US 2022/0055039 A1Published application

Method and arrangement for process water treatment

AssigneeMetso Outotec Finland Oy

InventorKaj Jansson

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Abstract

A method of treating process water of a flotation plant is disclosed. The flotation plant comprises a mineral flotation line and a process water circuit for treating underflow and/or overflow of the flotation line. The process water circuit comprises a gravitational solid-liquid separator for dewatering underflow and/or overflow of the mineral flotation line to separate sediment from supernatant comprising at least water and unrecovered fine particles comprising valuable material; and a recover water tank for collecting process water. According to the method, prior to leading supernatant from the gravitational solid-liquid separator into the recover water tank, it is subjected to cleaning flotation, in which at least 90% of the flotation gas bubbles have a size from 0.2 to 250 μm, in a cleaning flotation unit. An arrangement for treating process water of a flotation plant, and its use are also disclosed.

Claims37

Dependent claims

A method of treating process water of a flotation plant for the recovery of a valuable material, the flotation plant comprising a mineral flotation line, the mineral flotation line comprising

a grinding mill;
a classification circuit for classifying a feed of ground ore from the grinding mill into classifier overflow and classifier underflow;
and
a mineral flotation circuit for treating classifier overflow as infeed of ore particles comprising valuable material suspended in slurry, the flotation circuit comprising a rougher part for the separation of slurry infeed into rougher overflow of recovered valuable material and rougher underflow of reject, and a cleaner part arranged to receive rougher overflow from the rougher part as slurry infeed, for the separation of slurry into cleaner overflow of recovered valuable material and cleaner underflow arranged to flow back into the rougher part as slurry infeed,
the flotation plant further comprising a process water circuit for treating underflow and/or overflow of the mineral flotation line, the process water circuit comprising a gravitational solid-liquid separator for dewatering underflow and/or overflow of the mineral flotation line to separate sediment from supernatant comprising at least water and unrecovered fine particles comprising valuable material;
and a recover water tank for collecting process water comprising overflow and/or underflow from the mineral flotation line,
wherein, prior to leading supernatant from the gravitational solid-liquid separator into the recover water tank, supernatant is subjected to cleaning flotation, in which at least 90% of the flotation gas bubbles have a size from 0.2 to 250 μm, in a cleaning flotation unit for collecting at least unrecovered fine particles comprising valuable material;
for separating fine particles comprising valuable material from the supernatant into cleaning flotation overflow as recovered valuable material;
and for forming purified process water as cleaning flotation underflow;
and in that purified process water is recirculated into the mineral flotation line, or collected into the recover water tank as collected process water.

7 more elements

An arrangement for of treating process water of a flotation plant for the recovery of a valuable material, the flotation plant comprising a mineral flotation line, the mineral flotation line comprising

a grinding mill;
a classification circuit for classifying a feed of ground ore from the grinding mill into classifier overflow and classifier underflow;
and
a mineral flotation circuit for treating ore particles comprising valuable material and suspended in slurry, the mineral flotation circuit comprising a rougher part for the separation of slurry infeed into rougher overflow of recovered valuable material and rougher underflow of reject, and a cleaner part arranged to receive rougher overflow from the rougher part as slurry infeed, for the separation of slurry into cleaner overflow of recovered valuable material and cleaner underflow arranged to flow back into the rougher part as slurry infeed,
the flotation plant further comprising a process water circuit for treating underflow and/or overflow of the mineral flotation line, the process water treatment circuit comprising a gravitational solid-liquid separator arranged to dewater underflow and/or overflow of the mineral flotation line to separate sediment from supernatant comprising at least water and unrecovered fine particles comprising valuable material;
and a recover water tank for collecting process water comprising overflow and/or underflow from the mineral flotation line,
wherein the water treatment circuit further comprises a cleaning flotation unit employing flotation gas bubbles of which at least 90% have a size from 0.2 to 250 μm, operationally connected to the gravitational solid-liquid separator for receiving supernatant prior to it being led into the recover water tank, and arranged to collect at least unrecovered fine particles comprising valuable material;
to separate fine particles comprising valuable material from supernatant into cleaning flotation overflow as recovered valuable material;
and to form purified process water as cleaning flotation underflow configured to be recirculated into the mineral flotation line, or collected into the recover water tank as collected process water.

6 more elements

Dependencies are inferred from the claim text.