Хромат стронция

Химические свойства

Strontium chromate a light yellow crystalline solid or powder.

Strontium chromate is prepared by precipitating a suitably soluble chromate with an appropriate strontium salt. Finding a primary use in corrosion-inhibiting coatings, this pigment has poor tint strength, low opacity, and unsatisfactory alkali and acid resistance, which limits its more widespread use in the coatings industry. Little of this pigment is now manu- factured in the United States.

Использование

Strontium chromate is mainly used to prevent corrosion on aluminum, and primers containing this pigment are standard for the aviation industry. Strontium chromate is so effective at low loadings that it is often used to provide inhibition for coil coatings despite the fact that it is the most expensive chromate inhibitor. The pigment is sometimes combined with zinc chromate in water-based formulations. In these cases, to avoid stability problems, loadings are kept at low levels, about 2% total chromate.
Corrosion inhibitor in pigments; in electrochemical processes to control sulfate concentration of solutions.

Общее описание

STRONTIUM CHROMATE is a light yellow powder or granular solid. STRONTIUM CHROMATE is insoluble in water. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. STRONTIUM CHROMATE is used as a pigment, a protective coating against corrosion, and in pyrotechnics.

Реакции воздуха и воды

STRONTIUM CHROMATE is insoluble in water. Reactivity in Water: Produces hazardous solution.

Профиль реактивности

Oxidizing agents, such as STRONTIUM CHROMATE, can react with reducing agents to generate heat and products that may be gaseous (causing pressurization of closed containers). The products may themselves be capable of further reactions (such as combustion in the air). The chemical reduction of materials in this group can be rapid or even explosive, but often requires initiation (heat, spark, catalyst, addition of a solvent). Explosive mixtures of inorganic oxidizing agents with reducing agents often persist unchanged for long periods if initiation is prevented. Such systems are typically mixtures of solids, but may involve any combination of physical states. Some inorganic oxidizing agents are salts of metals that are soluble in water; dissolution dilutes but does not nullify the oxidizing power of such materials. Organic compounds, in general, have some reducing power and can in principle react with compounds in this class. Actual reactivity varies greatly with the identity of the organic compound. Inorganic oxidizing agents can react violently with active metals, cyanides, esters, and thiocyanates. Avoid contact with water, acids, and bases.

Опасность

Toxic by ingestion. Confirmed carcinogen.

Угроза здоровью

INHALATION: Irritating to mucous membranes. SKIN: Repeated skin contact can cause eczematous dermatitis, with edema and ulceration. INGESTION: Dizziness, intense thirst, abdominal pain, vomiting, shock and oliguria or anuria.

Пожароопасность

Behavior in Fire: Heat stable

Профиль безопасности

Confirmed human carcinogen with experimental carcinogenic and tumorigenic data. Moderately toxic by ingestion. Mutation data reported. See also CHROMIUM COMPOUNDS and STRONTIUM COMPOUNDS.

Возможный контакт

Strontium chromate is used as a metal protective coating to prevent corrosion, in wash primers; and aluminum flake coatings; colorant in polyvinyl chloride resins and pyrotechnics.

Перевозки

UN3086 Toxic solids, oxidizing, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, 5.1-Oxidizer. Technical Name Required.

Методы очистки

Crystallise strontium chromate from water (40mL/g) by cooling.

Несовместимости

Violent reaction with strong oxidizers, hydrazine. Incompatible with combustible, organic, or other readily oxidizable materials, such as paper, wood, sulfur, aluminum powder. Attacks plastics and coatings