Acid Resistant Refractory Materials

Choose Each Product by Its Function in the Assembly

An acid-resistant surface is only as dependable as its weakest path. A chemically suitable brick can be undermined by an incompatible joint; a resistant monolithic layer can fail where it crosses a moving crack; and a correctly selected material cannot compensate for an unstable or contaminated substrate. Start by deciding whether the project requires unit masonry, a vertical protective layer, a cast monolithic section or a jointing material.

Product	Supplied form	Principal function	Catalogue temperature
Acid-Proof Cement Mortar	Acidcas M two-part pack: 25kg powder and 11.5kg liquid stated online	Bedding and filled joints for compatible acid-resistant bricks and tiles	1400°C
Acid-Resistant Bricks	Fireclay units measuring 230 x 114 x 64mm, with stated dimensional variation	Low-porosity working face for floors, channels, pits, chimneys and selected equipment linings	400°C
Acid-Proof Render	Acidcas R two-part pack: 25kg dry material and 10kg liquid stated online	Protective acid-resistant layer on compatible vertical masonry or concrete	1400°C
Acid-Resistant Concrete	Acidcas C graded mix: 25kg dry material and 7.5kg liquid stated online	Monolithic floors, larger surfaces, formed details and compatible lining sections	1400°C

The four products are complementary, but they are not interchangeable. Mortar is formulated for a controlled bedding or joint thickness rather than bulk casting. Render is selected for a supported vertical layer rather than a deep structural pour. Acid-resistant concrete provides aggregate for monolithic construction but should not be treated as ordinary structural concrete without load and strength data. Bricks provide a robust working face, yet their 400°C rating governs any part of the system in which they are used.

What Acid Resistance Means in Practice

The Acidcas range is described by the manufacturer as a two-part silicate-based system resistant to most hot and cold acids, except hydrofluoric acid. Prolonged contact with alkaline substances is also excluded. These statements define important boundaries, but they are not a complete chemical-resistance chart. Mixed chemicals, salts, solvents, oxidising agents, cleaning products and process contaminants can change performance.

The online pages refer to BS 784 and a minimum figure of 96% acid resistance. That value should be supported by the current test report and interpreted against the relevant method before it is used in a project specification. It does not establish universal resistance to every concentration, temperature or duration of exposure.

Compatibility input	Information required	Selection consequence
Chemical identity	All acids, alkalis, solvents, salts, oxidisers, cleaners and impurities	The principal acid or pH alone cannot describe the complete duty
Strength of solution	Normal, minimum and credible maximum concentrations, including dilution events	Attack can vary non-linearly as concentration changes
Temperature	Liquid, vapour, condensate, lining-face and cleaning temperatures	Heat may accelerate reaction and alter permeation or condensation
Exposure pattern	Permanent immersion, frequent wash, intermittent splash, fumes, condensate or emergency spill	Contact time, renewal and wet-dry cycling affect severity
Physical duty	Traffic, impact, abrasion, pressure, vibration, thermal cycling and cleaning method	Chemical compatibility alone does not establish mechanical serviceability

Acid-Resistant Bricks and Mortar

The fireclay bricks form a dense, replaceable working surface where unit construction is preferred. Their page states resistance to mineral acids apart from hydrofluoric acid, plus resistance to abrasion, and gives a maximum temperature of 400°C. The published unit size is 230 x 114 x 64mm, with a manufacturing variation of plus or minus 3mm. Project quantities should include cuts, bond pattern, joint allowance and an agreed wastage factor.

Acidcas M provides the chemically compatible bed and joint between bricks or tiles. Fill joints completely and keep their geometry within the current installation data; wide cavities and substrate irregularities must not simply be packed with mortar. Ordinary building mortar can create a chemically vulnerable network between otherwise resistant units.

The brick page instructs users to allow at least 24 hours of curing. Treat this as a minimum statement on that page, not as a universal release-to-service time. Ambient temperature, humidity, joint dimensions, ventilation, lining thickness, first heating and first chemical contact may require a longer controlled schedule. Use the current mortar instructions for the installed system.

Acidcas Render and Concrete

Decision	Acidcas R Render	Acidcas C Concrete
Typical orientation	Supported vertical or overhead-compatible work only where the application method permits	Horizontal, formed or cast monolithic work within the specified placement limits
Aggregate and build	Render-grade formulation for a protective layer	Graded cement and aggregate mix for thicker monolithic construction
Substrate requirement	Sound, prepared and compatible masonry or concrete	Stable support or formwork designed for the section and loads
Main design risk	Debonding, slumping, uncontrolled thickness or bridging movement	Incorrect water or liquid addition, voids, shrinkage, joints or unverified structural loading

Select render when a defined protective layer is required on a suitable existing vertical surface. Do not apply it over dust, laitance, oil, salt deposits, active leakage, weak render or unidentified old coatings. Determine how corners, terminations, penetrations and construction joints will remain continuous without restraining necessary movement.

Select Acidcas C where a monolithic material is required, such as a compatible floor area, plinth, channel, sump detail or lining section. The word concrete describes its graded form; it does not supply the compressive, flexural, tensile, load-bearing or reinforcement data required for structural design. Confirm thickness, support, joints, falls, drainage and mechanical duty before placement.

Temperature Ratings and Combined Chemical Duty

The 1400°C figure shown for Acidcas M, R and C is a refractory temperature rating. It must not be read as evidence that an acid solution can contact the material at 1400°C. Chemical state, concentration and attack mechanism vary with temperature, while vapours may condense at cooler parts of a flue or vessel and create a different duty from the hot gas.

When bricks and Acidcas M are used together, the brick limit remains 400°C. Any membrane, substrate, anchor, insulation, seal, joint filler or steel shell may impose a lower allowable temperature. A thermal gradient also creates movement and stress even when every component remains below its individual maximum.

Industrial Applications for Acid-Resistant Materials

Industry names help identify likely areas of use, but they do not determine material compatibility. Each plant can contain acids, alkalis, solvents, cleaning chemicals and process contaminants under different temperatures and exposure patterns. Use the following sectors as an application guide, then select and verify the product against the actual duty.

• Petrochemical Industry: Brick-lined vessels, tanks, floors, channels, bunds and splash-exposed process areas handling defined acids or acidic process media. Confirm the complete chemical inventory, concentrations, temperature, contact duration, pressure and secondary-containment requirements.
• Food Industry: Selected floors, walls, drains and production areas exposed to acidic ingredients, by-products or cleaning cycles. Verify chemical and cleaning compatibility, cleanability, hygiene controls and any required food-contact or sector-specific approval.
• Pharmaceutical Industry: Process, containment and utility surfaces subject to specified acidic compounds. Check the full process chemistry together with contamination controls, cleanroom or GMP requirements, cleanability and validation obligations.
• Aluminium Industry: Pits, floors, channels, flues and process zones exposed to identified corrosive media. Assess acids, fluorides, alkalis, temperature, abrasion and wash-down duty; hydrofluoric acid is expressly excluded from this range.
• Power Generation: Selected flue-gas, acidic-condensate and process-water areas, including chimneys, ducts, floors and drainage details. Establish gas composition, condensate chemistry, acid dew point, thermal cycling, abrasion and support conditions.
• Steel Industry: Pickling-related floors, pits, drains, tanks, flues and maintenance areas. Define the acid family, concentration, operating temperature, traffic, impact, abrasion and chemical carry-over.
• Acidic Gas Chimneys: Brick, mortar, render or monolithic sections selected for the lining geometry and support arrangement. Confirm gas chemistry, wall temperature, condensation zones, thermal movement, joints, penetrations and inspection access.

Food, beverage and pharmaceutical references describe potential plant locations; they do not establish hygienic, cleanroom or direct food-contact approval. Similarly, an application in an aluminium plant must be screened carefully for hydrofluoric acid and fluoride-containing mixtures. Sector experience supports the enquiry, but the complete chemical and mechanical service envelope governs selection.

Substrate, Joints and Containment Details

Detail	Failure route	Required check
Existing concrete or masonry	Weak surface, contamination, trapped moisture or continuing chemical attack	Survey, removal criteria, preparation method, pull-off requirement and moisture condition
Movement or construction joint	Rigid material cracks or separates as the structure moves	Expected movement, compatible flexible detail and continuity of the chemical barrier
Pipe, drain or anchor penetration	Leak path forms around dissimilar material or difficult geometry	Chemical compatibility, movement, termination profile and inspection access
Floor-to-wall junction	Sharp corner concentrates stress and retains liquid	Designed radius, falls, drainage, impact exposure and cleaning access
Brick joint or monolithic interface	Voids, excessive width, cold joint or incomplete compaction	Permitted geometry, placement sequence and recorded quality inspection
Secondary barrier	Chemical reaches the supporting structure after a local defect	Need for a membrane, leak detection, drainage or secondary containment

Acid resistance and liquid tightness are separate properties. A rigid masonry or monolithic layer can contain pores, joints and unavoidable movement details. Where leakage has serious safety, environmental or production consequences, the full system may require a separately verified membrane, leak-detection provision or secondary containment.

Mixing, Placement and Commissioning

• Use matched components: Keep the powder and liquid for each Acidcas grade together. The online pack quantities differ between M, R and C.
• Follow controlled ratios: Measure complete or permitted partial batches using the current instructions. Do not add water or modify the liquid content unless the technical data expressly allows it.
• Prepare the work area: Isolate the process, make the substrate sound, remove incompatible residues and control ambient conditions before mixing.
• Respect working time: Plan labour, access and batch size so material is placed before loss of workability. Do not retemper material that has begun to set.
• Control geometry: Record mortar-joint dimensions, render or concrete thickness, falls, corners, terminations and interfaces.
• Protect the cure: Prevent premature chemical contact, water, freezing, excessive drying, traffic, vibration or heating.
• Commission deliberately: Complete the specified cure and dry-out before process chemicals or temperature are introduced, then inspect the lining under controlled initial duty.

Review the current safety data sheets for both dry and liquid components. The risk assessment should cover dust, splashes, skin and eye contact, ventilation, mixing equipment, waste and emergency response. Process acids require their own COSHH assessment and compatible spill-control plan; the presence of an acid-resistant lining does not reduce the hazards of the chemical.

Inspection and Maintenance

Establish acceptance criteria before installation. Useful records include batch numbers, component proportions, mixing and placement times, ambient conditions, applied dimensions, cure period and photographs of hidden details. Inspect joints, terminations, penetrations, corners and drainage routes before the area enters service.

During operation, look for open joints, hairline cracking, softening, surface loss, blistering, staining, damp patches and changes around drains or penetrations. Map defects and compare them with chemical events, temperature excursions and cleaning cycles. A local repair is appropriate only after the cause and the condition of the surrounding material have been established.

Frequently Asked Questions

Is acid-proof the same as resistant to every acid?

No. Acid-proof is retained in some product names, but technically the range has a defined resistance envelope. Chemical identity, concentration, temperature, contact time and mixtures must be checked for each application.

Which products are included in this category?

The range contains acid-resistant fireclay bricks, Acidcas M jointing mortar, Acidcas R render for suitable surfaces and Acidcas C graded concrete for monolithic work.

Can these materials be used with hydrofluoric acid?

No. The manufacturer specifically excludes hydrofluoric acid from the Acidcas range, and the brick page also identifies it as an exception. Select a separately proven system for HF or fluoride exposure.

Are Acidcas products resistant to alkaline cleaners?

They are not intended for extended alkaline exposure. Include every cleaning chemical and pH excursion in the compatibility review, even when the normal process is acidic.

Are all four products rated to 1400°C?

No. Acidcas Mortar, Render and Concrete are listed at 1400°C, but the acid-resistant bricks are limited to 400°C. The lowest-rated relevant element constrains an assembled system.

Does the 1400°C rating apply to hot acid immersion?

Not by itself. It is a material temperature rating rather than a hot-liquid compatibility chart. Obtain confirmation for the actual acid, concentration, phase, contact time and temperature.

Which mortar should be used with the acid-resistant bricks?

The bricks are intended for bedding and jointing with Acidcas M Acid-Proof Cement Mortar. Confirm the specified joint geometry, component ratio, working time and cure before installation.

Can ordinary cement mortar be used between the bricks?

Not in the exposed chemical layer. A vulnerable mortar network can allow attack to bypass the resistant brick faces and reach the substrate.

What is the difference between Acidcas Render and Acidcas Concrete?

Render is formulated as a protective layer for suitable vertical surfaces. Concrete contains graded aggregate for monolithic floors, formed details and larger sections. Neither should be substituted for the other without confirming the installation data.

Is Acidcas C the same as ordinary structural concrete?

No. It is a specialist two-part acid-resistant graded material. Structural use requires separate load, strength, reinforcement, thickness and support data that are not established by the category description.

Is existing concrete a suitable substrate for Acidcas Render?

Potentially, if the concrete is sound, compatible and correctly prepared. Test for contamination, weakness, active chemical attack, moisture, cracks and movement before specifying the bond.

What lining thickness should be applied?

No universal thickness applies across mortar, render and concrete. Use the current product data and project design, accounting for orientation, chemical duty, aggregate size, substrate profile, wear and required service life.

Does an acid-resistant lining automatically hold liquid?

No. Liquid tightness depends on pores, joints, cracks, penetrations, movement and any membrane or secondary barrier. Define containment performance separately from material chemical resistance.

Is Acidcas Concrete suitable for floors?

It is presented for selected acid-exposed floor areas, but traffic, point loads, impact, abrasion, cleaning, falls, drainage and substrate movement must be checked as part of the complete floor design.

Can these materials be used in chimneys?

They are offered for selected acidic-gas and condensate duties. Establish gas chemistry, wall temperature, acid dew point, cycling, abrasion, support and the temperature limit of every lining component.

Which industries use acid-resistant refractory materials?

Typical users include petrochemical processors, food and pharmaceutical manufacturers, aluminium and steel plants, power generators, and operators of acidic-gas chimneys or flues. Suitability still depends on the exact chemicals, concentration, temperature, contact pattern, substrate and mechanical duty; an industry label alone is not a specification.

Are the products approved for direct food contact?

The listed use in food or pharmaceutical facilities does not prove direct-contact, hygienic or cleanroom approval. Confirm all sector-specific certification, cleanability and contamination requirements independently.

Can water be added to make Acidcas easier to apply?

Do not add water unless the current controlled instructions explicitly permit it. Each grade is supplied with a matched liquid quantity; changing the ratio can affect setting, strength and chemical performance.

What information is needed before selecting a product?

Provide the complete chemical list, concentrations, temperatures, contact regime, cleaning cycle, substrate, geometry, movement, loads, abrasion, lining thickness, containment requirement, installation conditions and commissioning window.