Descaling and chemical cleaning agents are 11 acids, chelants and alkaline cleaners, used with acid corrosion inhibitors, that dissolve carbonate scale, silicate, iron oxide and copper deposits from heat exchangers, boilers, cooling towers, membranes and closed loops. Dissolving 1 kg of calcium carbonate takes 0.73 kg of hydrochloric acid but 1.94 kg of sulfamic acid, so which descaling chemical fits which deposit and metal?
Sulfamic (sulphamic) acid, citric acid, EDTA and TSP are typical members. Descaling and chemical cleaning agents form one of the 16 families of water treatment chemicals.
Every value on this page is checked against primary sources (eCFR, NSF listings, AMPP/NACE, PubChem, ECHA and the handbooks and supplier documents named in the text); see our methodology and fact-checking process.
What Is a Descaling Chemical?#
A descaling chemical is an acid, chelant or alkaline cleaner, usually with a corrosion inhibitor, that dissolves or loosens mineral scale and metal oxides from water-side equipment surfaces during a planned chemical cleaning. Hydrochloric acid at about 5 %, inhibited and complexed, is the most widely used boiler cleaning solvent (Veolia Water Technologies Handbook, chapter 15).
What scale and deposits do descaling chemicals remove?#
Descaling chemicals remove 5 deposit groups, listed below with the solvent each needs.
- Calcium carbonate: any acid, with CO2 released.
- Calcium phosphate: on-line chelant for moderate deposits.
- Silicate: hydrochloric acid with ammonium bifluoride or hydrofluoric acid.
- Iron oxide: hydrochloric acid, citric acid or EDTA.
- Copper: thiourea in hydrochloric acid, then an oxidizing step.
Scale forms where dissolved salts exceed their solubility on a heated surface, as explained under scale formation in water systems.
How is a chemical cleaning applied: off-line, on-line or by circulation?#
Chemical cleaning runs in 3 modes: off-line circulation of an inhibited acid or chelant through drained equipment, on-line chelant cleanup of a boiler in service, and an alkaline boil-out that removes oil and mill scale before acid cleaning.
How Do Descaling and Cleaning Chemicals Work?#
Descaling chemicals work in 3 ways: acids dissolve carbonate and oxide deposits, chelants bind calcium and iron into soluble complexes, and inhibitors slow the acid's attack on the base metal.
Acid dissolution of carbonate scale#
Acids dissolve calcium carbonate scale by converting it into a soluble calcium salt, water and carbon dioxide: each kilogram of CaCO3 releases 0.44 kg of CO2, about 224 L at 0 °C (32 °F). Acid mass per kilogram of scale follows molar masses, never a 1 : 1 weight ratio.
Chelation of calcium and iron#
Chelants dissolve deposits by binding calcium and iron into soluble 1 : 1 complexes: tetrasodium EDTA needs 3.80 mg/L as active per mg/L of hardness as CaCO3, and its iron(III) complex (log K 25.1) is far stronger than its calcium complex (log K 10.6). GLDA-Na4 needs 3.51 mg/L and MGDA-Na3 2.71 mg/L on the same basis.
Inhibition of acid attack on the base metal#
An acid corrosion inhibitor is the additive that protects the steel, copper alloy or stainless base metal during an acid cleaning, which is why boiler hydrochloric acid is always used inhibited. Acid attack on metal evolves hydrogen, so every acid cleaning is ventilated and kept free of ignition sources.
11 Descaling and Cleaning Chemicals in 5 Classes#
The 11 descaling and cleaning chemicals with their own pages fall into 5 classes: 4 mineral acids, 1 organic acid, 3 chelants and 3 alkaline cleaners, while acid corrosion inhibitors and additives such as ammonium bifluoride and thiourea are blended into the cleaning solution. The table below compares the 5 classes.
| Class | Members (pages) | Section chemicals | Removes | Related hub |
|---|---|---|---|---|
| Mineral acids | hydrochloric, sulfamic, phosphoric, sulfuric acid | none | carbonate, oxides | pH adjustment chemicals |
| Organic acids | citric acid | methanesulfonic, hydroxyacetic-formic (HAF), oxalic acid | iron oxide, carbonate on mixed metals | none |
| Chelants | EDTA, GLDA, MGDA | ammonium citrate | calcium, iron, calcium phosphate | chelating agents in water treatment |
| Acid corrosion inhibitors and additives | none | inhibitors, ammonium bifluoride, hydrofluoric acid, thiourea | protect metal; silicate; copper | corrosion inhibitors for water treatment |
| Alkaline cleaners | TSP, sodium hydroxide, STPP | sodium dodecyl sulfate, sodium hydrosulfite | oil, organics, mill scale, membrane foulants | phosphates in water treatment |
1. Mineral acids (4)#
Mineral acids are strong inorganic acids that dissolve carbonate and oxide scale; this class has 4 chemicals: hydrochloric, sulfamic, phosphoric and sulfuric acid.
Hydrochloric acid#
Hydrochloric acid (HCl) is the most widely used boiler cleaning solvent at about 5 % with inhibitor and complexors. Inhibited HCl descalers run up to 80 °C (176 °F), excluding aluminum and zinc (supplier figure).
Sulfamic acid#
Sulfamic acid (H3NO3S) is a solid strong acid that forms a soluble calcium salt without hydrochloric acid fumes. It is used as a 5 to 10 % inhibited cleaner up to 60 °C (140 °F) (supplier figure).
Phosphoric acid#
Phosphoric acid (H3PO4) is a mineral cleaning acid for boilers below 2,000 psig (138 bar). Zinc-compatible phosphoric descalers run up to 40 °C (104 °F) (supplier figure).
Sulfuric acid#
Sulfuric acid (H2SO4) is a mineral acid for boilers below 2,000 psig (138 bar). It is never used on RO or NF membranes, because calcium sulfate precipitates.
2. Organic acids (1)#
Organic acids are carboxylic or sulfonic cleaning acids that suit mixed-metal equipment; this class has 1 entity page, citric acid, plus 3 section acids.
Citric acid#
Citric acid (C6H8O7) is the organic cleaning acid for iron oxide and carbonate, used as inhibited ammonium citrate in boilers. Citric descalers run up to 40 °C (104 °F) on all common metals (supplier figure).
Methanesulfonic, hydroxyacetic-formic and oxalic acids#
Methanesulfonic acid is the high-temperature organic descaler, rated up to 90 °C (194 °F) in one supplier's data. Inhibited hydroxyacetic-formic acid (HAF) cleans superheaters and once-through circuits, and oxalic acid cleans UF membranes.
3. Chelants (3)#
Chelants are aminopolycarboxylates that dissolve calcium and iron deposits by complexing them; this class has 3 chemicals: EDTA, GLDA and MGDA.
EDTA#
EDTA (ethylenediaminetetraacetic acid) is the strongest common cleaning chelant, used inhibited for superheaters and on-line for moderate boiler deposits. Tetrasodium EDTA is sold as a 39 % liquid.
GLDA#
GLDA (tetrasodium glutamate diacetate) is a readily biodegradable chelant soluble at more than 50 wt % in 28 % acetic acid. It therefore controls iron in acidic cleaners.
MGDA#
MGDA (trisodium methylglycine diacetate) is a readily biodegradable chelant stable up to 170 °C (338 °F) for 6 hours (manufacturer data). It serves as an EDTA alternative in boiler cleaning.
4. Acid corrosion inhibitors and cleaning additives (sections only)#
Acid corrosion inhibitors and cleaning additives are blended into a cleaning acid to protect the metal or attack a specific deposit; none has its own page.
Acid corrosion inhibitors (inhibited acid)#
Acid corrosion inhibitors are proprietary additives that turn a cleaning acid into an inhibited acid, dosed at 0.5 to 3.0 kg per 1,000 L of hydrochloric acid bath in one supplier's data. Each inhibitor's composition and hazards are on its supplier SDS.
Ammonium bifluoride and hydrofluoric acid for silicate scale#
Ammonium bifluoride (NH4HF2) and hydrofluoric acid are fluoride additives that let hydrochloric acid dissolve silicate scale. Ammonium bifluoride is hazardous and can damage equipment.
Thiourea for copper deposits#
Thiourea is a complexing additive that keeps dissolved copper in solution during a hydrochloric acid cleaning, so copper does not plate onto steel. Copper oxide needs a separate oxidizing step.
5. Alkaline cleaners (3)#
Alkaline cleaners are high-pH solutions that remove oil, organics and mill scale; this class has 3 chemicals: TSP, sodium hydroxide and STPP.
Trisodium phosphate (TSP)#
Trisodium phosphate (Na3PO4) is the alkaline boil-out chemical, used at about 0.1 to 1 % with a surfactant in boilers and at 1 to 2 % in new closed loops.
Sodium hydroxide#
Sodium hydroxide (NaOH) is the caustic base of high-pH membrane cleaners, which run before the acid step. It neutralizes spent acid at 1.097 kg per kg of HCl.
Sodium tripolyphosphate (STPP)#
Sodium tripolyphosphate (Na5P3O10) is the alkaline builder of a high-pH membrane cleaner that pairs it with sodium EDTA at pH 10.0 (Hydranautics TSB107.30, April 2026).
Which Descaling Chemical for Which Deposit, Metal and System?#
Descaling chemical selection depends on 3 factors: the deposit, the metals and temperature limit of the equipment, and the system, and a corrosion test of the inhibited solution confirms the choice.
By deposit: carbonate, silicate, iron oxide and copper#
The deposit sets the solvent, following the 4 rules below.
- Carbonate: any inhibited acid, chosen by metal and temperature.
- Silicate: ammonium bifluoride or hydrofluoric acid added to hydrochloric acid.
- Iron oxide: hydrochloric acid, citric acid or EDTA.
- Copper: thiourea in the acid, plus an oxidizing step.
By metal and temperature limit#
Every cleaning acid has a temperature ceiling and a metal list: inhibited hydrochloric acid is rated to 80 °C (176 °F) but excludes aluminum and zinc, while sulfamic and citric cleaners also suit aluminum and zinc at up to 60 °C (140 °F) and 40 °C (104 °F) (supplier figures). The table below compares 5 cleaning acids from one supplier's 2024 cleaning guide.
| Cleaning acid | Maximum temperature | Metals listed as compatible |
|---|---|---|
| Methanesulfonic acid | 90 °C (194 °F) | not stated in the source |
| Inhibited hydrochloric acid | 80 °C (176 °F) | steel, stainless steel, copper alloys; not aluminum or zinc |
| Sulfamic acid, 5 to 10 % | 60 °C (140 °F) | steel, stainless steel, copper alloys, aluminum, zinc |
| Phosphoric acid (zinc-compatible cleaner) | 40 °C (104 °F) | zinc (product designation); others not stated |
| Citric acid | 40 °C (104 °F) | steel, stainless steel, copper alloys, aluminum, zinc |
By system: heat exchangers, boilers, cooling towers, membranes and closed loops#
Each system has its own cleaning chemistry: inhibited acids descale heat exchangers, 5 % inhibited hydrochloric acid and chelants clean boilers, organic acids clean cooling-tower fill, alkaline then acid cleaners restore RO membranes, and trisodium phosphate cleans new closed loops. Below 900 psig (62 bar) an alkaline cleaning alone may suffice before boiler startup (Veolia Water Technologies Handbook, chapter 15).
The table below compares 6 systems.
| System | Main cleaning chemicals | Key number |
|---|---|---|
| Heat exchangers and condensers | inhibited hydrochloric, sulfamic, citric, methanesulfonic acid | 10 % v/v charge; spent at pH 3.5 to 4 |
| Boiler chemical cleaning and descaling | 5 % inhibited HCl; phosphoric, sulfuric, sulfamic acid below 2,000 psig (138 bar); inhibited HAF, EDTA or ammoniated citrate for superheaters; TSP boil-out | alkaline alone may suffice below 900 psig (62 bar) |
| Cooling tower cleaning and disinfection chemicals | organic acids, sulfuric acid | organic acids dissolve calcite 10 to 20 times faster than sulfuric acid alone at pH 5 |
| RO membrane cleaning chemicals | alkaline cleaners first; HCl, citric or phosphoric acid for CaCO3 and iron; never sulfuric acid or cationic surfactants | clean at 10 % loss of normalized permeate flow |
| Pre-commission cleaning and flushing of closed systems | 1 to 2 % TSP for new systems; inhibited acid, neutralization and phosphatization for fouled systems | 5 to 7 days for a commercial building (service-firm figure) |
| Drinking water treatment chemicals, utility wells | citric acid and NSF Well Cleaning Aid products, off-line and flushed | maximum use "NA" |
Descaling Chemical Strength, Dosage and Acid Demand#
Descaling chemicals are dosed as a solution strength rather than in mg/L: about 5 % for inhibited hydrochloric acid in boilers, 5 to 10 % for inhibited sulfamic cleaners and 10 % by volume of a plate-exchanger circuit for a formulated descaler. The table below compares strengths with their basis.
| Chemical or use | Strength or dose | Basis | Limit |
|---|---|---|---|
| Hydrochloric acid, boiler cleaning | about 5 % | acid solution, with inhibitor and complexors | n/a |
| Inhibited hydrochloric acid, exchanger descaling | per product | formulated cleaner | 80 °C (176 °F) |
| Sulfamic acid cleaner | 5 to 10 % | solution of the inhibited formulated cleaner | 60 °C (140 °F) |
| Plate exchanger descaler | 10 % of circuit volume (10 L per 100 L) | as product, v/v | spent at pH 3.5 to 4 |
| Citric acid cleaner | per product | formulated cleaner | 40 °C (104 °F) |
| Methanesulfonic acid cleaner | per product | formulated cleaner | 90 °C (194 °F) |
| HCl acid inhibitor (supplier 1) | 0.5 to 3.0 kg per 1,000 L bath; replenish 0.5 to 2.0 kg per 100 kg concentrated acid added | as product | up to 40 °C (104 °F) |
| HCl acid inhibitor (supplier 2) | 0.02 to 1.00 % or more | % v/v on concentrated HCl (up to 37 %) before dilution | n/a |
| TSP alkaline boil-out | about 0.1 to 1 % plus surfactant | as TSP | 6 to 24 h per stage at about half operating pressure |
| TSP new closed-loop cleaner | 1 to 2 % | as TSP | n/a |
| Na4EDTA, GLDA-Na4, MGDA-Na3 | 3.80, 3.51, 2.71 mg/L per mg/L hardness as CaCO3 | active, stoichiometric | n/a |
| Acid demand per kg CaCO3 | HCl 0.73 kg (100 %), about 2.3 kg (32 %); sulfamic 1.94 kg; citric 1.28 kg | as acid, stoichiometric | 0.44 kg CO2 released |
How much acid dissolves a kilogram of scale?#
Dissolving 1 kg of calcium carbonate takes 0.73 kg of hydrochloric acid as 100 % HCl (about 2.3 kg of 32 % acid), 1.94 kg of sulfamic acid or 1.28 kg of citric acid, calculated from PubChem molar masses.
Worked example (inputs: 50 kg (110 lb) of scale taken as pure calcium carbonate; ratios above; 1 kg = 2.2 lb): the exchanger needs at least 36.5 kg (80 lb) of HCl as 100 %, or about 115 kg (253 lb) of 32 % acid, 97 kg (213 lb) of sulfamic acid or 64 kg (141 lb) of citric acid, and releases 22 kg (48 lb) of CO2, about 11,200 L at 0 °C. These are stoichiometric minimums before excess acid and inhibitor.
Unit conversions between kg, lb and L are handled by the chemical dosage calculator.
How much inhibitor goes into a cleaning acid?#
Cleaning-acid inhibitors are dosed in small fractions of the acid: 0.5 to 3.0 kg per 1,000 L of hydrochloric acid bath in one supplier's data, and 0.02 to 1.00 % by volume on concentrated HCl before dilution in another, both as product.
How Is a Chemical Cleaning Controlled and Tested?#
A chemical cleaning is controlled in 3 steps: the pH end point shows when the acid is spent, coupon tests prove the inhibitor, and rinsing and passivation prepare the metal for service.
Heat exchanger descaling procedure: strength, end point and neutralization#
A plate heat exchanger is descaled by circulating a formulated descaler at 10 % of the circuit volume until the pH rises to 3.5 to 4, then neutralizing and flushing to pH 7 (supplier guidance). The 6 steps are listed below.
- Isolate and drain the exchanger, ventilate the area and remove ignition sources (hydrogen).
- Charge 10 L of descaler per 100 L (26.4 US gal) of circuit volume.
- Circulate below the acid's temperature limit.
- Check the pH; the solution is spent at pH 3.5 to 4.
- Neutralize with 0.5 to 1 % neutralizing crystals for 15 minutes.
- Flush with water until the outlet reaches pH 7.
Target ranges by system are listed under pH in water treatment.
Inhibitor testing: NACE TM0193 and corrosion coupons#
Inhibited cleaning solutions are tested to NACE TM0193-2016, Laboratory Corrosion Testing of Metals in Static Chemical Cleaning Solutions at Temperatures below 93 °C (200 °F).
Weight-loss specimens are explained under corrosion coupons and corrosion monitoring.
Rinse, passivation and return to service#
Cleaned metal is passivated before service: a boil-out follows a mineral-acid cleaning, oxygen is injected into a spent chelant solution, and the boiler drains under a nitrogen blanket (Veolia handbook, chapter 15).
Which Standards and Regulations Apply to Descaling Chemicals?#
Descaling chemicals are governed in 3 layers: NSF/ANSI/CAN 60 product functions for drinking-water use, federal discharge rules for spent solutions, and hazard thresholds for the concentrated acids.
NSF/ANSI/CAN 60 functions for cleaning chemicals#
NSF/ANSI/CAN 60 lists cleaning chemicals under 5 product functions, and membrane cleaners and well cleaning aids carry a maximum use of "NA" because they are used off-line and flushed out before drinking-water service (NSF listings, 2026-10-21). The table below compares the 5 functions.
| Product function | Listings (companies / products / product-function rows) | Most frequent maximum use (as product) | Chemicals and note |
|---|---|---|---|
| Membrane Cleaner | 104 / 768 / 982 | "NA" (969 of 982 rows) | citric and phosphoric acid cleaners, proprietary EDTA-containing cleaners; "designed to be used off-line and flushed out" |
| Descaler | 26 / 189 / 374 | 52 mg/L (42 rows), 84 mg/L (39 rows), 40 mg/L (22 rows) | hydrochloric, phosphoric, sulfuric and polymaleic acid, sodium hypochlorite, miscellaneous; hydrochloric acid products dominate |
| Well Cleaning Aid | 48 / 224 / 247 | "NA" (246 of 247 rows) | citric acid; flushed and drained before service |
| Pipe Cleaning Aid | 26 / 75 / 78 | "NA" (77 of 78 rows) | function name on the listing |
| Well Rehabilitation Aid | 19 / 46 / 47 | "NA" (47 rows) | function name on the listing |
Descaler maximum use levels range from 20 to 500 mg/L as product (NSF listings, 2026-10-20). EDTA, GLDA, MGDA and sulfamic acid have no chemical category.
How maximum use levels are set is explained on NSF/ANSI/CAN 60.
Discharge of spent cleaning solutions: 40 CFR 423, pretreatment and RCRA#
Spent cleaning solutions from steam-electric plants are chemical metal cleaning wastes under 40 CFR 423.11(c), limited to 1.0 mg/L copper and 1.0 mg/L iron as daily maximum and 30-day average (40 CFR 423.13(e), BAT).
BPT under 40 CFR 423.12(b)(5) adds TSS 100.0 / 30.0 mg/L and oil and grease 20.0 / 15.0 mg/L; these limits bind steam-electric plants only, and other dischargers follow NPDES permits and chemical discharges.
No spent acid below pH 5.0 may go to a POTW (40 CFR 403.5(b)(2)), and waste at pH 2 or less or 12.5 or more is RCRA corrosive, D002 (40 CFR 261.22). Local limits follow the National Pretreatment Program.
Product standards and hazard thresholds for cleaning acids#
Sulfamic acid, citric acid and the 3 chelants have no AWWA or EN product standard, while hydrochloric acid has EN 939:2016 and sulfuric acid EN 899:2022 for drinking-water grades.
Phosphoric acid has ANSI/AWWA B507-23 and sodium hydroxide ANSI/AWWA B501-25; the European grades are compared under EN standards for drinking water treatment chemicals.
The harmonised CLP Annex VI classification of hydrochloric acid solutions (index 017-002-01-X) is H314 and H335; that of sulfamic acid (index 016-026-00-0) is H315, H319 and H412. Hydrochloric acid falls under EPA RMP only at 37 % or greater (15,000 lb, 6,804 kg), so 32 to 35 % acid is not RMP-listed, as compared under EPA RMP and OSHA PSM.
Complete List of Descaling and Cleaning Chemicals: All 11 in One Table#
The complete list below gives all 11 descaling and cleaning chemicals with their CAS number, class, cleaning function, systems, NSF/ANSI/CAN 60 status and product standard. MULs are mg/L as product for drinking-water functions (NSF listings, 2026-10-20).
| # | Chemical | CAS | Class | Cleaning function | Systems | NSF/ANSI/CAN 60 status | Product standard |
|---|---|---|---|---|---|---|---|
| 1 | hydrochloric acid | 7647-01-0 | mineral acid | inhibited boiler and exchanger solvent | boilers, heat exchangers, RO | Descaler function; potable MUL most commonly 40 mg/L | EN 939:2016 |
| 2 | sulfamic acid | 5329-14-6 | mineral acid (solid) | exchanger and boiler descaler | heat exchangers, boilers | no category | none |
| 3 | phosphoric acid | 7664-38-2 | mineral acid | boiler solvent; zinc-compatible descaler | boilers, heat exchangers, RO | Descaler function | ANSI/AWWA B507-23; EN 974 |
| 4 | sulfuric acid | 7664-93-9 | mineral acid | boiler solvent; never RO cleaning | boilers, cooling-tower fill | Descaler function | EN 899:2022 |
| 5 | citric acid | 77-92-9 | organic acid | iron oxide and carbonate cleaner; well cleaning | boilers, exchangers, RO, UF, wells | Membrane Cleaner, Well Cleaning Aid, "NA" | none |
| 6 | EDTA | 60-00-4 (Na4EDTA 64-02-8) | chelant | off-line and on-line boiler cleaning | boilers, RO | no category | none |
| 7 | GLDA | 51981-21-6 | chelant | iron control in acidic cleaners | exchangers, boilers | no category | none |
| 8 | MGDA | 164462-16-2 | chelant | boiler cleaning | boilers | no category | none |
| 9 | trisodium phosphate (TSP) | 7601-54-9 (12-hydrate 10101-89-0) | alkaline cleaner | boil-out; new closed loops | boilers, closed loops | potable MUL most commonly 17 mg/L | EN 1200 |
| 10 | sodium hydroxide | 1310-73-2 | alkaline cleaner | high-pH membrane cleaner; acid neutralization | RO, UF | potable MUL most commonly 100 mg/L | ANSI/AWWA B501-25; EN 896 |
| 11 | sodium tripolyphosphate (STPP) | 7758-29-4 | alkaline builder | high-pH membrane cleaner | RO | potable MULs 12 to 13 mg/L | ANSI/AWWA B503-23; EN 1210:2005 |
Every other chemical is filterable by CAS, function and NSF status in the water treatment chemical database.
Who Supplies Descaling Chemicals and Chemical Cleaning Programs?#
Descaling chemicals reach plants by 2 routes: commodity acids and chelants bought to a strength, and inhibited formulated cleaners applied by a provider who owns the procedure.
Commodity grades such as 31 to 32 % (20 °Bé) hydrochloric acid and 93 % (66 °Bé) sulfuric acid come from water treatment chemical suppliers.
Providers that select the solvent, test the inhibitor and handle neutralization and discharge are compared under water treatment companies.
Are Descaling Chemicals Safe to Handle and Discharge?#
Descaling acids are corrosive and need eye, skin and fume protection: hydrochloric acid carries an OSHA ceiling of 5 ppm (7 mg/m³), every acid releases chlorine gas when it meets hypochlorite, and acid cleaning can evolve flammable hydrogen.
What chemical is in a descaler?#
An industrial descaler is usually an inhibited acid, most often hydrochloric, sulfamic, citric, phosphoric or methanesulfonic acid, sometimes with a chelant such as EDTA or GLDA and an additive for silicate or copper.
What neutralizes hydrochloric acid after descaling?#
Spent hydrochloric acid is neutralized with an alkali such as sodium hydroxide, which takes 1.097 kg of NaOH per kg of HCl (the same ratio in lb), before rinsing to pH 7 and discharge.
Which chemicals must never be mixed with descaling acids?#
Descaling acids must never meet hypochlorite, which releases chlorine gas, and sulfamic acid must never meet nitrite, which releases nitrogen, or strong oxidizers.
Incompatible pairs are listed under water treatment chemical compatibility.
Is descaling the same as scale inhibition?#
No: descaling removes scale that has already formed, while scale inhibitors such as phosphonates and polymers are dosed to stop scale forming.
The prevention chemistry is compared on scale inhibitors for water systems.
Can hydrochloric acid alone dissolve silicate scale?#
No: silicate scale needs hydrofluoric acid or ammonium bifluoride added to the hydrochloric acid (Veolia Water Technologies Handbook, chapter 15).