Superplasticizers for cementitious compositions
Superplasticizers for cementitious compositions are produced from a raw material mixture of (1) naphthalenesulfonic acid formaldehyde condensate and (2) free sulfuric acid using a 1-step process or a 2-step process. In the 1-step process, the mixture is neutralized with a zinc compound such as zinc...
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Zusammenfassung: | Superplasticizers for cementitious compositions are produced from a raw material mixture of (1) naphthalenesulfonic acid formaldehyde condensate and (2) free sulfuric acid using a 1-step process or a 2-step process. In the 1-step process, the mixture is neutralized with a zinc compound such as zinc oxide to a pH of about 2 to obtain a superplasticizer mixture of the free acid of the naphthalenesulfonic acid formaldehyde condensate and zinc sulfate. In the 2-step process, the mixture is first neutralized with a zinc compound such as zinc oxide to a pH of about 2 and then with a base such as sodium hydroxide to a pH of about 6 to obtain a superplasticizer mixture of the sodium salt of the naphthalenesulfonic acid formaldehyde condensate and zinc sulfate. These superplasticizer mixtures are superior to a low salt content commercial sodium salt of a naphthalenesulfonic acid formaldehyde condensate where sodium sulfate content has been reduced by lime treatment. |
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