A method of increasing a solubility of a manganese oxide includes contacting the manganese oxide with an acid component in the presence of a dissolution accelerator that includes at least one of hydrazine, a hydrazine derivative, or a hydrazide. Also disclosed is a drilling fluid containing a carrier; MnO.sub.2; and at least one of a viscosifier, a rheology modifier, a dispersant, a weighting agent, a defoamer, a fluid loss agent, bentonite, or a lubricant.

Disclosed is a method for preparing a solid material including manganese, the method including the following steps: a. bringing into contact an aqueous effluent including manganese, for example at least 5 mg/L, typically at least 5 to 50 mg/L, and preferably 7 to 25 mg/L of manganese, with an oxidizing agent, manganese, preferably at a temperature between 10° C. and 50° C., and obtaining an oxidized aqueous solution; b. adding a base to the oxidized aqueous solution obtained at the end of step a) until a pH of between 8 and 12, preferably greater than 9, and preferably from 9 to 10.5, and obtaining a solution including a precipitate; c. filtration of the solution obtained at the end of step b); and d. obtaining a solid material including manganese, and especially manganese (IV) and/or Mn (III).

Disclosed is a method for preparing a solid material including manganese, the method including the following steps: a. bringing into contact an aqueous effluent including manganese, for example at least 5 mg/L, typically at least 5 to 50 mg/L, and preferably 7 to 25 mg/L of manganese, with an oxidizing agent, manganese, preferably at a temperature between 10° C. and 50° C., and obtaining an oxidized aqueous solution; b. adding a base to the oxidized aqueous solution obtained at the end of step a) until a pH of between 8 and 12, preferably greater than 9, and preferably from 9 to 10.5, and obtaining a solution including a precipitate; c. filtration of the solution obtained at the end of step b); and d. obtaining a solid material including manganese, and especially manganese (IV) and/or Mn (III).

Provided is a method for producing a lithium-containing solution that prevents the dissolution of the whole lithium manganese oxide while maintaining the efficiency of an elution step. The method for producing a lithium-containing solution comprises performing an adsorption step of contacting a lithium adsorbent obtained from lithium manganese oxide with a low lithium-containing liquid for adsorption to give post-adsorption lithium manganese oxide, an elution step of contacting the post-adsorption lithium manganese oxide with an acid solution to give a lithium-containing solution with residual manganese, and a manganese oxidation step of oxidating manganese to give a lithium-containing solution with a suppressed manganese concentration, performed in this order. The acid solution is a 0.5 mol/L or more and 4.0 mol/L or less hydrochloric acid solution. According to the production method, in the elution step, the dissolution of the whole lithium manganese oxide can be suppressed while maintaining the efficiency of exchange reaction between cations including Li.sup.+ and H.sup.+. Thus, the repeated use of the lithium adsorbent becomes possible.

Provided is a method for producing a lithium-containing solution that prevents the dissolution of the whole lithium manganese oxide while maintaining the efficiency of an elution step. The method for producing a lithium-containing solution comprises performing an adsorption step of contacting a lithium adsorbent obtained from lithium manganese oxide with a low lithium-containing liquid for adsorption to give post-adsorption lithium manganese oxide, an elution step of contacting the post-adsorption lithium manganese oxide with an acid solution to give a lithium-containing solution with residual manganese, and a manganese oxidation step of oxidating manganese to give a lithium-containing solution with a suppressed manganese concentration, performed in this order. The acid solution is a 0.5 mol/L or more and 4.0 mol/L or less hydrochloric acid solution. According to the production method, in the elution step, the dissolution of the whole lithium manganese oxide can be suppressed while maintaining the efficiency of exchange reaction between cations including Li.sup.+ and H.sup.+. Thus, the repeated use of the lithium adsorbent becomes possible.

A composite material includes electro-deposited manganese dioxide particles of up to 110 micron in size and in a form of γ-modification of manganese dioxide; and single-walled carbon nanotubes with a diameter of 1 to 2 nm and a length of 1 to 5 μm, wherein a content of the carbon nanotubes is 0.0001 to 0.1 wt % of the composite material. Optionally, the particles have an average size of about 40-60 microns. Optionally, the carbon nanotubes form a coating on a surface of the particles and extend inward from the surface. Optionally, the single-wall carbon nanotubes form a three-dimensional conductive network in the material.

A composite material includes electro-deposited manganese dioxide particles of up to 110 micron in size and in a form of γ-modification of manganese dioxide; and single-walled carbon nanotubes with a diameter of 1 to 2 nm and a length of 1 to 5 μm, wherein a content of the carbon nanotubes is 0.0001 to 0.1 wt % of the composite material. Optionally, the particles have an average size of about 40-60 microns. Optionally, the carbon nanotubes form a coating on a surface of the particles and extend inward from the surface. Optionally, the single-wall carbon nanotubes form a three-dimensional conductive network in the material.

A process for generating a metal sulfate that involves crystallizing a metal sulfate from an aqueous solution to form a crystallized metal sulfate in a mother liquor with uncrystallized metal sulfate remaining in the mother liquor; separating the crystallized metal sulfate from the mother liquor; basifying a portion of the mother liquor to convert the uncrystallized metal sulfate to a basic metal salt; and using the basic metal salt upstream of crystallizing the metal sulfate. So crystallized, the generated metal sulfate may be battery-grade or electroplating-grade.

The present invention relates to a magnetic resonance imaging (MRI) contrast agent, particularly a metal oxide nanoparticle-based T1-T2 dual-mode MRI contrast agent that can be used not only as a T1 MRI contrast agent but also as a T2 MRI contrast agent, and a method for producing the same. The metal oxide nanoparticle-based T1-T2 dual-mode MRI contrast agent can provide more accurate and detailed information associated with disease than single MRI contrast agent by the beneficial contrast effects in both T1 imaging with high tissue resolution and T2 imaging with high feasibility on detection of a lesion.

The present invention relates to a magnetic resonance imaging (MRI) contrast agent, particularly a metal oxide nanoparticle-based T1-T2 dual-mode MRI contrast agent that can be used not only as a T1 MRI contrast agent but also as a T2 MRI contrast agent, and a method for producing the same. The metal oxide nanoparticle-based T1-T2 dual-mode MRI contrast agent can provide more accurate and detailed information associated with disease than single MRI contrast agent by the beneficial contrast effects in both T1 imaging with high tissue resolution and T2 imaging with high feasibility on detection of a lesion.