CALERA DE ALTZO S.L.

CALERA DE ALTZO S.L. is a Spanish industrial-minerals company based in Altzo, in the province of Gipuzkoa in the Basque Country. It operates as a production plant within the Calcinor group, a family-owned Spanish industrial-minerals group whose corporate website presents it as dedicated to the preparation of industrial minerals used as chemical reagents. Within that group, Calera de Altzo is one of the named production sites for lime-based product families, appearing alongside Calmit Llierca, Andaluza de Cales, Cal de Castilla, Cales de La Plana, Dolomitas del Norte, Lafarge Calcinor Maroc and Eurocho. The company's activity centres on the manufacture of calcium oxides and hydroxides derived from limestone and dolomite. These are not consumer goods but industrial chemical reagents sold business-to-business into construction, civil works, soil stabilisation, agriculture and livestock farming, animal feed, iron and steel, metallurgy, chemicals, paints, adhesives and sealants, rubbers and plastics, and environmental applications such as water, sludge and gas treatment. Calcinor describes itself as a leader in its zones of influence in calcined products and especially in differentiated products such as dolomite refractories, PCC and talc. Calera de Altzo is specifically identified as a production plant for two of Calcinor's branded product lines. CALINTEC® is a micronized calcium oxide with a controlled particle size distribution centred in the 40 micron range, designed for high reactivity, high fluidity and improved dispersion; it is used as a drying and moisture-capturing agent in polymers, elastomers and adhesives, as a reagent in the saponification reaction for calcium soaps in ruminant feed, and for its biocidal action in agriculture and livestock. STABYCAL® is a range of calcium oxides and hydroxides developed to optimise the stabilisation of clay soils with lime, sold into civil works and agriculture, with a low-dust variant (STABYCAL SP) recommended for works near inhabited or sensitive sites such as airports, tunnels and railways. Because Calera de Altzo is a production entity rather than a consumer-facing brand, its public profile is largely subsumed within the Calcinor corporate identity. Calcinor presents itself as a family company with an industrial culture and a commitment to continuity in the industrial minerals sector, active on five continents, exporting its products and maintaining a network of companies across Europe and Africa, and committed to sustainable growth through the optimisation of resources and the development of new technologies and industrial processes. Calera de Altzo contributes to that network as a Spanish lime plant serving both domestic and export markets.

CALERA DE ALTZO S.L. is a Spanish company recorded in public data as a Spanish company and based in Altzo, in the Basque province of Gipuzkoa. Its name derives from the Spanish word 'calera' (lime kiln) and the locality of Altzo (also written Alzo), reflecting its origin as a lime-producing operation in the Basque Country. The company forms part of the Calcinor group, a family-owned Spanish industrial-minerals group. Calcinor's own corporate materials describe it as dedicated to the preparation of industrial minerals used as chemical reagents, as a family company with an industrial culture and a commitment to continuity in the industrial minerals sector, and as active on five continents, exporting its products and maintaining a network of companies set up around Europe and Africa. Within that group, Calcinor lists a set of production plants that includes Calmit Llierca, Calera de Alzo, Andaluza de Cales, Cal de Castilla, Cales de La Plana, Dolomitas del Norte, Lafarge Calcinor Maroc and Eurocho. Calera de Altzo appears in Calcinor's product documentation as a production plant for two branded lime lines. The first is CALINTEC®, a micronized calcium oxide with a controlled particle size distribution centred in the 40 micron range (CALINTEC 40 has a d50 below 40 µm, around 7 µm), developed for high reactivity, high fluidity and improved dispersion. Its featured applications include polymers and rubbers, where it acts as a drying and moisture-capturing agent in formulations of polymers, elastomers and adhesives; animal feed, where it is a chemical reagent designed for correct dispersion and incorporation into the saponification reaction during the preparation of calcium soaps used in ruminant feed; and agriculture and livestock, where lime has a biocidal action that counteracts, neutralises and prevents the action of harmful organisms. The second is STABYCAL®, a range developed through collaborations and R+D activities to optimise the stabilisation process of clay soils with lime. The STABYCAL® family selects and modifies calcium oxides and hydroxides to strengthen performance and reactivity and reduce product loss during application; it includes STABYCAL and STABYCAL SP, the latter offering a significant reduction in dust generated during dosing and application and recommended for agriculture and civil works close to inhabited places or sensitive sites such as airports, tunnels and railways. Calcinor's broader product portfolio, in which Calera de Altzo participates as a plant, also includes REFRADOL®, a sintered dolomite with high resistance to hydration produced through an industrial process Calcinor describes as unique in the world, used as a raw material for refractories in the iron and steel industry and metallurgy, including dolomite gunning plains for ladles and electric arc furnaces. Calcinor states that it is a leader in its zones of influence in calcined products and especially in differentiated products such as dolomite refractories, PCC and talc, and that it is committed to sustainable growth by optimising and using only strictly necessary resources through new technologies and industrial processes. As a subsidiary production entity, Calera de Altzo does not maintain a separate consumer-facing brand identity; its history is bound up with the growth of the Calcinor group and with the industrial lime sector of northern Spain. Public information about the company is limited to its identification as a Spanish company and its role as a Calcinor plant, and no founding date, founder or executive names are established in the available evidence.

• Calcinor publishes a feature titled 'If the minerals from Calcinor could speak…' referencing its mineral products.

• Cales de Llierca renews its corporate identity and will now operate as Calmit Llierca, another Calcinor plant named alongside Calera de Alzo.

• Kelsen presents its 2025 Sustainability Report, reinforcing its commitment to continuous improvement.

A production plant within the family-owned Calcinor industrial-minerals group, supplying differentiated lime-based chemical reagents to construction, agriculture, metallurgy and environmental industries.

• CALINTEC®

  A micronized calcium oxide with very low particle size and improved dispersion; controlled particle size distribution centred in the 40 micron range (CALINTEC 40: d50 < 40 µm, 7 µm). Used in polymers and rubbers as a drying and moisture-capturing agent, in animal feed for calcium soap saponification in ruminant feed, and in agriculture and livestock for its biocidal action.

• STABYCAL®

  A range of calcium oxides and hydroxides developed to optimise the stabilisation of clay soils with lime, strengthening performance and reactivity and reducing product loss during application. Includes STABYCAL and STABYCAL SP (low-dust, recommended for agriculture and civil works near inhabited or sensitive sites).

• REFRADOL®

  Sintered dolomite with high resistance to hydration, produced through a process Calcinor describes as unique in the world; a raw material for refractories used in the iron and steel industry and metallurgy, including dolomite gunning plains for ladles and electric arc furnaces.

1. 1CALCINOR. Minerales industrialescalcinor.com
2. 2CALINTEC® A reactive lime with improved dispersioncalcinor.com
3. 3STABYCAL® - CALCINOR. Minerales industrialescalcinor.com
4. 4REFRADOL® - CALCINOR. Minerales industrialescalcinor.com
5. 5CALERA DE ALTZO S.L. - Wikidatawikidata.org