Refractories by Industry: Steel, Cement, Glass, Non-Ferrous, Petrochemical and Power

Refractories line the high-temperature units of nine industries, from blast furnaces and cement kilns to glass melters, refinery cyclones and boiler water walls, and the steel industry alone takes around 70 % of them (World Refractories Association). Each industry wears its lining in a different way, so which refractory class fits which process?

The uses of refractory materials in industry follow the attack each process puts on its lining: basic slag in steel converters, alkali vapor in cement kilns, glass melt at the AZS sidewall, catalyst erosion in refinery cyclones and alkali corrosion in waste-to-energy boilers. Every guide below applies the same classes of refractory materials to one industry's process.

Steelmaking consumes 10 to 20 kg of refractory per tonne of steel (20 to 40 lb per short ton) (Nippon Steel Technical Report No. 125, 2020) and replaces linings within 20 minutes to 2 months, while glass melters run up to 10 years between rebuilds (RHI Magnesita, 2021, company estimate). Refinery linings are inspected under API Std 936, 5th edition (March 2024).

Every value names its standard and edition, the product data sheet or the dated source it comes from; see our methodology and fact-checking process.

What Are Refractory Applications by Industry?#

Refractory applications by industry are the linings that a process industry builds from refractory materials to hold heat, melts, slags and gases inside its high-temperature units. ISO 836:2001 (term 107, confirmed 2022-06-24) defines a refractory as a "non-metallic material or product (but not excluding those containing a proportion of metal) whose chemical and physical properties allow it to be used in a high temperature environment", with no temperature threshold. In the US, ASTM C71-12(2024) applies the term to materials exposed to environments above 538 °C (1,000 °F).

The nine consuming industries fall into four process families: metal production; minerals and glass; energy and chemicals; and foundry melting with cokemaking.

Nine Industry Guides to Refractory Linings#

Nine industry guides make up this section, one per consuming industry, and each maps the industry's process units and lining zones to the refractory classes that line them. Table 1 compares the nine guides by unit, class and main attack on the lining.

Rows list the classes each guide covers; values and zone limits are on the guide pages.

Table 2 below lists the six steel plant zone pages.

Metal Production: Iron, Steel, Aluminum, Copper and Nickel#

Metal production puts linings in contact with molten metal and slag, and steel refractories work at up to 1800 °C (3,272 °F) (RHI Magnesita, H1 2025 results). Magnesia-carbon brick was first developed for electric arc furnace hot spots and replaced dolomite-carbon in converters from the late 1970s (Nippon Steel Technical Report No. 125, 2020).

Aluminum reduction cells run electrolysis at about 960 °C (1,760 °F), where sodium vapor and cryolite attack the lining (SINTEF). Anode baking furnaces separate their pits with hollow dense refractory fluewalls (ICSOBA, 2022). In copper smelting, concern that spent magnesia-chrome brick could be hazardous waste drives chrome-free tests (Missouri University of Science and Technology).

Minerals and Glass: Cement Kilns, Lime Kilns and Glass Melters#

Kilns and glass melters run a year or more between relines, so chemical attack, not single-heat wear, sets their lining life. A producer zoning of the rotary cement kiln names six zones: calcining, safety, upper transition, central burning, lower transition and discharge. Alternative fuels bring alkalis, chlorine, sulfur and heavy metals into the kiln (UNITECR 2025 conference paper).

Rotary lime kilns take alumina-class brick in the charging and calcining zones and burned magnesite-spinel brick in the burning zone, according to a producer application page. Glass melters use fused-cast AZS, which ISO 10081-4:2014 groups as AZS30/30 and AZS30/40; the names AZS 33, 36 and 41 are trade grades, not ISO groups.

Energy and Chemicals: Refineries, Gasifiers, Boilers and Incinerators#

Refineries and boilers line steel shells and tube walls with castables and thin erosion linings, and slagging gasifiers add brick in contact with molten slag. Air-cooled slagging gasifiers run at 1325 to 1575 °C (2,417 to 2,867 °F) on high-chromia brick with 60 to 95 % Cr2O3, a class range from Bennett and Powell (NETL, MOLTEN 2009 conference paper).

About 90 % of boiler refractory sits on the water walls, outside the tubes, and the most common product there is a conventional cement-bonded medium-weight castable at about half the cost of SiC or high-alumina specialty types (US, 2010, relative cost factor, Insulation Outlook). Waste-to-energy grate chambers take alkali-resistant high-alumina low-cement castables and SiC tiles (Capital Refractories technical paper; NAWTEC 14 conference paper).

Foundry Melting and Cokemaking#

Coreless and channel induction furnaces use a rammed working lining that is acid (silica), neutral (alumina-spinel) or basic (magnesia), backed by coil cement and closed by a top cap. Induction lining life is counted as the number of heats a lining lasts, not in months.

Coke oven heating walls, floors, corbels and piers are silica brick, and the regenerator below them is filled with slotted checker brick. Ceramic welding mixes of silica, fused silica or fireclay repair these walls, according to a producer's coke oven product range.

Steel Plant Zone Pages From Blast Furnace to Reheating Furnace#

Six zone pages sit one level below the steel guide, one for each steel plant unit with its own lining. Table 2 lists the six pages with the zones each one covers.

The steel guide carries the plant-wide view of classes, binders and consumption, and each zone page carries the zoning and campaign data of one unit.

How Refractory Demand and Relining Cycles Differ by Industry#

Refractory demand differs by industry in volume, cost share and relining cycle: steel replaces linings within 20 minutes to 2 months, while glass melters run up to 10 years (RHI Magnesita, 2021, company estimate). Table 3 sets two estimates side by side: the end-use split of refractory raw materials and the replacement cycle and cost share of each industry group.

Estimates from the named sources; not a measured market split.

Both columns are estimates, not measured market data: the end-use split is a 2021 conference slide by Compson and Gross citing producer, association and analyst sources, and the cycles and cost shares are one producer's 2021 estimate.

Steel Takes the Largest Share of Refractory Output#

Steel is the largest consumer: around 70 % of refractories are sold to the steel industry (World Refractories Association). Specific refractory consumption in steelmaking is 10 to 20 kg per tonne of steel worldwide (20 to 40 lb per short ton), according to Nippon Steel Technical Report No. 125 (2020).

The same report puts the unshaped share of steelmaking refractory consumption in Japan at 60 to 70 %, so monolithic products outweigh brick in Japanese steelmaking.

Replacement Cycles From Minutes to 20 Years#

Refractories are either consumable goods replaced continually, as in steelmaking, or investment goods replaced at longer intervals, as in glass furnaces and reformers (World Refractories Association).

In steelmaking, refractories make up around 2 to 3 % of operating costs, and in other industrial plants they make up 0.2 to 1.5 % of total costs over a facility's life cycle, with replacement cycles of 1 to 20 years (RHI Magnesita FY2024 results, 2025-02-27). Steel producers book the lining as operating expense, other plants as capital expense.

How to Match a Refractory Class to an Industry Process#

The right refractory class for an industry process is the one whose chemistry resists the slag, melt or gas of the zone and whose form suits the installation route. Bricks suit fixed geometry, monolithics suit jointless or repairable shells, and insulation sits behind the working lining. A specification should name the zone, the attack and the standard, not a brand. Table 4 maps the six refractory families to the units of the nine industries.

Selection starts with the attack of the zone: slag and metal, alkali vapor, or erosion with campaign length.

Slag, Melt and Metal Contact#

Slag chemistry decides between acid and basic refractories, because acid refractories react with basic slags and basic refractories with acid slags (ISO 836:2001, terms 002 and 009). Neutral refractories show no appreciable reaction with either (term 089). At Peirce-Smith converter tuyeres, chrome spinel resists better than periclase, and magnesium sulfate forms in the brick (Canadian Metallurgical Quarterly paper).

Chemical attack by a metal differs from slag attack: molten aluminum reduces the silica of aluminosilicate linings to free silicon and grows corundum (Allaire, review of refractories for molten aluminum confinement). Metal-contact zones therefore take low-silica, non-wetting materials, and the mechanisms behind each class choice are set out under slag and chemical attack.

Alkalis, Sulfur and Chlorine From Fuels and Feeds#

Alkali vapors from fuels and raw meal condense in cement kiln systems at 750 to 1100 °C (1,382 to 2,012 °F) and crystallize in pores with 17 to 45 % volume expansion (UNITECR 2025 conference paper). The same paper recommends an alkali-sulfate modulus of 1: above 1, alkali attack forms beta-alumina, feldspathoids and feldspars, and below 1, sulfate attack takes over.

Waste-to-energy boilers show alkali chemistry at the tube walls. Below 1100 °C (2,012 °F), alkali corrosion precipitates thenardite, turns mullite into albite and, with potash, forms kaliophilite; above 1100 °C, beta-alumina forms (Capital Refractories technical paper).

Erosion, Thermal Cycling and Campaign Length#

Erosion governs refinery cyclones and circulating fluidized bed boilers, where thin phosphate-bonded linings sit in hexmetal 19 or 25 mm (3/4 or 1 in) thick and dense castables are tested to ASTM C704. The sources are the hexmetal definition of API 936, 4th edition (2014), and Prasad et al. (Interceram 66, 2017). Thermal cycling adds wear where units run in batches, as in the intermittently operated electric arc furnace (Nippon Steel Technical Report No. 125, 2020).

Si3N4-bonded SiC sidewalls in aluminum reduction cells last campaigns of 60 to 84 months (ICSOBA 2023 conference paper), while high-chromia gasifier brick lasts 3 to 24 months, lost to slag corrosion and to spalling from slag penetration (NETL, 2009). The abrasion tests behind erosion wear are compared under erosion resistance.

Binders and Additives by Industry#

Every industry lining depends on its bond and its additions: resin and antioxidants in steel's carbon brick, active spinel in cement kiln brick, anti-wetting additions for aluminum, phosphate in refinery erosion linings and boric acid in silica ramming mass. Table 5 lists the bond and the main additions for each industry.

Active spinels keep cement kiln brick flexible because Fe2+ and Mn2+ diffuse into periclase and Mg2+ into the spinel, forming secondary spinel with expansion (RHI Magnesita).

Boric acid (CAS 10043-35-3) carries the classification "Harmonised CLP Annex VI: H360FD" (index 005-007-00-2, Repr. 1B, Note 11, ATP 20, in application since 2025-02-01). It has been on the REACH Candidate List since 2010-06-18 as toxic for reproduction (Article 57c).

Standards for Industrial Refractory Linings#

Industrial refractory linings are specified with three layers of standards: definitions (ASTM C71-12(2024), ISO 836:2001), product classifications and tests (ISO 10081, ASTM C704, C831, C1223) and refinery installation quality control (API Std 936, 975 and 976). Table 6 sets the US and ISO or EN documents for each subject side by side.

API 936 never covers brick: brick systems belong to API Std 975 and fiber linings to API Std 976 (api.org recertification effectivity sheet, effective 2025-12-15). Every designation with its edition and status is listed under refractory standards.

Side by side means the same subject, never equivalent requirements: ASTM C704/C704M-15(2022)e1 and ISO 16282:2007 both test abrasion at room temperature, but a result under one is not a result under the other. EN ISO 16282:2008 replaced EN 993-20:2004.

Installation, Dry-Out and Relining Help by Industry#

Installation, dry-out and relining work follows each industry's outage rhythm: a steel plant slide gate may need replacing every four hours, and a primary steelmaking furnace is relined at about six-month intervals (RHI Magnesita FY2024 results). Kilns, melters and refinery units reline in longer planned shutdowns.

Industry also decides the method: refinery shells take cast, gunned or shotcrete castables, boiler water walls take medium-weight castables, and steel converters and EAFs take gunning mixes for hot repair. Procedures for all of them are set out under installation, dry-out and repair.

A contractor request names the industry, the service (installation, dry-out and heat-up, repair or inspection), the method (casting, gunning, shotcrete, bricklaying or fiber) and the region. The two practice guides behind such a request are listed below.

• refractory dry-out and heat-up schedules: heat-up holds and rates for castable linings.
• refractory lining design: working, safety and insulating layers.

Which Industries Use Refractories Beyond These Nine Guides?#

The nine guides cover the industries that consume most refractories; lime burning sits in the cement guide, foundry melting in the induction furnace guide, reheating furnaces in the steel guide and waste incineration in the boiler guide.

The refractory industry itself, meaning the producers and their market, is a different subject from the consuming industries. Market sizes, segments and regional splits are analyst estimates, each with its publisher and year, under refractories market.

Does One Refractory Class Serve Several Industries?#

Yes: one refractory class serves several industries when the same attack recurs in different plants. High-alumina brick lines hot blast stoves, cement kiln calcining zones and lime kilns. Silicon carbide serves aluminum reduction cell sidewalls and waste-to-energy boiler walls, and magnesia-chrome brick lines copper converters and steel RH degassers. Silica brick serves glass furnace crowns, coke oven heating walls and hot blast stove domes.

Which High-Temperature Uses Fall Outside Refractory Linings?#

Aerospace, electronics and semiconductor parts are technical ceramics, not refractory linings, and refractory metals such as tungsten and molybdenum are metals, not refractories; this reference covers neither. Furnaces, kilns and boilers appear here only through their linings, never as machines.