AMENDED AND RESTATED PURIFIED WET PHOSPHORIC ACID SUPPLY AGREEMENT

Exhibit 10.15

CONFIDENTIAL TREATMENT REQUESTED UNDER

C.F.R. SECTIONS 200.80(b)(4), 200.83 AND 230.406.

**** INDICATES OMITTED MATERIAL THAT IS THE

SUBJECT OF A CONFIDENTIAL TREATMENT REQUEST

FILED SEPARATELY WITH THE COMMISSION.

THE OMITTED MATERIAL HAS BEEN FILED

SEPARATELY WITH THE COMMISSION.

AMENDED AND RESTATED

PURIFIED WET PHOSPHORIC ACID SUPPLY AGREEMENT

This Agreement made this 23rd day of March, 2000, by and between Rhodia Inc., a Delaware corporation (“ Rhodia ”), and PCS Purified Phosphates, a Virginia general partnership formerly known as Albright & Wilson Company (“ Partnership ”).

W I T N E S S E T H:

WHEREAS, on July 29, 1988, Albright & Wilson Americas Division of Tenneco Canada, Inc., an Ontario corporation (“ A&W Canada ”), and Partnership entered into a Purified Wet Phosphoric Acid Supply Agreement dated of even date (as amended from time to time since that date, the “ 1988 Agreement ”); and

WHEREAS, Albright & Wilson Americas Limited, a Canadian corporation (“ A&W Ltd. ”), is a successor to A&W Canada under the 1988 Agreement and, thus, A&W Ltd. and Partnership are parties to the 1988 Agreement; and

WHEREAS, PCS Phosphate Company, Inc., a Delaware corporation, formerly known as Texasgulf Inc. (“ PCSP ”), Albright & Wilson Americas, Inc., an affiliate of A&W Ltd. (“ A&W Inc. ”), Partnership, and PCS Industrial Products, Inc., a Delaware corporation (“ PCSA ”), and Rhodia, have entered into a Distribution and Sale Agreement, dated as of March 23, 2000 (the “ Distribution and Sale Agreement ”), pursuant to which, among other things, Partnership has agreed to distribute certain assets of Partnership to A&W Inc. and A&W Inc. has agreed to sell its entire interest in Partnership to PCSP as provided therein; and

WHEREAS, in connection with the transactions contemplated by the Distribution and Sale Agreement and in order to satisfy a condition to the obligations of Partnership under the Distribution and Sale Agreement, Rhodia and Partnership desire to enter into this Agreement to effect various further amendments to, and to restate, the 1988 Agreement, and to designate Rhodia as the purchaser thereunder.

NOW, THEREFORE, for and in consideration of the premises and the mutual covenants herein set forth, Rhodia and Partnership hereby amend and restate the 1988 Agreement in its entirety and agree as follows:

1. Purchase and Sale; Specifications .

1.1 Partnership shall sell and deliver, and Rhodia shall purchase and receive, during the term hereof, low alkali purified wet phosphoric acid (“ Low Alkali Product ”), low alkali low sulfate purified wet phosphoric acid (“ Low Sulfate Product ”) and high alkali purified wet phosphoric acid (“ High Alkali Product ”; each of Low Alkali Product, Low Sulfate Product

and High Alkali Product sometimes referred to herein as a “Product”, and, collectively, the “Products”) in the quantities and subject to the terms and conditions hereinafter set forth.

1.2 Except as set forth in Section 1.3 hereof, the Products shall conform with the specifications described in Exhibit A attached hereto. Partnership’s analyses at point of transfer shall govern unless shown to be in error. A list of Partnership’s analytical procedures used for Products is attached hereto as Exhibit B. Partnership shall obtain analyses of all Products transferred and shall provide Rhodia a Certificate of Analysis with each transfer of the Products. In the event that Low Alkali Product or Low Sulfate Product shall not conform with any new Food Chemicals Codex standard, then upon sixty (60) days advance written notice to Partnership, Rhodia may elect to reduce or temporarily eliminate shipment and minimum purchases of the affected Products or any portions thereof under this Agreement, such notice indicating (i) the date on which any change in shipment and/or purchases shall occur and (ii) the volume of the applicable affected Product which Rhodia elects to purchase, until such time as the Partnership again offers products hereunder conforming with such standards. If Partnership subsequently notifies Rhodia that the affected Products then meet the minimum applicable Food Chemicals Codex standards and that no change in Product pricing is required hereunder, within sixty (60) days of such notice, Rhodia shall renew its purchase of Products at those then applicable levels set forth in Exhibit C. If Partnership advises Rhodia that an increased price for Products will be required to compensate Partnership for capital expenditures or increased operating costs, the parties shall negotiate in good faith as to such new prices and volumes for Product. If no agreement is reached within nine (9) months of Partnership’s notice, either party shall have the right to terminate this Agreement as to the affected volumes of Low Alkali Product and/or Low Sulfate Product upon not less than six (6) months notice. Except to the extent Rhodia declines to purchase Improved Products as set forth in Section 1.3 below, each type of Product sold hereunder shall be of Partnership’s typical quality.

1.3 The parties recognize that Partnership may develop materials from time to time that are capable of being substituted for one or more of the Products. In the event that Partnership develops any such materials and constructs or modifies facilities so as to be capable of manufacturing such materials, then Partnership shall provide Rhodia with a written notice of (i) the specifications for such materials and (ii) the Food Chemicals Codex applicable to such materials (in each such case, such grade of material is referred to hereinafter as the “ Improved Product ”). Within three (3) months following receipt of any such notice from Partnership, Rhodia shall notify Partnership in writing as to whether Rhodia intends to purchase Improved Product in substitution for a particular type of Product. The parties agree to negotiate with one another in good faith to determine the amount of an adjustment, if any, to be made to the pricing terms hereunder, the volume of the Improved Product to be purchased and any other provisions of this Agreement that shall be modified. In the event that the parties are unable to reach agreement regarding a mutually acceptable amendment to this Agreement concerning such Improved Product within six (6) months following the date that Partnership notified Rhodia under this Section 1.3, neither party shall thereafter have any obligation hereunder to purchase or supply the applicable Improved Product.

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2. Term . The term of this Agreement shall be for the period commencing on the date of this Agreement and ending on July 29, (****) (the “ Initial Term ”), and thereafter shall be extended without further action of the parties for additional terms of (****) years (each an “ Additional Term ”) upon the expiration of the Initial Term or any Additional Term; provided, however, that upon not less than twenty-four (24) months’ prior written notice to the other party hereto, either party may cause this Agreement to terminate upon the expiration of the Initial Term or any Additional Term thereafter.

3. Price and Terms .

3.1 Rhodia shall pay to Partnership in U.S. Dollars a price per short ton (“st”) of P ₂ O ₅ contained in Product F.O.B. at the Aurora Plant determined as follows:

The price for each of the Low Alkali Product, Low Sulfate Product and High Alkali Product shall be adjusted during the term of this Agreement in accordance with the provisions set forth on Exhibit C attached hereto.

As used herein, “ Contract Year ” means a calendar year commencing January 1 during the term of this Agreement, except that the first such period shall commence upon the date of this Agreement and terminate on December 31, 2000. As used herein “ Contract Quarter ” means a period of three (3) consecutive months, beginning January 1, April 1, July 1, or October 1, except that the first such period shall commence upon the date of this Agreement and end on the day prior to the start of the first full Contract Quarter.

3.2 On or before the September 30th prior to the commencement of each Contract Year (as defined in Section 3.1), Partnership shall give Rhodia written notice of its estimate of the price for each Product for such Contract Year. On or prior to June 30 of the next following Contract Year, Partnership shall determine the actual price for each Product purchased, and to be purchased by Rhodia during such Contract Year (based upon the calculations set forth in Exhibit C) and shall invoice or credit Rhodia for the difference, if any, between such actual price and the amount previously invoiced at the estimated prices to Rhodia for such Contract Year. For the remainder of such Contract Year, Partnership shall invoice Rhodia for the actual price for the Products as so determined.

3.3 Partnership shall invoice Rhodia for payment with respect to each shipment of Product hereunder, and the terms of payment for all Products purchased hereunder shall be net thirty (30) calendar days from date of the invoice.

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3.4 Partnership shall keep and maintain true and accurate records as may be necessary to verify volumes delivered and indices tracked as bases for prices charged to Rhodia under this Agreement. If Rhodia disputes any of the amounts charged hereunder, Partnership shall allow representatives of Rhodia immediate and full access (including the rights of physical inspection and to make copies) to such records and such other information maintained by Partnership as may be necessary for the verification of such amounts. Partnership and Rhodia shall use their best efforts to resolve such dispute within 45 calendar days after the relevant invoice date.

3.5 If it is determined that there has been an overcharge, then Partnership shall immediately refund the overcharge received by it to Rhodia or, if such amount has not been previously paid, Rhodia shall pay to Partnership the correct amount owed to Partnership. If it is determined that there has been an undercharge, Rhodia shall immediately pay the undercharge to Partnership plus any additional amounts not previously paid hereunder.

3.6 Notwithstanding anything to the contrary contained in this Section 3, with respect to any Contract Year after the (****) Contract Year hereunder, if Rhodia notifies Partnership of a bona fide opportunity, and provides a copy thereof in writing (showing all terms of the offer, including the offering party), under which Rhodia is to purchase a quantity of phosphoric acid of a quality equal to or better than a specific Product manufactured by Partnership at a price F.O.B. rail car customs cleared U.S. East Coast port that, giving effect to all conditions of such offer, is at least ten percent (10%) less than the price per short ton then in effect under this Agreement for the relevant Product (the “ Lower Offer ”), Partnership shall have the option to meet the Lower Offer within fifteen (15) calendar days after notification by Rhodia, for the same annual quantity as that to which the Lower Offer relates. In the event that Partnership does not elect to meet the Lower Offer, then (i) Rhodia shall be released from its obligation hereunder to purchase the annual volume of the Lower Offer up to an amount equal to the lesser of (a) (****) short tons of the Product or (b) (****) short tons of the Product minus the sum of all then effective Released Quantities and Met Quantities (both as hereinafter defined), and (ii) the portion of each type of Product required to be purchased by Rhodia as set forth in Exhibit C shall be proportionately reduced to equal the result of multiplying the annual amount of such Product which Rhodia is required to purchase as set forth in Exhibit C times a fraction, the numerator of which is the total annual number of short tons of all Product required to be purchased as set forth in Exhibit C minus the Released Quantity and the denominator of which is (****). “ Released Quantity ” means the annual quantity of short tons of Product that Rhodia has been released from its obligation to purchase hereunder pursuant to a Lower Offer presented to Partnership by Rhodia in accordance with this Section, “ Met Quantity ” means the annual quantity of short tons of Product for which Partnership has reduced the purchase price hereunder pursuant to a Lower Offer presented to Partnership by Rhodia in accordance with this Section. With respect to all Released Quantities hereunder, such right to purchase from such third party must be exercised in writing by Rhodia within sixty (60) calendar days and shall be effective twelve (12) months after Partnership’s receipt of Rhodia’s notice of the Lower Offer in accordance with the notice provisions set forth herein. In the event that Rhodia shall accept any Lower Offer from such third party pursuant to the terms hereof, then, upon the expiration of the contract or other arrangement entered into pursuant to such Lower Offer, Rhodia shall revert to

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the purchase of quantities of Product from Partnership, at the then effective price hereunder, which Rhodia was required to purchase prior to application of this Section. In the event that Partnership elects to meet the Lower Offer, then (i) Partnership shall sell to Rhodia on an annual basis the quantity of Product as to that which the Lower Offer relates, up to an annual amount equal to the lesser of (a) (****) short tons of the Product or (b) (****) short tons of the Product minus the sum of all then effective Released Quantities and Met Quantities at the price per short ton in the applicable Lower Offer (the “Met Price ”) for the term specified in the Lower Offer (the “Met Term” ), and (ii) the Met Price shall remain in effect with respect to the Met Quantity for the entirety of the Met Term despite any subsequent Lower Offer received by Rhodia that contains a price per short ton less than the Met Price. Upon the expiration of the applicable Met Term, Rhodia shall revert to the purchase of Product from Partnership at such price that Rhodia was required to pay prior to adjustment under this Section. Rhodia shall be entitled to present subsequent Lower Offers to Partnership under this Section so