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Patentability – Cement Production

Overview of Invention

Recently, a patentability search was assigned. After reading the IDF (invention disclosure form), I found out that the IDF is related to the composition of the cement manufacturing process by the addition of Calcium carbonate and Nitric acid to form a mixture to produce Calcium nitrate, further heating Calcium nitrate to decompose into Calcium oxide, Carbon dioxide and Nitrogen dioxide. The Calcium oxide is further heated with the mineral tailings in the presence of a mineralizer to form a cement composition.

Search Methodology

Initially the IDF was thoroughly analyzed, to make proper understanding and to extract the key-features from the IDF. Further, keywords and their synonyms were also extracted.

After that we started our search broadly to find relevant prior arts in the field of the cement production by using mineral tailings. The search strategies were made with different search combinations by using various keywords and IPC/CPC classes. The preliminary search was performed on the patent databases such as QUESTEL ORBIT, ESPACENET, GOOGLE PATENTS, FPO and PATENTSCOPE and Non patent search (NPL) was performed on the databases such as GOOGLE SCHOLAR, SCIENCE DIRECT, SPRINGERLINK, and so on. The other search strategies such as assignee and inventor search, citation analysis, similarity searches, and semantic search were also performed to find relevant references.

Challenges Faced During Search

The invention consisted of five features that were different from each other. During our search, we came across many methods of cement manufacturing that disclosed mixing of calcium carbonate and nitric acid to form calcium nitrate, but the real challenge was to find a process of cement manufacturing involving the heating process of calcium nitrate to form calcium oxide which is further heated along with mineral tailings in the presence of Calcium fluoride.

We also narrowed our search queries to find relevant references.

Approach to find a bang-on reference

While analyzing the references both patents and research papers, we analyzed that the most of the references were specifically of US, China and Spanish jurisdiction. It was an indication to us that these countries are actively working on this technology on a big scale. Then, we started searching broadly on the native databases such as INVENES, USPTO & CNIPA. Further, we also made some search queries and performed these searches on ORBIT by restricting the patent hits to these countries only.

The search was now directed to find the combustion of calcium nitrate to form calcium oxide and further heating of calcium oxide with mineral tailings to produce cement.

  • This strategy worked, we found US, GB and CN patents disclosing the formation of Cement by using mineral tailings involving heating of calcium nitrate to form calcium oxide.We also performed a broad non-patent literature search and found some companies working on processing of cement by calcium oxide and mineral tailings.

Types of references Shortlisted

 We shortlisted three patent references. The patent references are almost similar to the present invention and disclosed all the key-features of the present invention. Further, the two patent reference are closely relevant and disclose all key features, but the third reference failed to disclose the use of nitric acid. Therefore, we added two patent references in an additional section of the search report.


The features were mapped with most relevant prior arts and suitable comments were also provided to support the mapping. At the top of the search report, we also provided an overall search summary based on the analysis of the proposed invention. Further, we also provided important keywords, IPC/CPC classes and search strategies in the search report.