Sodium Metasilicate in Cleaning Applications: Hydration-Form Differences, Mechanisms of Action, and Selection Logic

1 The Nature of Sodium Metasilicate: Not Simply a Strong Alkali, but an Alkaline Silicate

Sodium metasilicate is a commonly used inorganic alkaline builder in household cleaning, industrial cleaning, metal cleaning, and powdered detergent systems. Its basic chemical composition is Na₂SiO₃, and it can form different hydrates. This article focuses on three forms: anhydrous sodium metasilicate, sodium metasilicate pentahydrate, and sodium metasilicate nonahydrate. Among them, anhydrous sodium metasilicate and sodium metasilicate pentahydrate are more commonly used in cleaning and detergent systems, while sodium metasilicate nonahydrate should be used with reference to the product specification and verified active content.

After sodium metasilicate enters water, it provides a strongly alkaline environment on the one hand and introduces silicate species on the other. Therefore, its role in cleaning systems is not limited to increasing the pH value. It also contributes to oil removal, detergency building, dispersion, anti-redeposition, and metal corrosion inhibition.

2 Hydration-Form and Active-Content Differences Among Anhydrous, Pentahydrate, and Nonahydrate Sodium Metasilicate

2.1 Basic Composition of the Three Product Forms

The core difference among anhydrous, pentahydrate, and nonahydrate sodium metasilicate lies in their different hydration states, that is, the different amounts of water of crystallization contained in the crystal. Water of crystallization is not simply external moisture; it is part of the crystal structure. It directly affects the molecular weight, active content, dissolution behavior, storage stability, and dosage conversion of the product.

Product Type	Molecular Formula	Relative Molecular Mass	Water of Crystallization Content	Calculated Anhydrous Na₂SiO₃ Content	Main Interpretation
Anhydrous sodium metasilicate	Na₂SiO₃	approx. 122.06	0	100%	Highest active content; provides the greatest alkalinity and silicate contribution per unit mass
Sodium metasilicate pentahydrate	Na₂SiO₃·5H₂O	approx. 212.14	approx. 42.5%	approx. 57.5%	Balanced active content, solubility, and handling properties; widely used in cleaning systems
Sodium metasilicate nonahydrate	Na₂SiO₃·9H₂O	approx. 284.20	approx. 57.1%	approx. 43.0%	Lower active content than the pentahydrate; dosage should be converted based on active content

The data in the table are theoretical values calculated from the molecular formulas of pure substances. For actual industrial products, indicators in the product certificate of analysis, such as sodium oxide, silicon dioxide, water-insoluble matter, loss on ignition, particle size, and moisture, should be used as the basis.

2.2 Influence of Active-Content Differences on Formulation

When comparing different hydrates, the appropriate approach is to evaluate how much effective Na₂SiO₃, Na₂O, and SiO₂ is provided per unit mass of product.

For example, from the perspective of theoretical effective Na₂SiO₃ content:

Target Effective Amount	Required Anhydrous Sodium Metasilicate	Required Sodium Metasilicate Pentahydrate	Required Sodium Metasilicate Nonahydrate
To provide approx. 1 kg of anhydrous Na₂SiO₃	approx. 1.00 kg	approx. 1.74 kg	approx. 2.33 kg

If 1 kg of anhydrous sodium metasilicate is directly replaced with 1 kg of sodium metasilicate pentahydrate, the actual effective Na₂SiO₃ content is only about 57.5%. If it is replaced with 1 kg of sodium metasilicate nonahydrate, the actual effective Na₂SiO₃ content is only about 43.0%. In detergent, machine dishwashing powder, metal cleaner, and similar systems, this will affect the pH value, alkali reserve, oil-removal performance, soil-dispersion ability, and product cost.

2.3 Performance Differences Caused by Water of Crystallization

Water of crystallization changes not only the active content but also the physical behavior of the product. Anhydrous sodium metasilicate has a high active content and is suitable for highly concentrated powders or moisture-sensitive formulations. However, issues such as moisture absorption, caking, localized high alkalinity, and heat release during dissolution require careful control.

Because sodium metasilicate pentahydrate contains water of crystallization, its effective content per unit mass is lower than that of the anhydrous product. However, it is generally more balanced in terms of solubility, ease of dosing, and formulation compatibility. Sodium metasilicate nonahydrate has an even lower active content and is suitable for systems with specific dissolution or handling requirements.

2.4 Na₂O and SiO₂ Are Conventional Composition Expressions in the Silicate Industry

The chemical formula of sodium metasilicate can be written as:

Na₂SiO₃

However, in industrial products such as silicates, water glass, and sodium metasilicate, compositions are commonly expressed in oxide form:

Na₂SiO₃ = Na₂O · SiO₂

Here, Na₂O and SiO₂ represent the composition of sodium metasilicate converted into “sodium oxide content” and “silicon dioxide content.”

Expression	Meaning
Na₂SiO₃	Chemical formula expression, indicating that the substance is sodium metasilicate
Na₂O	Calculated alkaline oxide component, used to represent the alkaline contribution
SiO₂	Calculated siliceous oxide component, used to represent the silicate contribution
Na₂O + SiO₂	Can be understood as important components of the effective solids in sodium metasilicate
SiO₂/Na₂O or Na₂O/SiO₂ molar ratio or composition ratio	Indicates the relative proportion of siliceous and alkaline components in a silicate system

It should be noted that Na₂O and SiO₂ are oxide-equivalent expressions used in the silicate industry. They do not mean that free Na₂O or free SiO₂ actually exists in the product.

3 Basis of Action After Sodium Metasilicate Enters Water

3.1 Strong Alkalinity Is the Starting Point of Cleaning Action

After dissolving in water, sodium metasilicate forms a strongly alkaline environment. A higher pH helps reduce the adhesion between oily soils and the substrate, promotes the neutralization of fatty acid soils, and, under appropriate temperature, alkalinity, and contact time, promotes partial hydrolysis or saponification of oils and fats. This makes some oily soils easier to emulsify, disperse, and detach from surfaces. In laundry powders, machine dishwashing powders, hard-surface cleaners, and metal degreasers, the alkalinity provided by sodium metasilicate is an important basis for its oil-removal performance.

3.2 Silicate Species Distinguish It from Caustic Soda

The silicate species formed after sodium metasilicate dissolves in water can participate in soil dispersion, particle suspension, mitigation of hard-water effects, and metal surface protection. This is the key feature that distinguishes sodium metasilicate from caustic soda. Caustic soda mainly relies on strong alkalinity to rapidly increase the system pH, making it suitable for strong degreasing and saponification. Sodium metasilicate, in addition to increasing pH, can also improve the overall interaction of the cleaning system with soils, hard-water ions, and metal surfaces.

4 Cleaning Mechanisms of Sodium Metasilicate

4.1 Oil Removal: High pH Promotes Oil Detachment and Saponification

Oily soils in household and institutional cleaning typically include animal and vegetable oils, sebum, food oil residues, industrial oils, and mixed organic soils. The strongly alkaline environment provided by sodium metasilicate can promote hydrolysis or saponification of oils and fats, converting some oily soils into substances that are more easily carried away by the aqueous phase. At the same time, high pH can weaken the bonding between oily soils and the substrate surface, making it easier for surfactants to enter the interface between the soil and the substrate, thereby promoting oil detachment, emulsification, and dispersion.

4.2 Builder Function: Improving the Effectiveness of Surfactants

The core role of a builder is to improve the overall efficiency of a cleaning system, rather than to perform cleaning alone. As an inorganic builder, sodium metasilicate mainly improves the performance of surfactants through the following mechanisms:

Builder Function	Mechanism
Maintaining alkalinity	Acidic soils and oils consume alkalinity during cleaning; sodium metasilicate helps maintain an effective pH value
Reducing hard-water effects	Ca²⁺, Mg²⁺, and other hard-water ions can reduce the efficiency of some surfactants; silicate systems can reduce the negative effects of hard water to a certain extent
Promoting emulsification	An alkaline environment facilitates emulsification and dispersion of oily soils
Suspending soils	Detached soil particles need to remain stably suspended to prevent redeposition

4.3 Dispersion and Anti-Redeposition: Keeping Soil from Returning After It Leaves the Surface

Cleaning is not only about detaching soils from surfaces; it also requires keeping soils in the cleaning solution and preventing them from reattaching to fabrics, tableware, equipment, or metal surfaces. The silicate system provided by sodium metasilicate helps improve the dispersion stability of soil particles in the aqueous phase. For mud, oily deposits, carbon black, metal oxide particles, and mixed soils, this dispersion effect can reduce soil redeposition and improve cleanliness after washing.

5 Corrosion Inhibition and Metal Cleaning Functions of Sodium Metasilicate

5.1 The Core Role in Metal Cleaning: Degreasing and Protection Together

In metal processing, mechanical maintenance, equipment cleaning, and parts cleaning, common surface contaminants include cutting oils, rust-preventive oils, greases, dust, metal chips, oxide particles, and mixed soils. The role of sodium metasilicate in metal cleaning mainly includes two aspects:

① Providing alkaline conditions to promote emulsification, saponification, and detachment of oily soils.

② Providing silicate species that, under certain conditions, participate in the formation of a protective layer on metal surfaces, thereby reducing the risk of continued corrosion during cleaning or flash rust after cleaning.

5.2 Corrosion-Inhibition Mechanism: Silicate-Based Surface Protection

The corrosion-inhibition effect of sodium metasilicate does not mean that it is safe for all metals. Rather, it means that under suitable pH, silicate concentration, water-quality, and formulation conditions, silicate species may provide a certain protective effect on specific metal surfaces. Its corrosion-inhibition mechanism is usually related to the adsorption, deposition, or reaction of silicate species on metal surfaces.

Under suitable conditions, silicate species may interact with oxides, hydroxides, or metal ions on the metal surface to form a surface layer with a certain barrier effect, thereby reducing the opportunity for corrosive media such as oxygen, water, and chloride ions to come into direct contact with the metal substrate. For steel surfaces, silicates may act through adsorption, deposition, or interaction with surface iron oxides to form less soluble silicates or composite protective layers, thereby showing certain corrosion-inhibition and flash-rust-reduction effects.

It should be noted that silicate protection is strongly system-dependent. Factors such as pH, temperature, sodium metasilicate concentration, contact time, water hardness, chloride ion content, metal type, and formulation components such as surfactants, chelating agents, phosphates, and phosphonates can all affect the final corrosion-inhibition performance. For alkali-sensitive materials such as aluminum, zinc, tin, plated parts, and certain alloys, sodium metasilicate systems should not be assumed to be safe by default. Substrate compatibility should be confirmed through testing under the actual cleaning concentration, temperature, and contact time.

6 Selection and Differences Between Sodium Metasilicate and Caustic Soda

6.1 Common Features

Both sodium metasilicate and caustic soda can provide alkalinity and can be used to remove oils, greases, and some organic soils. In strongly alkaline cleaning, both require attention to risks involving the skin, eyes, respiratory tract, and metal corrosion. However, having common features does not mean that they can be directly substituted for each other. They differ in chemical identity and formulation function.

6.2 Fundamental Differences

Comparison Item	Sodium Metasilicate	Caustic Soda
Chemical name	Sodium metasilicate	Sodium hydroxide
Typical molecular formula	Na₂SiO₃·nH₂O	NaOH
Chemical property	Alkaline silicate	Strong base
Main function	Provides alkalinity, builder function, dispersion, buffering, and corrosion inhibition	Rapidly provides OH⁻ and strongly increases pH
Cleaning characteristics	Emphasizes synergy in the overall cleaning system	Emphasizes strong alkaline saponification and degreasing
Effect on metals	Has certain corrosion-inhibition potential, but still requires testing	More direct corrosion risk, especially for amphoteric metals such as aluminum and zinc
Substitution relationship	Cannot replace caustic soda on an equal-mass basis	Cannot replace the silicate functions of sodium metasilicate

6.3 Selection Logic

Caustic soda is suitable for systems that require rapid pH increase, strong saponification of oils and fats, and strong degreasing, such as heavy-oil cleaning, strong alkaline degreasing, pipeline cleaning, and certain industrial cleaning scenarios. However, caustic soda is highly corrosive, releases significant heat during dissolution, poses higher risks to metals such as aluminum and zinc, and requires stricter operational safety controls.

Sodium metasilicate is more suitable for systems requiring comprehensive cleaning performance, such as laundry powders, machine dishwashing powders, hard-surface cleaners, metal degreasers, and powdered industrial cleaners. It not only provides alkalinity but also improves soil dispersion, anti-redeposition, and metal corrosion inhibition.

In actual formulations, the two can be combined according to cleaning strength, material compatibility, safety requirements, and cost targets. However, they cannot be simply substituted on an equal-mass or equal-pH basis.

7 Does Sodium Metasilicate Have Rust-Removal Function?

7.1 Sodium Metasilicate Is Not a Typical Primary Rust Remover

Sodium metasilicate can help treat certain rust-related soils, but it is not a typical primary rust remover. Rust is usually mainly composed of iron oxides and hydrated iron oxides. The true removal of firmly adherent rust layers generally relies on acid dissolution, complexation, reduction, or mechanical action. Common rust-removal systems include phosphoric acid, hydrochloric acid, oxalic acid, citric acid, sulfamic acid, chelating agents, or reducing components.

Sodium metasilicate belongs to alkaline cleaning systems and is better suited for oil removal, dispersion, suspension, and corrosion inhibition. It has a good auxiliary cleaning effect on oily soils, mud, and loose rust powder, but it is not the main active component for removing firmly adherent oxide scale or thick rust layers.

7.2 Why Sodium Metasilicate Sometimes Appears to Remove “Rust Stains”

The actual soils on metal surfaces are often not single-component rust, but mixed layers of oil, dust, mud, loose oxides, and rust powder. Sodium metasilicate can make the surface appear cleaner through the following actions:

Target Soil	Actual Role of Sodium Metasilicate
Oil-covered layer	Removes oil through alkalinity, emulsification, and saponification
Loose rust powder	Helps carry away particles through dispersion and suspension
Oil-rust mixed soil	First disrupts oil binding, then carries away some loose particles
Metal surface after cleaning	Reduces the risk of flash rust through silicate protection

Sodium metasilicate is not a primary rust remover. Rather, it is an auxiliary component in metal cleaning, oil removal, rust-powder dispersion, and post-cleaning corrosion-inhibition systems.

8 Application Selection of Anhydrous, Pentahydrate, and Nonahydrate Sodium Metasilicate

8.1 Selection by Application Objective

Application Objective	Suitable Choice	Reason
Highly concentrated strong alkaline powder	Anhydrous sodium metasilicate	High active content; large alkalinity and silicate contribution per unit mass
Laundry powder, dishwashing powder, general cleaning powder	Sodium metasilicate pentahydrate	Balanced overall performance and good formulation compatibility
Metal degreasing and industrial cleaning	Anhydrous or pentahydrate sodium metasilicate	Can be selected according to cleaning strength, solubility, and cost
Systems requiring more balanced dosing and dissolution behavior	Sodium metasilicate pentahydrate, or sodium metasilicate nonahydrate after evaluation based on specifications	Hydrated forms generally offer better handling properties, but active content must be converted
Strong saponification of heavy oily soils	Caustic soda or caustic-soda-based blended systems	NaOH provides a more direct strong alkaline effect

8.2 Composition, Physical Properties, and Application Indicators to Consider During Selection

Indicator	Importance
Effective Na₂SiO₃ content or calculated Na₂SiO₃ content	Reflects the amount of effective sodium metasilicate provided per unit mass of product; the core indicator for dosage conversion and cost comparison among anhydrous, pentahydrate, and nonahydrate products
Na₂O content	Reflects the calculated alkaline component content; affects pH value, alkali reserve, oil-removal ability, and material corrosion risk
SiO₂ content	Reflects the calculated siliceous component content; affects silicate builder function, soil dispersion, anti-redeposition, and metal surface protection
SiO₂/Na₂O molar ratio, or Na₂O/SiO₂ composition ratio	Reflects the relative relationship between siliceous and alkaline components; affects solution alkalinity, distribution of silicate species, buffering capacity, dispersion performance, and metal surface interactions
Water-insoluble matter	Affects clarity after dissolution, residue risk, and surface cleanliness after cleaning
Particle size and dust	Affect dosing, dissolution rate, dust exposure, and production operation safety
Bulk density	Affects packaging, metering, transportation, and powder-formulation volume
Hygroscopicity and caking tendency	Affect storage stability, dosing flowability, and consistency of batch use
pH value of a 1% aqueous solution	Reflects the actual alkalinity at a specified concentration and can be used to compare different batches or different hydrate products
Metal compatibility	Affects the cleaning safety of aluminum, zinc, plated parts, and precision metals; confirmation through application testing is required
Certificate of Analysis (COA) and Safety Data Sheet (SDS)	The COA is used to confirm batch composition and quality indicators; the SDS is used to confirm hazard classification, storage conditions, and protective measures during use

9 Misconceptions to Avoid When Using Sodium Metasilicate

9.1 Misconception 1: Anhydrous, Pentahydrate, and Nonahydrate Products Can Be Replaced on an Equal-Mass Basis

The three forms cannot be replaced on an equal-mass basis. Hydrated products contain a large amount of water of crystallization, so their effective Na₂SiO₃ content per unit mass is significantly lower than that of the anhydrous product. Equal-mass replacement will change pH value, alkalinity, cleaning power, cost, and product stability.

9.2 Misconception 2: Sodium Metasilicate Is Simply a Milder Version of Caustic Soda

Sodium metasilicate is not simply a milder version of caustic soda. It is still a strongly alkaline raw material with corrosive and irritating properties. Its advantage is not that it is “milder,” but that it provides both alkalinity and silicate functionality.

9.3 Misconception 3: Because Sodium Metasilicate Has Corrosion-Inhibition Properties, It Is Safe for All Metals

Sodium metasilicate has certain corrosion-inhibition potential, but this does not mean it is safe for all metals. Aluminum, zinc, tin, plated parts, and certain alloys may corrode under strongly alkaline conditions. Actual use must be confirmed through testing based on concentration, temperature, contact time, and substrate.

9.4 Misconception 4: Sodium Metasilicate Can Serve as a Primary Rust Remover

Sodium metasilicate can assist in removing oil-rust mixed soils and loose rust powder, but it is not a typical primary rust remover. For firmly adherent rust and oxide scale, acidic, complexing, reducing, or mechanical rust-removal systems should be used.

10 Classification Tables of Representative Chemicals Related to Sodium Metasilicate and Cleaning Systems

Table 1 Metasilicates and Alkaline Cleaning Builders

Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Core sodium metasilicate product	6834-92-0	S102095	Anhydrous sodium metasilicate	SiO₂, 44–47%	Used for active-content conversion of anhydrous sodium metasilicate, strong alkaline building, powdered cleaning agents, metal degreasing, and research on silicate-based corrosion-inhibition systems
Core sodium metasilicate product	10213-79-3	S100563	Sodium metasilicate pentahydrate	≥95%	Used for research on the hydration structure, active content, dissolution behavior, detergent builder function, and metal-cleaning formulations of sodium metasilicate pentahydrate
Sodium metasilicate-related hydrate	13517-24-3	S108358	Sodium metasilicate nonahydrate	AR, ≥98%	Used for comparison of different sodium metasilicate hydrates, the influence of water of crystallization, effective alkalinity conversion, and dissolution behavior of hydrated salts
Silicate builder	1344-09-8	S302436	Powdered instant sodium silicate	For use as a synthetic detergent builder	Used for research on silicate building, soil dispersion, anti-redeposition, powdered detergents, and cleaner formulations
Silicate builder	1312-76-1	P299428	Potassium silicate	Liquid, modulus 3.1–3.4	Used for research on potassium silicate systems, inorganic bonding, metal protection, alkaline cleaning, and the influence of silicate modulus
Strong alkaline cleaner	1310-73-2	S111498	Sodium hydroxide	GR, ≥96%	Used for comparison between caustic soda and sodium metasilicate, strong alkaline degreasing, saponification reactions, pH adjustment, and corrosivity evaluation
Strong alkaline cleaner	1310-58-3	P431767	Potassium hydroxide	Anhydrous grade, ≥99.95% metals basis	Used for research on strong alkaline cleaning, oil and fat saponification, liquid alkaline cleaners, and comparison of potassium-based systems
Alkaline builder	497-19-8	S755762	Anhydrous sodium carbonate	UltraBio™, anhydrous grade, ≥99.5% (T)	Used for alkalinity adjustment, detergent building, control of hard-water effects, and research on sodium metasilicate blended systems
Mild alkaline auxiliary	144-55-8	S112339	Sodium bicarbonate	Pharmaceutical grade, PharmPure™	Used for research on alkalinity buffering, mild cleaning, acid-base neutralization, and comparison of alkaline auxiliaries
Phosphate alkaline builder	7601-54-9	S113693	Trisodium phosphate, anhydrous	≥96%	Used for research on strong alkaline cleaning, degreasing, hard-surface cleaning, and comparison of inorganic builders
Amine alkaline auxiliary	102-71-6	T478536	Triethanolamine	Reagent grade, ≥98%	Used for research on pH adjustment, metal cleaning, corrosion-inhibition assistance, oil emulsification, and alkaline formulation stability
Amine alkaline auxiliary	141-43-5	E103808	Ethanolamine	Refined grade, ≥99.5%	Used for research on alkaline cleaning, pH adjustment, oil removal, metal cleaning, and comparison of amine-based auxiliaries

Table 2 Chelating Agents, Complexing Agents, and Dispersing/Anti-Redeposition Auxiliaries

Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Anti-redeposition auxiliary	9004-32-4	C104986	Sodium carboxymethyl cellulose (CMC)	Viscosity: 1000–1400 mPa·s, USP grade	Used for research on detergent anti-redeposition, soil suspension, system thickening, and synergy with sodium metasilicate cleaning systems
Green chelating agent	51981-21-6	T303874	Tetrasodium N,N-bis(carboxymethyl)-L-glutamate	Active content ≥47%	Used for research on biodegradable chelation, hard-water ion control, alkaline cleaning formulations, and metal ion sequestration
Hydroxycarboxylate chelating agent	527-07-1	G278703	Sodium D-gluconate	≥99%	Used for research on metal ion complexation, hard-water effect control, metal cleaning, alkaline cleaners, and corrosion-inhibition assistance
Carboxylate chelating agent	6132-04-3	S116311	Sodium citrate dihydrate	AR, ≥99%	Used for research on mild complexation, buffering systems, hard-water ion control, cleaners, and descaling formulations
Aminocarboxylate chelating agent	6381-92-6	E116429	Disodium ethylenediaminetetraacetate dihydrate	GR, ≥99%	Used for research on metal ion sequestration, hard-water effect control, analytical experiments, and chelating performance in cleaning formulations
Aminocarboxylate chelating agent	60-00-4	E112487	Ethylenediaminetetraacetic acid	AR, ≥99.5%	Used as a classic chelating-agent reference and for research on metal ion complexation, hard-water control, and cleaning-system evaluation
Dispersant and scale inhibitor	9003-04-7	P434409	Sodium polyacrylate (PAAS)	Average Mw ~8000, 45% in H₂O	Used for research on soil dispersion, scale inhibition, anti-redeposition, inorganic salt deposition control, and cleaning formulation stability
Aminocarboxylate chelating agent	140-01-2	D302814	Pentasodium diethylenetriaminepentaacetate	ca. 50% in water	Used for research on efficient metal ion sequestration, alkaline cleaning, industrial cleaning, and chelation under complex water-quality conditions
Aminocarboxylate chelating agent	10378-23-1	E109307	Tetrasodium ethylenediaminetetraacetate dihydrate	AR, ≥99% (T)	Used for research on metal ion control in alkaline systems, cleaning-builder blending, and hard-water ion sequestration
Aminocarboxylate chelating agent	67-43-6	D108513	Diethylenetriaminepentaacetic acid (DTPA)	AR, ≥99% (T)	Used for research on strong chelating performance evaluation, metal ion control, industrial cleaning, and descaling systems
Green chelating agent	164462-16-2	T161558	Trisodium N-(1-carboxyethyl)iminodiacetate	≥95% (T)	Used for research on biodegradable chelation, hard-water ion control, alkaline cleaners, and environmentally friendly builder systems

Table 3 Phosphates, Phosphonates, and Scale-Inhibition/Corrosion-Inhibition Auxiliaries

Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Phosphate builder	7758-29-4	S433949	Sodium tripolyphosphate	Industrial grade, ≥85%	Used as a classic builder reference and for research on hard-water ion control, detergent formulations, and sodium metasilicate blended systems
Phosphonate scale and corrosion inhibitor	2809-21-4	E107456	1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP)	Moligand™, 60% aqueous solution	Used for research on scale inhibition, complexation, corrosion inhibition, metal cleaning, and synergy with silicate-based corrosion-inhibition systems
Phosphate builder	7722-88-5	S108847	Sodium pyrophosphate	AR, ≥99%	Used for research on alkaline building, metal ion control, dispersion, and comparison of detergent builders
Molybdate corrosion inhibitor	7631-95-0	S433698	Sodium molybdate	Anhydrous grade, ≥99.9% metals basis, powder, >100 mesh	Used for research on metal corrosion inhibition, rust-prevention systems, inorganic corrosion-inhibitor references, and silicate surface-protection effects
Molybdate corrosion inhibitor	10102-40-6	S104867	Sodium molybdate dihydrate	AR, ≥99%	Used for research on hydrated molybdate corrosion inhibition, metal protection, circulating water systems, and post-cleaning rust-prevention systems
Phosphate dispersant	10124-56-8	S108858	Sodium hexametaphosphate (SHMP)	AR	Used for research on dispersion, hard-water ion control, scale inhibition, detergent building, and inorganic salt deposition control
Oxidizing corrosion inhibitor	7632-00-0	S433708	Sodium nitrite	Anhydrous grade, high-purity, reagent grade, ≥99%	Used for research on steel corrosion inhibition, rust-prevention systems, metal surface protection, and comparison of inorganic corrosion inhibitors
Phosphonate scale and corrosion inhibitor	6419-19-8	N433216	Nitrilotris(methylenephosphonic acid)	≥95%	Used for research on scale inhibition, corrosion inhibition, metal ion control, industrial cleaning, and circulating water treatment
Copper corrosion inhibitor	95-14-7	B101002	Benzotriazole	≥99%	Used for research on corrosion inhibition of copper and copper alloys, metal surface protection, and post-cleaning anti-discoloration systems
Copper corrosion inhibitor	29385-43-1	M158120	Methyl-1H-benzotriazole, mixture (TTA)	≥98% (GC)	Used for research on corrosion inhibition of copper and copper alloys, water treatment, metal cleaning, and protective formulations

Table 4 Products Related to Acidic Rust Removal, Descaling, and Metal Surface Treatment

Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Strong acid rust remover	7647-01-0	H485680	Fuming hydrochloric acid, 37% (regulated precursor chemical)	GR, suitable for analysis, max. 0.001 ppm Hg	Used for research on acid pickling and rust removal, dissolution of metal oxides, inorganic acid cleaning, and comparison with the rust-removal effect of sodium metasilicate
Organic acid cleaner	64-19-7	A116166	Glacial acetic acid	GR, ≥99.5%	Used for research on mild acidic cleaning, light descaling, acid-base neutralization, and organic acid cleaning systems
Organic acid descaler	77-92-9	C108869	Anhydrous citric acid	AR, ≥99.5% (T)	Used for research on mild descaling, metal ion complexation, light rust cleaning, and acidic cleaning formulations
Organic acid rust remover	144-62-7	O107179	Oxalic acid, anhydrous	Anhydrous grade, ≥99%	Used for research on rust-stain cleaning, iron ion complexation, acidic rust removal, and comparison with the rust-removal effect of sodium metasilicate
Organic acid rust remover	6153-56-6	O433119	Oxalic acid dihydrate	Suitable for synthesis	Used for research on oxalic acid rust-removal systems, iron ion complexation, metal oxide treatment, and acidic cleaning
Acidic descaler	5329-14-6	A432844	Sulfamic acid	Suitable for analysis, premium grade	Used for research on scale removal, metal surface pickling, industrial descaling, and acidic cleaning systems
Organic acid descaler	5949-29-1	C433031	Citric acid monohydrate	Reagent grade, ≥98% (GC/T)	Used for research on descaling, metal ion complexation, mild acidic cleaning, and comparison of hydrate forms
Inorganic acid surface-treatment agent	7664-38-2	P112025	Phosphoric acid	HPLC grade, ≥85%	Used for research on phosphoric-acid rust removal, metal surface treatment, oxide dissolution, and acidic cleaning systems

Table 5 Surfactants and Solubilizing Auxiliaries

Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Hydrotrope	1300-72-7	S485589	Sodium xylene sulfonate solution	Mixture of isomers, 40 wt.% in H₂O	Used for research on solubilization in liquid cleaners, system stability, surfactant compatibility, and high-alkaline cleaning formulations
Anionic surfactant	151-21-3	S432157	Sodium dodecyl sulfate (SDS)	Anhydrous grade, ACS, ≥99%	Used for research on oil emulsification, interfacial tension reduction, foaming systems, and synergy with sodium metasilicate cleaning
Anionic surfactant	25155-30-0	S592217	Sodium dodecylbenzenesulfonate (SDBS)	Anionic active matter, 85%	Used for research on detergent cleaning, hard-surface cleaning, oil emulsification, and synergy with alkaline builders
Anionic surfactant	9004-82-4	S196294	Sodium laureth sulfate	≥25%	Used for research on cleaning, foaming, emulsification, liquid detergents, and compatibility in alkaline systems

Table 6 Oxidative Cleaning and Bleaching Synergy Products

Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Oxidative cleaner	7722-84-1	H112515	Hydrogen peroxide solution (hydrogen peroxide) (explosive precursor chemical)	AR, 30 wt.% in H₂O	Used for research on oxidative cleaning, bleaching, surface treatment, and oxidative synergy in alkaline cleaning systems
Solid oxygen bleach	10486-00-7	S466982	Sodium perborate tetrahydrate	9–11% available oxygen	Used for research on oxygen-bleach cleaning, powdered detergents, stain oxidation, and blending with alkaline builders
Solid oxygen bleach	15630-89-4	S189038	Sodium percarbonate	≥13% active oxygen	Used for research on oxygen-bleach washing, powdered cleaners, stain oxidation, and blending with sodium metasilicate alkaline systems

Note: The products listed above are representative Aladdin products related to scientific research and formulation studies. For more product specifications, grades, and COA information, please search by “product name/CAS/catalog number” on the Aladdin official website.

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