Three activity levels
High Activity, Standard Activity and Refractory grades let compounders match MgO reactivity to the polymer, cure system and service temperature.
Specialty Chemical
Magnesium Oxide — Manufacturer & Exporter from India
Light-burned and hard-burned MgO for rubber compounding, polymers, construction and refractories, produced in Gujarat and supplied with batch test data.
Light-Burned MgO PowderHard-Burned MgO Powder
ISO 9001 certified processes
NABL-accredited lab testing
CoA, TDS & MSDS with every shipment
Export packaging worldwide
Overview
What is Magnesium Oxide?
Magnesium oxide (MgO) is a white, high-melting inorganic oxide produced by calcining magnesium-bearing raw materials such as magnesite or magnesium hydroxide. In elastomer compounding it is best known as an activator and acid acceptor for chloroprene (CR) and fluorocarbon (FKM) rubbers, where it controls cure rate, improves scorch safety and neutralises the acidic by-products released during vulcanisation.
Calcination temperature defines the material. Light-burned MgO, calcined at comparatively low temperature, keeps a fine crystallite size and a high specific surface area, which makes it chemically reactive. Hard-burned MgO is calcined at higher temperature, giving larger, denser crystals with low reactivity and good thermal stability. Between these two forms, surface area, and with it activity in a compound, can be tuned to the job.
That reactivity is why grade selection matters. A high surface area grade reacts quickly with the hydrogen chloride or hydrogen fluoride liberated from CR and FKM, protecting the polymer and the mould. A lower activity grade suits general-purpose uses where a slower, more predictable reaction is preferred, while hard-burned material serves refractory and high-temperature applications where stability, not reactivity, is the priority. Because light-burned MgO picks up moisture and carbon dioxide from air, packaging and storage also influence performance in the plant.
Obsidian Minerals manufactures magnesium oxide in Gujarat, India, and supplies three grades: High Activity, Standard Activity and Refractory. Production runs under ISO 9001 certified processes, with testing in an NABL-accredited laboratory. Every shipment carries an MSDS/SDS, Technical Data Sheet and batch Certificate of Analysis. Material is packed in 25 kg or 50 kg HDPE or paper bags, or in 1 MT and 1.2 MT jumbo bags, and samples are available for qualification trials.
Magnesium Oxide grades
Select a grade for its typical properties, applications, usage guidance and FAQs.
Magnesium Oxide
High Activity MgO
Light-burned MgO with a specific surface area above 100 m²/g, built for fast acid acceptance in CR and FKM compounds.
Rubber Accelerators Magnesium OxideStandard Activity MgO
A moderately reactive MgO for rubber, resins, magnesium binders and neutralisation, where a steady and predictable reaction rate is preferred.
General Purpose Magnesium OxideRefractory Grade MgO
Hard-burned, low-reactivity magnesia for refractory mixes, phosphate cements and ceramic batches where thermal stability matters most.
High-Temperature Applications| Grade | Specification | Primary use | Link |
|---|---|---|---|
| High Activity Magnesium Oxide | SA >100 m²/g | Rubber Accelerators | Specs |
| Standard Activity Magnesium Oxide | On TDS | General Purpose | Specs |
| Refractory Grade Magnesium Oxide | On TDS | High-Temperature Applications | Specs |
From deposit to dispatch
- 01
Raw material selection and testing
- 02
Controlled calcination (light-burned or hard-burned)
- 03
Milling and air classification
- 04
Surface area and chemical analysis
- 05
Moisture-protected packing
Why source Magnesium Oxide from Obsidian Minerals
Tested batch by batch
Surface area, MgO content and loss on ignition are checked in an NABL-accredited laboratory and reported on the batch Certificate of Analysis.
Packed for reactive grades
HDPE bag options help protect light-burned MgO from moisture and carbon dioxide pick-up between our Gujarat plant and your mixing room.
Where Magnesium Oxide is used
Magnesium Oxide — frequently asked questions
What is magnesium oxide used for in rubber?
In rubber compounding, magnesium oxide is used mainly as an activator and acid acceptor in chloroprene (CR), fluorocarbon (FKM) and other halogen-containing elastomers. It neutralises hydrogen chloride or hydrogen fluoride released during cure, moderates the onset of vulcanisation to give scorch safety, and helps stabilise the finished part. Grade choice depends mostly on the reactivity, or surface area, the compound requires.
What is the difference between light-burned and hard-burned magnesium oxide?
The difference lies in calcination temperature. Light-burned MgO is calcined at lower temperature and keeps a high surface area, so it is reactive and suited to rubber, resins and neutralisation. Hard-burned MgO is calcined at higher temperature, producing dense crystals with low surface area and low reactivity, which suits refractory and high-temperature uses where stability matters more than chemical activity.
Which magnesium oxide grade should I choose?
Choose the High Activity grade for CR and FKM compounds that need fast, efficient acid acceptance. Choose Standard Activity for general rubber goods, polyester resin thickening, magnesium binders and neutralisation. Choose the Refractory grade for basic refractories, phosphate cements and other high-temperature uses. If you are unsure, share your formulation and process, and we will suggest a grade and send a sample.
How should magnesium oxide be stored?
Store magnesium oxide in its original closed bags in a cool, dry area, off the floor and away from acids. Light-burned grades slowly absorb moisture and carbon dioxide from air, which lowers their activity, so part-used bags should be resealed straight away and stock should be used in date order. Hard-burned material is less sensitive but should still be kept dry.
What documents are supplied with magnesium oxide shipments?
Every shipment is accompanied by an MSDS/SDS, a Technical Data Sheet and a batch Certificate of Analysis. The CoA reports the tested values for that lot, such as MgO content and, where relevant, surface area and loss on ignition. Testing is carried out in an NABL-accredited laboratory, and production follows ISO 9001 certified processes.
Can I get a sample or a custom magnesium oxide grade?
Yes. Samples are available for laboratory and plant trials, and custom grades or particle sizes can be developed with customers where a standard grade does not fit. To help us respond accurately, tell us the application, current grade or specification, expected annual volume, preferred packaging and destination country when you send your enquiry.
What packaging options are available for Magnesium Oxide?
Standard export packing is 25 kg or 50 kg HDPE / paper bags and 1 MT or 1.2 MT jumbo (FIBC) bags, palletised and shrink-wrapped on request. Custom and private-label packaging can be arranged for volume orders.
Do you provide MSDS and technical datasheets?
Yes. A Technical Data Sheet and MSDS are available for every grade, and each shipment is accompanied by a batch-specific Certificate of Analysis.
Request a quote
Interested in Magnesium Oxide?
Tell us your application, preferred grade and volume. Our engineering team will recommend the right grade and send a datasheet, sample and quotation.
- Technical Data Sheet & MSDS
- Samples for qualification trials
- Bulk and recurring supply pricing