Intellectual Property Rights Agreement

• Date: 10 February 2017
• Parties: Synchron ("Investor"), Rare Element Resources Ltd. ("Company")
• Section: Commercial Contracts

Exhibit 4

Rare Element Resources Ltd.EXECUTION COPY

IP Rights Agreement

INTELLECTUAL PROPERTY RIGHTS AGREEMENT

Synchron, a California corporation having a principal place of business at 3550 General Atomics Court, San Diego, CA 92121-1122 (or one

or more Affiliates, the "Investor"), and Rare Element Resources Ltd., a British Columbia Corporation having a principal place of business at P.O. Box

271049, Littleton, Colorado 80127 (the "Company") (Investor and Company each a “Party” and together the "Parties"), agree as follows:

I. Background of Agreement

1.00Company is the owner of certain Patents and related Technical Information relating to rare earth mineral processing and rare earth

separation.

1.01Investor wishes to acquire certain rights under the Patents and related Technical Information in accordance with the terms of this IP

Agreement.

1.02Company and Investor are concurrently entering into an Investment Agreement ("Investment Agreement") whereby Investor is

making a monetary investment in Company.

1.03Company is issuing the Option pursuant to which Investor will be entitled to purchase common shares of Company.

II. Definitions

As used herein, the following terms have the meaning set forth below:

2.01Any term set out in this IP Agreement with its initial letters capitalized, shall have the same meaning as it has in the Investment

Agreement, unless a different meaning is explicitly assigned to the term in this IP Agreement.

2.02"Affiliate" has the meaning set forth in the Investment Agreement.

2.03“Business Day” has the meaning set forth in the Investment Agreement.

2.04“Company” has the meaning set out above in the introductory paragraph.

2.05“Company Improvements” has the meaning set out below in Article 5.00.

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Source: RARE ELEMENT RESOURCES LTD, SC 13D, 10/19/2017

Rare Element Resources Ltd.EXECUTION COPY

IP Rights Agreement

2.06“Dispute” has the meaning set out below in Article 18.00.

2.07“Dispute Notice” has the meaning set out below in Article 18.00.

2.08"Effective Date" has the meaning of the "Closing Date" set forth in the Investment Agreement.

2.09“Escalation to Mediation Date” has the meaning set out below in Article 18.01.

2.10"Improvement" or "Improvements" means any modification of a process or other technology described in a Patent, and any

modification to Technical Information.

2.11“Investment Agreement” has the meaning set out above in Article 1.02.

2.12“Investor” has the meaning set out above in the introductory paragraph.

2.13“Investor Improvements” has the meaning set out below in Article 5.01.

2.14"IP Agreement" means this agreement, including all Exhibits referenced herein and attached hereto.

2.15“Joint Improvements” has the meaning set out below in Article 5.02.

2.16"Option" has the meaning set forth in the Investment Agreement.

2.17"Option Period" has the meaning set forth in the Investment Agreement.

2.18"Patent" or "Patents" means: (a) any and all patents and patent applications owned by Company anywhere in the world as of the

Effective Date relating to rare earth mineral processing and rare earth separation including without limitation those patents and patent applications

listed in Exhibit A; (b) any and all divisions, continuations, continuations-in-part of any of the patents and patent applications within subdivision

(a); (c) any and all patents that may directly or indirectly issue from any patent applications within subdivisions (a) and (b); (d) any and all re-

issues, substitutes and extensions of any of the patents within subdivisions (a), (b) and (c); and (e) any and all counterparts or equivalents to any

of the foregoing in any country of the world.

2.19“Party” and “Parties” have the meanings set out above in the introductory paragraph.

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Source: RARE ELEMENT RESOURCES LTD, SC 13D, 10/19/2017