To provide means for reducing reaction interference observed when AT III is subjected to limulus test, whereby the limulus test of antithrombin III can be carried out at high accuracy. Reaction interference observed when AT III is subjected to limulus test can be reduced by subjecting AT III to a protein inactivation treatment in the co-presence of a divalent metal salt.

To provide means for reducing reaction interference observed when AT III is subjected to limulus test, whereby the limulus test of antithrombin III can be carried out at high accuracy. Reaction interference observed when AT III is subjected to limulus test can be reduced by subjecting AT III to a protein inactivation treatment in the co-presence of a divalent metal salt.

The present invention provides an analytical method for precipitated particles during co-precipitation reaction, comprising: running a co-precipitation reaction in a reaction vessel to form a precipitated product; injecting a tracking metal to the reaction vessel for a given time duration; collecting the precipitated product containing the tracking metal from the reaction vessel in increments of time to obtain multiple product samples; filtering each collected product sample to separate precipitated particles from filtrate; performing elemental analysis for the tracking metal in the precipitated particles of each collected product sample, to obtain the residence time distribution of the precipitated particles in the reaction vessel according to the concentration of the tracking metal in the precipitated particles. By the analytical method, the preferred residence time of the precipitated particles in the reaction vessel can be ascertained, so that it is clear when the precipitated particles should be collected from the reaction vessel.

The present invention provides an analytical method for precipitated particles during co-precipitation reaction, comprising: running a co-precipitation reaction in a reaction vessel to form a precipitated product; injecting a tracking metal to the reaction vessel for a given time duration; collecting the precipitated product containing the tracking metal from the reaction vessel in increments of time to obtain multiple product samples; filtering each collected product sample to separate precipitated particles from filtrate; performing elemental analysis for the tracking metal in the precipitated particles of each collected product sample, to obtain the residence time distribution of the precipitated particles in the reaction vessel according to the concentration of the tracking metal in the precipitated particles. By the analytical method, the preferred residence time of the precipitated particles in the reaction vessel can be ascertained, so that it is clear when the precipitated particles should be collected from the reaction vessel.

A process disclosed herein is related to the isolation and purification of substantially pure chemicals, including silica gel, sodium silicate, aluminum silicate, iron oxide, and rare earth elements (or rare earth metals, REEs), from massive industrial waste coal ash. In one embodiment, the process includes a plurality of caustic extractions of coal ash at an elevated temperature, followed by an acidic treatment to dissolve aluminum silicate and REEs. The dissolved aluminum silicate is precipitated out by pH adjustment as a solid product while REEs remain in the solution. REEs are captured and enriched using an ion exchange column. Alternatively, the solution containing aluminum silicate and REEs is heated to produce silica gel, which is easily separated from the enriched REEs solution. REEs are then isolated and purified from the enriched solution to afford substantially pure individual REE by a ligand-assisted chromatography. Additionally, a simplified process using one caustic extraction and one acidic extraction with an ion exchange process was also investigated and optimized to afford a comparable efficiency.

A process disclosed herein is related to the isolation and purification of substantially pure chemicals, including silica gel, sodium silicate, aluminum silicate, iron oxide, and rare earth elements (or rare earth metals, REEs), from massive industrial waste coal ash. In one embodiment, the process includes a plurality of caustic extractions of coal ash at an elevated temperature, followed by an acidic treatment to dissolve aluminum silicate and REEs. The dissolved aluminum silicate is precipitated out by pH adjustment as a solid product while REEs remain in the solution. REEs are captured and enriched using an ion exchange column. Alternatively, the solution containing aluminum silicate and REEs is heated to produce silica gel, which is easily separated from the enriched REEs solution. REEs are then isolated and purified from the enriched solution to afford substantially pure individual REE by a ligand-assisted chromatography. Additionally, a simplified process using one caustic extraction and one acidic extraction with an ion exchange process was also investigated and optimized to afford a comparable efficiency.

The present invention relates to a process for reducing in a gas stream the concentration of carbon dioxide and for reducing in an aqueous stream the concentration of sodium chloride, which process comprises contacting a feed gas comprising greater than or equal to 0.1% by volume carbon dioxide with an aqueous feed comprising: (a) sodium chloride; and (b) calcium oxide and/or calcium hydroxide at a total concentration of greater than or equal to 0.5% by weight,
wherein the pH of the aqueous feed is greater than or equal to 10.0. A product aqueous stream obtained from the process of the invention is also described.

The present invention relates to a process for reducing in a gas stream the concentration of carbon dioxide and for reducing in an aqueous stream the concentration of sodium chloride, which process comprises contacting a feed gas comprising greater than or equal to 0.1% by volume carbon dioxide with an aqueous feed comprising: (a) sodium chloride; and (b) calcium oxide and/or calcium hydroxide at a total concentration of greater than or equal to 0.5% by weight,
wherein the pH of the aqueous feed is greater than or equal to 10.0. A product aqueous stream obtained from the process of the invention is also described.

A method of improving rheological properties of a divalent brine based downhole treatment fluid at an elevated temperature comprises adding to the divalent brine based downhole treatment fluid a rheological modifier, which comprises a carboxylic acid ester, or a phosphate ester blended with an ethoxylated glycol, or a combination comprising at least one of the foregoing in an amount effective to improve the rheological properties of the divalent brine based downhole treatment fluid at a temperature of greater than about 200 F. The divalent brine based downhole treatment fluid comprises calcium bromide, calcium chloride, zinc bromide, zinc chloride, or a combination comprising at least one of the foregoing.

A method of improving rheological properties of a divalent brine based downhole treatment fluid at an elevated temperature comprises adding to the divalent brine based downhole treatment fluid a rheological modifier, which comprises a carboxylic acid ester, or a phosphate ester blended with an ethoxylated glycol, or a combination comprising at least one of the foregoing in an amount effective to improve the rheological properties of the divalent brine based downhole treatment fluid at a temperature of greater than about 200 F. The divalent brine based downhole treatment fluid comprises calcium bromide, calcium chloride, zinc bromide, zinc chloride, or a combination comprising at least one of the foregoing.