Fluoride concentration reduced from 20mg/L to <1mg/L

　　4. High-efficiency sterilization and disinfection system

　　Calcium hydroxide in water treatment can reduce the oxygen demand of biochemicals, bacteria and germs in the water body have a killing effect. Calcium hydroxide can change the characteristics of sludge, enhance sludge dewatering, sterilization and hydrolysis of organic matter, thus reducing the difficulty of water treatment. It also provides effective removal of ammonia nitrogen from sewage.

　　Principle of action:

　　Alkaline environment (pH>11) destroys microbial cell membranes and synergizes calcium ion flocculation to encapsulate pathogens.

　　Application Scenario:

　　Municipal wastewater plant secondary effluent disinfection

　　Inactivation of pathogens in aquaculture wastewater

　　5. Emulsion breaking key technology

　　Calcium hydroxide can also destabilize and break emulsion of emulsion wastewater, calcium hydroxide can make the water-in-oil emulsion with sodium soap as the emulsifier to transform the oil-in-water emulsion with calcium soap as the emulsifier. However, in its transformation process there is a dominant transformation from sodium soap to calcium soap dominant transformation point, when the emulsion is very unstable, can be used for oil-water separation.

　　Technological breakthrough point:

　　Destruction of the surface potential of oil droplets by charge neutralization (zeta potential rises from -35mV to -5mV)

　　Calcium ions and emulsifier generate calcium soap (Ca(RCOO)₂) to realize oil-water separation

　　Treatment effect:

　　COD of oily wastewater reduced from 5000mg/L to <100mg/L

　　6. Coagulation and adsorption synergistic treatment

　　Calcium hydroxide in water treatment through its dissolution of Ca²⁺ neutralize the negative charge on the surface of the colloidal particles, reduce the zeta potential, prompting particles to aggregate, while the generation of CaCO₃ and Ca(OH)₂ colloids in the settling process of trapping suspended solids, the formation of large particles flocs. In addition, calcium hydroxide particles have a large specific surface area (15-25m²/g), which can effectively adsorb organic matter and some heavy metal ions in water, and form surface complexes with certain pollutants to further enhance the removal effect and significantly improve the efficiency of water treatment.

　　Mechanism of action:

　　Generate CaCO₃ colloid (particle size 0.1-10μm) adsorption of suspended matter

　　Combined with PAC (polymerized aluminum chloride) to improve flocculation efficiency by 30%.

　　7. Heavy metal and complex cracking technology

　　Calcium hydroxide can effectively break heavy metal complexes (such as EDTA-Cu, NTA-Cd, etc.) through its strong alkalinity (pH>11) and the competitive ligand effect of calcium ions, so that the heavy metal ions are released from the stabilized complexes and combined with hydroxide to produce insoluble hydroxide precipitates (such as Cu(OH)₂, Pb(OH)₂, etc.), and at the same time the generated CaCO₃colloid further adsorbs microscopic metals through co-precipitation. Co-precipitation further adsorption of trace heavy metal ions, and finally realize the efficient removal of heavy metals, the removal rate can reach more than 99%, widely used in electroplating, mining and other heavy metal-containing wastewater treatment.

　　Core reaction:

　　Ca(OH)₂ + Cu²⁺ → Cu(OH)₂↓ + Ca²⁺(Ksp=2.2×10-²⁰)

　　Pb²⁺ + Ca(OH)₂ → Pb(OH)₂↓ + Ca²⁺ (Ksp=1.2×10-¹⁵)

　　Technology Highlight:

　　Breakage of stabilizing complexes such as EDTA-Cu

　　Removal rate of lead, chromium, nickel, etc. >99.9

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Our products and services advantages

　　1. High quality calcium hydroxide products

　　Purity: ≥95%.

　　Fineness: 200-400 mesh can be customized

　　Packing: 25kg/bag or ton bag.

　　2. Customized solutions

　　Free water quality treatment program design

　　Continuous tracking service and optimization suggestions

　　3. Cost-effective analysis

Treatment process	Ton of water treatment cost (yuan)	Comparison with traditional process
Calcium hydroxide method	0.5-0.8	40-60% lower
Sodium hydroxide method	1.2-1.5	——

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Suggestions for comprehensive application of calcium hydroxide

　　1. Process optimization

　　Segmented dosing: first adjust pH to 8.5-9.5, then add coagulant.

　　Temperature control: maintain the reaction temperature at 20-35℃.

　　Stirring intensity: control G value at 50-80s-¹.

　　2. Cost analysis

Treatment process Ton of water treatment cost (yuan) compared with the traditional process
Calcium hydroxide method 0.5-0.8 40-60% lower
Sodium hydroxide 1.2-1.5 –

Successful Cases

　　Case 1: Electroplating wastewater treatment

　　Customer pain point:

　　Low pH value of wastewater (2.5-3.5)

　　Heavy metal content exceeds the standard

　　Solution:

　　Adopt calcium hydroxide two-stage neutralization process

　　Combined with special flocculant

　　Treatment effect:

　　pH value stabilized at 8.5-9.0

　　Heavy metal removal rate >99.5%

　　Annual cost savings of about 1.2 million yuan

　　Through the systematic application of calcium hydroxide treatment technology, the enterprise can significantly improve the efficiency of wastewater treatment, while reducing 30%-50% of the operating costs.If you are interested in Calcium Hydroxide Water Treatment Solutions， We are looking forward to cooperating with you to jointly promote the development of environmental protection.

If you need Calcium Hydroxide for Water Treatment, welcome to contact us!